2006 Mazda MX-5 NC 2.0 Sport
Discussion
Only a few things to update. I recently sat in the car, turned the ignition, and was then greeted by a completely dead car. I popped the bonnet to find that the positive terminal had lifted off entirely. Very odd. I've tightened it as much as I can without sheering the head of the bolt, but it's not as tight as I'd like it to be. Going to have to find another way of tightening that terminal.
One of my xenon bulbs has stopped igniting, which is slightly annoying. It ignites after about 30 attempts of on/off switching, which isn't healthy to the working bulb. I think it's the ballast, so we shall see.
Aside from that, it's had a good was and gained some new tattoos. Tegiwa messed up an order a while back, but the customer service was great in all fairness. They sent through a decal sheet as an apology, so thought I'd make good use of them. Because stickers.
And a tiny moustache
Both of our cars had gotten a clean by the end of the evening
In time for a spectacular sky
I've realised that it's been a year since servicing the car, and it's had three track days since too. I won't be driving it much until I change the fluids, though I'm not sure what fluids to change.
The oil with its filter will of course be changed, but that could be it. The air filter is a cleanable foam filter and the sparks are iridium. In terms of fluids, I'm not sure whether I need to change the gearbox oil, LSD oil or brake fluid, having done three track days on them.
Should I?
One of my xenon bulbs has stopped igniting, which is slightly annoying. It ignites after about 30 attempts of on/off switching, which isn't healthy to the working bulb. I think it's the ballast, so we shall see.
Aside from that, it's had a good was and gained some new tattoos. Tegiwa messed up an order a while back, but the customer service was great in all fairness. They sent through a decal sheet as an apology, so thought I'd make good use of them. Because stickers.
And a tiny moustache
Both of our cars had gotten a clean by the end of the evening
In time for a spectacular sky
I've realised that it's been a year since servicing the car, and it's had three track days since too. I won't be driving it much until I change the fluids, though I'm not sure what fluids to change.
The oil with its filter will of course be changed, but that could be it. The air filter is a cleanable foam filter and the sparks are iridium. In terms of fluids, I'm not sure whether I need to change the gearbox oil, LSD oil or brake fluid, having done three track days on them.
Should I?
rfn said:
Love this thread.
What Xenon bulbs do you have and would you recommend them? The existing headlights on my Sport Black are like candles and feel like I'd like to fix that before the next winter...
These exact ones:What Xenon bulbs do you have and would you recommend them? The existing headlights on my Sport Black are like candles and feel like I'd like to fix that before the next winter...
https://www.hids4u.co.uk/H7-HIDS4U-Stealth-35W-Xen...
In 6000k. Build quality is far superior to any other bulb/ballast I've bought. Ebay are cheap chinese kits, and HIDs-Direct are a re-seller for cheap chinese rubbish. Endless problems with them, but HIDs4U have been outstanding. I'm on the same kit 5 years running.
And as if by magic, one of my bulbs failed!
I've bought some replacement 6000k bulbs from the same company, so all is back to normal. But while I was shopping, I thought I'd try something a little different (for me).
3000k bulbs, yellow in colour. I've been inspired by watching the WEC lately, so forgive me if I've been 'that guy' and bought yellow bulbs.
I'll be honest, I quite like them. The good thing is that I have a spare set of 6000k's to go back to normal if I get sick of them, and these were only £9.99.
I've not had a chance to test them in the night as one of the bulbs had arrived faulty, flickering constantly. They're sending out a new set, but I suppose you get what you pay for.
Working on a nice flat driveway makes such a big difference from the gravel drive of our old house, that's for sure!
I've bought some replacement 6000k bulbs from the same company, so all is back to normal. But while I was shopping, I thought I'd try something a little different (for me).
3000k bulbs, yellow in colour. I've been inspired by watching the WEC lately, so forgive me if I've been 'that guy' and bought yellow bulbs.
I'll be honest, I quite like them. The good thing is that I have a spare set of 6000k's to go back to normal if I get sick of them, and these were only £9.99.
I've not had a chance to test them in the night as one of the bulbs had arrived faulty, flickering constantly. They're sending out a new set, but I suppose you get what you pay for.
Working on a nice flat driveway makes such a big difference from the gravel drive of our old house, that's for sure!
I'm now realising how little I've done to this car. The last post was mid-2022, and it's now March 2023!
In all honesty, I'm not sure if that's a good thing or a bad thing. It's great that I haven't needed to spend anything on it, but there's been little time or chance to do anything else. I still drive it every week though.
The yellow bulbs have been swapped out with the 5000k xenon's once again (I enjoyed pretending I was a WEC endurance racer for all of 2 weeks). I've also removed the stickers from the bumper so that it's back to a clean look again.
I spent the rest of the summer enjoying the car for what it was, went to the odd meet or two, but honestly 2022 has been a crazy busy year (for some amazing reasons), so there just hasn't been much time to work on the car.
A quick meet with Felix and his C6 last year made me realise how hilariously small my car is.
One modification I wanted to make were spacers. Unfortunately, there's a minimum width of 25mm that you have to use if you are to use the standard NC wheels. With no gaps in the back of the wheel for the original studs to protrude into, you'll need a spacer that creates a flush face for the wheel to sit on, hence the 25mm minimum width. Ideally I'd go for 15mm or 20mm, but I'll re-visit this in the future. For now, I was happy to try 25mm.
Ian (the blue MX-5 track car thread) was kind enough to sell me his Eibach 25mm spacers due to his wider tyres rubbing on the arches. I'm running the standard 205/45/17 tyres here, so shouldn't have an issue. I did worry about them on the track, but with the negative camber I'm running I've heard it would be fine. Time will tell...
It's worth noting that the suspension needed time to settle, so the camber and height are a little off. After a day or two, the car now sits like this:
I must admit, I think the look of that is great. It seems to suit the fenders of the NC that much better.
Now then. One of the biggest N/A performance modifications you can do to these cars is to replace the manifold. The NC has two catalytic converters, one in its usual place underneath the car, and another that's on the exhaust manifold itself. Not only is this additional cat quite restrictive, it's horrendously designed in regards to airflow.
You can clearly see from the photo how restrictive this is in regards to airflow, with all four pipes being pinched into the size of a postage stamp before they enter the catalytic converter.
De-cat manifolds for the NC can be quite expensive, so I spent months searching for a good used one, right up until I found a brand new one on Ebay for £250:
I messaged the seller to find out more information about this manifold. The seller was lovely and went out of his way to post the item, even to their own expense. They mentioned:
"They're British made, a company that was in Oxford/Bicester that used to make exhaust systems for all sort of race cars, F1, custom stuff etc. They've since ceased trading I learned. They're nicely made items, the welding is all tig. Its a 'Chris Tullet' unit. It seems they are now 'CTE advanced technologies'."
A brand new de-cat manifold for £250 by a company that's made exhaust systems for F1 in previous years... yup, looks like that's the find of the century.
It arrived a few days later, and the build quality is outstanding.
Replacing this with a de-cat manifold makes a huge difference. Coupled with a remap (needed to code out the O2 sensor), it brings the car from 157bhp to around 190bhp, which shows how restrictive that catalytic converter is. Regarding the MOT, it's technically illegal. Having spoke to my local garage, they mentioned that if a cat was present and it's now removed, it's a fail. However, the car still passes its emissions test without the manifold cat, and there's already one underneath the car where the tester would expect one. This means that, unless the tester is aware that there should be one on the manifold, it would pass. With the heat shields back in place it's almost invisible, so I have no concern of it passing an MOT.
I'm just waiting for warmer weather and longer days to fit this. I've heard it'll be a little tricky, so I'd rather take my time when it's warm. I also need a re-map shortly after as I won't be using one of the original O2 sensors (to check if the cat was working on the original unit), so that needs to be programmed out, as well as to re-tune the ECU with more airflow in mind. Very much looking forward to this.
Speaking of waiting for warmer weather; I haven't been using the car much flately or obvious reasons. These cars don't take kindly to road salt and water, and I'm not a huge fan of the swiss cheese approach to sub frames.
A day or two after the snow cleared, I took the car to the shops. A slow start naturally, but taking the long way to the store would help. Unfortunately, the battery decided to give up the ghost at a store car park with the freezing weather we've been having. No zoom zoom's anymore with this battery.
I picked up a Yuasa 5000 Silver battery that was in my local Halfords, dropped it in the next morning and all is well.
Ish. Since swapping the battery, whenever I come off the throttle and let the revs drop to idle, they drop a little too low, and the car feels like it wants to stall before it finds its natural idling RPM again. Aside from this, the car drives fine. I've driven it about a week now to see if it needed to re-learn air/fuel ratios, but it's no different.
Some investigation is needed...
In all honesty, I'm not sure if that's a good thing or a bad thing. It's great that I haven't needed to spend anything on it, but there's been little time or chance to do anything else. I still drive it every week though.
The yellow bulbs have been swapped out with the 5000k xenon's once again (I enjoyed pretending I was a WEC endurance racer for all of 2 weeks). I've also removed the stickers from the bumper so that it's back to a clean look again.
I spent the rest of the summer enjoying the car for what it was, went to the odd meet or two, but honestly 2022 has been a crazy busy year (for some amazing reasons), so there just hasn't been much time to work on the car.
A quick meet with Felix and his C6 last year made me realise how hilariously small my car is.
One modification I wanted to make were spacers. Unfortunately, there's a minimum width of 25mm that you have to use if you are to use the standard NC wheels. With no gaps in the back of the wheel for the original studs to protrude into, you'll need a spacer that creates a flush face for the wheel to sit on, hence the 25mm minimum width. Ideally I'd go for 15mm or 20mm, but I'll re-visit this in the future. For now, I was happy to try 25mm.
Ian (the blue MX-5 track car thread) was kind enough to sell me his Eibach 25mm spacers due to his wider tyres rubbing on the arches. I'm running the standard 205/45/17 tyres here, so shouldn't have an issue. I did worry about them on the track, but with the negative camber I'm running I've heard it would be fine. Time will tell...
It's worth noting that the suspension needed time to settle, so the camber and height are a little off. After a day or two, the car now sits like this:
I must admit, I think the look of that is great. It seems to suit the fenders of the NC that much better.
Now then. One of the biggest N/A performance modifications you can do to these cars is to replace the manifold. The NC has two catalytic converters, one in its usual place underneath the car, and another that's on the exhaust manifold itself. Not only is this additional cat quite restrictive, it's horrendously designed in regards to airflow.
You can clearly see from the photo how restrictive this is in regards to airflow, with all four pipes being pinched into the size of a postage stamp before they enter the catalytic converter.
De-cat manifolds for the NC can be quite expensive, so I spent months searching for a good used one, right up until I found a brand new one on Ebay for £250:
I messaged the seller to find out more information about this manifold. The seller was lovely and went out of his way to post the item, even to their own expense. They mentioned:
"They're British made, a company that was in Oxford/Bicester that used to make exhaust systems for all sort of race cars, F1, custom stuff etc. They've since ceased trading I learned. They're nicely made items, the welding is all tig. Its a 'Chris Tullet' unit. It seems they are now 'CTE advanced technologies'."
A brand new de-cat manifold for £250 by a company that's made exhaust systems for F1 in previous years... yup, looks like that's the find of the century.
It arrived a few days later, and the build quality is outstanding.
Replacing this with a de-cat manifold makes a huge difference. Coupled with a remap (needed to code out the O2 sensor), it brings the car from 157bhp to around 190bhp, which shows how restrictive that catalytic converter is. Regarding the MOT, it's technically illegal. Having spoke to my local garage, they mentioned that if a cat was present and it's now removed, it's a fail. However, the car still passes its emissions test without the manifold cat, and there's already one underneath the car where the tester would expect one. This means that, unless the tester is aware that there should be one on the manifold, it would pass. With the heat shields back in place it's almost invisible, so I have no concern of it passing an MOT.
I'm just waiting for warmer weather and longer days to fit this. I've heard it'll be a little tricky, so I'd rather take my time when it's warm. I also need a re-map shortly after as I won't be using one of the original O2 sensors (to check if the cat was working on the original unit), so that needs to be programmed out, as well as to re-tune the ECU with more airflow in mind. Very much looking forward to this.
Speaking of waiting for warmer weather; I haven't been using the car much flately or obvious reasons. These cars don't take kindly to road salt and water, and I'm not a huge fan of the swiss cheese approach to sub frames.
A day or two after the snow cleared, I took the car to the shops. A slow start naturally, but taking the long way to the store would help. Unfortunately, the battery decided to give up the ghost at a store car park with the freezing weather we've been having. No zoom zoom's anymore with this battery.
I picked up a Yuasa 5000 Silver battery that was in my local Halfords, dropped it in the next morning and all is well.
Ish. Since swapping the battery, whenever I come off the throttle and let the revs drop to idle, they drop a little too low, and the car feels like it wants to stall before it finds its natural idling RPM again. Aside from this, the car drives fine. I've driven it about a week now to see if it needed to re-learn air/fuel ratios, but it's no different.
Some investigation is needed...
gazzarose said:
That manifold looks very nice. I'd be interested to hear the difference it makes. I've got a few bits if like to do to mine now that it is mine (for the last 9 or so years it was my wife's daily, including during the time since our first child was born, alas no good with 2 kids, so we bought my grans Jazz off her and the 5 now lives in the garage!). I need to do coilovers of some description, that is a genuine NEED! One of the rear shocks had an advisory for dampness, so coilovers at half the price of OE is a no brainer. After that I am considering a bit more power, but nothing too much, just a bit more pep and willingness.
I've had a few dead batteries in the 5 over the years, and just driving it does take a surprisingly long time so sort the idling fuelling out. It needs a decent amount of time at idle, which it doesn't really get when driving normally. The last time mine was doing it I left it running in my works carpark for 30 mins and that pretty much got it. Obviously not ideal if it's not parked somewhere secure though.
I'll hopefully have it fitted in the next few weeks. It should make a notable difference by itself, but with the future remap it would hopefully release a lot more power out of it.I've had a few dead batteries in the 5 over the years, and just driving it does take a surprisingly long time so sort the idling fuelling out. It needs a decent amount of time at idle, which it doesn't really get when driving normally. The last time mine was doing it I left it running in my works carpark for 30 mins and that pretty much got it. Obviously not ideal if it's not parked somewhere secure though.
That's a fair shout with the coilovers. I'd have gone down the same route, but as all of my shocks were brand new when I bought the car, it seemed a shame to remove them. I loved the damping of the original shocks, but wanted a little less roll and a little less ride height. Hence, the springs and ARB's.
Thanks for the tip with the battery, I'll give it a long idle later today and I'll see how it goes!
I've been modding my other MX-5. Added the stripes so that it matches the real thing. Yes, I'm sad.
Anyway. I've noticed that my oil temperature isn't getting up to running temp at all lately. Even after some hard driving, it doesn't get over low 70's. This is the oil temperature read-out after 40 minutes driving:
The water temperature gauge is somewhat normal, although I have seen it dip below half now and again.
Knowing that the water gauge spits out as much truth as Trump, I thought I'd order another thermostat and replace it for peace of mind.
£16(!!) later for a brand new unit.
Interesting to see the logo buffed off. These are normally around £50, so I'm not surprised.
While draining the coolant, I noticed these small black marks which I think is rubber.
I'm guessing a hose is deteriorating somewhere? From the outside they all look fine. Haven't got much of a choice but to continue until one fails, though hopefully that doesn't happen.
Removal of the pipe work to access the throttle body is dead easy. I'm quite surprised to see how clean this is.
It's a little dirtier on the other side, so a quick clean is always a good idea at this stage.
After 20 minutes of yoga, I managed to get into position to remove all three bolts from the thermostat, and off it popped. The only issue with the whole job is the tight access to the bolts, not that it's hard to reach, but they're hard to catch when removing (and hold when screwing back in) in case you drop them, so an extendable magnet here is a must.
New left, old right. The longer thermostats are the uprated versions, apparently.
The old one looked fine. I've never quite understood how these fail...
I didn't have any FL22 coolant on me, and wanted to head to North Wales the next day in the car, so I decided to filter the rubber bits out of the coolant and re-use it.
I hand-pumped the majority of it back into the car, avoiding the bits, then filtered the rest.
After 30 minutes of driving, this was the read-out:
Lovely. Looks like it was indeed a bad thermostat.
The car was cleaned up, ready for a drive to North Wales the next day.
If anyone's driven these roads (mainly A470, but diverting off now and again for some fun), you'll know how good this journey is.
The weather was beautiful, so it's a perfect day for it!
I stopped off at Betws-y-Coed; a beautiful little town with some seriously gorgeous scenery.
It's definitely a car I look back twice at.
I really love those proportions. The arches wrapped around the wheels, and how stumpy that ass is.
Stopped off to say hi to my parents, who were staying in North Wales at the time.
I keep looking at how 'busy' the numberplates on this car are. Ignore the filth from the drive.
Borders, slogans, badges, etc. I'd rather have something quite clean and simple.
Like these!
That should look better.
Some double sided tape was applied that had more power than god.
Far, far cleaner.
The drive to North Wales and back got me thinking about what I'd like next on the car. I'll be fitting the manifold tomorrow, but the drive made me realise that safety really needs to be the next thing. I had one hell of a time on those roads, but having a creative brain, am always thinking about the 'what if' side of things.
With that justification and man maths, I placed an order for this:
A GCFabrications NC GC2 roll bar. Accelebrate has one on his, and the build quality seems second to none. I did a little bit of research and these seem to be a great option. They have a video of an MX-5 being dropped from 10m onto its roof multiple times, and the bar doesn't move an inch. The car actually bends slightly around the bar, with no deformation of the cockpit area at all. Having saw the video, I gave them a call as they stated 'On Backorder' on their website.
Lovely guy, super happy to help and to answer any questions. He's mentioned that they have a few coming in next week, so the turn around of this should be pretty fast. If it's before July, I'm happy, as that may be an Anglesey track day!
Anyway. I've noticed that my oil temperature isn't getting up to running temp at all lately. Even after some hard driving, it doesn't get over low 70's. This is the oil temperature read-out after 40 minutes driving:
The water temperature gauge is somewhat normal, although I have seen it dip below half now and again.
Knowing that the water gauge spits out as much truth as Trump, I thought I'd order another thermostat and replace it for peace of mind.
£16(!!) later for a brand new unit.
Interesting to see the logo buffed off. These are normally around £50, so I'm not surprised.
While draining the coolant, I noticed these small black marks which I think is rubber.
I'm guessing a hose is deteriorating somewhere? From the outside they all look fine. Haven't got much of a choice but to continue until one fails, though hopefully that doesn't happen.
Removal of the pipe work to access the throttle body is dead easy. I'm quite surprised to see how clean this is.
It's a little dirtier on the other side, so a quick clean is always a good idea at this stage.
After 20 minutes of yoga, I managed to get into position to remove all three bolts from the thermostat, and off it popped. The only issue with the whole job is the tight access to the bolts, not that it's hard to reach, but they're hard to catch when removing (and hold when screwing back in) in case you drop them, so an extendable magnet here is a must.
New left, old right. The longer thermostats are the uprated versions, apparently.
The old one looked fine. I've never quite understood how these fail...
I didn't have any FL22 coolant on me, and wanted to head to North Wales the next day in the car, so I decided to filter the rubber bits out of the coolant and re-use it.
I hand-pumped the majority of it back into the car, avoiding the bits, then filtered the rest.
After 30 minutes of driving, this was the read-out:
Lovely. Looks like it was indeed a bad thermostat.
The car was cleaned up, ready for a drive to North Wales the next day.
If anyone's driven these roads (mainly A470, but diverting off now and again for some fun), you'll know how good this journey is.
The weather was beautiful, so it's a perfect day for it!
I stopped off at Betws-y-Coed; a beautiful little town with some seriously gorgeous scenery.
It's definitely a car I look back twice at.
I really love those proportions. The arches wrapped around the wheels, and how stumpy that ass is.
Stopped off to say hi to my parents, who were staying in North Wales at the time.
I keep looking at how 'busy' the numberplates on this car are. Ignore the filth from the drive.
Borders, slogans, badges, etc. I'd rather have something quite clean and simple.
Like these!
That should look better.
Some double sided tape was applied that had more power than god.
Far, far cleaner.
The drive to North Wales and back got me thinking about what I'd like next on the car. I'll be fitting the manifold tomorrow, but the drive made me realise that safety really needs to be the next thing. I had one hell of a time on those roads, but having a creative brain, am always thinking about the 'what if' side of things.
With that justification and man maths, I placed an order for this:
A GCFabrications NC GC2 roll bar. Accelebrate has one on his, and the build quality seems second to none. I did a little bit of research and these seem to be a great option. They have a video of an MX-5 being dropped from 10m onto its roof multiple times, and the bar doesn't move an inch. The car actually bends slightly around the bar, with no deformation of the cockpit area at all. Having saw the video, I gave them a call as they stated 'On Backorder' on their website.
Lovely guy, super happy to help and to answer any questions. He's mentioned that they have a few coming in next week, so the turn around of this should be pretty fast. If it's before July, I'm happy, as that may be an Anglesey track day!
Edited by geraintthomas on Saturday 8th April 01:19
Edited by geraintthomas on Saturday 8th April 01:20
Cambs_Stuart said:
That is a handsome car. I think the rollover bar is a good idea. What's involved with fitting. Do you have to drill into the body?
Surprisingly it's a simple bolt-in job that uses the same mounting points as the original. There's one or two nuts that need replacing but other than that it's not too bad. It's the seatbelt mounting that I think needs some attention as I don't think it comes with the holes.Manifold time
I've been putting this off for some time, but I finally got round to doing the job.
Underneath the five (FIVE) heat shields lies the primary cat. With the heat shield bolts being rusty (even at 56,000 miles) and the cat being quite large for the space it's in, I was expecting this to be a tricky job. I wasn't wrong.
The heat shield needed to come off, and for some bizarre reason, Mazda bolted this from the bottom, rather than from the top.
No go, the bolt is still out of reach. Luckily a 10mm flexi-head ratchet spanner is your friend here, thanks to a friend for recommending it.
Onto the second heat shield. Two bolts came out easily, then there was one at the rear in an awful place that decided to round off when I finally reached it with a flexi-head spanner. The bolt was rusted to the shield, but turning.
Oh fun. I had to hit it with a chisel to snap the heat shield off the bolt.
There's a heat shield underneath the manifold pipes, as you can see. Again, this put up a fight, but not half as bad as the last.
Next up is the O2 sensor removal.
The original intention was to remove this, but...
That's almost impossible to fit a ratchet to that, so that sensor has to stay on.
Should be enough room to come out now though, right?
No.
The steering column is blocking it.
Well, looks like I'll have to move the engine by unbolting the engine mount and jacking it up. Thankfully, that gave me enough room to clear the steering column.
So it can come out now, right?
No.
Thanks to another heat shield bolt that's rounded off, I can't lift the thing out without it hitting the back of the alternator.
I found it impossible to reach the bolts for the alternator (I pray that this never fails), so I removed the rear casing of it instead.
Surely it can come out now?
With the alternator cover removed and the engine tilted, it finally came out.
Quite a difference
I had to stop at this point. My back was in bits, and decided to continue the next day.
To give myself a bit of a break, I extended the pre-cat O2 sensor wiring; required to complete the job. I did consider purchasing more wire, but as I understand these can be quite picky about gauge and resistance. As I wasn't using the post-cat O2 any more, I decided to use its original wiring.
The plan is to mix these two together.
Cable ties hold back the heat proof wrapping
As clean of a soldering job as I could possibly do
You'd never guess.
The spring-loaded bolts at the bottom of the original manifold needed to be removed
I realised I was un-bolting these the wrong way, as those nuts aren't exactly supposed to move. Still, I managed to snap them off.
Thankfully there's no need to use the nuts again, as the new manifold has threaded holes
All ready to go on.
Ish
Didn't quite fit on one hole. I used a round file and quite literally only had to file for about 20 seconds before it would fit after the second attempt so nothing major here.
That looks quite spicy that.
It was a nightmare to get the alternator cover back on. You couldn't fit it before putting the manifold in, as the manifold would hit it. After the manifold was fitted, there was barely enough room to reach. And if that wasn't bad enough, the rear cover has a rubber seal, which made it impossible for it to fit back on without loosening the alternator.
Which I didn't do. I decided to file back a tiny protruding part of the engine block that was causing the cover not to fit properly. Man math.
Aluminium tape ensures that heat shouldn't be an issue here.
It's in! I wish I could keep it like this.
I decided to bolt the heat shield back on from the top this time, like a normal human being.
Barely noticeable.
Firstly, a big thanks to Accelebrate for putting up with my constant pestering, as he'd already completed the job, seemingly more straightforward than my experience. I owe you a beer or seven.
First impressions when starting the car; absolutely no difference in sound. It sounded identical to stock on start-up and idle, which isn't a bad thing at all. The sound does open up quite a bit upon driving though, with a throaty tone and the (subtle) sound of air through the pipes under wide-open throttle.
The performance was much more noticeable than the sound, though. For starts, the engine is far more eager to rev, and also to loose its revs too, making for some easy heal and toe.
The CEL is due to the post-cat O2 sensor no longer being used - I'll get it mapped out.
The torque improvement is very welcome, being more noteable between 2-4k. I found myself not having to change down as often to get moving, which was a huge flaw in the performance before. This is without the remap, so I should see some lovely gains when the car gets re-mapped.
A quick trip to my local Mazda dealer to take it for a test drive, and to buy some FL22 coolant
Is there any better colour than this..
I've been putting this off for some time, but I finally got round to doing the job.
Underneath the five (FIVE) heat shields lies the primary cat. With the heat shield bolts being rusty (even at 56,000 miles) and the cat being quite large for the space it's in, I was expecting this to be a tricky job. I wasn't wrong.
The heat shield needed to come off, and for some bizarre reason, Mazda bolted this from the bottom, rather than from the top.
No go, the bolt is still out of reach. Luckily a 10mm flexi-head ratchet spanner is your friend here, thanks to a friend for recommending it.
Onto the second heat shield. Two bolts came out easily, then there was one at the rear in an awful place that decided to round off when I finally reached it with a flexi-head spanner. The bolt was rusted to the shield, but turning.
Oh fun. I had to hit it with a chisel to snap the heat shield off the bolt.
There's a heat shield underneath the manifold pipes, as you can see. Again, this put up a fight, but not half as bad as the last.
Next up is the O2 sensor removal.
The original intention was to remove this, but...
That's almost impossible to fit a ratchet to that, so that sensor has to stay on.
Should be enough room to come out now though, right?
No.
The steering column is blocking it.
Well, looks like I'll have to move the engine by unbolting the engine mount and jacking it up. Thankfully, that gave me enough room to clear the steering column.
So it can come out now, right?
No.
Thanks to another heat shield bolt that's rounded off, I can't lift the thing out without it hitting the back of the alternator.
I found it impossible to reach the bolts for the alternator (I pray that this never fails), so I removed the rear casing of it instead.
Surely it can come out now?
With the alternator cover removed and the engine tilted, it finally came out.
Quite a difference
I had to stop at this point. My back was in bits, and decided to continue the next day.
To give myself a bit of a break, I extended the pre-cat O2 sensor wiring; required to complete the job. I did consider purchasing more wire, but as I understand these can be quite picky about gauge and resistance. As I wasn't using the post-cat O2 any more, I decided to use its original wiring.
The plan is to mix these two together.
Cable ties hold back the heat proof wrapping
As clean of a soldering job as I could possibly do
You'd never guess.
The spring-loaded bolts at the bottom of the original manifold needed to be removed
I realised I was un-bolting these the wrong way, as those nuts aren't exactly supposed to move. Still, I managed to snap them off.
Thankfully there's no need to use the nuts again, as the new manifold has threaded holes
All ready to go on.
Ish
Didn't quite fit on one hole. I used a round file and quite literally only had to file for about 20 seconds before it would fit after the second attempt so nothing major here.
That looks quite spicy that.
It was a nightmare to get the alternator cover back on. You couldn't fit it before putting the manifold in, as the manifold would hit it. After the manifold was fitted, there was barely enough room to reach. And if that wasn't bad enough, the rear cover has a rubber seal, which made it impossible for it to fit back on without loosening the alternator.
Which I didn't do. I decided to file back a tiny protruding part of the engine block that was causing the cover not to fit properly. Man math.
Aluminium tape ensures that heat shouldn't be an issue here.
It's in! I wish I could keep it like this.
I decided to bolt the heat shield back on from the top this time, like a normal human being.
Barely noticeable.
Firstly, a big thanks to Accelebrate for putting up with my constant pestering, as he'd already completed the job, seemingly more straightforward than my experience. I owe you a beer or seven.
First impressions when starting the car; absolutely no difference in sound. It sounded identical to stock on start-up and idle, which isn't a bad thing at all. The sound does open up quite a bit upon driving though, with a throaty tone and the (subtle) sound of air through the pipes under wide-open throttle.
The performance was much more noticeable than the sound, though. For starts, the engine is far more eager to rev, and also to loose its revs too, making for some easy heal and toe.
The CEL is due to the post-cat O2 sensor no longer being used - I'll get it mapped out.
The torque improvement is very welcome, being more noteable between 2-4k. I found myself not having to change down as often to get moving, which was a huge flaw in the performance before. This is without the remap, so I should see some lovely gains when the car gets re-mapped.
A quick trip to my local Mazda dealer to take it for a test drive, and to buy some FL22 coolant
Is there any better colour than this..
Accelebrate said:
No problem at all, glad you got there in the end. I felt a bit bad for suggesting it was a relatively straightforward swap - with the bolts on my heatshields coming out relatively easily, along with the sensors I managed to get both manifolds out and in without touching the engine mounts or the alternator cover.
Flex head ratcheting spanners are such a godsend for this job!
Technically it is straight forward, but Murphy's Law was prevalent throughout the whole job...Flex head ratcheting spanners are such a godsend for this job!
freedee said:
Great write up, thanks.
I have a decat manifold sitting next to me waiting to go on. I will ask the garage to fit it and remap the car at the same time
Make sure it's not the same garage that does your MOT's!I have a decat manifold sitting next to me waiting to go on. I will ask the garage to fit it and remap the car at the same time
gazzarose said:
Whats the deal with MOTs and decat manifolds these days? I'd love to do a manifold on mine, but the difference between a non cat and cat'd one is just too much money. But reading the faff its taken to change yours, it's not looking like something I fancy swapping back and fore like you read about folks with normal decat pipes doing. Because it has another cat, is the deal just hoping the tester doesn't notice it and the exhaust readout will still be fine? The place I have my MOTs done does alot of performance cars, but are also quite proper in how they do most things, so don't know which way it would go with them. Also one of those things I don't want to ask in advance in case that just tips them off. 
That's exactly what the deal is. If a mechanic was none-the-wiser, they'd look at the car, see a cat installed, see it pass emissions and will think everything is fine. However if a cat is present from the factory and you remove it, it's an automatic fail, regardless if there's one on the car still. If the garage doesn't know that there should have been one on the manifold in the first place (and it's pretty hard to see with the heat shields back on), then you can quite comfortably get away with it.Similar to Xenon bulbs. If you install them into projector headlights and they have the correct colour and cut-off pattern, then they're fine with it, even though it's not legal. On that note, the MX-5's head lamp cut-off pattern is that of a xenon bulb, even though it has halogens. Really interesting...
Cambs_Stuart said:
That looks like a painful job. Good work getting through the issues and completing it! Also good to read that you can feel the benefit.
If you were to do it again, would you do it differently?
Thanks, it was certainly an experience. It wouldn't be half as bad the second time as I know what to do - leave the lower heat shields in place, un-bolt the rear cover off the alternator, and slightly silt the engine, and it'll come out fine. If the guide I followed had mentioned that from the start, it would have been an easy job. It was the fact that I ran into problem after problem, and finding those solutions the hard way.If you were to do it again, would you do it differently?
I wouldn't want to put anyone off doing it, I'd just recommend that you have a flexi-head 10mm spanner (for the heat shields), an offset swan neck 14/15mm spanner (for the bolts under the car connecting it to the mid-pipe), but the most important set of tools was a 3/8" socket set that had a mini breaker bar, and a large selection of extensions and deep sockets. These were critical for the manifold bolts to get to those under the pipes. The 3/8" head could fit where you needed it to fit, the deep sockets allowed the bolts to sink into the socket while undoing the nut, and the mini breaker bar gave you the force to crack them loose.
Secondly, a set of shock absorber ratchets - I wouldn't have been able to complete the job without these. The two bolts that are right at the back are so close to the bulkhead that no ratchet could fit there. A shock absorber ratchet is very stumpy, which gave me access to them. My neighbour came to the rescue with all of these tools; I don't know what I would have done had he not given them to me.
So I'd like to say "I'd make sure I have the right tools", but the only way I found out was by doing the job. If anyone's thinking of doing it, I'd be happy to give advice.
gazzarose said:
Good to know its tricky to see if its got a cat when the shields are back on. My MOT isnt until Oct/Nov, and I probably won't be in a position to do the manifold this year, so it may be a good winter project post MOT this year or next then at least I get most of a year before I need to worry about it.
Let us know how it feels after you get it mapped, and also where, I'm in Bridgend so will be looking as and when I do mine.
Ah! You're not far away at all. Shall do. It looks like I'll be going with a company called Fab9, who specialise in tunes. They're american, and they send the map to you along with the software for you to upload to the car yourself. You can ask them to post a cable (though from the US it can be pricey), but they've emailed me a list of cables that are compatible, and more importantly, ones that are not.Let us know how it feels after you get it mapped, and also where, I'm in Bridgend so will be looking as and when I do mine.
The software also allows you to disable the O2 sensor too. In all it's about £279. The beauty is that it's tailored for the MX-5 NC, and you have the opportunity to tell them that you've made modifications (exhaust, headers, intake) so they can modify the map. They've been super helpful so far, so I'll most likely go with that. I'd rather that than some generic VAG tuner.
If you ever wanted to have a look/drive of the car with the manifold, give me a shout - I can pop over.
Had an issue last night. My neighbour rang the doorbell at 11pm, telling me that I've left my lights on. I looked, but the tail lights and interior lights were all off. Stumped, I checked the cabin to find that I didn't leave them on at all; they've come on by themselves, and I couldn't turn them off.
It was also raining heavily, so you've probably already put 2 and 2 together.
It's common for these to leak under the windscreen scuttle, but in my first few pages of this thread I replaced the grommets to prevent this from happening. But it looks like even new grommets aren't fit for purpose, as I've had a leak, straight down into the fuse box. I disconnected the battery, and left it until today where (until now) we've had good weather.
That's not a great sign, but also not uncommon. Running my finger underneath the heater blower confirmed that there was a slight leak.
Here is where they leak.
I've removed the grommet to seal underneath it.
Not the prettiest, but you won't see it anyway.
I let the hair dryer dry the area, though by this time there wasn't any obvious signs of water by the fuse box, thankfully.
I'll leave this silicone bag here just in case. I'm not too sure how effective it'll be, but it's better than nothing.
The car seems back to its normal self now, with no gremlins to be seen. Hopefully that was caught early.
It was also raining heavily, so you've probably already put 2 and 2 together.
It's common for these to leak under the windscreen scuttle, but in my first few pages of this thread I replaced the grommets to prevent this from happening. But it looks like even new grommets aren't fit for purpose, as I've had a leak, straight down into the fuse box. I disconnected the battery, and left it until today where (until now) we've had good weather.
That's not a great sign, but also not uncommon. Running my finger underneath the heater blower confirmed that there was a slight leak.
Here is where they leak.
I've removed the grommet to seal underneath it.
Not the prettiest, but you won't see it anyway.
I let the hair dryer dry the area, though by this time there wasn't any obvious signs of water by the fuse box, thankfully.
I'll leave this silicone bag here just in case. I'm not too sure how effective it'll be, but it's better than nothing.
The car seems back to its normal self now, with no gremlins to be seen. Hopefully that was caught early.
The car has been performing awfully recently. A steady throttle feels like someone feathering it. It was all over the place, so I read the codes and found something unusual.
I'm expecting a CEL as I've obviously removed sensor 2, but I didn't expect a code for sensor 1. After some investigation, it looks like my extension job for the O2 sensor was at fault. I presumed it was the soldered areas somehow shorting.
I wasn't wrong. It's not that clear in this photo, but two of the wires have quite sharp bits on the solder. The heat from the manifold had shrunk the shrinkwrap further making a lovely fit, but also causing the sharp solder bits to pierce through, causing a short.
I wrapped the wires individually with insulation tape, and managed to fit the original heat wrapping over it.
That's better. The performance is solid, no hiccups and only the one expected CEL.
I'm expecting a CEL as I've obviously removed sensor 2, but I didn't expect a code for sensor 1. After some investigation, it looks like my extension job for the O2 sensor was at fault. I presumed it was the soldered areas somehow shorting.
I wasn't wrong. It's not that clear in this photo, but two of the wires have quite sharp bits on the solder. The heat from the manifold had shrunk the shrinkwrap further making a lovely fit, but also causing the sharp solder bits to pierce through, causing a short.
I wrapped the wires individually with insulation tape, and managed to fit the original heat wrapping over it.
That's better. The performance is solid, no hiccups and only the one expected CEL.
MB140 said:
If your going to join two wires in a loom like that it’s better to stagger the joints if possible (I’m viewing this post in an old phone so the photo isn’t mega clear) to prevent this from happening.
I work in the aviation industry and when repairing looms on aircraft there is often a manufactures specified minimum distance between repairs in the same loom.
Nice work on the manifold by the way. Looked a bit of a pig of a job.
That's a great tip, thank you!I work in the aviation industry and when repairing looms on aircraft there is often a manufactures specified minimum distance between repairs in the same loom.
Nice work on the manifold by the way. Looked a bit of a pig of a job.
DHL came bearing gifts
Four weeks from ordering to manufacturing and delivery. That's quite good, compared to how long others have waited. I wouldn't have minded waiting if the quality is good.
And the quality is good.
I'll need a cutting wheel for the dremel to trim some of the plastics before I fit this. To be honest, I could do with a new dremel. It's started making some horrible grinding noises, which I'm a little uncomfortable with considering how fast it's spinning, and the pressure I'm putting on the motor shaft. They're quite cheap anyhow.
As soon as I have a sunny and free weekend, I'll crack on with the fitment. I'm now on the lookout for a decent pair of seats, most likely used. I've seen some very good ones pop up on Facebook Marketplace recently, so I'll just have to keep an eye out. The harnesses will have to be ASM-type harnesses (or 6-point), and I'd need new mounts for the car. After that, the car is pretty much there for track use.
The only things remaining is the remap for the manifold, and some semi-slick tyres. The latter can wait, I'm very happy with how these Falkens have performed on-track and off-track, and how they're lasting. It's giving me no reason to purchase semi's at the moment, so that'll be the last thing I'd buy.
Four weeks from ordering to manufacturing and delivery. That's quite good, compared to how long others have waited. I wouldn't have minded waiting if the quality is good.
And the quality is good.
I'll need a cutting wheel for the dremel to trim some of the plastics before I fit this. To be honest, I could do with a new dremel. It's started making some horrible grinding noises, which I'm a little uncomfortable with considering how fast it's spinning, and the pressure I'm putting on the motor shaft. They're quite cheap anyhow.
As soon as I have a sunny and free weekend, I'll crack on with the fitment. I'm now on the lookout for a decent pair of seats, most likely used. I've seen some very good ones pop up on Facebook Marketplace recently, so I'll just have to keep an eye out. The harnesses will have to be ASM-type harnesses (or 6-point), and I'd need new mounts for the car. After that, the car is pretty much there for track use.
The only things remaining is the remap for the manifold, and some semi-slick tyres. The latter can wait, I'm very happy with how these Falkens have performed on-track and off-track, and how they're lasting. It's giving me no reason to purchase semi's at the moment, so that'll be the last thing I'd buy.
I had some free time in the late afternoon/evenings over the past few days, so I put this time to installing the roll bar. The installation looked pretty straight forward, and aside from cutting plastics, it was.
First off, the plastics behind the seats, the side skirts, and boot plastics (for easier access) need to be removed.
Believe it or not, this wasn't everything.
Those rear speakers won't be going back in. Honestly, they're useless, and I could never hear them. There's also no mounting points on the new roll bar for them, which I'm not bothered about.
That's everything out, including the original roll bar.
The difference is enormous. The old bar is tiny in comparison, with only limited contact points. I'm not sure how good this would have been in a roll, but I suppose it couldn't have been manufactured if it had failed safety tests.
The new one mounts not only to the original mounting points, but to the top of the suspension too.
The belt guide was a little tricky as there weren't any areas for this to bolt onto the new roll bar. A little odd, as it wouldn't take much for GCFabrications to put in a hole for this.
In the end, I removed a 10mm bolt just above the retentioner and placed it underneath, lower down than where it should be. I was afraid that this would affect retraction, but after testing it with all plastics back in, it's made no difference.
The plastics need to be cut. I didn't take many photos of this as I just wanted to get the job done at the time.
I've not done the prettiest job because I'll be covering this later. Accelebrate has done a great job at covering his, so I'll no doubt be going down the same route.
It's quite amusing sitting in the drivers seat with this behind you. It gives the car a more purposeful look which is always a plus, but the added benefit on top of the safety benefits is chassis rigidity. I've not had a chance to really test this yet, a quick pop to the shop didn't prove much of a difference.
With the spoiler and roll bar, my rear view is slowly becoming less and less. It's still good considering.
I have to say, it looks great.
First off, the plastics behind the seats, the side skirts, and boot plastics (for easier access) need to be removed.
Believe it or not, this wasn't everything.
Those rear speakers won't be going back in. Honestly, they're useless, and I could never hear them. There's also no mounting points on the new roll bar for them, which I'm not bothered about.
That's everything out, including the original roll bar.
The difference is enormous. The old bar is tiny in comparison, with only limited contact points. I'm not sure how good this would have been in a roll, but I suppose it couldn't have been manufactured if it had failed safety tests.
The new one mounts not only to the original mounting points, but to the top of the suspension too.
The belt guide was a little tricky as there weren't any areas for this to bolt onto the new roll bar. A little odd, as it wouldn't take much for GCFabrications to put in a hole for this.
In the end, I removed a 10mm bolt just above the retentioner and placed it underneath, lower down than where it should be. I was afraid that this would affect retraction, but after testing it with all plastics back in, it's made no difference.
The plastics need to be cut. I didn't take many photos of this as I just wanted to get the job done at the time.
I've not done the prettiest job because I'll be covering this later. Accelebrate has done a great job at covering his, so I'll no doubt be going down the same route.
It's quite amusing sitting in the drivers seat with this behind you. It gives the car a more purposeful look which is always a plus, but the added benefit on top of the safety benefits is chassis rigidity. I've not had a chance to really test this yet, a quick pop to the shop didn't prove much of a difference.
With the spoiler and roll bar, my rear view is slowly becoming less and less. It's still good considering.
I have to say, it looks great.
Edited by geraintthomas on Thursday 18th May 23:07
There's a few cosmetics on the car that I had been wanting to sort for a while. The cut marks due to the roll bars was one, but also there are some scratches on the glove box that have been there since I've bought the car. I had an idea for both.
Said scratch marks. Ignore the santa hat.
I had some spare stretchy suede/faux alcantara that would look good, and would be easy to fit due to the shape too.
Turned out really well, with the lips of the glove box allowing me to tuck the ends in for a proper finish.
That's better! It's got me wondering if I should do any other pieces of trim, but I also don't want to overdo it. The triangular pieces to the left/right of the radio (you can see it in the photo above) would be easy and would compliment it, so that's tempting.
After the success of the glove box, I thought I'd do something similar here. So I went about designing a 3D printed cover set that would cover the holes.
Velcro is used (thanks for the tip Accelebrate) so that I can re-position them to get them just right.
Far better, and now matches the glove box. Lastly, Accelebrate designed a blank that fits into the wind breaker holes, which he kindly supplied the files to me so I could print.
A job well done.
A few other thoughts. I'll be removing the 25mm spacers. It's a shame as I do want the wheels to be pushed out a little more, but I'm a bit paranoid of a couple of things. Firstly, the alignment will be off; it was already -2 camber on the rear, so no doubt that would have increased it even more. But the negatives of having these spacers would be the risk of cutting the tyres on the arches if I'm tracking the car, as well as bearing failure (apparently anything over ET40 is a risk), and lastly uneven tyre wear due to the increased camber. As much as I like the look, I'd prefer the car to perform better, so I'll be removing the spacers today. In the future I'll look at slightly wider wheels (for a happy medium), or I'll find aftermarket wheels that have pockets in the back for the original studs to stick into so that I don't need to run such big spacers. However, the stock NC wheels are very light, so it would be quite an expense to replace them, and due to the lightness of the originals, it wouldn't be for performance sake. I may just refurbish them and keep them as is.
The seats are another pain in my ass; literally. They're bloody awful. I'm now realising that I'd want the car to be useful on the road more than the track, but to not ignore the fact that I want to get back onto the track more often. It seems that the NC's options are limited to the standard tombstone-like seats, or full-on buckets. Neither of which appeal to me as both sacrifice something. A happy-medium would be OEM-style buckets (like Recaro's) that have the functionality of standard seats, a bit more supportive, and have harness holes.
Something like these:
They're Recaro's from a Vauxhall Corsa D, and because they're from a Corsa, they're quite cheap for what they are (£500 for the pair). Unfortunately there's no guarantee they'd fit, and that's a big risk to take. A bit more research into seating options is needed.
Said scratch marks. Ignore the santa hat.
I had some spare stretchy suede/faux alcantara that would look good, and would be easy to fit due to the shape too.
Turned out really well, with the lips of the glove box allowing me to tuck the ends in for a proper finish.
That's better! It's got me wondering if I should do any other pieces of trim, but I also don't want to overdo it. The triangular pieces to the left/right of the radio (you can see it in the photo above) would be easy and would compliment it, so that's tempting.
After the success of the glove box, I thought I'd do something similar here. So I went about designing a 3D printed cover set that would cover the holes.
Velcro is used (thanks for the tip Accelebrate) so that I can re-position them to get them just right.
Far better, and now matches the glove box. Lastly, Accelebrate designed a blank that fits into the wind breaker holes, which he kindly supplied the files to me so I could print.
A job well done.
A few other thoughts. I'll be removing the 25mm spacers. It's a shame as I do want the wheels to be pushed out a little more, but I'm a bit paranoid of a couple of things. Firstly, the alignment will be off; it was already -2 camber on the rear, so no doubt that would have increased it even more. But the negatives of having these spacers would be the risk of cutting the tyres on the arches if I'm tracking the car, as well as bearing failure (apparently anything over ET40 is a risk), and lastly uneven tyre wear due to the increased camber. As much as I like the look, I'd prefer the car to perform better, so I'll be removing the spacers today. In the future I'll look at slightly wider wheels (for a happy medium), or I'll find aftermarket wheels that have pockets in the back for the original studs to stick into so that I don't need to run such big spacers. However, the stock NC wheels are very light, so it would be quite an expense to replace them, and due to the lightness of the originals, it wouldn't be for performance sake. I may just refurbish them and keep them as is.
The seats are another pain in my ass; literally. They're bloody awful. I'm now realising that I'd want the car to be useful on the road more than the track, but to not ignore the fact that I want to get back onto the track more often. It seems that the NC's options are limited to the standard tombstone-like seats, or full-on buckets. Neither of which appeal to me as both sacrifice something. A happy-medium would be OEM-style buckets (like Recaro's) that have the functionality of standard seats, a bit more supportive, and have harness holes.
Something like these:
They're Recaro's from a Vauxhall Corsa D, and because they're from a Corsa, they're quite cheap for what they are (£500 for the pair). Unfortunately there's no guarantee they'd fit, and that's a big risk to take. A bit more research into seating options is needed.
snotrag said:
The Corsa Recaros have definitely been done in an NC before, so its doable.
Really? I tried to look it up but couldn't find anything on an NC.The other option is the Sparco R100+, which has been done, and are around £500 a pair brand new. That's another route to consider, which at the moment is the main one.
snotrag said:
100% - there was a white car at the OC national rally that had them. Search on NC Europe and you'll find the owner.
I'll take a look. Someone who's selling a set close to me has allowed me to visit them and place the seat in the cabin to see if it fits, so will update you on that. It would be a case of ensuring the original runners fit the new seats - how would I do it, can I drill holes, and so on. Not done this before.Pent said:
well done on the glove box. i did give you credit for the roll bar hoops on facey
I saw - thank you!A few more pieces trimmed as I felt they'd compliment the glove box.
These radio sides pop off easily, and are quite easy to wrap. Took me a total of 10 minutes per piece.
Very happy with how they've turned out.
Gassing Station | Readers' Cars | Top of Page | What's New | My Stuff