Which would be faster for my hillclimber / autotest car?
Which would be faster for my hillclimber / autotest car?
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Shoestringracer

Original Poster:

2,101 posts

223 months

Wednesday 6th April 2011
quotequote all
I'm having difficulty getting reliable figures but I want to know which is faster a) accelerating in a straight line.
b) on a tight and twisty track

Option 1: sub £2000 Mk1 1.8 with torsen LSD

Option 2: sub £2000 Mk2 1.8 with LSD

My research says Mk1 slightly lighter but slightly less powerful. The only place I've found with both listed is Autotrader which has the mk2 .6 of a second faster to 60. (0-60 is a very relavant stat for hillcimbing / sprinting). This seems like a lot given that it has only 10 extra bhp and is heavier. On the other hand, a lighter car should stop and corner quicker, all other things being equal.

Does either respond better to an exhaust manifold / system / intake mods?

Thanks

Chris


MX-5 Lazza

7,954 posts

243 months

Wednesday 6th April 2011
quotequote all
They are pretty much the same car so any mod would have a very similar effect on either car. The Mk2 has a better flowing head and VICS which gives it more mid-range torque as well as more top-end power so realistically there is more gain that the 8bhp at the top end. Mk2 also has slightly modified suspension which gives it a bit more grip and the weight difference between Mk1 1.8 and Mk2 1.8 is minimal.

They don't really benefit that much from breathing mods. A complete exhaust system including header is only likely to gain you 10bhp or so and intake mods do next to nothing other than sound good. If you can control fuel & spark a bit better (standalone or piggy-back ecu) there are more gains to be had as the stock map is pretty conservative.

The Mk1 will feel more responsive as the Mk2 is a bit softer but that's mostly because Mk2 has a stiffer chassis which allows them to fit softer suspension without affecting handling. I suspect you'd want to swap the suspension for something a bit more appropriate though - I'd recommend GAZ Gold Pro.

Shoestringracer

Original Poster:

2,101 posts

223 months

Wednesday 6th April 2011
quotequote all
MX-5 Lazza said:
They are pretty much the same car so any mod would have a very similar effect on either car. The Mk2 has a better flowing head and VICS which gives it more mid-range torque as well as more top-end power so realistically there is more gain that the 8bhp at the top end. Mk2 also has slightly modified suspension which gives it a bit more grip and the weight difference between Mk1 1.8 and Mk2 1.8 is minimal.

They don't really benefit that much from breathing mods. A complete exhaust system including header is only likely to gain you 10bhp or so and intake mods do next to nothing other than sound good. If you can control fuel & spark a bit better (standalone or piggy-back ecu) there are more gains to be had as the stock map is pretty conservative.

The Mk1 will feel more responsive as the Mk2 is a bit softer but that's mostly because Mk2 has a stiffer chassis which allows them to fit softer suspension without affecting handling. I suspect you'd want to swap the suspension for something a bit more appropriate though - I'd recommend GAZ Gold Pro.
Excellent reply. Thank you. I'd been on some of the specialst forums but they seemed abit vague. I'll check about piggy-back ecus but I suspect they are not allowed. I assume the standard ones can't be "chipped"?

I'll drive to and from events. Are Mks 2s any differnt interms of long distance high speed (I set out at 5am!) comfort and watertigtness? I'm also drawn to Mk2s becuase it seems I can work out if it has an LSD without having to undestand the myriad of specials and imports on the Mk1!

MX-5 Lazza

7,954 posts

243 months

Wednesday 6th April 2011
quotequote all
Both are pretty much the same in terms of engine & drive-train so both are pretty much the same on the motorway. Mk2 might be slightly more comfortable. Both will be fairly noisy at high speed on the motorway. The hood is the same on both too so weather protection is also the same.

They can of course be chipped but I've never seen a chip that does anything other than make it over-fuel which is more likely to rob it of power. A piggy-back or standalone ecu would allow you to advance the timing to optimum levels all over the rev range and give a useful power boost though you'd need to know what you are doing to keep it all safe.

Have you thought about a roll bar.

Shoestringracer

Original Poster:

2,101 posts

223 months

Wednesday 6th April 2011
quotequote all
MX-5 Lazza said:
Both are pretty much the same in terms of engine & drive-train so both are pretty much the same on the motorway. Mk2 might be slightly more comfortable. Both will be fairly noisy at high speed on the motorway. The hood is the same on both too so weather protection is also the same.

They can of course be chipped but I've never seen a chip that does anything other than make it over-fuel which is more likely to rob it of power. A piggy-back or standalone ecu would allow you to advance the timing to optimum levels all over the rev range and give a useful power boost though you'd need to know what you are doing to keep it all safe.

Have you thought about a roll bar.
I'll need to get my Blue book and check about extra or replacement ECUs. I don't think they are allowed though. Why can't chipping alter timing? I thought most ECUs contol timing and fueling? Please remember - I'm used to carbs and points!

I've given quite a lot of thought to a roll bar but I've not come to an answer. Class rules don't require anyting at all. My current car has a full cage and, though it is heavy, I think it gains me time as I feel safe and therefore more able to push. However, a lot of the bars of the cage pass close to my and my passenger's heads. Although they are well padded I can't help worrying that a minor crash would cause someone to break their skull as their head hits the bar.

Its more likely that I would have a minor crash than turn the car over. But I did once see one of my competitors roll at Goodwood and walk away. So I want a roll bar that will protect me when I turn over but not be near my head the rest of the time! Any ideas?

MX-5 Lazza

7,954 posts

243 months

Thursday 7th April 2011
quotequote all
I'm not sure but I think chips on MX5s can only affect fuelling. I'm not aware of any that affect timing. To get any real reliable advantage you'd need to be able to control the timing intelligently anyway and I doubt a simple chip would be able to do that.

Take a look at TR Lane for roll bars. They do a Track Day single hoop roll bar that is high enough to do a proper job but far enough behind the seats to be safe on the road. Quite cheap and easy to DIY fit too wink

snotrag

15,509 posts

235 months

Thursday 7th April 2011
quotequote all
The standard ECU is pretty basic with only basic 'write only' chips, hence why theres not really a lot you can do with them. ISTR the timing just works from a fixed advance 'curve' and you simply adjust the starting point or base of this curve.

If aftermarket ECU's are allowed then I reccomend it - even on stock engines people seem to be able to get decent gains, a bit of power and better response. Things like megasquirt can do all sorts of clever stuff that might be useful for sprint events, run shift lights, even launch control, though I suspect that might not be allowed!

As for roll bars - I highly reccomend. I rode in my mates car the other day which is broadly similar to mine except he has the TR Lane full roll-bar - the difference in the feel of the chassis was marked, depsite mine already having a half-decent bolted in belt-tower brace and just about every underbody brace there is. I will be going for the GP bar though as the full trackday one is far too close to your head for road use IMO.


Lazza - surprise you reckon that a +10hp boost from a full exhaust is modest. From a starting point of 120-something I'd say if you got another 10hp out changing the exhaust then your doing pretty well!

aeropilot

39,766 posts

251 months

Thursday 7th April 2011
quotequote all
Shoestringracer said:
I'll need to get my Blue book and check about extra or replacement ECUs. I don't think they are allowed though. Why can't chipping alter timing? I thought most ECUs contol timing and fueling? Please remember - I'm used to carbs and points!
What class are you intending to run in...?

Standard Production class or modified?

If standard production class, then you are usually restricted to a change of wheels and exhaust (but not ex.manifold) and that's it apart from safety equipment if you choose to fit it.

Modified class would allow ECU's, suspension, LSD, etc.,etc.

MX-5 Lazza

7,954 posts

243 months

Thursday 7th April 2011
quotequote all
snotrag said:
Lazza - surprise you reckon that a +10hp boost from a full exhaust is modest. From a starting point of 120-something I'd say if you got another 10hp out changing the exhaust then your doing pretty well!
I'd say a 10hp increase from a £1000+ spend (back box, mid-pipe, cat replacement or sports cat and manifold) is relatively expensive £ for hp.

Shoestringracer

Original Poster:

2,101 posts

223 months

Thursday 7th April 2011
quotequote all
aeropilot said:
Shoestringracer said:
I'll need to get my Blue book and check about extra or replacement ECUs. I don't think they are allowed though. Why can't chipping alter timing? I thought most ECUs contol timing and fueling? Please remember - I'm used to carbs and points!
What class are you intending to run in...?

Standard Production class or modified?

If standard production class, then you are usually restricted to a change of wheels and exhaust (but not ex.manifold) and that's it apart from safety equipment if you choose to fit it.

Modified class would allow ECU's, suspension, LSD, etc.,etc.
Will be "roadgoing series production" class - ie the lowest level of the MSA hill climb classes in terms of modifications. However, this does allow manifolds and suspension to be changed. LSDs are standard on many MX5s but would be allowed anyway, as long as the casing remains standard.

In fact the amount of development allowed puts me off (and excites me!)


aeropilot

39,766 posts

251 months

Thursday 7th April 2011
quotequote all
Shoestringracer said:
Will be "roadgoing series production" class - ie the lowest level of the MSA hill climb classes in terms of modifications. However, this does allow manifolds and suspension to be changed. LSDs are standard on many MX5s but would be allowed anyway, as long as the casing remains standard.

In fact the amount of development allowed puts me off (and excites me!)
Fair enough, I wrongly assumed Hillclimb classes were the same as Sprint classes, but clearly not, as the lowest class in Sprinting is Standard Production, which sits below the 'Roadgoing' classes.

Shoestringracer

Original Poster:

2,101 posts

223 months

Thursday 7th April 2011
quotequote all
aeropilot said:
Shoestringracer said:
Will be "roadgoing series production" class - ie the lowest level of the MSA hill climb classes in terms of modifications. However, this does allow manifolds and suspension to be changed. LSDs are standard on many MX5s but would be allowed anyway, as long as the casing remains standard.

In fact the amount of development allowed puts me off (and excites me!)
Fair enough, I wrongly assumed Hillclimb classes were the same as Sprint classes, but clearly not, as the lowest class in Sprinting is Standard Production, which sits below the 'Roadgoing' classes.
As far as I'm aware they are sprint and hillclimb classes are the same. I wasn't in those classes at the time (my car had its own class effectively) my understanding is that standard class was stopped for the 2010 season.

However, several clubs have created their own standard class. Blue book is on line if you want to check. I'd be interested to know what you find.

aeropilot

39,766 posts

251 months

Thursday 7th April 2011
quotequote all
Shoestringracer said:
However, several clubs have created their own standard class. Blue book is on line if you want to check. I'd be interested to know what you find.
Yes, must be a club or association thing then, as the regs for the Association Central Southern Motor Clubs Speed Championship has the first two classes in the Road Going Series Production Classes (A1, A2) defined for 'standard production' up to 1600cc (A1) and 1600-2000cc (A2) and restricted to the mods as I descibed earlier.
I'm a bit gutted really as they don't have a over 2000cc 'standard' class anymore frown



Shoestringracer

Original Poster:

2,101 posts

223 months

Thursday 7th April 2011
quotequote all
MX-5 Lazza said:
Take a look at TR Lane for roll bars. They do a Track Day single hoop roll bar that is high enough to do a proper job but far enough behind the seats to be safe on the road. Quite cheap and easy to DIY fit too wink
Thanks for this - site looks just the thing.