Mazda MX6 2.5 V6 manual

[MX6]

...just thought I'd do a quick little lack of progress update. Basically the turbo conversion is complete and the car is in one piece, it appears to need a new head gasket or two now though so I need to take it all apart again. No recent progress due other projects, the biggest of which include having a baby and suffering a protracted house move saga. The latest is that I have a completion date for next Friday, so the '6 with be off to her new home shortly...

Edited by MX6 on Thursday 19th December 11:04

[MX6]

...so the MX6 is re-homed now, as am I. As ever the new gaff is something of a project so there'll be no shortage of DIY-ing to do, I will be making time to get the car on the road next year though. I've been slowly clearing the crap out of the garage so I can get the car in there, planning to resume the project over the Xmas hol's.

[MX6]

Thanks, I really want to get back on with it soon, I'm interested to see how it turns out too! There's an element of planning and an element of making things up as I go along...

With regards to the head gasket issue mentioned, basically these is a fair bit of white smoke from the exhaust when the motor is run, plus the cooling system appears to be pressurised as well. I haven't actually done a compression test so that is one of the first things I need to get done before properly assessing things and deciding what to do next.

Before I started work on the turbo conversion I did know that there seemed to be a problem with overheating, I think I mentioned this in an earlier post or two. There didn't seem to be a problem with lost compression, the engine seemed to run okay. During the course of the work I've changed the water pump, thermostat, radiator and coolant temp sensors so I've ruled out any issues with those. I actually deleted the coolant expansion tank as it was located where my air filter is now positioned, so that situation is likely to be causing problems as well and needs sorting.

[MX6]

Thanks for the comments Paul. The standard MX6 is around 165bhp so not a particularly high output for 2.5L really, but even with that the car goes pretty well given the circa 1250kg weight, and sounds good. My power goals are for the output to be in the 250-280bhp area which should be achievable with around 6-8psi of boost. I think that will be plenty for me to have fun with on the road and also realistically enough for this chassis.

These motors are pretty strong and take boost well by the accounts I've read, the weak link is the transmission which can start to fail at around 300bhp+ apparently. I've a 3.63psi wastegate spring fitted so for starters I will just try and get things working well at that level, the power will obviously just be whatever it makes at that boost pressure. A guy in the states who did a similar build to mine made 240bhp at 4psi on the dyno.

You are right regarding the bodywork, I'd like it to be all flawless and glossy but I will just have to deal with one thing at a time. I'm more into doing the oily bits than restoring bodywork, I'm just not very good at it. Given this is a budget build and a car with minimal value I can't justify having a body shop sort everything out. For now it's function over form.

[MX6]

danllama said:

Just making my presence known for encouragement etc only found this brilliant thread yesterday and read it all now. I'm a fan of the mx6, what's not to love? You've done great work on yours, it sits really well. I have a 1mz MR2 and would love to turbocharge it.

Shame it's all stalled because of possible hgf but no doubt you will have it all up and running soon. Hopefully see it at a PH meet one day. If not a YouTube video will suffice. Until then, watching

Thanks for the encouraging reply, sorry I missed this earlier and didn't reply. I really like the MR2, must be great with the V6 I always liked the idea of that.

Well, the project has still stalled, but I've managed to make some progress towards being able to make some progress at least... Following the house move the garage had been used as a store room stuffed full of various household contents and rubbish. Getting the house interior into shape has been a priority over the last several months (plus I've a 5 month old baby, life, etc.) but I've recently been able to turn to the man cave side of things. It's basically just a brick shell but is on the side of the house so light and power, I've managed to get the space into some kind of reasonable order now and free enough of stuff to allow the '6 to actually fit in there.



I was hunting for a little while for storage solutions, found these secondhand black cupboards on ebay, very solid, £15 for the three.



It might not look like much but I'm chuffed to have it finally straight and tidy. It is a space purely for the car and car related tools, no other rubbish. Thankfully the garage has a pitched roof and a boarded loft space so all the parts and other assorted bits and pieces are up there. Obviously the space needs more work, I want to paint it out, get a proper workbench and all the rest of it in there but it's a start.

The car is a tight fit length ways, I've had remove the front bumper but it still only just fits with the door closed. I did plan to run a beer fridge in there but it didn't fit with the car in, shame.

Edited by MX6 on Monday 16th March 16:46

[MX6]

In more car specific news, I've bought a new part. I've not been expecting the standard clutch to be up to stratch so have bought this, an XTD "level 3" uprated item, supposedly good for 385 lbs/ft.



As per usual it's a bargain basement ebay part - £58.02, plus £18.64 postage from the US, plus import duty. Cheap and cheerful, let's give it a spin and see. From the states as there are no tuning parts available in the UK for the MX6, there just aren't any left now so I guess there is no point for anyone to stock these kinds of parts.

It looks decent enough on paper, it has a 6 puck copper ceramic clutch disc, heavy duty pressure plate, plus comes with the release bearing and alignment tool. There was a "stage 4" type available with a solid rather than sprung clutch disc, more of a part for track use, but I primarily want this to be a road car still so the one I went for seems ample.

Edited by MX6 on Monday 16th March 16:47

[MX6]

BrettMRC said:

You need a short wheelbase Mx6! (Not an Mx3)

Ha, yeah that would certainly help with the space issues!

To be honest I have actually had some thoughts about swapping to building an MX3, basically swapping the 2.5 KL-DE turbo motor in, but I really prefer the long sleek shape of the MX6.

[MX6]

threespires said:

Great thread ---

Sorry for belated reply to the thread, many thanks.

Steven77742 said:

Hi kieran, have missed your input on facebook mate but appreciate your change in curcumstances. . Shame about your working conditions but smal price to pay when finding the best family home. Hope you all are ok and stay safe in these strange and scary times. Give us a shout if you decide to change projects. . As im sure some of us would really appreciate your hard work. I will try and check in here from time to time for a catch up. Steve

Hi Steve, yes I left FB altogether, the car groups were the best thing about it. It's unfortunate to have restricted space now but I will have to make do and get done what I can. We are all good here, I'm working from home. As for changing projects, given my change in circumstances I am open to offers if someone has the time and is keen to complete the work themselves or wants to do a turbo conversion on their own MX6. Your car's looking great by the way.

ElmerFud said:

Hi Kieran.
Sorry to see you leave the UK FB section.
Just read your whole thread. Amazing work. NOW. Do mine!

I like your narration of tasks done. Are you an engineer by any chance?

Look forward to seeing the end result.
Elmer

Hi Elmer, as mentioned above I left FB altogether hence why I departed from the MX6 group as well. Thanks for the kind comments! Yes I'm a mechanical design engineer, though I don't work on anything automotive related, it's industrial electronic products. I'm looking forward to seeing the end result too, if I ever get there...

[SteadyAsSheGoes]

It's been a while since an update on the project and there's not much of note to report on the turbo conversion. As I've mentioned before, I seemed to have a failing/failed head gasket issue, so was facing pulling the motor apart to deal with that. In addition to that the shell and chassis were going to need quite a lot of work to get to a reasonable standard. The car was never a particularly good example, a £430 effort with around 160k on the clock and various issues. Obviously it's all fixable but it was going to take quite a significant amount of time effort to get thing where I wanted them to be.

Luckily for me an opportunity presented it's self. After some discussions with long time MX6 enthusiast and all round top guy ElmerFud, who replied to the thread above, I've been able to take ownership of his MX6, "Lara", so the latest development is that I've acquired another MX6! The thinking behind this move is that as it's a much better shell with quite a number of chassis and other modifications that are appropriate for a higher power output, so will be an ideal home for all the turbo conversion and various other parts I've been fitting. Although it's a not inconsiderable amount of work to swap over all the parts, in the long run I see this a much quicker route to having a clean and well sorted turbocharged MX6 with all the appropriate modifications.

The new car is not currently a runner since it appears to have an electrical issue with the immobiliser, whereby it will run for a few seconds then cut out. I'm fairly confident she can be fixed by swapping over the ECU, immobiliser module and ignition barrel from my old car, which is a P plate car as well and runs without issue. Despite this it has to be one of the best remaining MX6 examples in the UK, with a solid shell that has minimal rust and 56k on the clock. It was delivered over on Friday, more details to follow...

Edited by MX6 on Sunday 2nd August 23:06

[MX6]

Superhoop said:

Before you swap the PCM, immobiliser etc. over.. have you checked the intake pipe from the air box to the manifold? They used to split for a past time when they got older and brittle and that caused then to start and then stall...

If it is split, swap it over from your blue one and see if that resolves it..

Hi Superhoop, thanks for the suggestion, I will certainly be checking everything over including the intake. There's a bit of a story behind the issue, but basically the car had what was diagnosed to be an ECU fault. As a consequence a new ECU, immobiliser module and ignition barrel were swapped over from another car in an effort to resolve the problem, but the engine has not run properly since. The engine starts, runs and idles fine and then is cut. I've previously tried removing the immobiliser module from my old car to see what happens and it causes the exact same result. As the engine runs fine on my old car, I believe I should be able to get the new one working if I swap enough parts onto it.

I'd like to remove the need for the immobiliser and ignition barrel, bypass them so that the ECU just runs the motor without them. But for now I want to see if I can get the car running as standard.

Edited by MX6 on Monday 3rd August 11:14

[MX6]

I will check that for sure, good to know, I always appreciate any suggestions like this.

So a little bit more info about the new car, "Lara". She's wearing a rare TWR full bodykit, has JDM door mirrors and is de-badged front and rear.


There's a serious brake upgrade at both front and rear. The fronts are apparently K Sport 8 pot calipers with 356mm floating disks. There are staggered OZ Superleggera wheels fitted, 18" since this size is required to fit over the brakes.


There are a number of suspension mods including adjustable BC Racing coilovers, aftermarket wishbones, trailing arms, anti-roll bar, drop links, etc. There's a custom stainless exhaust system.


Indoors there's a full black leather interior, the drivers seat is electric which I've not seen in an MX6 before.

[MX6]

A comment on the exterior look of the new car. I really like the bodykit, and modified but clean look the previous owner has maintained, quite OEM style I think, could have came from the factory this way. There are several things I'm thinking of addressing though, primary of which is the "stance". I like the style of the OZ Superleggera wheels, but they are staggered with 8" fronts and 9" rears, which I don't think fit quite right. The fronts are a good size but the offset seems a bit high, I would prefer them to be positioned a bit further out towards the arches. The rears poke out of the arches, meaning the rear suspension needs to be high enough to accommodate them not coming into contact with the wheel arch. I would prefer the rear wheels to sit inside the arches and the rear suspension to be a bit lower, I'm considering the options to achieve this.

[MX6]

A good further update, I managed to get the new car running, as I suspected there was an issue with the immobiliser module or perhaps the ECU. Either way she fired up and ran fine on the afore mentioned parts from the old car.

Someone at Mazda didn't want the ignition barrel removed, the heads of the screws securing just had domed tops with no slot or other indentation. I had to use a dremmel to cut slots for a flat bladed screw driver, the one on the left is the first I cut.


...the ignition barrel and immobiler module...


...the ECU...


I just need to put the interior back together and then I should be able to get out for a drive soon.

[MX6]

shalmaneser said:

those style of security fastener is fairly common on ignition assemblies.

wrt to the wheels I would have thought a square setup would be better on a FWD car. No point having extra grip at the rear. New car looks in good condition though.

I've not actually come across that type of security fastener before, but then I don't recall removing an ignition barrel before.

Yes I agree and think that a square setup is the way to go, 18x8" front and rear is what I need really, with the same offset, maybe around 35mm-ish. It's a bit of a shame since the Superleggera's are a decent wheel and have very good tyres, but I'm just not satisfied with the fitment. I've been having a look at different wheels but I've not settled on anything yet.

The new car is in good shape, it's had a respray previously which is not the best in fairness but the overall condition is much better than my old one. There are some cosmetic improvements to be made but needless to say I'm concerntrating on the functional stuff first.

[MX6]

A bit of pottering about done today. The car came to me as a non-runner with bits of interior trim removed to get at the electrical parts, in an effort by a garage to fix the engine running issue.


As mentioned previously, I fitted the Ecu, immobiliser module and ignition barrel from the other car which got it running, so I refitted them properly and threw the interior trim back in today. Plus gave it a good vacuum out, I shall do more of a deep clean at a later date.



A minor modification, I fitted a set of clear wing indicators in place of the amber lens'.


I'm still working on resolving the wheel fitment issue, I've a couple of options in mind so let's see what comes to pass. The car does needs an MOT, I seem to have a minor issue with several of the lights not working so need to resolve that before getting it down to the garage.

Edited by MX6 on Sunday 9th August 21:39

[MX6]

W00DY said:

New one looks fantastic! Like the Elmer Fudd stitched headrests!

Hi Woody, thanks, I'm enjoying the look of it too.

The Elmer Fudd images on headrests, rear window and wheel center badges were a fun personal addition made by the previous owner, he had a personalised plate which complemented the theme as well. I'm in the process of removing them though as it's not something that's meaningful to me in the same way. The image on the headrests was actually a sticker and not stitching, you may notice in the above pic that I've removed these. I'm going to replace the wheel center badges with plain black ones.

Edited by MX6 on Monday 10th August 14:56

[MX6]

I've bought some new wheels. The rims are Borbet H, 18x8J, offset is et45. They've been refreshly refurbed in gloss black which I think will look more interesting on a silver car, rather than the silver/silver look. They have a clean multi-spoke style, quite OEM I think. The shape of the Superleggera's looks a bit fussy by comparison.


They should be a better fit, I may want to run spacers but we shall see. I'm planning to run the coilovers a bit lowerer, the fronts seem to be pretty much okay but rear could go at least an inch lower.

I need to get myself the appropriate size spigot rings, plus some new center caps as the existing ones are tired. Might treat myself to some new plain black wheel nuts as well.

[MX6]

Hi Elmer, many thanks for the positive message. The condition of Lara is a credit to your ownership and I feel lucky to get this car at the right time for both of us as it turned out. The Ultraleggera's (I keep calling them Superleggera's...) are a high quality set of wheels so it's something of a shame that the fit isn't quite right for me. I didn't want to do any body modifications like widebody, etc., very happy with the TWR bodykit and general overall look of the car besides the stance. I'll try and keep the thread here updated, keep me posted on the H gate.

[MX6]

Hi Jaaack, always pleased to hear that folks are enjoying the read through. It's a shame that I'm not going to continue with the blue car, as you say with some minor mod's the MX6 does look like something half decent. As standard the stilt like ride height and small wheels don't do the look any favours but it's a sleek shape.

I do prefer a 16“s like the RX7 FD wheels, or a 17" on these, but need to go 18s for the brakes. The silver car was just too good to turn down, the previous owner has done some top work already as you can see, the chassis is well sorted.

I think 300 brake tops is the sensible limit on the standard engine and transmission for turbo, 280-ish will be fun in this relatively light FWD chassis. The Prelude sounds great, have you got a build thread link? I think it's another FWD 90s coupe that is somewhat similarly overlooked, if that and the MX6 were RWD I think there would be much more of an enthusiast following.

[MX6]

I was fitting the new wheels this afternoon until rain stopped play. I bought a new set of plain black wheel nuts and a new extendable wheel brace. I procured some spigot rings too, to adapt the wheel centers from 72.6mm to the 67.1mm of the MX6. I've also ordered some new Borbet center badges, black with silver text, currently on their way from Germany.



As anticipated the Borbet H wheels are a better fit, I plus I like the look of them. I'm not ruling out another change to something else but for now I'm satisfied with these. The ride height is sensible but I'd be happy to lose at least an inch now that the rears are sitting inside the arches. To this end I've ordered a new coilover adjustment spanner, will have a go with that next weekend hopefully.