Performance modifications for 2004 n/a MK3 Race Car

[Rowland]

Hi all,

As you may or may not know I'm entering the MR2 Championship race series in a mk3 next year, having raced for two years in a mk2.
I'm after some advice regarding aftermarket performance modifications, or rather the tried and tested modifications of those in the know, you guys.
Now my background is with mk2's and have tailored my mk2 race car with suitable 'function over form' modifications from a build up of knowledge first hand, and from various forums.


The basic car is this that I picked up for a song the other week.





An eBay purchase, a 2004 UK Roadster, 30,000 miles with small n/s front accident damage - £2150!
It's currently in the bodyshop and rough estimates should see it back on the road for £1000-£1200 spend.

My budget then for race prep is in the region of £7000, which may sound substantial but bare in mind a roll cage supplied and fitted is roughly £1k alone.
Other than stripping weight out and the various safety measurements needed, i.e extinguisher ignition cuts offs etc I could do with some guidance on the following.

Suspension:
The regulations stipulate that non-adjustable fixed dampers must be used. Lowering springs are permitted.
What would be the combination of choice for springs and dampers for a mk3?

Exhaust:
I see Blue Flame, Cobra and other exhausts mentioned frequently on here, but I wondered which would offer the most performance gains for an n/a mk3?
First hand experiences would be fantastic and /or dyno plots.
Weight would be another aspect to consider.
A lightweight performance exhaust which offers a small increase in bhp, retains the necessary back pressure and isn't one of the god awful systems on eBay would be ideal.


Induction:
Again, air filter of choice for maximum breathability and performance gains.


Brake pads will probably be Carbotech after using them successfully for the past two years in the mk2.
Any advice or data you can offer would be kindly appreciated.

Rowland

  s:D s:D

[Anonymous]

What engine mod's are you allowed???

Rob

[custardavenger]

Ah thats who bought it then. Was gonna have a go at that myself but went out of my price range.

[Chris_h]

Sorry I cant contribute, but I hope you keep the thread updated as you make the mods - as I am sure I wont be the only one really interested.

[Rowland]

What engine mod's are you allowed???

Rob

Hi Rob,

Engine modifications aren't permitted with the exception of air filter and exhaust.
So no turbo kit, no lairy cams or tricked up ECU for example.
The ethos of the series is focused around driver ability rather than who has the most money to throw at their car.

  s:) s:)

[markiii]

do you have to keep emissions gear?

[Ilogik]

I have a really nice light weight exhaust mate.

I would recommend the Kakimoto GT 1-OZ single exit system with pre cats removed unless you can totally replace the cat system section? The kakimoto is very light weight.

Suspension I have KYB New SR specials, really nice non adjustable shock. Tein springs to go with them maybe?

kyb's maybe Patrick can get you them?
 m http://216.239.59.132/search?q=cache:Da ... cd=2&gl=uk m

Exhaust

LINK TO kakimoto jp
 m http://www.kakimotoracing.co.jp/image_T11356.html m

they are uber light mate.

made ok power with it on a 99 car with a blitz induction kit and the exhaust.



Its not to loud either.

[ChrisGB]

I would go for the lightest exhaust possible. Weight off the rear end is quite noticeable in terms of the handling.

Are you allowed to uprate anti roll bars and end links?

Chris

[kentsmudger]

I have a really nice light weight exhaust mate.

I would recommend the Kakimoto GT 1-OZ single exit system with pre cats removed unless you can totally replace the cat system section? The kakimoto is very light weight.

they are uber light mate.

made ok power with it on a 99 car with a blitz induction kit and the exhaust.



Its not to loud either.

So how much do you reckon you gained fitting that?

[ChrisGB]

Problem for you is that the limitations of the class will mean that at best you will see maybe 6bhp from exhaust and filter. This does not make much difference to lap times. I think you are going to find the biggest gains in suspension. Sportivo setup may be worth a look. Are you allowed stiffer suspension bushes? What about chassis bracing? Of course tyres will be significant. Can you run slicks or are you limited to road legal tyres? Toyo R888 could yield a big advantage.

Chris

[markiii]

I think they run control tyres

if allowed I'd look at ligtweight wheels, weight saved there will be worth more in terms of lap times than a light exhaust

[Ilogik]

I have a really nice light weight exhaust mate.

I would recommend the Kakimoto GT 1-OZ single exit system with pre cats removed unless you can totally replace the cat system section? The kakimoto is very light weight.

they are uber light mate.

made ok power with it on a 99 car with a blitz induction kit and the exhaust.



Its not to loud either.

So how much do you reckon you gained fitting that?

Not sure mods were all done to the car when I got it, standard is 135 right?

Since pre cat removal it feels like it gained a lot more torque lower to mid range, still feels like a wet fart top end though ol.

Once the softtop is taken out, hard top fitted, and light weight wheels. Did you see the racing battery the guy from greece had rowan?

[markiii]

stock is 138

[Ilogik]

stock is 138

Not to bad on a 99 car then really, nearly 10 years later and 60k covered. What is standard Torque>

[Kool PT]

125.8 ft·lb I think

[roger]

I had it in 125 -130 range.

[Anonymous]

Here's the dyno plot for my car fitted with the following:

Zero custom manifold - 4 into 2
SP de-cat pipe
Blueflame custom exhaust
K&N panel filter
Markiii pipe



It's a pity you can't mod the engine a little, you would get something like this:

 

The above was achieved with the above plus:

Apex PFC
Stage 1 Crower cams.
Standard engine - no up-rated piston etc.

Thanks
Rob.

[Ilogik]

Here's the dyno plot for my car fitted with the following:

Zero custom manifold - 4 into 2
SP de-cat pipe
Blueflame custom exhaust
K&N panel filter
Markiii pipe



It's a pity you can't mod the engine a little, you would get something like this:

 

The above was achieved with the above plus:

Apex PFC
Stage 1 Crower cams.
Standard engine - no up-rated piston etc.

Thanks
Rob.

How much were the  manifold and de cat, btw what is the markii pipe?

[ChrisGB]

IF you can change the manifold, you may want to look at the PPE setup as well. This will make more top end power than the Zero on an otherwise stock engine when combined with a free flowing exhaust, though you will get more mid range with the Zero setup. Check out the dyno on my MR2 Page (link in Sig).

Chris

[silversprint]

Best best advice is to try to get the car as light as possible and spend as little money on engine mods as possible. Without an aftermarket ECU you will not gain muc  if anything from exhaust mods or intake mods. A simple short ram intake is all I would do.

Remove soft top, keep the car open top to save weight. No hardtop (hardtop is 50lbs that you don't need)
Remove A/C to loose weight and free up some hp
Remove the whole exhaust system and run a titanium straight pipe, (if noise is not restricted)

Change the transmission to a C60 6-speed this will improve acceleration and top speed, this will make the car only slightly slower than a 2zz spyder and is probably the best bang for the money mod you can do. Don't forget to add LSD. Light weigt flywheels, race clutch. Poly engine mounts.

Gut the doors and remove glass= lose 50lbs/door

Remove everything inside the car. Remove heater core. Carbon fiber trunk lid and hood, Add a rear wing. Smaller battery.

For suspension if you are limited to fix struts then nothing beats custom valved Koni shocks with custom springs. Spring rates (6kg front, 10kg rear) to start.

Roll the crap out of the fender and run 225/15 front and 235/15 tires R888. If slicks are permitted then 13 or 14" wheels and tires.

A fully stripped  spyder will be close to 850lkg if not under.

[silversprint]

If running Carbotech pads xp10 on the spyder works great.

[custardavenger]

I would have thought there would be a benifit in having the hard top fitted rather than being open. I'm sure my top speed was higher with the hard top. Just replace the rear glass with polycarb.

But as you said silversprint. There's a whole load of weight to be lost all over the car. Also if there is something than can't be removed (eg battery) try putting it as low as possible to reduce roll radius, and also concider moving weight from the rear to the front if needed to get a good weight balance.

I doubt you'll need to add any bracing if your fitting a full cage presuming it ties the front struts together well.

Was thinking (and someone else may be able to correct me on this) how about loosing the ABS and also fitting a non power steering rack. You'd loose weight and well as take power drain of the alternator. (Smaller alternator?)

[loadswine]

Can you lose the water pump and go electric? Might save a couple of horsepower.

[Innocent]

A fully stripped  spyder will be close to 850lkg if not under.

Problem is the weight is limited to 1000kg on the grid to keep Mk1 2 & 3's balanced on power to weight ratio, which means you can only loose about 25-50kg over standard depending on the driver. Also the restrictions on what you can modify are very tight, induction is free, exhaust & suspension mods very limited and everything else has to be standard. You can strip out what you want though to save weight. I think i would focus on saving weight at the back so you can add balast to the front as it has a 55% rear weight bias.

Anti roll bars are the only free suspension mod so I would definately get them sorted to stiffen things up, that should really reap some rewards.

Can't wait to see the Mk3's debut this year, I really think they will spank the Mk1 & 2's. Handling is leagues above the others and should be able to keep level on straight line speed too. Good luck Rowland!

[custardavenger]

Ah well its still worth removing as much as you can and then fitting balast weights as low as possible. That will help losts to remove roll.


 

Also the restrictions on what you can modify are very tight, induction is free

How about a big bore throttle body   s:D s:D