Jdm Sti Track Car

[DR Motosport]

It’s been a couple of months now since I sold my Impreza WRX ra track car, so I thought it was time to start on a new project.

Realistically I’d taken the WRX as far as was sensible to go with it. It went pretty well, handled brilliantly, and had somewhere in the region of 300-320 bhp. The problem I now had was if I wanted to take it to the next level it was going to cost a fair amount. 400 bhp would be nice figure, but it was only a WRX and not the STi model. So a replacement STi or a forged built engine together with a stronger gearbox would be needed. Add on bigger injectors, bigger turbo, mapable ECU, and I was looking at a bill of more than £5000………………… I don’t think so, not on a 15 year old car anyway. So when I was asked to name my price for it, I did and it was sold, with a nice profit too.

As well as owning the white WRX classic, I also own a blue new-age JDM STi. This was more or less my everyday road car, with a few track days thrown in too. I imported it new back in 2002 when the yen / pound made it worthwhile, and being the JDM STi it came with more power than the UK version. 330 bhp after a few very basic mods.

Converting this STi to a track car made a lot more sense. Being the bug-eye JDM model meant it came with the rarer forged piston engine rather than the hypereutectic UK engine, and closer ratio JDM 6 speed gearbox, both capable of 450bhp ish. I had already done some back to back testing with the 2 cars and knew the WRX was slightly quicker at lower speeds – probably due to its lighter weight, but at higher speeds there was really nothing in it. Both cars have also lapped Knockhill in the 60-61 sec bracket in the past. Power / weight calculations showed that an extra 50 bhp from the STi would compensate for it’s extra weight. But I was looking for a bit more than that. An extra 100+ bhp, combined with a 100 kg weight loss was the new target.

More later,

Davy

[cullenmin]

Another track car project under way

These threads are always good reading, keep the updates coming

Rich

[Phil MC]

Nice one Davy .

I was just reading the write-up on your website about this today, so would be good to read what you've done with it since making it your track car .

[wilky]

Good stuff Davy!

I enjoy reading these projects and look forward seeing what your up to!

Callum W

[hi_jac]

Mon the bugs

I got ma lard ass UK bug down to 1340kg with half a tank of juice, with not much effort.

Your target of 100kg will be easily achievable. Good luck and keep us posted on ypur progress.

[the squiggle]

JDM Bugeye is certainly a good starting point.

A STD Bugeye Spec C is not that much heavier than a late model Classic so things should go well for a decent end product.

[DR Motosport]

Cheers guys.

I am actually a bit further forward than I've written about so far, but I'll get typing as quickly as I can.

I was in 2 minds about selling this car too, but what I would get as a trade-in wouldn't be much, and it's too good a base car to just sell.

I've already weighed the car at 1430kg full of fuel. I think that's about 30kg less than the UK bug-eye, but still 50kg more than a Spec-C. I've got plenty of idea from doing my classic track car, so we'll see where it end up.

Davy

[Rice Rocket]

Looking forward to seeing the progress David, is it going down the lines we spoke about down at Silverstone?

Ricey

[DR Motosport]

Looking forward to seeing the progress David, is it going down the lines we spoke about down at Silverstone?

Ricey

Probably, but keep that under your hat for now

I'll drop you an email soon.

What about you, got your plans for 2010 worked out?

I enjoyed your recent write ups in Jap Performance and Total Impreza.

[irish al]

Looking good so far, your old one was nice as well.

[Rice Rocket]

Cheers David, got ALOT of plans for next year, but don't know where to start lol

I'll await on the full run down in the email.

Ricey

[john_stevenson2]

Liking it David, look forward to the end product

[dipsy]

Look forward to here more about this project

[gambler]

Looking forward to reading the project thread. A bug eye is a good start for a track car is it is not much heavier than a classic but a fair bit stiffer.

[braveheart]

Great news David looking forward to the threads on this, and some progress pics what's the plans got to ask you dont ask you dont get lol...

Chris

[bigbird]

This sounds interesting!!

Have you bought an exciting "day to day" car to replace the bug?

[DR Motosport]

I've not bought anything else yet Colin. Not really been looking.

Carolines still got her car, so if we're going out as a family we take that. Can't beat leather heated seats at this time of year either.

Chris, I don't honestly know where I'll end up with the car.

But I said that about the white wrx too, and that ended completely stripped out with a cage, sparco seats and harnesses.

Remember I'm still using the 2.0 engine, so that will be the limiting factor to start with. But as you know Chris - come the Summer time there could be a 2.5 build, sitting in the garage.

I'd like to see what can be done to these new-age cars without spending a fortune.

It'll maybe encourage other owners, rather than sell up, this is what you can do to get a quick track car for Knockhill and Crail.

[johns]

Looking forward to the updates, and seeing you on track next year

[P1_Paul]

If it's going to be a track car I'd stick with the JDM 2.0, it loves a big turbo and being reved out to 8KRPM.

[DR Motosport]

Time for the next update,

Although the car is only at the 50,000 mile mark, I felt the clutch was starting to feel its age. So this was a good time to fit an uprated Helix clutch and flywheel that would be able to handle the new power. I’d asked AWD in Perth to do this while I was on holiday, and also decided as an extra precaution to get them to fit a new timing belt, along with new tensioner and idlers. Andy at AWD also suggested a later spec uprated oil pump, so that was fitted at the same time as the timing belt. So, thanks to everyone at AWD for helping me out at short notice.

Since I now had the sensible head on with all this precautionary work, I then changed all the oils and fluids, fitted another set of PFR7B spark plugs and a nice new Walbro fuel pump.

So now after all that, it really was time to get started.

Although the STi top mount intercooler is a good piece of kit and capable of handling what I was looking for at this time, I opted for a FMIC for that extra bit of cooling needed on the track. I’ve known Harvey Smith for about 8 years now, and have supplied him with various parts for his Impreza’s. So it made sense to give him a call, and a nice new Hybrid Intercooler arrived the following day, and at a cracking price.

The Hybrid intercooler also comes supplied with a cold air intake pipe, and it was all pretty straightforward to fit. The only tricky bit is working out how much to cut from the front bumper, and with the intercooler being 100mm thick – it’s a lot of cutting.

Trying to get a big enough filter to fit inside the wing space, was the next problem, but I already had a large Ramair filter in the garage, it’s good for 450bhp, and I was able to squeeze it in - just.

I decided to box in the underside of the inner wing to stop water and dirt getting to the filter using a 3mm sheet of plastic. This sheet together with the bumper itself and inner wheel arch trim made up the boxed area. I then replaced the fog lamp covers with some new ducts I had made up to keep the filter supplied with plenty of cold air and fitted a small plastic deflector to stop the filter getting wet in the rain.

Still to be fitted is the original front lip spoiler, this has still to be trimmed for the front mount and then a fresh coat of paint for it.

And just when you think it's all going too well, it goes badly wrong..............................

Stay tuned.

[sparky_sj04]

This looks like it could be a great one.

Can't wait to see how it all works out, looking forward to the next instalment!!

Cheers,

Mark

[DR Motosport]

It's been a while, and it's about time I got all this nearly up to date.

The bug-eye JDM STi comes as standard with a VF30 turbo. The VF30 is less known over here, but it’s actually the same size as the popular VF34 but uses a thrust bearing instead of a roller bearing.

After speaking to Grant and Andy at AWD, and discussing various options, we decided upon a Garrett turbo supplied by AET Turbos.

New Garrett next to the old VF30

Now over the years I’ve fitted plenty of Subaru turbos so I wasn’t expecting any dramas. But with a Garrett turbo the water pipes and the oil pipes are all different thread sizes to the original Subaru ones. Imperial sizes rather than metric.

AET supplied a fitting kit, but I was really disappointed with it; cheap gaskets, no oil or water hoses, and the new banjo fittings didn’t fit very well either. The kit was returned to them, and I bought a “proper” fitting kit from Roger Clark Motorsport. That came with genuine gaskets, better banjo fittings and Samco water hoses.

Linking up the turbo with the CAIK I used a larger 76mm SFS silicone intake pipe. Andy Forrest had told me when I came to fit it due to it’s bigger size – make sure you start it in the morning and have a big breakfast first. He wasn’t wrong, what a pain to fit.

The car still had it’s original catted downpipe fitted with a straight through 2.5” centre section and a 3” H&S backbox. When I first bought the car I was given an Invidia 3” decat downpipe to try, but had never used it. I then had Stainless Creations in Falkirk make me up a straight through 3” centre section to join it all up.

The last part of the mods at this stage would be the injectors. I had a few debates about this, on what size and make to go for, but still hadn’t made up my mind. Due to a booking with Andy Forrest looming quickly I thought I’d get it mapped as it was with the standard 550cc injectors, then take it from there.

[DR Motosport]

As most people will know, when this level of mods has been done, you really can’t use the car, and the drive through to Andy has to be off boost. So up to this point I hadn’t been able to run the car properly other than a short run to check for leaks.

Andy put in the Ecutek map to match the cars new spec, then we went out on the road for the next part of the mapping. Then a big problem, he couldn’t get anymore than 0.5 bar. We checked for any obvious leaks – didn’t find any, then Andy checked the actuator, and it was still operating at the correct level. Only thing left was a problem with the turbo itself. Bugger, or something like that. Ok, it was a lot worse than that.

So back home and the next day the turbo was removed. As soon as I had it off I could see the problem, the wastegate was open. And when I touched it, I could open it with my fingers and move it about on the shaft. The weld hadn’t been done properly and had no penetration onto the shaft. I think when it arrived it was just holding it and no more, but as soon as Andy put some boost through the turbo it came apart. Relieved it was something simple, but angry that AET had sent out a turbo without checking it. Quality Control?????? I was angry, that I had to waste an afternoon removing and refitting the turbo, and angry that I had wasted an afternoon of my time and Andy’s time with the mapping.

I decided not to send the turbo back to AET – didn’t trust them basically, but had the turbo re-welded at a local specialist who also checked out the rest of it.

Turbo Problem. Wastegate in it's proper closed position.

But I could also slide it along the shaft,

And open it,

And move it back to the correct position, all with my finger tips.

I did send an email to AET about their lack of quality checks, and their reply was pathetic, straight out the book of “palm you off excuses”, blaming a material supplier. Eh NO, nothing to do with a material supplier – just poor welding and no quality checks either. Very, very disappointed with AET. Ok Rant over.

So now with the turbo fitted to the car again, it was back to Andy Forrest for mapping again. And apart from having to adjust the actuator slightly, all was well.

I knew before going to Andy’s the injectors would be the limiting factor. He told me the intercooler and filter were well within their limits, but he had to lower the boost so not to max out the injectors. He would normally run this at 1.65bar right up the rev range, but for now it was 1.5 bar tailing off to 1.3 bar and just hitting the 400bhp mark. I’ll make a final decision on injectors soon, then get Andy to map them in.

[RA Dunk]

Glad you got it sorted out eventually Dave, what made you go for the Garrett over the MD series or the S206 though?

Hows the spool on the 2.0L then? is there still much to come from the turbo once you have bigger injectors?

[fai17]

Nice read up Dave and such a shame on AET Turbo as i always thought they were a reputable turbo dealer.