An Odyssey of Tuning a Big Power VX220

[nevcontractor]

Over the last four years I have undertaken a major project tuning my Vauxhall VX220 Turbo in 2 phases, the first being power, the second being bodywork/aero. I did this out of curiousity and a general interest in mechanics as well as a desire to end up with a faster car.

I know tuning cars up is not to everyones taste but for those of you considering such a thing yourself you may gain some insight into the costs, effort, rewards and practical issues that I faced by reading from my website. Progress is logged chronologically on the left hand menu with updates 24 and 25 being the most recent, and updates 10 to 18 being the most technical.

Edited by nevcontractor on Tuesday 16th February 18:34

[nevcontractor]

Thanks for all the positive comments chaps. The car is currently still having 2 different splitters being made up for it (1 for road and 1 for track) and some other vital suspension/geo mods at the moment as well as some other tweaks. I will hopefully get it back in a week or so. I've just been sent a couple more pics of last weeks PVS 2012 show by a friend:

[nevcontractor]

Thanks, I suppose it does a bit (though a little less threatening than an Appolo)

[nevcontractor]

Yep, there was a lot of learning as I went along, the main thing being how it take 1000% more time than you expect !

I have logged most of my experience on my website so others can avoid some of my mistakes and speed up their own builds.

[nevcontractor]

Now with it's small 2 inch "road" splitter finally. For tracking it will have considerably bigger one.

[nevcontractor]

There have been a couple of Time Attack VX220s, one this year and one last year, both of which were supercharged to around 260 to 300 BHP respectively.

[nevcontractor]

The car is performing wonderfully. Went for a lovely 165 mile drive around the Black Mountains last weekend and took some pics. I am currently planning a new ECU for it (with multiple maps and on board laptop) and some new uprights for it to adjust the ride height/centre of roll of the front wishbones.

[nevcontractor]

Thanks, there are more pics (and an in depth write up) here: https://sites.google.com/site/z20letpower/home

[nevcontractor]

MrFrodo said:

What a fantastically mad creation!

What's the driving experience like at 500bhp (aside from bonkers quick)? Is it still fairly drivable?

As the car only weighs 900 Kg, it is quite nippy in a straight line. I've spent quite a bit of effort widening the wheels/tyres/track so it can sustain 1.4g round the corners too. This winter it is getting a new ECU to help make it more drivable, with in gear boost limits, multiple maps, another 1 bar of boost available, all connected to a permanent laptop in the car. Also I have specced up a couple trick running gear parts which are being machined up for me at the moment. Once these are on, the car should be fully ready.

Sorry, no public videos of it

Driving it (for a new person to the car) would be rather tricky, as the power is not linear at all. However with a few months of learning it, I think an adaptive drive could pedal it moderately fast. Ultimately though for that last 5% that you want for the track it would be less easy to control than it should be. However the new ECU will remedy this.

Edited by nevcontractor on Thursday 4th October 12:00

Edited by nevcontractor on Thursday 4th October 12:05

[nevcontractor]

OlberJ said:

Considered twin charging at all for a better power spread?

Yes, I have recently. There is room for a rotrex supercharger near the boot. That would provide the torque it needs before the turbo spools up. I have looked into this in some detail, but a new rotrex, bypass valves, bracket, pulley and pipework would come to around £2000. It would make the car much more 'streetable'. However, if you are in 'race mode' there is good flat torque from 4000 RPM to 8000 RPM, so if you stay in that band the car is epically quick, it's just that if you drop below 4000 RPM you can be caught with your pants down !

[nevcontractor]

I'm sure the wing isn't to everyones taste, but unlike most cars it is there for function, not fashion. The OEM car becomes very light at around 140 leptons and this wing is highly effective (in conjuntion with the splitter) to overcome that issue. Basically from 160 leptons the wing could be the difference between life and death as you go round corners quickly. It is connected to the chassis by strong legs and can take the weight of person lieing on it carefully or be used as a towing point.

As for a dyno graph, there is one here, my current map is the pink line.

Edited by nevcontractor on Thursday 4th October 13:37

Edited by nevcontractor on Thursday 4th October 13:49

[nevcontractor]

I've just stuck some 4" inlet piping and a massive home made airbox in. Writeup and pics at the bottom of here: https://sites.google.com/site/z20letpower/07---upd...

Edited by nevcontractor on Wednesday 17th October 05:21

[nevcontractor]

Went for a test drive the other day and the new intake has deffo helped with engine pick up and power.

[nevcontractor]

I just popped out to the garage and measured it for you.

25.5 inches from the bulkhead to the front edge of the rear subframe. May I ask why you want to know - are you considering fitting a different engine into a VX220 ?

[nevcontractor]

Building a new rear sub-frame would be a good idea ~(and mandatory for a longitudinal layout) as the OEM one can crack under hard cornering and also it flexes too much for my liking.

[nevcontractor]

What V6 and V8 are you considering and what transaxle?

[nevcontractor]

LaurasOtherHalf said:

In fact I think it looks better than the gumpert! Well done op, don't listen to the suggestions about black wheels, this time next year they'll be about as fashionable as TSW venoms

Thanks for the compliment, I don't subscribe to the all blacked out look anyway

At the moment I am prepping up for a new Adaptronic 440 ECU and a permanent onboard laptop to allow me to 'hot' remap it for differing situations whilst driving. The turbo is only running at around 1/2 capacity, so with the boost raised a bit from it's current 1.35 Bar to 2.00 Bar i am expecting to see circa 600 BHP. However, in general I think it unlikely to need to run this sort of power, as even using 500 BHP is hard. The prime aim of the new ECU is to smooth the power delivery and allow in gear boost limits, as I can't safely boot the accelerator in 1st, 2nd or 3rd.

[nevcontractor]

[quote=OlberJ]Audi 6/8's and the new OB1 gearbox. It's nifty as hell because it runs the driveshafts right along the face of the flywheel which shortens the whole caboodle enormously.

Having something i can remove the whole rear clamshell to work on the car easily would be so much better, not to mention so much lighter.
quote]

Ah, that sounds wonderful, having the drive shafts takeoffs close to the flywheel will easily allow you to fit the engine in with the gearbox hanging out of the back.

With some modifications to the wiring loom, the rear cam can be made to be removable in 30 minutes.

Im off to look up the specs on the Audi V6 and V8s now... !

[nevcontractor]

OlberJ said:

Thanks for the heads up Nev, i'll be in touch when the time comes.

Question for you though, how does the VX handle all this extra go? Does it get too much for the chassis and become all about the engine or can you still drive the thing as intended?

I always thought the little Mk3 Mr2 struggled with anything over 200 bhp due to short wheelbase etc but would be interested to hear if you think the VX can adequately handle a lot more go? That was my main point of moving up to the "GT" Mk2 in that it could handle a lot more than the Mk3 would.

It would be brilliant to have a lightweight car that copes with a V8 in the middle.

Have a good read here: https://sites.google.com/site/z20letpower/20-concl...

Basically once you get over 300 BHP it is prudent to increase tyre width. I run 285mm on the rear and 245 front with sticky semi slicks. With 500 BHP I can make the back squirm in 1st, 2nd, 3rd in the dry on good tarmac. 4th and 5th gear is safe though.

There are individual components (notably running gear) that start needing upgrading too once you get > 300 BHP. I can advise on these if you go ahead with your project. The chassis is fabulously stiff - it take 11000 newton/metres of force to twist it longitudinaly by 1 degree... beat that if you can with a spot/seam welded monocoque production car!

Edited by nevcontractor on Wednesday 17th October 15:48

Edited by nevcontractor on Wednesday 17th October 15:49

[nevcontractor]

OlberJ said:

Smashin, i'll read it later.

Any pics of the rear suspension and driveshaft/hub set up at the minute, from underneath?

You've fair inspired me to get this on the go sooner rather than later.

I have 100s of photos of just about any part. PM me your normal email address and Ill send you some.