924 GT Look-a-like.

[pfgascoigne]

I'd like to build a 924 GT look-a-like (evocation seems to be the new word!), with about 300ish bhp. But what do I start with?

I've got a lot of experience building classic racing cars, so complication isn't a problem.

Obviously it needs to look like the real thing from the outside, so a body kit needs to to be bought.

Do I buy a bodily good 924 and put 944 Turbo front and rear axles and engine into it?

Do I buy a 944 Turbo and put the body kit on that, and will the GT rear arch extensions go onto the 994's different rear archs?

Do I start with a 924 Turbo, will I get one of these with a good body?

Do I buy a bodily good 924, a rough 924 Turbo, put the mechanicals into the good body?

The combinations are endless!

Does anyone know what the brakes/suspension differeces are between a 924 Turbo and a 924 GT are?

Does anyone have any other ideas? (mine is, buy a TVR M series and put a Ford 302 V8 in it, might be simpler)

 

[Robin]

Phone Ricki Caesar who is the Register Secretary for the 924 Carrera GT Register who knows all about the model. He is not on line. Be careful though he is not a fan of re-creations but does know a lot about the model. He will probably have his 924GTS at the Silverstone Supercar display on 1 &2 May so if you are there you can see one for yourself. Phone Club office for tickets.

 

[924nutter]

If you want more than 245 bhp sensibly, moneywise, then a two litre engine is out, and 245 bhp wouldnt be exactly cheap anyway. In order to meter enough fuel the GTS (245) uses a fuel distributor from a V8 Mercedes installation with the outlets siamesed together. If you settled for 220 bhp then you could probaly get that from a 2.0 with a good intercooler and modified cam. A body kit is available for the 924 with prices around £1000. 924 Turbos can be found with good bodywork, a 944 would have the wrong colour gauges and inevitably has the potential for all that cill rot we read about on the 944 forum. Just my two penn'orth.

 

[carreraboy]

Audi 5 pot Turbo engine?

 

[pfgascoigne]

100 bhp per litre should be easy to achieve out of any naturally aspirated engine. 150 bhp per litre should also be achievable from a turbo. After all the turbo cars in 1980s F1 were getting up to 1500bhp out of 1.5 litres with their qualifying engines.Turbocharged BMW F1 engines were using a standard (ish) M12 1.8 litre block that was used in various mundane BMWs of the 60s and 70's !

However to get 300 bhp out of the VW/Audi unit you would need to throw all that K-Jetronic stuff away and the turbo, then start again with modern kit. Which was why I was saying look-a-like rather than replica.

I don't know how strong the engine internals are, but custom forged piston and con-rods are surprisingly cheap in the US (a couple of years ago when I asked Porsche how much 924 Turbo pistons were, they told me £1200 plus VAT!! You'd get the same thing for a third of the price, or possibly a quarter of the price if they already had a pattern, in the US).

What is the standard crank in a 924 turbo made from, that might be the stumbling block. Can you get upgraded bits for this engine ?

What I envisage, is something that looks correct on the outside and in the cab, but not in the engine bay. I'd like to use the standard engine, but maybe the current 1.8 turbo VW engine might be a better bet (apparently it goes straight on to the standard 924 bellhousing ?).

 

[924nutter]

I have some factory manuals and the only difference between the 924t and the 210 bhp CGT internally is a clear chill casting for the cam. The power is achieved through intercooling and higher boost. I have aready purchased a new cam especially designed for the 924 turbo engine with more lift and duration but less overlap so that there is reduced "blow-through". The next step is to get a bell intercooler with custom tanks for intercooling. I am then going to get some salt and pepper because if that doesn't make 220 on the dyno then I will eat my hat, having come across some Kolbenschmidt +0.5 pistons on ebay which I got for £350, including mains and big ends. Std mains are rare if not unobtainable.

 

[Alan Woods]

What I envisage, is something that looks correct on the outside and in the cab, but not in the engine bay.

The red/black pinstripe seats unique to the GCT might be an ask.

 

[CarreraRSR]

For the costs involved to do a really good job on a 924 Turbo and 300bhp I'd start with a genuine CGT or convert the rear quarters on a late 944 Turbo for the look a like option. Not sure starting at the 924 end of the scale is going to save a great deal of money unless you have good sourcing.

Plenty of people have started to do half hearted CGT conversions and then hit financial brick walls. I was thinking on it when I bought my Turbo. I am now sticking with enhancing performance and handling for the medium term as this is causing some pressure on the wallet in itself.

 

[pfgascoigne]

924nutter,
What I think you are saying here is, all the engine internals in a 924t are the same as the internals of a CGT, therefore capable of coping with 210bhp. So, get the cam, sort out the intercooling and get the spark advance curve sorted, 200(ish)bhp,. Sounds like a good starting point.
Does the manual say the GTS internals are the same?

carreraboy,
You can get lots of bhp out of that engine, but how much heavier is it than the original? I don't want to upset the balance of the car.

Carrera RSR,
I thought I start with a basic car , rather than butcher up a genuine CGT. Aren't CGTs very expensive, or do you know of a cheap one?

 

[CarreraRSR]

ORIGINAL: pfgascoigne

Carrera RSR,
I thought I start with a basic car , rather than butcher up a genuine CGT. Aren't CGTs very expensive, or do you know of a cheap one?

Whats your budget? I am not sure it will be as cheap as your think. CGT's are selling around £10-20k but some with questionable history sometimes pop up under £10k. A good 924 Turbo will be circa £2k and hopefully its running well. An OK one will be around £1k but will need work and money thrown at it. I have just spent £2k on the car with a top end rebuild and solid chassis, £1.5k+ on suspension mods and now need to look at up to £1k on a new clutch kit + 1st/2nd gear syncros. Still want an intercooler, cam, wastegate upgrade, boost enhancer etc. etc. to get around 220bhp. Bearing in mind its just been weighed at just over 1100kgs it is currently quite quick with a dyno'd 160bhp. I reckon on another £1 -2k to get the mechanicals right. Another £500 - 1000 for an LSD. Internally bucket seats and rear cage are on the list at £1500. Soon mounts up. All this before any external bodywork.

For an idea on performance mods view these

http://www.jmgarage.com/modify/modify-924.htm

http://www.356-911.com/post1974/moderntuning/porsche924turbo.htm

http://www.924gt.com/specification.html

 

[924nutter]

To get details on that the internals of the GTS contact Ricky Caesar

 

[924nutter]

ORIGINAL: CarreraRSR

ORIGINAL: pfgascoigne

Carrera RSR,
I thought I start with a basic car , rather than butcher up a genuine CGT. Aren't CGTs very expensive, or do you know of a cheap one?

....... now need to look at up to £1k on a new clutch kit + 1st/2nd gear syncros.

Last I heard a clutch was £450 and synchro for 1st and second was £750, and that was years ago for the synchro rings.

 

[CarreraRSR]

ORIGINAL: 924nutter

ORIGINAL: CarreraRSR

ORIGINAL: pfgascoigne

Carrera RSR,
I thought I start with a basic car , rather than butcher up a genuine CGT. Aren't CGTs very expensive, or do you know of a cheap one?

....... now need to look at up to £1k on a new clutch kit + 1st/2nd gear syncros.

Last I heard a clutch was £450 and synchro for 1st and second was £750, and that was years ago for the synchro rings.

Are you getting the syncros and dogteeth gears mixed up. Dogteeth have always been expensive and NLA.

Replacements here http://garage.ideola.com/prod-Trans.html

Searching for clutch kits right now. Seem to be around £600 if you can find one. Still waiting for GSF to quote. Will be calling my OPC tomorrow. Seem to find S2 listed which is the same as 924s and early 944's but the S1 is different

 

[924nutter]

Well actually the female part of the synchro-cone is an integral part of first gear, and the male part is a wierd collar with a floating segment. as first gear goes to engage the dogs, the floating ring tucks into the back of the gear. If you miss third and hit first on a change down you can distort this ring and it will prevent first gear engaging. Ask me how I know.

 

[924nutter]

components

 

[pfgascoigne]

924nutter,
Could you post a picture of one of your Kolbenschmidt pistons please?

A few years ago I sold a tidy 924t to my friend Dave Walker at Emerald, he fitted a custom intercooler, used one of his ECUs to get a decent and reliable spark advance curve. No other mods, a fairly high mileage engine, and he achieved 200bhp on petrol and 230bhp on E85 Bio! Both of the figures @12psi boost. The car is now doing Trials events in the mud!

 

[pfgascoigne]

Anybody got a picture of a normal 924t piston please?

 

[924nutter]

I will sort out a picture, possibly tomorrow. In the meantime, two significant differences to a non-turbo piston.

• turbo piston has deep bowl, no valve cut outs. 170 bhp piston the bowl is offset a long way from centre. 177 bhp more or less central
• non turbo piston has lower deck height, as it doesn't run in the last 8-9 mm of the top of the bore. Turbo piston comes right up, as part of the combustion chamber is in the head.

 

[924nutter]

It is generall accepted and bourne out by examples on the various web pages that a good charge cooling system be it water or air to air can give, reliably, 196 BHP without other mods. Bigger turbo and higher boost pressure on the CGT give the extra 14. My plan is to leave the boost where it is, take 0.002" from the block face to raise the CR by about 0.5 :1 for an overall 8.5:1. this will help the off boost a bit, although the boost comes in a lot quicker on the 924 than it does on my 944T. The combination of new camshaft with extra lift, inccrease in CR and a 13x8x3 inch intercooler with scoop should get me 220 reliably, on petrol. Pass the salt.

 

[lali]

:cough: