924Board.org

[Ghostcloak]

I was just curious....

First of all, How much hp and torque would a stock 1981 924 turbo have? I've been looking at figures all over the internet. From what I understand, the U.S. version has somewhere between 140-150 hp and 145-160 torque while the european version has approx. 177 hp and 180 torque? Now... My main question is how much boost can the 931 engine take before I'll have to upgrade the cams, valves, and all the other inards? I'm hoping to achieve about 250 hp, 250 ft/lb torque. Any suggestions how you guys would go about this? Lastly, what is the most powerful engine the 931 can import into its engine bay? If possible, I might try to find/swap the stock 924 turbo engine for something a bit more powerful, and forge it (if not already set up) for a larger turbo. What are your thoughts on twin turbos?

THANKS GUYS!
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1993 Ford Probe SE
(FOR SALE!)
1987 924S (Purchase Pending!)

[gohim]

You might as well start with a 951 (944 Turbo). Early 951 cars are rated about 250hp.

Since you don't have a 931, why waste you money buying one, then trying to turn it into a 951?

[garthfan]

[CBass]

First things first, make sure the engine is in good running tune, have a compression test and leakdown test done, and make sure the ignition system is in good running order.

I think at those power output levels you're going to want to ditch the mechanical fuel injection that the car left the factory with in favour of tuneable EFI, Megasquirt being the easiest and the cheapest way to go.
Figure around $400 for all the parts, including fuel injectors, making a rail etc, if you do it yourself.

A boost controller will be needed, you can make one for around $15 from a grainger valve, buy a ready made mechanical unit from $50-$100, or shell out a few hundred and get an electronic "fuzzy logic" controller.

An intercooler is a must, as the cars did not come with one. This will require some custom work to be done, the tried and true method is fitting a 951 intercooler, which are not that hard to come by, they run about $100-150 on ebay for a good cooler.

For 250hp, you're probably going to need a hotter camshaft, but this is no big job. $150 gets you a regrind from any number of suppliers. Removal of the catalytic convert is also a boon, but may cause problems with emissions/vehicle inspections. Don't worry about 3" exhaust as these power levels, although you may want to change out your muffler to a straight through absorbtion type.
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'81 931 in various states of assembly

[79turbo]

I have a 924 turbo (931) euro and I just had it dyno tested.

it has the gt-intercooler
and some adjustments and it came out as 185 hp, 250nm torque.

next step is to boost up the pressure for the turbo, and have it tested again.
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1979 porsche 924 turbo (euro)