924Board.org

[justvisiting]

Just curious what kind of numbers you folks have been able to reach with your NA 2.0 blocks? Sounds like the heads are a limiting factor.

Have any of you been able to force-feed your stock 924 2.0 NA block with a turbo or supercharger? Does it hold up OK, or do you need 931 internals, like forged pistons?

Do the stock torque tube, clutch, and tranny hold up to high power?

I'm trying to decide on whether to purchase a 924, and I'm wondering what sort of potential it holds for more power. I've found some posts, but I'm still curious

[81turbo]

People do have some luck tuning the 924 NA, But the results typically are not that great, It seem that the concensus is a max of about 150hp. To reach this you are looking at a lot of money. These cars are not all that cheap to modify. Do some research on the D-Production 924 race car to see the kind of gains that are proven on this car. Although again that is a full factory race spec car.

If you are looking to get a powerful car go buy one. The turbo model has a lot more power potential. With just a variable boost controler you are looking at 175hp+.

But if you really want a fast car by todays standards I would pass on the 924. Don't get me wrong it is an amazing car if you like to tinker and twisty roads.

[Raceboy]

without major modification: very little if nothing, with turbo, new pistons etc, pretty much It depends how much time and money are you willing to spend.
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'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S, sold
'91 944 S2, sold
'82 924S/931 "Gulf", sold
'84 924, turbocharged, sold.
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[justvisiting]

Thanks for the advice, it's much appreciated

[AznDrgn]

Are we just talking about NA or turbo? the turbo uses the same block as the NA just with different pistons and I'm pretty sure that there are a few 250HP turbos running around.
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-'87 Jeep Cherokee 4.0L 6" of lift 33" Super Swampers

-'83 Callaway 944 2.5L turbo, 300HP, 1 of 42 ever made

[justvisiting]

Well, I was thinking about purchasing an NA, then (hopefully) cobbling together a supercharger or turbo for it.

Would the (cast?) NA pistons hold up to this?

That's cool, that there are a few 250HP turbos running around. Sounds promising

[AznDrgn]

The NA cast pistons would probably be good up to ~200HP but anything past that I'd get forged.
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-'87 Jeep Cherokee 4.0L 6" of lift 33" Super Swampers

-'83 Callaway 944 2.5L turbo, 300HP, 1 of 42 ever made

[ideola]

I still say the cheapest bolt-on power would be a 75-shot of nitrous. Biggest bang for the buck for an NA based on everything I've read.
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erstwhile owner of just about every 924 variant ever made

[ESC944]

Boost wise --- you could proably make more than 200 HP, but making it isnt the question, keeping it together...

HEAT kills, you have to worry about the head gasket as well. Then their are the increased stresses on everything. Assuming the engine is in good order, it might last quite a while. Now if you are doing a rebuild, well thats the time, to improve on everything and ensure a long life under boost.

NOS is not much better it is hard on the pistons, with heat and stress.

If you assume a base line HP number of 100 (between 95-110) then you assume that each PSI = and increase of 10%. Well the first thing would be to get as much naturally out of the NA before boosting and with out increasing the Compression. Lets assume that you are able to get to 125 HP via mods(exhaust, header, air intake, etc...)

Then lets look at the math
125 + 7 PSI(+70%) = 212.5 -- this assumes you maintain a constant increase for each 1 PSI added, however after 5 PSI you begin to see a lot of heat, so you would need a way to cool the charge, I would include Alcohol and water injection) maybe a small effecient intercooler with fan.

Chance are in realty taking into effect the losses expected as you increase boost you see something more like 180-185. So to hit 200 you would be around 9 PSI and you could keep going, problem is going to be the stress load on the engine components and breathing capability of the NA head -- which is not very good at all, good thing about the turbo is it will add air, but doesnt do much to extract the exhaust.

Assuming you could get the head to stay sealed... you might be able to hit larger boost numbers and larger HP an torque.

Trust me at 7 PSI the torque would be rather outstanding and far more important that HP.


(7 PSI is reasonable for a NA assuming the engine is in good to great shape)

[Eturbo924]

go to my site
www.geocities.com/eturbo924

Then go to the 924 power tricks link.

Most of the better articles done on the 924 and power increases are there.

Eric
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1992 968
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