924Board.org

[Frank.Ind]

Looking for a consensus of opinion at the moment.

Im looking to get to 200bhp from my 2.5. How acheivable is this?

The obvious work needed would be cams, head work, exhaust and filter.
How "chippable" is the 924S?

Just to make things a little aukward, when I pop the bonnet I want it to look 100% stock...

Any idea's/advise?

Thanks in advance.

[Off Camber]

From what I have heard 180 hp out of the 2.5 NA is about as much as you will get & you better have Lots of $$ say well over $10k

If you want that kind of HP sell it and buy a Turbo
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"Growing Old is Mandatory"
"Growing Up is Optional"

[cgalyon]

Check out AppleBit's website. Lots of info about how to get more performance out of your car. However, as I understand it the 924S is less modifiable than the 924 N/A or 931.
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1988 924S Navy Blue - Phone Dials

[Paul]

CAR/ENGINE STAGE 1 (HP) SRE (HP) STAGE 2 (HP) STAGE 3 (HP) STAGE 4 (HP) CORE CHARGE KIT DISCOUNT

PORSCHE 944 $6200 (174) $6800 (201) $6800 (217) $7600 (264) $9800 (332) $4000 $800

http://www.paeco.com/Engine%20Price%20Two.htm
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

[ideola]

FWIW, if it was my car I wouldn't trust Paeco. They lost my ignition distributor, and they gave me bad information about the 2.0L stroker. They job everything out and do very little work (from what I can tell) on site. Slow to respond as well. The only good thing I can say about them is that the did refund my money and covered the cost of a core deposit on the lost dizzy.

{EDIT 1}
It's also worth pointing out that Applebit's info is limited to the 2.0L cars, not the 2.5L.

Consensus view on the 2.5L forums indicates that the FRWilk chip is the best of the bunch, although I don't believe it will get you close to 200bhp.

I would also suggest doing an A/C delete and consider going with underdrive pulleys to free up some existing horse power. Broadfoot Racing have built some killer 2.5 motors. I can't vouch for them personally, but you could probably ping some folks over on Rennlist.

Of course, you should also lighten the car. Every 100 lbs = 10RWHP.

{EDIT 2}
Here's one more source for early 2.5L stuff.
http://www.944online.com/cgi-bin/ASI_Store.cgi?Entrance
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erstwhile owner of just about every 924 variant ever made

[Off Camber]

John Milledge is one of the Guru's of the 944/924s 2.5na engine.
They have spent a lot of R&D developing race engines for the SCCA ITS class among others.

The most they can get out of a 2.5NA is close to 182hp with following mods
.040 over bore with custom pistons fully blue printed and balanced engine custom dme/ignition system, under drive pulleys hand picked cams and balance shafts etc.

Now this is to ITS specs. you could probably get more with bigger cams but to get 200+ out of the 2.5NA is going to cost a fortune. as the list above shows.
I would like to know what they do to get 332hp out of this engine. it seems a bit far fetched to me.
_________________
"Growing Old is Mandatory"
"Growing Up is Optional"

[ideola]

[edh]

Talk to EMC in Birmingham - they build a lot of the the UK 944/968 race engines.

Bear in mind it will cost more than the car is worth.

If you want a faster track car, make it lighter

If you want a faster road car, sell it and buy one
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current - '90 944S2, '00 986S,
ex - '90 944 turbo '86 924S, '88 924S

[ideola]

[pettybird]

if you were hell bent on it, does the 2.7l late motor fit with no issues? or can you backdate a 3.0 968 motor with an SOHC head?

you'd be an idiot to follow through option 2, but hey...

ok so the best would be just the 968 motor, then tell everyone it's supposed to be there. how many porschephiles do you plan on trying to fool?

[JSilverman]

[Rasta Monsta]

Nothing wrong with a 3.0 in a 924. . .I've heard tell of a few, and they are monsters.
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[Frank.Ind]

Thanks for the responces everyone.

Im a little shocked at (what seems to be) general opinion, that the 2.5 is quite untunable. I would of thought a car with a 2.5L only producing 140bhp would be comparitively easy to get to 200bhp.

It wont stop me but I may well need to think a little more creatively and look to slightly more focused engine work. Maybe ITBs etc and having to loose the "stock look" I wanted.

I could sell up and go for something quicker to start with. But strangely Ive wanted a 924S for about 15yrs, so Im going to stick with it.

My final goal for this car could take a little longer than I envisioned, but as this cars a keeper Im not to worried.

[ideola]

Frank, that's the spirit, mate! Don't let anyone tell you it can't be done...however, IMO it will make things much more challenging if you insist on keeping the stock look.

Rule #1: as all the big block boys say here in the Motor City, there's no replacement for displacement. If money is not the primary gating factor, I would start there: go for maximum overbore on the cylinders, spec out some custom pistons with the highest compression ratio you can safely run (11:1???). Diamond Racing is an excellent source, and I can put you directly in touch with Eric Simons if you like. Since you're making custom pistons, have your crank welded and offset ground to maximize your stroke. If you plan carefully you can maintain stock rod length, journals and pin sizes by adjusting the pin height in the piston (based on the modified stroke), which will eliminate the need for custom rods. [EDIT] Just be aware that you might need to remove material from the bottom of the cylinder bores or the big ends of the rod to accommodate the extra stroke [/EDIT] Depending on your exact goals, lightening the flywheel and crank may be desirable.

After the low end is sorted, the next priority IMO would be to budget for a modern engine management system. One could argue that engine management should be your first priority, but as I subscribe to the displacement theory above, so if it were me, engine management would be secondary to maximizing the bottom end.

Once those are done, I would then balance my remaining budget across head, cam, valve train, and induction modifications.

Once the power plant is mapped out, focus on removing as much weight as possible. Every 100 pounds is the equivalent of 10 HP, so lightening magnifies whatever output improvements you achieve with the power plant.

Going from 140 BHP to 200 BHP is not quite a 50% improvement. There are plenty of examples of forced induction applications where stock BHP can be doubled (or more), but examples seem to be more scarce for normally aspirated applications. At first blush, this would seem fairly trivial, but the real questions in my mind are A) at what cost (what is the BHP per $$$ ratio?); and B) is there enough "headroom" in the bottom end to achieve significant increase in displacement. I personally don't know anything about SCCA regs, so obviously, that may force you to modulate your plans somewhat.
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erstwhile owner of just about every 924 variant ever made

[Rasta Monsta]

There is nothing wrong with the 2.5 ECU. My buddy's 500+ HP 951 has all stock engine management, except for the AFM (replaced with Lindsey MAF).

Just had to disagree with Dan!

But seriously, the cheapest way to get reliable power from an S is to bolt in a 3.0. This has been done by a few folks, so info is out there. At my preferred salvage yard, a runner can be had for $5k, and a 2.5 + $5k will not get the power of a 3.0.
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3