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How to improve the 944s performance - no turbos or swaps

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Old 02-11-2021, 03:46 AM
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jpdp
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Default How to improve the 944s performance - no turbos or swaps

I have done some searching and I know that there's a limit to the power I can get from my 1987 944s.
I don't really want a lot more power, just a bit more drama and excitement.
I had a 76 911 and when it hit 4,000rpm or so, it just took off.

It's not worth going for a turbo, as we have a 911 and an M4, if we want to go faster. It's all about the fun factor.

I read that the 944s is supposed to be a bit like that - mine's very linear in power delivery - a bit slow really. It's done 124,000 miles, so that could be part of it

Here's what I am thinking:
1. The top-end needs a rebuild. I read that many 944s have worn valve guides and this drops the power down by about 40 hp.
2. If I am going to rebuild the top end, then I may as well put some decent cams in it, with some more aggression.
3. Upgrade to the S2 MAF / throttle body. Or go for a newer induction & DME.
4. Lower diff ratio. Where I live, in Australia, you can't speed, or your car gets impounded, so getting to 60 and not slowing down for corners, is about all we can do.

If I could get 200 at the wheels, that would be great. I am thinking it's going to cost about $US8k.
I saw that another member said he got 198 at the wheels with basically just cams.

I have looked at selling and getting a S2, which is the logical thing to do. But, good S2's with under 150,000 miles are a bit hard to find around here.

Any advice would be greatly appreciated.
Old 02-11-2021, 08:58 AM
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Gage
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What is your current camshaft timing?
Old 02-11-2021, 10:30 AM
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SC924S
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I'm asking because I'm genuinely curious: how do you figure that you'll get 40hp by replacing worn valve guides? That sounds like a crazy jump for such a simple part.
Old 02-12-2021, 06:41 PM
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jpdp
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Originally Posted by Gage
What is your current camshaft timing?
Good questions / point - the timing in Australia might be more aggressive than in the US / Canada due to our emissions not being as strict in the 1980's
I suspect I have stock Australian timing.
Old 02-12-2021, 06:42 PM
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Here's a good article on how to improve the performance: http://forums.pelicanparts.com/porsc...-upgrades.html

I am still looking for the one that mentioned the valve guides.

I probably should do a dyno to work out where I am before doing anything further...
Old 02-12-2021, 07:48 PM
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The 944S was a "world" car - the cam timing and ignition timing is the same in Oz as in the USA.
No way valve guides will cost 40hp. Valve guides only cause oil consumption.

Get the MAF conversion if you can get one, and then look into upgrading the puny stock camshafts. Extractors are great if you can get some too.

The 944S already has the shortest diff ratio of the 944 series (3.889) so no off the shelf upgrade there.

The MAF conversion will really wake the car up.
Old 02-12-2021, 11:31 PM
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I can't help but feel naturally aspirated 944s have very limited options to raise power unlike BMWs of same era where you could see quite substantial gains just by doing cams, intake and a tune. Aftermarket is massively overpriced for Pcars..
Old 02-13-2021, 12:55 AM
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Sounds like a MAF conversion, cams and exhaust is what might be needed.
Once you start doing more, it's going to get expensive for very little gains.

I am going to have to do some research on the MAF conversion.
The throttle body remains; it's just a new air flow meter and DME that I need?

Is this the recommended DME replacement: https://www.stuttcars.com/part/2027/ ?
Old 02-13-2021, 11:08 AM
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I think something folks miss is: The things you discuss like cams, deleting the MAF, headers are all standard "hot rodding" techniques to improve the air flow through the engine. But to go along with the increased air flow you need more fuel. And that requires a modern(ish) fuel management system that allows you to tweak the fuel flow. Something like a Megasquirt will do this and also let's you get rid of the MAF. There are workarounds such as bigger injectors, messing with the fuel pressure, but if you really want to get a gain that you can feel, be sure and consider the fuel management side of things as you make your plans. And for gods sake don't replace the stock cold air intake system with one of those aftermarket filters (cough, cough, K&N) that suck hot air directly from the radiator! BTW I would start with a good quality rebuild, to factory specs (which will consume quite a bit of your budget) and see what you think. Agree with others that valve guides are not the culpret but worn rings might be costing you a few ponies. I would consider new pistons and rods as almost mandatory if you are serious. See my website for a nice rebuild along these lines.

Don't forget weight reduction. What's the rule of thumb? Each 10 pounds of weight reduction will feel like 1 hp, I think. Racing battery. Remove back seats. Lexan back hatch glass substitute. Aluminum or composite hood. Track oriented shell type seats. Fuchs wheels. Leave the spare tire at home. Light weight door cards. Removal of sound deadening material.

My wife has an 06 Cayman. If I want to be pressed into the back of the seat, that is the car I pick for my Sunday drive, not the 944. Enjoy it for what it is.

Last edited by harveyf; 02-13-2021 at 11:09 AM.
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Old 02-13-2021, 08:51 PM
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Originally Posted by V2Rocket
The 944S was a "world" car - the cam timing and ignition timing is the same in Oz as in the USA.
No way valve guides will cost 40hp. Valve guides only cause oil consumption.

Get the MAF conversion if you can get one, and then look into upgrading the puny stock camshafts. Extractors are great if you can get some too.

The 944S already has the shortest diff ratio of the 944 series (3.889) so no off the shelf upgrade there.

The MAF conversion will really wake the car up.
Spencer, what is an extractor?
Old 02-13-2021, 08:57 PM
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I doubt you'd see much gain from an exhaust system. I think on the 2.5litres the diameters are very well tuned to the engine. If you were W.O.T. then, exhaust would make sense, but it sounds like torque is the problem. I agree, standalone ecm and cams. Gearing-wise, I wonder if you were to drop the tire size an inch would there be a noticeable difference?

Last edited by Noahs944; 02-13-2021 at 09:28 PM.
Old 02-13-2021, 09:31 PM
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It's funny, in Gramps, the grumpy old 924, I once swapped in a set of light racing buckets (which made us sit like 4" lower). Immediately the feeling changed. The vibe was different. You just felt "racier", but the comfort was less and ease of getting in/out was much harder. There is something I like about feeling a bolster when cornering.

Last edited by Noahs944; 02-13-2021 at 09:53 PM.
Old 02-13-2021, 09:41 PM
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V2Rocket
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Originally Posted by Noahs944
Spencer, what is an extractor?
British for headers. Figured it translated to the rest of the Empire but you didn't get it
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Old 02-13-2021, 09:58 PM
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Originally Posted by V2Rocket
British for headers. Figured it translated to the rest of the Empire but you didn't get it
Im British and never heard that before. We called them exhaust manifolds across the pond.
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Old 02-13-2021, 10:01 PM
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"Extractors"... sounds BOSS
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