porsche 944 engine performance rebuild book
09-08-2008, 11:50 AM
#16
Nordschleife Master
Ill ask you the same question, is it really relilable? I consider a car to be reliable if it runs how it was designed to from the factory with simply doing the required maintenence, and that there is a reasonable life for replacing other components. As an example, I do not consider a car reliable if you need to keep an extra fuel pump relay in the glove box because the one thats in there is going to crap out eventually. I do not consider a car with an interference engine that needs timing belts every 30k miles reliable. I do not consider a car to be reliable if the easiest way to get the power steering system to stop leaking is to replace it with manual steering. Im not saying I dont enjoy my 924S, just that its not what Id consider reliable....
Given all the positive aspects: excellent balance, low unsprung weight, whole body galvenizing, good tunability, over-engineered strength etc, it seems that the reliability has been let down by some stupid design flaws that should have been fixed a long time ago.
Mike
09-08-2008, 02:30 PM
#18
Nordschleife Master
09-09-2008, 12:19 AM
#19
Nordschleife Master
Your guy's definition of "reliable" is different than mine.
A lot of modern engines are interference engines. Most need maintenance a few times in the cars life.
A fuel pump relay (DME relay) is fine. Mine is original, but if it needs replaced, I have one. I won't be pulling the tank to change the pump on the side of the road.....Porsche even thought of that. I can change a fuel pump in about 20min.....full or empty tank.
When you want to talk about reliable, I talk about how many times I've had to walk, or how many times I've been on my back in the weeds with my car supported on the scissor jack. I have never done either in my 944. It keeps me from getting bored on the weekends, but mechanically might be one of the best cars ever made. The N/As are bulletproof.
A few quarky design flaws doesn't mean unreliable. It means fun to tinker with. If you want something you don't ever have to lift the hood on, go buy a Honda.
A lot of modern engines are interference engines. Most need maintenance a few times in the cars life.
A fuel pump relay (DME relay) is fine. Mine is original, but if it needs replaced, I have one. I won't be pulling the tank to change the pump on the side of the road.....Porsche even thought of that. I can change a fuel pump in about 20min.....full or empty tank.
When you want to talk about reliable, I talk about how many times I've had to walk, or how many times I've been on my back in the weeds with my car supported on the scissor jack. I have never done either in my 944. It keeps me from getting bored on the weekends, but mechanically might be one of the best cars ever made. The N/As are bulletproof.
A few quarky design flaws doesn't mean unreliable. It means fun to tinker with. If you want something you don't ever have to lift the hood on, go buy a Honda.
09-09-2008, 02:37 AM
#20
Drifting
^ that's what I meant. my car is over 20 years old and if the sunroof starts to leak or there is an oil leak that doesn't make the car unreliable lol. The drivetrain in the 944 seems pretty tough and should last a long time.
about more power. obviously the 944 motor can still make more power. The euro spec motor made 165 hp vs 143 hp for the earlier 944 na that's over 20 more,
if I had the money i'd like to get the SFR stage 2 supercharger kit just because I think a supercharged 944 would be cool.
about more power. obviously the 944 motor can still make more power. The euro spec motor made 165 hp vs 143 hp for the earlier 944 na that's over 20 more,
if I had the money i'd like to get the SFR stage 2 supercharger kit just because I think a supercharged 944 would be cool.
09-09-2008, 01:18 PM
#23
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Stock internals in a 2.5L and I got about 190 hp...(that's nearly 30 up from stock) --> www.sdsefi.com $2k and it works like a charm! Requires some garage engineering though, and is best done during a full rebuild since you need to modify the flywheel.
I have no hard data yet, but my performace is up at least 10% overall, and 15% down low. My injectors are maxed out meaning (according to their little calculation) that I'm making 200hp. So my 190 is modest
I have no hard data yet, but my performace is up at least 10% overall, and 15% down low. My injectors are maxed out meaning (according to their little calculation) that I'm making 200hp. So my 190 is modest
09-09-2008, 01:50 PM
#24
Rainman
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we neeed dynooooo.
so new computer, new injector/spark management, new airflow calculation...id think youd need to do some head modification at least for that much gain.
so new computer, new injector/spark management, new airflow calculation...id think youd need to do some head modification at least for that much gain.
09-09-2008, 02:12 PM
#25
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Actually the killer is the fact that my barndoor is no more. Even with the barn door fully open, that part of the intake has twice the surface area now: I replaced it with a pipe with the same diameter as the round side of the barndoor: 68mm ID (even when fully open the barndoor I think it has a tad less surface area than the throttle body). HUGE difference. Funny how people are messing with exhausts, intakes, etc, yet the biggest restriction is left untouched (except for those few who install a piggyback MAF).
And the fact that it's fully programmable. I can tune it to 13:1 AFR for *** hauling, and economy on part throttle at the same time (although that's the usual, you can tweak it pretty good).
I do want to dyno it sometime so that I can play with the ignition timing to find where I can squeeze out a bit more, and of course to get an indication of what I'm putting on the road. Too bad I don't have a definitive before-run, I'd like to see the actual improvement. Although I could safely say if I'm putting down 160hp, that my engine is darn close to 190hp (I should compare with a good 944S, actually, I'm sure I can beat em now).
Some really rough performance figures though:
50-100 (on the speedo, 3rd gear, ~2k-4k rpm): was 7 now 6 seconds (meaning on avg. 16% more torque/power in that region)
100-140 (3rd gear, ~4k-6k rpm): was 5.6 now 5 seconds (12% more)
Of course the question remains how good the engine was before, I say pretty good since I'd done a rebuild 3k km's before installing the system.
And the fact that it's fully programmable. I can tune it to 13:1 AFR for *** hauling, and economy on part throttle at the same time (although that's the usual, you can tweak it pretty good).
I do want to dyno it sometime so that I can play with the ignition timing to find where I can squeeze out a bit more, and of course to get an indication of what I'm putting on the road. Too bad I don't have a definitive before-run, I'd like to see the actual improvement. Although I could safely say if I'm putting down 160hp, that my engine is darn close to 190hp (I should compare with a good 944S, actually, I'm sure I can beat em now).
Some really rough performance figures though:
50-100 (on the speedo, 3rd gear, ~2k-4k rpm): was 7 now 6 seconds (meaning on avg. 16% more torque/power in that region)
100-140 (3rd gear, ~4k-6k rpm): was 5.6 now 5 seconds (12% more)
Of course the question remains how good the engine was before, I say pretty good since I'd done a rebuild 3k km's before installing the system.
09-09-2008, 03:53 PM
#27
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Here's one for a us 928S with some euro parts (pistons, heads, cams, and I believe an MSDS exhaust). Lowest line is with stock ECU, red&blue with a basic tune for this system (a simpler model that only does injection, not ignition). The low range has a crappy AFR with the old ECU. The system hasn't been tuned properly for power (AFR 13:1) yet here. Where the AFR for hte stock ECU is decent it picks up a good 10% on power. In absolute terms it picked up an equal amount of HP over the entire range, so when looking at the percentage it picked up more in the low range.
Note the incorrect max torque rating for the before run: it's an automatic and the wheel speed was too low when he rolled on the power.
A rule of thumb is +10% when the barndoor can be removed. We already had a performance chip which bumped power up ~10-15hp (supposedly), so add 10% to 173 and that equals 190. Not bad for a 22 year old
I do wanna dyno that biatch though
Note the incorrect max torque rating for the before run: it's an automatic and the wheel speed was too low when he rolled on the power.
A rule of thumb is +10% when the barndoor can be removed. We already had a performance chip which bumped power up ~10-15hp (supposedly), so add 10% to 173 and that equals 190. Not bad for a 22 year old
I do wanna dyno that biatch though
09-09-2008, 05:18 PM
#29
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The 944 has nothing special, all stock euro internals. (of course, I live in the netherlands...). Only thing is a K&N filter (although I measured the new acceleration times before installing that).