Joe S.

Steve already answered your question.

S4-on-your-back-door

so porsche designed a car that if you go 200 more rpm the engine will fall apart?

S4-on-your-back-door

and all those people out there running those after market chips that increase the RL buy 400 rpms are blowing there engines?

TheOtherEric

lol, the reason you're getting smarta** responses is cuz nobody understands exactly your question. Steve answered it, yet you say noone has. Another reason for the responses is that few (if any) people know what a 993 torque curve would look like with an 8000 rpm redline. Why? Cuz it's not done. Again, pls refer to steve's response above. Sorry I can't give you the exact answer you're seeking, grasshopper.

But suffice it to say that people don't push it too hard with redlines considering the cost of a blown engine.

Red rooster

Yup, you got it. How about getting a 928 ?

Geoff

jimbo3

Well, try it! As you said, to you "it's a used car, and just a super VW at that".

S4-on-your-back-door

read closer in the begining post gasshopper and youll see two questions there. first is at wat rpm does a NA stop making usable power? my car pulls strong all the way to redline and probably beyond that point maybe 7 to 7.4 i dont know and that is what im asking. steve did answer the question but it seems to fit more for the second question, hard to believe that if one increases the RL by 200 rpms the engine will throw a rod. At 7.3 to 8K then yes all he said make good since to me, but there selling chips out there that increases the RL by 400rpms andi have not heard anyone throwing rods yet or that comp. being sued. I know the 928 can be safely increased by 500 rpms before you get in trouble and thats been proven ond overcomed.

S4-on-your-back-door

hav 3 of them thanks

deltawedge

Okay, let's try this.



It depends on the definition of usable power. If useable power is anything that will cause the car to accelerate (in the absence of shifting gears), then usable power will be any power level in excess of that lost to mechanical friction and aerodynamic drag (amounts to ~15-20 hp at 60mph). Therefore, a good two cylinder Briggs and Stratton motor could provide usable power.

Now back to the question, when would a NA 993 stop providing usable power? When it self-destructs is the simple answer. As can be seen from the dyno run, more than 125hp are available at ~6700 rpm (on one run). By extrapolation, the power curve will cross the 50 hp mark around 7100rpm. This is still usable power at 60mph, but probably about break even around 100mph. But from the engine experts on the board (not me), the stock engine is not made to safely spin above 7000 (that’s why the rev limiter is at ~6700 rpm).

With all that said, I can’t say what your engine could handle, but there’s only one way to find out.

Steve Weiner-Rennsport Systems

The risk of valve spring retainer or rod bolt failures goes up exponentially with RPM.

The 993 heads do support power levels well beyond 300 HP but the limitations in a stock engine are mechanical and if one extends the RPM cutoff beyond the stock 6750, you put a VERY expensive engine at high risk. Ultimately, its your car and you are well entitled to do whatever you wish.

Speaking only for myself, we never raise rev limiters in any performance software unless one can prove that these components have been upgraded. To do otherwise would be irresponsible, IMHO.

S4-on-your-back-door

THK YOU !!! FINALLY SOMEONE THAT KNOWS SOMETHING ABOUT THE CAR HE DRIVES now thats info i can use. is it just me or are half the people on this board really dont know anything about the car they drive and they try to hide it by just being sarcastic or saying it cant be done take it to a speicalist. Its seems to me that a lot of people out here have pulled second mortages and bought someone elses used car and they now they think that thier somehow part of the elite class. Please its just a used car so come down of your high horse now if you go out and pay cash for a new 300k+ GT then your the elite and i tip my hat to you but untill then your just a regular joe so at like one.

Flying Finn

You want to get rid of the "rev limiter"? You need a divorce lawyer's, not a Steve Weiner's help.

Just kidding!

TMc993

Look in your owner's manual. According to mine, the stock 1997 NA C2's torque curve (Usable power?) peaks at approximately 6250 RPM and drops off after that. Running past that point with a stock engine is stressing the engine without generating any additional "usable power."

Add the pieces Steve mentioned, increase the compression ratio, dump more fuel/air in and you'll create more "usable power." Dump more fuel/air without beefing up the components that take the additional abuse and eventually, you'll blow the thing up.

Is Porsche's 7000 RPM redline absolute? Probably not...Every manufacturer builds in a little "wiggle room" and states limits in conservative terms. Additionally, each engine is different...One may run to 7500 RPM without breaking and the next one on the assembly line may "only" stand 7200 RPM.

The only way to know what the limit of an engine is is to run it up until it breaks...Basically, that's what they do in the factory...Repeatedly break them until the get the "right" balance of power and reliability/durability.

If you don't believe the factory or the folks here, then just keep twisting that sucker up until it blows hot, oily pieces all over the road...Then you'll know...After all, it's only a "Super VW."

The Brewmeister

The factory's determination for redline has nothing to do with `usable power'.
It has to do with at what RPM (7000) the valves will "float". The valves float when
they cannot return to their seated position fast enough to avoid colliding with the compressing piston.
When collisions take place in the motor it usually
results in a motor that will give you a nice consistent zero hp.

brucec59

First you ask a rather insipid question, then you make insulting generalizations about people on this forum. Is it just me, or do you have a big L on your forhead?