993RS down on power?
Discussion
Is this the cam slippage issue? The pulleys are held on to the end of the cams by friction rather than the usual woodruff key type fitting, which means that over time the pulley can slip slightly, meaning you lose timing. I think a common conversion is going back to 964 style pulleys, or possibly just converting to vernier pulleys.
I'd really love to know the "real" story on this.
There are some that say it's all total bollox and that 993RS is fine.
There are also those that swear blind that the 993RS was a rare exception in Porsche production and that they all (or at least a large number of them) left the factory without the advertised donkeys.
My understanding from friends who've had/have them is that they were down on power.
Surely easy to test though - find someone "reliable" with a "reliable" dyno, and get it tested. Of course dyno's can be frigged to read high, or low - and of course, even with a correctly set up dyno and an experienced and honest operator, the readings will vary from day to day to some extent.
There are some that say it's all total bollox and that 993RS is fine.
There are also those that swear blind that the 993RS was a rare exception in Porsche production and that they all (or at least a large number of them) left the factory without the advertised donkeys.
My understanding from friends who've had/have them is that they were down on power.
Surely easy to test though - find someone "reliable" with a "reliable" dyno, and get it tested. Of course dyno's can be frigged to read high, or low - and of course, even with a correctly set up dyno and an experienced and honest operator, the readings will vary from day to day to some extent.
The guy who did the 911 & PW readers running reports on his new 993 RS all those years ago (Trevor something), had a big run in with Porsche over his car not making the quoted power. I wouldn't swear to it, but think he ended up with a new engine.
As an aside, it's also oft said that the 968 may have been quoted a bit optimistic at 240bhp, but I guess if manufacturers state that the quoted output was obtained under perfect conditions etc etc their numbers are quite difficult to disprove.
As an aside, it's also oft said that the 968 may have been quoted a bit optimistic at 240bhp, but I guess if manufacturers state that the quoted output was obtained under perfect conditions etc etc their numbers are quite difficult to disprove.
Joe911 said:
Surely easy to test though - find someone "reliable" with a "reliable" dyno, and get it tested. Of course dyno's can be frigged to read high, or low - and of course, even with a correctly set up dyno and an experienced and honest operator, the readings will vary from day to day to some extent.
Alan at Weltmeister (uktrucks on these forums) does the independent Evo rolling road tests for checking the power outputs of their cars' engines. His rolling road is very sophisticated and he has no interest in having it over or under read. He just puts the car on and says what the dyno says. Might be a good guide.
www.weltmeister.co.uk
The common reasons we have found why the 993RS engine fails to make its predicted power output are:
1. Throttle travel
2. Cam timing
3. Resonance flap inoperative
4. Varioram inoperative
If all the above are right they make a minimum of 300bhp.
With a live remap we have seen up to 317bhp from standard engines, but the torque is never spectacular, usually 380Nm at best.
1. Throttle travel
2. Cam timing
3. Resonance flap inoperative
4. Varioram inoperative
If all the above are right they make a minimum of 300bhp.
With a live remap we have seen up to 317bhp from standard engines, but the torque is never spectacular, usually 380Nm at best.
As always Colins right ...............had a 136000 k comfort that still showed 304 BHP JUST BEFORE I SOLD IT , NEVER BEEN TOUCHED
Still got a Clubsport , lost vacum hence no varioram ,tank split went down to 260 ........after repair ,on Alans road back to where it should have been...................pegging the cams does nt hurt while ur in there if something else needs doing.
Still got a Clubsport , lost vacum hence no varioram ,tank split went down to 260 ........after repair ,on Alans road back to where it should have been...................pegging the cams does nt hurt while ur in there if something else needs doing.
ninemeister said:
The common reasons we have found why the 993RS engine fails to make its predicted power output are:
1. Throttle travel
2. Cam timing
3. Resonance flap inoperative
4. Varioram inoperative
If all the above are right they make a minimum of 300bhp.
With a live remap we have seen up to 317bhp from standard engines, but the torque is never spectacular, usually 380Nm at best.
Do these 4 probs also occur in normal (varioram) 993?
1. Throttle travel = any car (except fly by wire, perhaps ?)
2. Cam timing = all 993s after March '95 TTBoMK
3. Resonance flap inoperative = all 993s (964s too)
4. Varioram inoperative = vacuum leak or actuator failure usually
Are you avoiding a test, or preparing to fix the under-power ?
cheers, Maurice
2. Cam timing = all 993s after March '95 TTBoMK
3. Resonance flap inoperative = all 993s (964s too)
4. Varioram inoperative = vacuum leak or actuator failure usually
Are you avoiding a test, or preparing to fix the under-power ?
cheers, Maurice
MauriceC2S said:
1. Throttle travel = any car (except fly by wire, perhaps ?)
2. Cam timing = all 993s after March '95 TTBoMK
3. Resonance flap inoperative = all 993s (964s too)
4. Varioram inoperative = vacuum leak or actuator failure usually
Are you avoiding a test, or preparing to fix the under-power ?
cheers, Maurice
No, just interested.
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