996 Turbo / GT2 Turbo discussion on previous model 2000-2005 Porsche 911 Twin Turbo and 911 GT2.

Ruf car backpressure issues... anyone?

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Old Dec 30, 2003 | 08:10 PM
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Ruf car backpressure issues... anyone?

I have a 03tt with a ruf 550 kit done about 8 months ago. Car runs great but has little or no backpressure when lifting off the throttle at high rpms.

Almost feel like the car freewheels. Not fun when charging into a corner, downshifting at high rpms around 7k and expecting backpressure (enginebraking) and have to stomp the brakes.

Could exhaust valves be hanging up? Weissach didn't seem to know much about this problem. But it has just started in the last 1000 miles.

Any advice is much appreciated!
 
Old Dec 31, 2003 | 09:48 AM
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no one has even a pennies worth of advice or even heard of this sypmtom, if there is one? C'mon boys....
 
Old Dec 31, 2003 | 10:23 AM
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I have the same Ruf package as you do and really cannot say that I noticed this issue. In so far as the Ruf package does not delve into the engine internals, I am at a loss to understand what may be wrong...if anything.
 

Last edited by john stephanus; Dec 31, 2003 at 10:27 AM.
Old Dec 31, 2003 | 10:45 AM
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just to be sure I'm clear, I mean the valves in the exhaust system. Not the motor...
 
Old Dec 31, 2003 | 02:07 PM
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Are you referring to the engine braking that one experiences when lifting off throttle in any manual trasmissioned car? If so, I get very little in my TT (non RUF) the reason being the lower compression ratio of the turbo-charged motor. My '99 C2 Cab had much more off-throttle engine braking as does my Ferrari 360, due to their normally aspirated higher compression ratio engines.

I really dislike the lack of engine braking on turbo charged cars. I always like to take advantage of engine braking to minimize use of the brakes, for example when I am on the highway I take advantage of engine braking to slow down when I am coming up to a car in front of me, without having to use the brakes. With the TT if I don't hit the brakes I will crash right into the cars in front of me, it feels like there is almost no engine braking at all.

-- Michael
 
Old Dec 31, 2003 | 03:41 PM
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Since the throttle butterfly is controlled by the computer it is probably an electronic problem. If you let off the gas at hi rpm and quickly put it in neutral does the engine rapidly drop to idle speed?
 
Old Dec 31, 2003 | 06:19 PM
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Thanks for the replies. Michael it seems we share the same symtom although mine has been noticably worse in the last 1000 miles, maybe I'm just driving a little more aggressive...

ebaker, I'll try out your idea. have you or anyone else ever heard off any throttle problems with the computer?
 
Old Dec 31, 2003 | 07:35 PM
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ebaker:

With the stock flywheel the engine will never "rapidly" drop to idle speed when put in neutral, more of a lazy drop.

-- Michael
 
Old Jan 1, 2004 | 02:38 AM
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There is normally a slight delay (about 1/4 second) between when you let off the gas and the engine power drops off. Steven said this was for emissions purposes. It may be just the lag time in the electronics and the time it takes the electric motor to close the throttle butterfly. The "egas" does not respond as quickly as a direct throttle cable. I thought the lazy drop off in RPM was due to the lazy action of the egas more than the heavy flywheel(?) I haven't driven a light flywheel turbo for comparison. I do feel this delay is one of the reasons the 1-2 shift is so difficult on a Turbo.
 
Old Jan 1, 2004 | 06:45 AM
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I have not experienced the above problem. Then again, I run a single mass clutch and very light flywheel. This setup has it's own little problems.
 
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