Hey guys. My 911 just started giving me problems.
When I take off I can hear the supercharger then after 3k rpm my car feels like it's in limp mode. No boost at all. The boost gauge stays steady so there's no boost leaks. Do you guys have an idea of what's wrong?
We originally thought it was a misfire so we replaced the plugs. Still no change.
Any help would be appreciated.

 

Hey,
I can certainly help, but I need more information. Where is the boost sensor located? It should be immediately before (as the air goes) the throttle body. Where does your boost gauge measure boost? When you saw "limp mode" what do you mean? How many PSI/ Bar are you seeing?

I'm guessing there's a clamp off, but tell me more, and send me detailed photos of your engine bay.
CATTMAN

 

sound like she has a big leak...somewhere. Make sure all hose clamps are tight.

 

Stupid question, but if there was a big leak, wouldn't he see a drop in intake pressure?

 

You are correct, there are lot of missing information here to diagnose the problem.

- what exactly is "Limp mode"? hesistate, sputter, detonate, backfire, etc...
- "No boost at all" at low rpm or WOT?
- "Boost gauge stay steady" this contradict to "no boost", doubt a centrifugal supercharge would be at full boost at 3,000 rpm. Steady could mean at vacuum or pressurized. What is expected boost of the setup?

Not enough info.

 

Seems like giving TPC a call would've my first step.

 

I have a different kit in my car, but you might want to check the air filter.

 

Yeah, that is what I would do, Tom Chan is very knowledgeable and helpful.

 

If boost stays steady and power falls that reads like the DME is pullng timing, big time, probably to save the engine from detonation.

You might be able to see this if you were data logging engine telemetry.

Are you running too much boost?

Are the plugs/coils good?

Fuel supply good? Fuel pressure good?

Have you confirmed the AFR are good at all engine speeds/loads?

Do you have a "hot air intake" mod? (Exposed air filter in the engine compartment so the engine gets engine compartment -- and heated -- air rather than cooler air.)