Larry Weinstein

I asked an experience 944 turbo S racer to try my car last week on the track. He commented that there was considerably more turbo lag in my car than in two other cars he had raced. The motor was rebuilt by Memphis Motorworks two years ago with maximum legal work done on the head apparently. The exhaust is open with an open (no plates) supertrapp muffler. I don't think the turbo was rebuilt with the motor. The car has approx. 80,000 miles. Any suggestions regarding what might be causing this extra lag? Thanks.

Larry Weinstein
robinlarry@aol.com

Jeremy Martin

eh, he might be right, but it will be easier to analyze if you had any dyno charts... off hand i'd say you might have a vaccum leak, but who really knows without looking. can you hear any leaks when you tap the throttle a little while you're standing over the engine?

aka 951

Most of the lag in the 951S is due to the stock and even aftermarket klr chips. Once programmed correctly the lag is similar to a k26/6.

aka 951

Jeremy - do you go to RPI? I guess so - why the hell else would you be in Troy with a 951. I graduated with a BSME in '97. Best of luck.

Konstantin

check the o ring at the exhaust that goes to teh wastegate. if it is lose or broken you loose spool up time

Konstantin

Larry Weinstein

Thanks to all for your suggestions...one more question: how do you evaluate the condition of the wastegate? (Someone suggested that as a possible problem.)I do also seem to hear an air leak around the metal pipe on the driver side, around the short large diameter rubber hose. Or maybe the leak is below that area...or is that just the sound of the air entering toward the filter?

Konstantin

if the pipe behind the wastegate is hot during idle then it is stucked open.

Konstantin
Do you have a cat in your car? if so it may be clogged. A friend of mine had this 1 month ago

BJCamp

With the supertrapp you are supposed to ADD plates to reduce backpressure.

IanM

A common problem area is a torn diaphram in the stock 951 recirculation ("blow-off") valve. If yours is leaking, you will lose boost pressure, which will effectively slow your spool up. A leaky or stuck wastegate will also cause a similar problem. Test your bov by applying a 10psi vacuum to it, and see if it leaks. Test your wastegate by checking to see if your crossover pipe is hot when your car is idling.

Larry Weinstein

Thanks for the additional ideas..
Re the Supertrapp...I have all plates and the end cap removed. In effect, running an open pipe.
Larry

Larry Weinstein

I think the problem's solved...although I was running the Supertrapp without any baffles or the end plate, I still had the tube and insulation installed. (THIS IS THE long SUPERTRAPP NOT THE END CAP MODEL). I removed those and...MUCH LOUDER running..certainly not streetable...but much faster response above 3500 rpms or so. The sound insulation was blocking the opening apparently making the car sluggish. We'll verify the improvement at MidOhio in June!