Turbo lag question.

rnoswal · 02-10-2006, 03:14 PM

I am curious about turbo lag. My car has the stock turbo and everything else but a larger 3' exhaust system. If I rev the heck out of the engine and shift quickly I can keep the lag at almost tolerable levels, but just moderate shifting, the lag is about 2 seconds before spooling up again. I had always thought it was a matter of the stock turbo being too small for large HP gains, but I thought the smaller turbo meant quicker spooling up times and less lag. Unless the exhaust hurt that part of it. I bought the car with the large exhaust on it so I have nothing to compare with before and after.

It has the stock elbow from the turbo and I know that is somewhat restrictive, but again is a large lag time normal? The car came with another turbo boost guage on the pillar and seems to mimic the stock guage pretty well. The wastegate/bov seems to be working well. The manifold pressure is around -15 to 0 psi under normal driving conditions before I want to use the turbo. On the freeway in 5th gear it really accelerates nice and very strong under booste, no problem with turbo lag there.................but if I down shifted, that is another story. Lost manifold pressure and then the time to catch back up again.

Any help is appreciated.

Russ

02-10-2006, 03:14 PM	#1
rnoswal Lexus & 550's Join Date: Apr 2005 Location: Bossier City LA Posts: 556	Turbo lag question. I am curious about turbo lag. My car has the stock turbo and everything else but a larger 3' exhaust system. If I rev the heck out of the engine and shift quickly I can keep the lag at almost tolerable levels, but just moderate shifting, the lag is about 2 seconds before spooling up again. I had always thought it was a matter of the stock turbo being too small for large HP gains, but I thought the smaller turbo meant quicker spooling up times and less lag. Unless the exhaust hurt that part of it. I bought the car with the large exhaust on it so I have nothing to compare with before and after. It has the stock elbow from the turbo and I know that is somewhat restrictive, but again is a large lag time normal? The car came with another turbo boost guage on the pillar and seems to mimic the stock guage pretty well. The wastegate/bov seems to be working well. The manifold pressure is around -15 to 0 psi under normal driving conditions before I want to use the turbo. On the freeway in 5th gear it really accelerates nice and very strong under booste, no problem with turbo lag there.................but if I down shifted, that is another story. Lost manifold pressure and then the time to catch back up again. Any help is appreciated. Russ