I have an 89 Supra 7mgte with an xs power manifold, garret t04e turbo with a p-trim turbine with a .70 a/r housing and a 57trim compressor housing. A precision 46mm wastegate, a tial 50mm bov, an hks vpc, ic hardpipes, and that's about it. The car lags so terrible, it won't build full boost in first gear, and in second it only builds 9. I have the 12psi springs in the wastegate. It also sounds like the turbo is surging when boosting up and at full boost. It only builds full boost at over 4800 in 2 gear and up. Any ideas? Ask me anything if anyone needs more info.
Lag 7mgte
- Thread starter 89blackturbo
- Start date
Intake leak from the install? As in something you over looked when installing? I overlooked two differnet things this summer. Your engine could also be tired. Unless it is new or rebuilt properly.
whats the millage on the block? some pics of your engine bay would be good to, maybe even a short vid so i can see and hear what its doing. could be a leak in the ic/piping a clamp is not doing its job, any exaust leaks? is the wastegate closing fully?
Ill check for boost leaks and try to get you guys a few pics and vids of what its doing. Block has 150,000 miles on it. Turbo is brand new and does not have any lack of oil, no shaft play, no bad noise, nothing. Yes the wastegate is fully closing, ill double check just to make sure. Some college kids did the headgasket before i owned it and had the cam timing retarded one notch, i fixed that now and it is running even less boost now and is even more laggy. It ran 10.5 psi before I did the cam timing change. No exhaust leaks, this is all a brand new fresh turbo setup.
your A/R may be to big, read the book Maximum Boost by Corky Bell, I have the same problem and all I can say is works great on the street at speed but sucks from the dig, the bigger the A/R the more power but also more lag
