goes boost more than wastegate spring
I have a 2003 Tahoe 5.3l with 7675 pte also precision wastegate 46mm and I have a problem with boost.
I had a borla catback and boost was on wastegate spring 15psi and running GOOD but after I dumped the exhaust and exits the fender I had problems with boost which it will reach 20psi.
if some one can chime in and help BTW its has ON3 turbo kit!
2003 Tahoe 5.3L turbo PTE 7675 604rwhp on 14.7 psi
2011 Silverado 416ci turbo 9 psi 629rwhp
2006 Cadillac cts-v lingenfelter 427ci 630hp package
2010 Silverado LSx 427 with maggy 650 awhp
make sure you have the your boost reference line on the correct side of the wastegate, most wastegates have 2 ports and i have seen the over boost happen when the ref is on the wrong side of the gate, the ref line should be on the bottom port not the top
The spring is a guide. Different manifold designs, wastegate position, backpressure amongst other things affect boost.
What you have described sounds normal to me.
To me it seems that your catback had a lot of back pressure. Hetting rid of it the turbo is performing better. If you are already running off the spring then you migh have to go to a lighter spring. Wastegate placement and size will make a difference too.
First turbo build i did the engine was going into boost with no springs on the wg due to the location of the wg.
Thanks guys for the help
I have the top port of the wastegate open like i mean there is no vaccum hose on it because i cancelled the boost controller and i think Maybe from it.
If that doesnt work ill go with a smaller spring and will give it a try
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