my friend is running a gsr with custom turbo setup. for fuel management he's running the vortech fmu and he's running two check valves that come right before the map sensor. the car runs fine and has had no problems, except that he didn't have a boost gauge at first. i told him he should get one asap and he did, only to install it and find that he wasn't boosting.

we know the gauge works properly, and it even reads vacuum, but when he gets on the gas, the needle will only jump up to 0 and won't go above, as if its still all motor and not reading boost.

i was suspecting that he might have a leak in his piping and we checked that out and found one tonight, but we fixed it up with new piping and silicone sleeves. the turbo is definitely suckin in air thru the filter and pushing air out the outlet to the intercooler. right where the piping runs from the intercooler to the intake manifold, we unattached it temporarily to see if the turb was pushing air through the piping and there was definitely air shooting out. it just seems as if the air isn't getting to the manifold.

any suggestions or diagnosis? could it be a problem with the intercooler? it shouldnt matter which end is inlet/outlet right? the air should run through the intercooler either way? i'm almost positive all his vacuum lines are all complete and run properly, and the car definitely feels faster than before. we've been stumped by this all night. please help. thank you


-alan

 

Check the intercooler piping again to make sure none came apart. On the end of the piping sand it a little to make a rough contact surface and make sure all the clamps are on tight as possible. Use a ratchet torque it down good.

 

Check the BOV. Put your hand over it and rev the motor, shouldnt have any leaks until you let off the gas.

 

no bov leaks. yea i'm still convinced its the piping maybe around the intercooler, but we checked for leaks so many times and we havent been able to find any

 

You didnt put the boost gauge inline with the check valves did you?

Try a different boost/vac source like off the fuel pressure regulator.

 

Take a close look at the wastegate. I bet it is not operating properly. What wastegate setup is he running?

I bet the wastegate spring is stuck open or the vacuum lines are connected wrong.

Randy

 

i bet this is what happed.

if the wg was stuck open the turbo would barley spin

 

so should the vac source for the boost gauge be entirely by itself? or can it be tee'd off with a few other things such as wg and fmu? now that i think of it, the gauge is currently tee'd off the intake manifold with the BOV, but not the check valves. the check valves and MAP sensor have their own source.

how to check if the wg is working properly? we thought of this too but didnt know how to check. i believe he has a tial 35mm. the turbo spins a little at idle, and definitely spins faster when you get on the gas.

thanks for all the help guys. we've been waiting forever to get this car on the streets. the other day we just realized the tranny he got has lsd, cuz both tires were spinning like crazy off the line

-alan