Turbo Grand Prix 3500 swap

[robertisaar]

Santa came, except he was black and wearing a Fedex uniform

not that there's anything wrong with that...

HUGE improvement over that little T25 you have.

[Joseph Upson]

Santa came, except he was black and wearing a Fedex uniform

What's the turbine housing size and boost pressure you're aiming for? I noticed the oil return fitting is on the backside of the pan near the bellhousing, since you're running an automatic, did the clearance become an issue to the point where the oil return line required an obtructive bend to clear it? I ask because the turbo is high enough that you shouldn't have any problems with oil return. If the fitting at the pan is clear of interference, what is your idle oil pressure? If minimum at idle is above 50 psi and climbs from there and the drain is not obstructed you may need to consider a restrictor unless it's a name brand turbo like Garrett.

You should have ~35 psi at the turbo minimum from what I was told by one manufacturer. Pressure can be higher but you don't need it so high it out paces the drain back rate. Excessive bearing clearances in a turbo can cause backup in the drain hose also.

Consider posting more pictures here for future use by others, I've noticed that threads with links to outside pics usually end up with most if not all of the pictures lost due to account closure, etc, as time goes by.

[Jonpro03]

It's a Godspeed GT3076R. I have no idea what the oil pressure is because I don't currently have an oil pressure gauge. Honestly, right now the only gauges that work on the dash is the fuel gauge, due to the megasquirt. I've been shopping for a set of aftermarket gauges, and I've also considered using a small carputer as a dash. I've got a linux installation on a laptop that boots in ~6seconds right to gauge display in TunerStudio

I did have a problem with the oil return line in the rear and it has a 90* fitting right on the oilpan.


I don't think there will be a problem with back pressure though. I drilled a pretty large hole in the oil pan LOL


If there is anybody in the future who is interested in the entire build thread it's here but the TGP doesn't start until page 7 or something

http://www.gmforum.com/showthread.php?t=293566

[Joseph Upson]

You should plug that hole and put your oil drain in the front of the pan for easy access in the event of a leak or something else. I have to drop my pan because I managed to measure in error and place the drain at oil level.

[Jonpro03]

It was absolutely the worst decision I made putting the oil return back there. But I figured with all of the stuff in the front of the engine, there wouldn't be enough room for a return. If I ever have the motor out again, I'll likely move it to the front.

[Jonpro03]

I got the turbo in.

[Jonpro03]

Alright, turbo in and done. Downpipe was fabricated yesterday and o2 bung welded on. Installed L67 injectors. Now I'm all set to start tuning. Going to tune up to 14 psi.