newish turbo lacking umph.

hey i recently replaced a cracked turbo with a NEW (not used) 16G s. it ran INCREDIBLE. two weeks later the fuse to my radiator fan blew and as i am sitting in road construction traffic, my head gasket blew. so i rebuilt the top end, put got it back to running order, but the turbo just doesnt have hardly ANY umph to it. as you guys know boosting 3rd to 4th is like blinking and it feels like its loosing power after about 3500-4000 RPM's. i had a buddy that owns #477/1000 drive it and he says his stock turbo pulls harder, so its definitely not putting out like it did. any clues?

thanks

Andrew

 

[GVR4_1057]

It is probably a leak in the intake system. Pressurize your pipes and check for leaks. There is probably a big one somewhere.

 

[ApexHunter]

Compression and/or leak down test after putting on rebuilt head?

 

[Wizardawd]

I doubt it the turbo or the head. Seen a lot of bottom ends (piston/cylinders/rings) that have worn out or gotten damaged/warped during an overheat. Car still runs ok, just lacks the power it had. Especially when the motor is cold. Will boost full, but just doesn't really go anywhere.

Compression check (dry AND wet) and leak down will help you narrow it down.

Wiz

 

[Andy_S]

Check the mechanical timing. When you put the headgasket on, you may have reinstalled the belt a tooth or two off.

 

timing is on right, haven't re torqued the head yet so i need to do that. Wiz, i really hope its not the rings, this is my DD, i dont have the time to replace the rings... but thank you. ill run the compression check. PSI i should be running?

 

[Wizardawd]

164psi for 1g pistons with a service limit of 121psi, 178psi for 2g pistons with service limit of 133. And any variance of more than 14psi between cylinders. Make sure to do both wet (pour about 1/2 capful of motor oil into spark plug hole) and dry comp check. If you get 130 dry and 160 wet, it's rings. If you get very little increase (15psi or less increase) doing a wet check, you'll need to do a leakdown.

Wiz

 

ok ill run the compression check after work, dry first, then wet probably eh? thanks. whats a leakdown check?

 

oh another question, the waist gate off the inter cooler return line, that runs off of vacuum and not off the mechanics of the turbo right? is it possible that could be bad/malfunctioning?

 

Are you asking about your Blow Off Valve or your waste gate? The BOV is on the intake, normally right before the throttle body. The wastegate is mounted to the turbo if yiou have the stock setup, or a similar replacement.

Regardless, both of them are vacuum actuated, but obviously have mechanical parts in them that could be broken. If you are hitting full bosst i would doubt either of those items would be bad though.

 

well. checked the compression,it was 147lbs both wet and dry all 4 cylinders. but, granny drove it in to town yesterday and the engine blew... anybody want 12/1000 GVR-4? cant afford the time to do rebuild number two on this thing. would if i had another DD... but i dont.

thanks for your guys' help, appreciate it.

 

[Andy_S]

Your Grandma blew your engine?

 

[Brunoboy]

^^^ epic

 

Quoting akglynn:
well. checked the compression,it was 147lbs both wet and dry all 4 cylinders. but, granny drove it in to town yesterday and the engine blew... anybody want 12/1000 GVR-4? cant afford the time to do rebuild number two on this thing. would if i had another DD... but i dont.

thanks for your guys' help, appreciate it.



how did it blow? /ubbthreads/images/graemlins/confused.gif