Hey Enthusiasts,

I got a 94.5 7.3l and recently bought a new tp38 CHRA for my turbo. Old turbo was fine but the bearing housing was cracked and i wasn't able to rebolt to new pedestal. These new CHRA's have the SD compressor blades on them as opposed to the "wicked wheels" or 5 point blade that was on my truck to begin with. Anyways, after installing my truck makes a terrible noise when i let off the throttle. Seems to do it very often not just when i let off fast at high rpms. Seems to do it more when the engine is warmed up too. Sounds like its coming from the turbo and i feel lots of vibrating in the floor like the vibration is going through the downpipe or something. I'm curious if any OBS guys have an SD compressor wheel on their trucks and have a similar issue. I did have trouble getting my downpipe lined up to the turbo outlet and exhaust right when reinstalling so im wondering if maybe its rubbing against my firewall now or something making the noise more exaggerated, or if maybe there was an exhaust leak that would contribute to these symptoms. It also doesnt do this when i let off the throttle in neutral, only when in hear. Thanks for your guys' time.

 

The noise could just be the down pipe rubbing the firewall. Not doing it in neutral would make sense cause the engine isn't moving as much when not under the load of the drive line. I would check that out real good first. May not be coming from the turbo at all.

 

From who you buy the chra? Its weird that they send you a sd 7 blade wheel as they all "upgrade" to the obs 5 blade design and yes they flutter and make a fuufuuufuuu... sound after a wot run and letting go of the pedal.

 

Yeah, im gonna try and reposition the downpipe a bit. Would a leak cause these symptoms? I guess all new tp38 CHRA's come with the SD wheels. : /

 

Do you still have the stock down pipe? If not might be the down pipe hitting the firewall or the clamp is hitting the heat shield on the bottom of truck

 

I agree with Bill, post #2.

 

That would make sense because i noticed also that it will make the same noise when i hit the brakes sometimes and also when i turn the wheel a certain way. Will readjust and report back. Thanks for you guys' time.

 

Mine made more noise when I turned right.

 

+3 with Bill, happened to me too, only turning left or right. It was on my old truck so I forget but yeah, not a fun sound/vibration to hear...

 

So, went out and readjusted. Seemed like the clamp connecting the downpipe to the straight pipe wasnt too tight. Seemed like it was touching the transmission as well (i have a zf5) Could not seem to get everything bolted up without it touching the transmission. Made sure the clamp for the dp and straight pipe was tight and was fitting a bit better. Took it for a test drive and didnt hear the noise but i only drove around the neighborhood maybe getting up to 40 mph. But didn't hear the noise. Seems to be ok for now. I'll will test her at operating temp and on the freeway when i can. Hopefully she is all sorted out! Seems to be a touch more responsive too. Was wondering if the connection from the DP to the exhaust was loose, would it exhibit similar symptoms?

 

If it was able to move around then yes. On mine I adjusted several times and it always worked its way back to where it wanted to be. I then used a metal strap off the frame to hold it over.

 

Yeah, i figure i shouldn't have to do anything as it was fine before i unbolted the dp to remove the turbo, also this is the first time unbolting it since i was in an accident so not sure if something somewhere on the exhaust system was shifted. Still, didn't have any issues after accident. It is a MBRP system, which i have heard can be a pain.

 

Mine also is a MBRP but I got the T4 mount and a different DP.