Can you overspool and damage a turbo by simply runnig a screen over the turbo inlet instead of a filter? I'm sure I know the answer to this question, but I'd like to hear some of your responses to verify that I know what I think I know.

A buddy of mine has been having a problem where he cannot boost past ~2psi (on his super60, I believe) and in the car you hear a whining/whirring noise (not the whining/whirring you should expect to hear from a turbo). The car would work fine cold, and then after being driven hard for a few moments, this problem will surface. Now, it does it all the time (i.e., its been getting gradually worse). We did an exhaustive set of tests to try and determine what was going on (ie, verified that the BOV is opening and closing properly, ensured there was no piping leaks, etc and came to the conculstion that the problem was somewhere in the turbo).

Back to the point: his turbo mechanic diagnosed his car and told him that because he was running a screen rather than a filter, it caused the turbo to overspool and bend the shaft and tear up the fins. I know that running a screen does not filter smaller particles nearly as well as a filter, but I really don't think that simply running a screen will "cause the turbo to overspool and bend the shaft/tear up the fins". I've got my own personal experience with running screen vs. filter, but I'd like to hear what you guys know first.

 

From everything I've read, NO, not possible at all. How high the turbo spools is a function of the pressure differential across the exhaust half of the turbo and the rate of the exhaust flow (ie the wastegate is involved in regulating the pressure differential).

The only thing the filter does is clean the incoming air... well technically it creates a low pressure zone outside the turbine inlet, but that's not going to affect spool.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by raene &raquo;</TD></TR><TR><TD CLASS="quote">From everything I've read, NO, not possible at all. How high the turbo spools is a function of the pressure differential across the exhaust half of the turbo and the rate of the exhaust flow (ie the wastegate is involved in regulating the pressure differential).

The only thing the filter does is clean the incoming air... well technically it creates a low pressure zone outside the turbine inlet, but that's not going to affect spool. </TD></TR></TABLE>


no, Filters do restrict air coming in and the turbo has to work harder to make the same boost. not much harder Tho.

 

I could talk about how the shape of the filter smooths the path of the incoming air to help negate the effects of the low pressure zone but I'll skip it as long as we both agree that having a filter or a mesh screen isn't going to cause overspooling

 

The only thing i have read about that can bend the shaft would be someone not using a T wrench or their head when disassembling one.

ya filter, no filter, screen, I have tried all three, all of them work well enough to boost around. I'm a fan of a filter on a short tube but thats a diffrent thread...