Hey guys,

I need your advice, specifically those running the dom2 turbo setup. It seems that my stock diverter valve cannot handle the job anymore. I am heavily surging on part throttle adjustments, especially when lightly backing off the throttle. It is sometimes so bad that I'm getting very worried about the turbo's internals.

I've done some searching on this topic, but would like to know which aftermarket units have been working for this turbo running peak boost around 28psi.

Any help would be greatly appreciated, thanks.

 

Any BOV/DV with a bigger valve would be fine, since it seems you are outflowing the stock unit. I would stick with a standard pull type instead of a push pull.

If you wanna stick stock like, you could always just get another stock DV and run both. Some old school DSM guys used to run 2 1g BOVs.

 

Whatever you go with, report back on your success since I'm in the same boat. Funny thing is the pre turbo exhaust leak that is dropping 300-400 rpms of spool for me right now has the oddly positive side effect of eliminating any compressor surge that I had before. Obviously not the right way to tackle that but if you get a higher flow BOV that responds to light and full throttle properly it should help. Likely most of the flutter is actually the BOV unless you are getting the comrpessor surge at full throttle. Mine would show up in 5th gear at 3600 when it tried to boost past 20 psi but was fine in all other gears.

 

Forge RS or Tial FTW! Either should fix your problem

 

tial mmmmmmmmmm

 

Apologies .. Compressor surge is the turbo operating at / close / beyond the surgeline on the compressor maps .. meaning the turbo is pushing more air than the engine can ingest ?? Meaning you're just spooling too early too much ?? mismatch of too small a turbine to too big a compressor ??

If thats the case ..how can the DV be an issue ?? Unless its liftoff surge that you guys are experiencing ??

I'm really confused on this based on my understanding .. so maybe you guys see it in a different light ?

Thanks
As quoted direct from Garrett :

•Surge is most commonly experienced when one of two situations exist. The first and most damaging is surge under load. It can be an indication that your compressor is too large. Surge is also commonly experienced when the throttle is quickly closed after boosting. This occurs because mass flow is drastically reduced as the throttle is closed, but the turbo is still spinning and generating boost. This immediately drives the operating point to the far left of the compressor map, right into surge.

 

How about crushing the one you have until you get a new one. This worked on subarus and old evos.

 

My question to the OP, when you get this "part-throttle surge" what PSI are you usually at?

 

Yea .. even at part throttle as long as its not lift off the DV is not the issue .. hence my question ..

I attribute everything else to mismatch turbo sizing though .. hopefully I can learn something new here

 

A certain bright engineer was talking about making a replacement compressor housing to correct for that in the Dom2. Hit me up on PM and I'll get you in touch with him if you're interested.

 

Thanks for the discussion guys, I'm still learning quite a bit so this is definitely helpful.

gunzo:
You're absolutely right, it definitely sounds like the engine cannot ingest the turbo's flow when I back off or close the throtte. And the diverter valve should be handling this job. To my knowledge, the valve will redirect the built up pressure back behind the compressor... equalizing both sides and keeping the compressor from surging. That's why I'm thinking that my valve is at fault, please correct me if I'm wrong.

AWDTerror:
The heavy flutter/surging is happening at low boost. It hasn't been happening at full throttle/boost although I have experienced slight flutter at full throttle a few times.

mrMTB,
Good to know regarding the housing mod, but removing the turbo AGAIN is giving me the creeps right now...

 

Hey as long as its lift off .. then you're absolutely right .. that is a possibility ..
I was thinking along the line of part throttle boosting .. not at lift off .. thanks ..

 

the only one you want for your evo x unless you want it to go into limp mode in 5th gear under part throttle on the highway is the gfp (go fast bits) unit
dave