Turbo Kit with No Blow off valve

[Hicktown]

I have an '08 M8 with some custom turbo set-up built by a Cat dealer. It's running a garret turbo fueled, oiled, cooled, intercooler, everything is set up and works great! Pump gas, wastegated at 7lbs.
My concern is the fact that there is no blow-off valve!
From my experiences with building diesel engines, is that without a BOV if your pushing alot of boost, you damage your compressor wheel/ shaft bearings from tubo surge, when the compressed air that cannot be used pushes back out through the turbo when you cut throttle.
I do not want to be putting this stress on my sled's turbo! At 7 lbs is it not enough to worry about? What boost would require a BOV?

 

[Coxy]

Bumpin this up for ya, just because I have the same situation!

 

[beeonaplug]

I have an '08 M8 with some custom turbo set-up built by a Cat dealer. It's running a garret turbo fueled, oiled, cooled, intercooler, everything is set up and works great! Pump gas, wastegated at 7lbs.
My concern is the fact that there is no blow-off valve!
From my experiences with building diesel engines, is that without a BOV if your pushing alot of boost, you damage your compressor wheel/ shaft bearings from tubo surge, when the compressed air that cannot be used pushes back out through the turbo when you cut throttle.
I do not want to be putting this stress on my sled's turbo! At 7 lbs is it not enough to worry about? What boost would require a BOV?

You will get more on-off throttle response with a blow off valve. Better to put one on.

 

[Hicktown]

I kinda figured so, air movement can occur faster, aannndddd saves turbo life. Anyone know where I can pick one up??
Thanks!

 

[DILLIGAF]

call up absolute power and performance (APP) in edmonton. 140 bucks for a turbosmart blowoff valve from them

 

[moyiesledhead]

The mother load of turbo stuff here! :d:d

BOV

 

[Dr. K]

Depending on your turbo part number it may not require a BOV. According to Garrett all of their new ball bearing turbos do not require a blow-off valve (theoretically). Also this may stir up a bunch of arguements but Im going to say it anyways. I have personally seen dyno sheets on a few cars that actually recover hp faster without a BOV. It doesnt really make sense but I have seen it with my own eyes. Id check with a few guys who have ran without them and then put one on. It would be interesting to hear their feedback on the recovery rate. My .02

 

[Polarblu]

The reason you run one on a diesel is the strength of the shaft in the turbo. When you let off you stall the compressor really quickly (as air flows back out)which with the enertia of the turbine acting against it shears the shaft connecting. If the turbo your running can take it then you dont need one IMO. Diesels running 50 pounds run a fatshaft turbo and are fine without. @ 7 psi can the turbo take it.

Also as you go up in elevation the turbo will stall faster cause the drop in atmospheric presure makes it easier for the air to flow back out!!
(pulling my fifth wheel up from Iowa to Denver was a huge difference in turbo farts, by the time we got to Breckenridge it farted on every shift)

 

[Hicktown]

The reason you run one on a diesel is the strength of the shaft in the turbo. When you let off you stall the compressor really quickly (as air flows back out)which with the enertia of the turbine acting against it shears the shaft connecting. If the turbo your running can take it then you dont need one IMO. Diesels running 50 pounds run a fatshaft turbo and are fine without. @ 7 psi can the turbo take it.

Also as you go up in elevation the turbo will stall faster cause the drop in atmospheric presure makes it easier for the air to flow back out!!
(pulling my fifth wheel up from Iowa to Denver was a huge difference in turbo farts, by the time we got to Breckenridge it farted on every shift)

Ahhhhh that's what I was wondering after I posted. That makes complete sense!!
I am not going to worry about it then till I start running more boost. Thanks!!!

 

[glassman]

I have a race gas kit with a BOV. It only seems to kick in when I am running over 10 lbs boost. Anything under that and it never opens. It might be just the way the tenston is set, but I put a mini intercooler on this year and will also be loosing the BOV. At lower boost you dont need one for sure. You need a little back pressure in the charge tube to minimalize the lag.