BOV or compression surge?

DjSpecter · Post by **DjSpecter** » Sat May 16, 2009 1:13 am

compresion surge...? Well i was wondering if it will hurt anything and yes i know it will hurt teh turbo in the long run. But I been hearing alot of talk on other forums that compresion surge is not good but yet its not bad.. I went to wiki.com and looked in to it but didnt get a good enough explanation about it. I know some aussies and japanese turer shops do it. And by it i mean not running a blow off valve thus creating a funny whirling sound when shifting not being able to release the boot pressure and being pushed back in to the turbo. Or vise versa. I need to do more research so forgive me if i am not understanding this, But if you turbo a car and not run a BOV is it bad to do so?

Projectgofast · Post by **Projectgofast** » Sat May 16, 2009 8:28 am

Surge is always bad for a turbo, but there are different types of surge it can happen at wot if you dont match the right turbo for your setup and it can also happen if you dont have a bov, On some low boost factory setups on the automatic cars they dont run a bov, but if your going to pay $$$$ to turbo a motor you should run a bov

rage · Post by **rage** » Sat May 16, 2009 1:21 pm

if its a shitty turbo, who cares, haha

DjSpecter · Post by **DjSpecter** » Sat May 16, 2009 10:26 pm

I know it sounds lame but all I want to hear is the SWOOSH sound from the blow off valves and I want it to be loud like the SRT-4 or close to. But then I hear some cars that have a blow off valve and you cant heven hear a thing from it. I mean is it like diffrent BOV have diffrent sounds?

Projectgofast · Post by **Projectgofast** » Sun May 17, 2009 11:56 am

It all depends on the type of BOV you run if you want loud HKS ssqv is the way to go I run a greddy type r on my supra it just sounds like a rush of air, then on some cars you have to recirculate the air or the car will have stalling issues mainly on maf based ecu's, map dose not have that issue

rally_2w · Post by **rally_2w** » Sun May 17, 2009 3:07 pm

When you don't run a BOV or compressor bypass valve (which just reroutes the air to the inlet side of the turbo and doesn't "woosh") what it really does is to screw up the thrust bearing on the shaft. My understanding is that if you have ball bearing turbos they are not affected (or not as much) as if you have a thrust bearing that relies on an oil film. Most OE turbo cars come with a compressor bypass valve which would be why they don't make that noise. If you run an air flow meter the engine will run rich every time the blow off valve opens as the ECU supplies fuel for air that went out the BOV.

Post by **nt66** » Sun May 17, 2009 4:56 pm

I ran a t25 at 12 psi for months and at 7psi for almost a year with no blow off and it still works perfect. My new turbo has an anti-surge housing so still no blow off for me. I personally think compressor surge sounds way cooler than a blow off valve and the damage it can do is very minimal at best on small turbos. A lot of the rumors about compressor surge are just here say so I wouldn't worry to much if you don't have one on a mild setup.

DjSpecter · Post by **DjSpecter** » Sun May 17, 2009 8:22 pm

Well I plan on running a small t3/t4 turbo and nothing big. And plan to run 6psi or maby 9. idk. I tried reading up on it and its pretty cool seeing how everything works. So If I want a loud one I would go HKS?