Blow off valve?

[jo_slider]

I wanted to know if it's necessary to use a blow off valve on an external wastegate turbo setup? I planned on using a non flanged hotpipe and a T28 turbo with the internal actuator removed. Thanks.

[Mister.E]

the blowoff valve is a separate function from the wastegate. you dont necessarily have to run a blowoff valve, but the wastegate is a must. the wastegate controls your boost pressure by letting off excess exhaust gases once the intake system is pressurized to whatever pressure the wastegate is set to open.

the blowoff valve releases pressure from the system once the throttle is let off and all that pressure is no longer required. when using a stock turbo you dont have to use a blowoff valve, but you will get turbo surge. the choice is up to you.

(let's not turn this into a surge is/isn't bad debate)

[SlideWell]

you could just recirculate your bov. mine is and i dont get compressor surge.

[clovers525e]

a bov is a must unless you have a turbo diesel since they dont have throttle bodies on thoes. look for a "pop off" style bov like the hks ssq bov

[Mister.E]

the HKS SSQV is a fucking fail labeled as a BOV. and no, a BOV is not a must on a stock turbo on stock boost. a lot of people run without them. if you want to run a BOV at least get something reliable like a Greddy Type-R.

[Ceepo]

^ very true, i hate my hks bov i need to order a new one soon, greddy ftw...

[anton1o]

a BOV is not even required at higher boost levels, its just better safety on your turbo.

I ran no BOV with 19psi for a while, since im now rebuilding my motor im adding 1 in :)

[4x4le]

What is you guys beef with the ssqv? I used to hate them because every time I was in someones car that had them I still heard surge. Then Andy ordered one for his car (from hks) and it acted so well, unlike all of the others I had seen. I ended up figuring the others might have been fake ebay ones especially knowing the people that were running them.

I too have one on my car and everything about it is so much better than my old turbo xs rfl. I miss the sound of the rfl, but it was just so inconsistent and took too long to close.

[Soup Nazi]

^ very true, i hate my hks bov i need to order a new one soon, greddy ftw...

Why do you hate yours?

Hmm I'm beginning to not like my HKS SSQV anymore either. After the install, I'm getting surge like crazy. I went with it because it's a pull type, and I didn't have to worry about setting/adjusting the BOV springs like in the Greddy.

I might be wanting to get a new one too.

[GFBPete]

Hi everyone,
Anyone planning on looking for a BOV might find the following articles interesting:

Learn stuff - Turbo lag, how to beat it. Part I - RaceDotCom.com with SuspensionParts.info (http://racedotcom.com/showthread.php?t=27445)

Learn stuff - Turbo lag, how to beat it. Part II - RaceDotCom.com with SuspensionParts.info (http://racedotcom.com/showthread.php?t=27446)

Learn stuff - The truth about compressor surge. Part I - RaceDotCom.com with SuspensionParts.info (http://racedotcom.com/showthread.php?t=27498)

The first two are parts 1 & 2 that cover in depth the lag reduction potential of the GFB TMS principle. In a nut shell, venting too much air can be detrimental to throttle response.

Factory style valves, and aftermarket valves that are too large for the task (that's right, a BOV CAN be too large!), tend to vent every last bit of pressure from the intercooler during a gearshift. Choosing a valve and setting it up to only vent "enough" air can help hold a small amount of boost pressure in the intercooler and pipes during a gearshift, resulting in a faster return to peak boost. These articles show the data logs of the above principle as tested on a CA18 with a T28 turbo and a front-mount intercooler, so the results are quite applicable in this case.

The third article is a bit more on compressor surge and its effects - as E Double suggested, let's not enter the old compressor surge debate, I only threw this in for anyone interested.

I hope this helps!

Best regards,
GFB Pete

[K_style]

Hi everyone,
Anyone planning on looking for a BOV might find the following articles interesting:

Learn stuff - Turbo lag, how to beat it. Part I - RaceDotCom.com with SuspensionParts.info (http://racedotcom.com/showthread.php?t=27445)

Learn stuff - Turbo lag, how to beat it. Part II - RaceDotCom.com with SuspensionParts.info (http://racedotcom.com/showthread.php?t=27446)

Learn stuff - The truth about compressor surge. Part I - RaceDotCom.com with SuspensionParts.info (http://racedotcom.com/showthread.php?t=27498)

The first two are parts 1 & 2 that cover in depth the lag reduction potential of the GFB TMS principle. In a nut shell, venting too much air can be detrimental to throttle response.

Factory style valves, and aftermarket valves that are too large for the task (that's right, a BOV CAN be too large!), tend to vent every last bit of pressure from the intercooler during a gearshift. Choosing a valve and setting it up to only vent "enough" air can help hold a small amount of boost pressure in the intercooler and pipes during a gearshift, resulting in a faster return to peak boost. These articles show the data logs of the above principle as tested on a CA18 with a T28 turbo and a front-mount intercooler, so the results are quite applicable in this case.

The third article is a bit more on compressor surge and its effects - as E Double suggested, let's not enter the old compressor surge debate, I only threw this in for anyone interested.

I hope this helps!

Best regards,
GFB Pete

Woah @

thanks for whole a lot info !