DBW as BOV

Hi all, I'm upgrading my turbo hayabusa drag bike with an emtron kv8 and have seen some drag cars running a DBW on their turbo charge pipe to act as a BOV and maintain the turbo in the optimal pump curve.

My question is what specific mods are done to the DBW to ensure no boost leakage? I've been told they are modded but I can't get an answer as to how they are modded.

Hi Matt,

Normally the modification done to the DBW throttles is to use a compound (usually a flexible compund) to build up the area around the 0 position of the throttle plate so that the plate seals and holds boost. Some of the newer DBW throttles will also close enough that they will hold with very minimal boost leakage.

Thanks for the response BlackRex, id love to see some pics if you have seen anything on the web could you share a link? I have searched high and low but cant find anyhting

I did read an article a while ago that showed the process that someone went through to to make a DBW throttle usable for boost control, but I haven't been able to find it again.

I found this

https://youtu.be/B_QuRA1qQSA

and also from more research "think" that if the top of the DBW can be opened, you can adjust the stops for the butterfly or move it a tooth on the drive gear and it will be fully closed and sealed. DBW's are partially open by default to allow limp mode in a failure.

Also require temp and pressure sensors on either side of the compressor. I spoke to Emtron support and they were fantastic in supplying answers,

The DBW's have to be driven closed to seal, as they have a neutral point between the open and close springs for a fail-safe, this is usually around 10% ~ 15% of the available opening window so that the vehicle can be limped to safety. The change in the tooth on the drive gear is done to move where this balance point is in the throttle and require less current to maintain a closed throttle.