DIY Turbo install in progress

[NINE31]

BOV is not there to protect the throttle body. That may be one of its purposes, but the main purpose is to protect the turbo compressor from compressor surge. The throttle body snaps shut the air bounces off the TB butterfly and back towards the turbo, which as a result can slow the compressor wheel, creating lag among other things.

There is theory on both ways, close to throttle body and close to turbo. Many stock turbocharged cars have the BOV built into the turbo compressor housing or very close to the turbo, what does that tell you?

You can put it near the turbo, and recirculate it which would be most beneficial.

[norcalE30]

^^^ not true, blow off valves are designed to protect the TB and engine from compressor surge. This happens at high boost levels when the butterfly is quickly shut, pressure buildup can actually break it off and blow it into the intake. This has nothing to do with protecting the turbo itself. BOV's have nothing to do with lag

[ForcedFirebird]

It's to protect the tubo compressor. The air becoming static between the compressor and throttle plate causes unnecessary stress on the blades and can ruin it over time.

[LowR3V'in]

^^^ not true, blow off valves are designed to protect the tb and engine from compressor surge.

wtf

[norcalE30]

when the butterfly closes rapidly at high boost excess pressure builds up between the turbo and the throttle body. without a BOV this would severly damage the TB and possibly the engine as well. this can also happen during a spike in boost (surge). BOVs are there to protect the engine, which is why they are located near the intake, not near the turbo. the air in a turbo system is never "static" its always being moved in one way or another.

[ForcedFirebird]

when the butterfly closes rapidly at high boost excess pressure builds up between the turbo and the throttle body. without a BOV this would severly damage the TB and possibly the engine as well. this can also happen during a spike in boost (surge). BOVs are there to protect the engine, which is why they are located near the intake, not near the turbo. the air in a turbo system is never "static" its always being moved in one way or another.

And you have experience with this? You have built turbo kits and seen the effect of said "surges" or "spikes" that you are talking about? Have you ever adjusted a BOV to work properly, or listened to an incorrecly adjusted BOV surge?


The BOV is located near the TB to keep the air moving in the same direction. IN THEORY this is so that the air moving towards you engine from the turbo won't have to go the opposite direction to be released through the BOV, even though I have seen the BOV placed on the intercooler, or near the compressor due to space, and the system worked flawlessly.

Air most certainly CAN become static in a turbo system. If the turbo is blowing air into a closed area, it has no where to go and will become static. Then you have the compressor that's still trying to pump air into that location, you are causing the compressor wheel to slow down, in turn slowing your turbine causing restriction.


I'm not talkin out the side of my head here, either. I'm working on my 4th turbo kit in about a year's time. One consists of a 12 second 1994 V6 Chevy Corsica...

[norcalE30]

i helped with a few turbo builds at Tri-Star where i used to work. i havent seen the effects of turbo surge because we built them properly. Im sure you can mount the BOV anywhere after the turbo, but they are more effective when mounted near the TB, because as you said the air doesnt have to change directions (thank you for agreeing.)

i get what youre saying, and it makes sense. but mounting the BOV near the TB is just more effiecient. the little strain that is applied to the turbo during the milliseconds it would take for the BOV to open and relieve pressure isnt even measurable. better to protect the expensive engine than take caution against something thats almost irrelevant

[Devil Inc]

Most race applications don't utilize a BOV. But then again those applications don't see on/off the throttle like a daily driver would.

[EvoStevo]

Hi, turbo n00b here. Don't mean to interrupt the discussion on BOV's, but I'm confused as to where the AFM and Idle Air Control valve went. Are they not needed in a turbo settup? Does having a fuel management system eliminate the need for those parts? Thanks.

[ubernasty]

nice build... not sure why you keep dodging the question on what your doing about fuel/spark though? no idea yet eh? lol

[blueapplesoda]

Hi, turbo n00b here. Don't mean to interrupt the discussion on BOV's, but I'm confused as to where the AFM and Idle Air Control valve went. Are they not needed in a turbo settup? Does having a fuel management system eliminate the need for those parts? Thanks.

If the OP is using a speed density/alpha-n type engine management that replaces the stock ecu, than he doesn't need them.

Derek

[aznbo187]

Hello Derek.


fail.

[J-tec]

Wow great DIY you got going on here, read the whole thing

I'll be watching this thread for sure

[chrise30]

nice job

[Jamster]

any updates?