Thought about blow off valves

LEAKER · Post by **LEAKER** » Tue Jul 05, 2011 8:46 pm

Random thought id like to open up for discussion
if you were to take a turbo car with a blow off valve that has a feedback into the intake and then move the feedback to feed into the exhaust manifold would it create anywhere near enough air pressure to assist with spooling the turbo quicker between changes and make the car faster in anyway or would it be a complete waste of time?

Website · Tue Jul 05, 2011 9:02 pm

I would imagine you'd end up just heating up your intake
couldnt see it helping at all

LEAKER · Post by **LEAKER** » Tue Jul 05, 2011 9:06 pm

There wouldn't be a feed going to the intake. It would now go into the exhaust manifold.

Luke - BZG · Post by **Luke - BZG** » Tue Jul 05, 2011 9:07 pm

I think it would do bugger all, feeding into the exhaust manifold it would would be expanding not only towards the turbo but also towards the exhaust valves, pushing against exhaust gases on their way to the turbo.

LEAKER · Post by **LEAKER** » Tue Jul 05, 2011 9:10 pm

Yeah good point, I hadn't thought about that side of things.

OMG so shiny! · Post by **Dell'Orto** » Tue Jul 05, 2011 9:13 pm

And possibly the exhaust gas would push back through the path of least resistance aka the small low pressure feed

Website · Tue Jul 05, 2011 9:13 pm

but the air that is blown off is on the intake side of things is it not, so if that was plumbed to the exhaust, heat would travel back up the plumbing to the intake

Adoom · Post by **Adoom** » Tue Jul 05, 2011 9:29 pm

LEAKER wrote:... a complete waste of time

As I see it, you would get not enough air and it would be at the wrong time.
The pressure difference would also probably be wrong and you would get exhaust going backwards through the BOV instead of the excess intake charge going out. Shit you don't want hot would end up getting hot. You would be better off hooking some compressed air or something up to the exhaust housing to spool it up faster when you mash your foot down. Not sure that would work either.

Adoom · Post by **Adoom** » Tue Jul 05, 2011 9:31 pm

I type too slow...

tsoob · Post by **tsoob** » Tue Jul 05, 2011 9:36 pm

Adoom wrote:
LEAKER wrote:... a complete waste of time

As I see it, you would get not enough air and it would be at the wrong time.
The pressure difference would also probably be wrong and you would get exhaust going backwards through the BOV instead of the excess intake charge going out. Shit you don't want hot would end up getting hot. You would be better off hooking some compressed air or something up to the exhaust housing to spool it up faster when you mash your foot down. Not sure that would work either.

its called nitrous oxide.

Malcolm · Post by **Malcolm** » Tue Jul 05, 2011 10:41 pm

On the ST205 Group A models, there was a system similar to what you describe, as part of the non-functional antilag system. I'm not certain whether the purpose of this additional air was to provide some cooling to the exhaust components to mitigate some of the premature failure of components that antilag can cause, or whether it was to provide fresh air to help the fuel combust in the exhaust runners to make the system more effective.

tim_blair · Post by **tim_blair** » Tue Jul 05, 2011 10:53 pm

by using the plumb back in the standed setup you are basicly doin what you want to do any way as the rush of air going into the intake from your valve before the turbo has only two ways to go, out the intake/ airfilter against the flow of air and/or down the intake towards the turbo with the flow of air, as it goes towards the intake of the turbo compressor it has muchly the same effect as going into the inlet of the turbine (its still pushing the turbo around in the same direction)

however haveing the air push your turbo around via the compressor isnt as efficient as pushing it via the turbine because of the shape of the vanes its still going to be better than disrupting the exhaust gas flow and possibly haveing exhaust gas push its way into your intake

h8wrxs · Post by **h8wrxs** » Tue Jul 05, 2011 10:55 pm

Malcolm wrote:On the ST205 Group A models, there was a system similar to what you describe, as part of the non-functional antilag system. I'm not certain whether the purpose of this additional air was to provide some cooling to the exhaust components to mitigate some of the premature failure of components that antilag can cause, or whether it was to provide fresh air to help the fuel combust in the exhaust runners to make the system more effective.

i think some of the evo4s onwards had a similar setup? dont think it worked very well though

Malcolm · Post by **Malcolm** » Tue Jul 05, 2011 11:03 pm

didn't work very well on the ST205s either, due to being completely disabled

LEAKER · Post by **LEAKER** » Wed Jul 06, 2011 7:48 am

Well it was worth a thought anyway.

Akane · Post by **Akane** » Wed Jul 06, 2011 9:27 am

and if you take the ST205 WRC blow off valve, it actually has 2 halves, a really complex system if you ask me, and IMO it's to provide fresh air for the badadadadadada VROOOOOOOOOOOOOOOM! :lol:

rollaholic · Post by **rollaholic** » Wed Jul 06, 2011 2:35 pm

it would make for some sweet flames out the back im sure.

not to mention causing all kinds of fits for your o2 sensor

CelicaGT8 · Post by **CelicaGT8** » Wed Jul 06, 2011 5:14 pm

AFM has registered the air coming in, and if it wasn't there it would make it run rich for a split second?

VR-4Squid · Post by **VR-4Squid** » Wed Jul 06, 2011 5:53 pm

CelicaGT8 wrote:AFM has registered the air coming in, and if it wasn't there it would make it run rich for a split second?

Throttle is closed, engine rpm is (way) above idle, therefore fuel injected = zero.

Internet/magazine myth #2296 debunked.

strx7 · Post by **strx7** » Wed Jul 06, 2011 7:57 pm

VR-4Squid wrote:
CelicaGT8 wrote:AFM has registered the air coming in, and if it wasn't there it would make it run rich for a split second?

Throttle is closed, engine rpm is (way) above idle, therefore fuel injected = zero.

Internet/magazine myth #2296 debunked.

not true. Take 1 Series 4 or 5 rx7, vent the BOV to atmosphere = flamage on gear, for this exact reason.

Toyspeed

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