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[How to] Install a blow-off valve

Fri Nov 11, 2005 4:02 pm

http://www.turbocelica.nl/howto-blowoffvalve.htm

Or go to http://www.turbocelica.nl --> Tuning --> How to.. --> How to install a blow-off valve (BOV)
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Last edited by Meurz on Sun Mar 22, 2009 9:03 pm, edited 4 times in total.

Fri Dec 16, 2005 11:19 am

dont know if i can raise a Q here but, i was under the impression the alltrac been AFM needed to plumback and couldnt vent to atmoshpehere.. Is this true?

Fri Dec 16, 2005 2:24 pm

You're supposed to, since if you don't, you're blowing off air that has been measured, and so the car won't run correctly. It will rich out, and if it riches out too much the car can stall.
However, it's been discovered that a properly adjusted BOV vented to atmosphere won't stall the car, while providing all the "benefits" of a BOV.

Basically, we're supposed to recirculate it but we don't, because we're ricers 8)

Fri Dec 16, 2005 3:41 pm

^^ What he said. My BOV is vented to the atmos and the worst that happens for me is a puff of black smoke when I'm shifting with a good amount of boost built up.

I do get small amounts of backfire (little pops in the exhaust) sometimes but since I have no cats its hard to tell if the BOV is influencing it or not.

Oh, and I didn't recirc mine simply to keep the install simple.

Tue Nov 14, 2006 10:46 pm

Adydas wrote:dont know if i can raise a Q here but, i was under the impression the alltrac been AFM needed to plumback and couldnt vent to atmoshpehere.. Is this true?


whats plumback, is that recirculation? and is there thing you can do to fix running to rich, besides recirculate/ bypass?

Tue Nov 14, 2006 10:58 pm

88alltracohio wrote:whats plumback, is that recirculation?


Yes


88alltracohio wrote:and is there thing you can do to fix running to rich, besides recirculate/ bypass?


No...unless you are running a standalone EMS.

Sun Jan 14, 2007 2:52 am

has anyone know of someone that has succesfully recirculated an mr2 bpv using the stock intake system? also anyone have pics of where the vacuum line should be connected?

Tue Jun 12, 2007 7:34 pm

from what i understand from what is said here, that there is disadvantages to have a BOV?...such as ur car will run richer?...are there other disadvantages?

Sun Jun 24, 2007 4:16 pm

LegacyofDan wrote:from what i understand from what is said here, that there is disadvantages to have a BOV?...such as ur car will run richer?...are there other disadvantages?


Aside from scaring pedestrians and needing to be quite while shifting around cops?

You'll only have the disadvantages if you don't recirculate it.

Fri Dec 14, 2007 1:01 pm

Hmm, i`m not sure, but maybe i got a bad construction bypass valve or smth. I have a bypass valve from nissan s14, but the problem is that it is open whenever there is a vacuum in the intake manifold. so its open also when idle. best available place for bov/bpv in our engine bay is right after the turbo BEFORE the IC, so whenever idling, the air would circulate through the turbo all the time and would get extremely hot.
the same applies when boosting and switching gears(or just releasing gas pedal) at that moment the air mass would circulate through the hot turbine without flowing through the IC to cool down - this is asking for detonation when you press the pedal again...

Fri Dec 14, 2007 2:12 pm

BriinumsBo wrote:Hmm, i`m not sure, but maybe i got a bad construction bypass valve or smth. I have a bypass valve from nissan s14, but the problem is that it is open whenever there is a vacuum in the intake manifold. so its open also when idle. best available place for bov/bpv in our engine bay is right after the turbo BEFORE the IC, so whenever idling, the air would circulate through the turbo all the time and would get extremely hot.
the same applies when boosting and switching gears(or just releasing gas pedal) at that moment the air mass would circulate through the hot turbine without flowing through the IC to cool down - this is asking for detonation when you press the pedal again...

Come again?
Also, BPV should be closed when idling.

Fri Dec 14, 2007 2:30 pm

i mean its not the best, but the easiest place to attach a bov - either putting a T-piece hose instead of the stock rubber between turbo and IC ur just weld it on the IC front piping.. the best option is after the IC, but the space is limited...

but still the problem persists if the BPV is put BEFORE the IC, so the air is getting hotter while circulating through the turbo (while changing gears), doesnt it?

i tried to vent to atmosphere but i didnt really enjoy the overfueling after gear change..

Fri Dec 14, 2007 3:48 pm

BriinumsBo wrote:but still the problem persists if the BPV is put BEFORE the IC, so the air is getting hotter while circulating through the turbo (while changing gears), doesnt it?

I don't think it is a big deal since Toyota also place the stock BPV right after
the compressor outlet.
The BPV doesn't recirculate air all the time, just a short burst after the boost changes to vacuum.

Wed Dec 19, 2007 9:18 am

Gary wrote:
BriinumsBo wrote:but still the problem persists if the BPV is put BEFORE the IC, so the air is getting hotter while circulating through the turbo (while changing gears), doesnt it?

I don't think it is a big deal since Toyota also place the stock BPV right after
the compressor outlet.
The BPV doesn't recirculate air all the time, just a short burst after the boost changes to vacuum.


stock BPV? wtf is that? on a st205? :shock:
anyways, after a bit of googling i read that when idling the inlet has vacuum of 0.5 bar, but when changing gears, it dorps to 0.8bar vacuum.. is that right?

Wed Dec 19, 2007 3:04 pm

Not only on ST205, MR2T also came with stock BPV.
That is what I have in my ST185.
I does vent to the atmosphere though.
Here is a clip.
You can also see the boost gauge when it vents.
http://www.youtube.com/watch?v=REoG0k_LVjs
BTW, stock idle is 18-21 in.Hg. or 0.6-0.7 bar (vacuum)


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