newbie with blow off valve question
 

My stock bow off valves have gone bad, is it possible to convert to one blow off valve. My mechanic has done it before but not on an Rx7. If not what is the best set up to go with? Any help is appreciated.

One BOV, one Charge Relief Valve. IIRC, they are not the same thing. How do you know they are bad?

yea my mech told me to keep them i believe the charge relief valve and take off the stock bov when you put on an aftermarket one.. but leave the CRV he said

Check out this link for info on the CRV
https://www.rx7club.com/showthread.p...=charge+relief

Also, I believe the BOV is the one on top, and the CRV is the one further down...and if your mechanic doesn't know the difference, then your car is about to get f'd up.

my car has only 1 bov and i am still running the twins. i put a hose that connects the holes from the two stock bovs. And put one 50mm bov on the ic pipe. everything works normal.

I find it strange to hear both of your stock valves are bad. They don't fail very often. The odds of *both* failing are very slim.

As such, you can buy used stock bov's for very cheap - like a total of $30 for two. If your goal is to fix the boost, then do that first and install the aftermarket part after you've gotten it back up and running.

How do you know your stock BOV's are bad?

Dave

You can hear the air pressure escaping unless I am at almost full throttle, boost gauge gets to 5 psi and creaps higher, but you can hear the air leaking almost all the time

Sounds like a boost leak, but I can't say since I'm not there to hear it.

If the stock bovs aren't holding closed, start by following the vacuum line and see if there are any leaks in the vacuum line that controls the bov.

Dave

Have you had the valves tested??

whell i forgot which one it is the bov or the crv but 1 will always blow out air till the second turbo kicks in i believe..... surprised no one asked but whats your boost at?

where is the stock bov located?

Right here. Follow the red arrow.

check the rubber hoses that hook to the bov. they can crack with heat and bingo big time boost leak. this is what happened to me on my secondary one.

thanks for the help....but is there two bov??? i replaced the ones you guys showed me with the red arrow and mines doesn't sound the same as the ones i hear

Unhook the BOV to let it vent out to the air

Click here for info on troubleshooting the stock boost and how it works:
http://www.autosportracetech.com/RX-...leshooting.htm

The charge relief valve is the one closer to the firewall, it is not a blowoff/bypass valve. The stock bypass valve is the one closer to the front of the car on the Y-pipe. The bypass valve releases excess boost pressure when you let off the throttle. The charge relief valve remains open while the secondary turbo is prespooling until 4500 rpm at which point the CRV shuts. So, you can see that those two valves, although they look very similar, have a VERY different function. Check both valves with a mityvac to make sure they work OK. Also check the 1" diameter hoses that those valves connect to. If they are hard and feel more like plastic than rubber, and you can rotate them even though the clamp is still on, replace them.

How to test the stock BOV

Remove the stock blowoff valve. Place your finger inside it, the passageway should be shut. Get a hand vacuum pump (Mity-Vac is fine, Sears has it) and apply about 9 inches of mercury to it. It should open.

https://www.rx7club.com/attachment.p...1&d=1251935976

I think the spring pressure of the stock BOV is lighter than some/most aftermarket ones. If your venting it to atmosphere, on slow acceleration you will hear it. It's likely working fine.

This seems like familiar territory......

Mine does the same thing. Can`t hear it when it is hooked into the airbox but vent it to atmosphere...Phissssssshhhhh! :) I am assuming that they are quiet from the factory but don`t know as I didn`t buy my car new. The valve checks out fine just no Phisssssshhhhh unless you vent it outside of the airbox.

for those of you venting the stock air bypass valve to atmosphere, isn't it open at idle and drawing in unfiltered air?

Not if it's filtered ;)

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