BOV Leaking.

[AllBeItMine]

I thought i would post this up because it may be of interest to some of you.

After having some serious fueling problems in my car (running very rich on my latest dyno run) i was convinced i had an air leak somewhere.

so with the help of my brother we tested my car.

he lathed me up 2 bungs, 2.5 inches in diametre, one of which was fitted with a valve. we plugged up the piping, at the y-joint and at the intake and using his compressor, we began to pressurize the system

long story short we found that the standard factory BOV was opening somewhere between 3 and 5psi...

now correct me if i am wrong, but it was my understanding that a BOV should only open when there is Positive pressure on one side and negative pressure (-20psi) on the other, effecting the plenum and opening the valve in the form of a vacum from the inlet manifold after the throttle body closes.

So i pulled out the BOV plugged up the whole and pressurized the system up to 25pounds. held it fine and had to bleed the valve to de-pressurize the system

so a BOV is definitely on the shopping list. i think either the spring or plenum in my standard one has gotten tired.

just as a side note... at 15 pounds, those factory rubber intercooler pipes inflate like Balloons!

[bradc]

thats no good at all. Are you going to get an aftermarket BOV now? You do have a manual car, so you would of course make use of it.

Is there a chance you could take a picture of your rubber balloons at 15psi? I'm just curious....

[AllBeItMine]

just going to get a cheap replacement plumb back. and i will see about the photo.

[ShadyNZer]

i got a GFB mach1 which has seized up (probabaly for a while now)...anybody know anything about taking them apart?? gotta clean the piston, its movin p!ss all giving me no sound whatsoever...so im back to factory sucks man...
so yer any help...??

[to4garret]

i would probably imagine the BOV would start leaking around 10psi in real life

remember that there would also be 10psi of pressure acting on the diaphram holding it closed as well. looking at your dyno sheet seems to be opening early though, my factory one didnt start leaking till about 15psi

[AllBeItMine]

i would probably imagine the BOV would start leaking around 10psi in real life

remember that there would also be 10psi of pressure acting on the diaphram holding it closed as well. looking at your dyno sheet seems to be opening early though, my factory one didnt start leaking till about 15psi

yeap. but she shouldn't open around 5psi - thats just nuts.

remember they open when there is X boost pressure pushing on oneside and a -20psi vacum also sucking it open.

[Kenneth]

Try turning your stock BOV backwards. that way the boost pressure is holding it closed. I don't know if it will open properly, but you could give it a go.