Installing A Bov?

[bradstaR33]

hey all,

i've got a turbosmart dual port on my s1 r33 gts-t, running about 13psi the BOV just starts opening and releasing pressure

therefore im losing power, i went to autobahn to buy a harder spring and the guys there said the vac line to my BOV was connected to the wrong spot.

they said it should come off the cooler piping before the throttle body, is this true? it's connected on the otherside of the throttle body off the intake manifold.

Im confused,,,,,,,,

PPPllleeeeaaasse help

Cheers,

Pricey

[Midnight R33]

Hey dude,

I get the picture what your talkin bout. I have had a few BOV's and have always had the

vac. line running from the intake plenum and i haven't had any problems. I have my BOV

wound on the looser side too and it has never leaked under boost before. I have heard of a couple of cases where Turbo smart BOV's(if thats what you have) being faulty though.

So did they show you where exactly you were suppose to have the hose to?

Because where i'm from the boys from auto barn wouldn't know there arse from there elbow.

No offence to any skyliners who may work there

[WazR32GTSt]

vac line should be coming from after the TB, ie the intake manifold

thus, when the TB closes, the pressure before the TB is higher than the pressure after the TB, and this overcomes the spring pressure and the bov opens

[bradstaR33]

haha, thats why im not sure whether i want to believe what they are trying to tell me,

they said i need to drill a hole in the cooler piping somewhere before the intake and screw in a hose connecter,

and run it to there, but i thought that if it ran from the intake side of the cooler piping it wouldn't be vac it would be boost..

not real sure,,,,

maybe it is just a faulty bov,,,

cheers for the input

[bradstaR33]

thats where its connected to at the moment, im only on 13psi and with the bov fully tightened the pressure at around 4500rpm just goes out the bov instead of going through the TB and into the intake plenim

[Midnight R33]

Yes yes. not much point in having the same pressure on both sides. You'd be better just

plating it off, HAHA! I have a mate who actually cuts his springs slightly shorter and its works

pretty well and sounds phat! So i don't think your problem is the spring stiffness.

[bradstaR33]

ive heard of cutting the spring, what does that actually do?

will help the bov stay closed for longer?

how much do i cut off?

Edited March 12, 2007 by bradstaR33

[Midnight R33]

It's actually to make it lighter. So even the slightest bit of boost goes out the BOV instead of building back pressure on your compressor when you let off the right pedal. I haven't actually done this myself but seems to work fine. i wouldn't cut much off though. I have seen where some piston type blow off valves don't sit back in there seat hence making a leak. Thats why i love the Jap brand ones. They keep my boost where it should be

[R33silverS2]

The Vac line from the top of the bov should run directly to the plenum, the same as the stock setup. Also the turbosmart bovs have an adjustable spring compression by rotating the head of the bov. You may just need to turn it clockwise to harden up the spring if you havent already done so.

[bradstaR33]

i've tightened it as tight as it will go, i plumbed it back, turned the boost to 11psi, still leaks pressure through the higher rev range, still lacks at 5000rpm,

is it possible the spark plug gap is to small, it's gapped at 0.7 at the moment, would it be better if it was about 0.9 to 1.0?

[bradstaR33]

i've tightened it as tight as it will go, i plumbed it back, turned the boost to 11psi, still leaks pressure through the higher rev range, still lacks at 5000rpm,

is it possible the spark plug gap is to small, it's gapped at 0.7 at the moment, would it be better if it was about 0.9 to 1.0?

[WazR32GTSt]

how do you know the bov is leaking at high rpm?

you say it "lacks" after 5000rpm, this could simply due to the characteristics of an engine with the stock turbo on it...

[bradstaR33]

i could hear air-pressure coming out the bov, iv'e just re-gapped my plugs to 0.8 and serviced my bov and the car is running alot better so i think

it might have been more the gaps in the plugs being a bit small,,,,

thanks heaps for everyones input,

cheers

[WazR32GTSt]

there's just no connection between the spark plugs and the bov..

you're probably just hearing exrta intake noise or maybe the wastegate opening if you have a split dump/front pipe

you would need a trained ear to realyl tell the difference between noises when at full throttle, and itdoesn't seem like this ear is one you have

but at the end of the day as long as you're happy with how the car drives, then that's what s most important...