On3Performance 3v build

[SilentScope]

He gave me the photos and stuff he's saying to run the bov and wastegate together. And run it into the line above the fuel rail. So I guess that's what I'll do, even though my boost gauge is hooked up there to.

hmmm id have to see instructions on how that all works.. im pretty lost

 

[08nastygt]

Yeah I know nothing about how those work I know how a turbo works, and everything else but no idea. I guess I'll hook itup like that and if it doesn't work try something else. I'm hoping my tuner will be pretty cool with everythig and let me make changes if I have to.

 

[SilentScope]

im sure he will. i thought the boost controller connects to read the boost and then connects to the WG. the BOV is independent right?

 

[JeremyH]

The bov is independent, it opens when it sees vaccum from the vac line. I.e you are boosting making 10lbs at wot, you relase the throttle the tb shuts and shows vac, opening the the bov and releasing the boost from the piping to keep it from trying to go back into the turbo.

 

[SilentScope]

ah, so ideally your bov spring is set a bit higher than your max boost, and you connect the vac line from the bov to a vac nipple on the manifold? mas correctio ?

 

[JeremyH]

A boost controller opens or closes the wastgate which either feeds exhuast to the turbo to make more boost or vents it to make less. A manual bc has a set psi at which it opens venting exhuast gas so the turbo cant make any more boost.

 

[SilentScope]

ok so the WG operates by the boost controller reading the boost pressure and adjusting the WG valve accordingly

 

[JeremyH]

ah, so ideally your bov spring is set a bit higher than your max boost, and you connect the vac line from the bov to a vac nipple on the manifold? mas correctio ?

Not exactly

"The spring is actually fighting the manifold pressures not the charge pipe pressures. Remember when youre making boost there positive pressure in your manifold, so theres positive pressure against the diaphram in the BOV, and the same for negative pressure or vacuum. The spring choice is based on the amount of vacuum your motos is going to make."

Tial Recommends are:

VAC spring rate.

22-23 12lb
18-21 11lb
14-17 9lb
10-13 7lb

My car makes about 20 vac right now at idle with the cams, im going to be using an 11lbs spring, stock vac is 22-23lbs but a 10-11lbe spring will work.

 

[SilentScope]

ah it all makes sense now.
thanks for the info, rep point +1 for your time at 2 in the am..

ok one more question..
The BOV is before the MAF, even though its a blow through design, now, can the BOV be vented into atmosphere, or must it be vented back into the pre-compressor intake?
this is all before the MAF so it should matter right?

EDIT: also, do you measure your vac at idle? is that what you base your spring choice on?

 

[JeremyH]

ok so the WG operates by the boost controller reading the boost pressure and adjusting the WG valve accordingly

An electronic boost controller does, it will have the two vac lines and a solenoid to adjust the wasegate on the fly. Giving you better control off your boost curve. Manual bc is pretty much open or shut.

So your manual bc is set at 10lbs. when you hit 10lbs the vac line from the mnifold to the wastegate shows 10lbs and opens and you loose a little boost, then it shuts again, opens, shuts etc. So throught he rpm range your boos tisnt as steady it will vary (10-8-9-10-8 lbs)

The ebc will make slight more precise wastgate adjustments to maintain a rock solid 10psi throughout the rpm range. Alot of them have features for fine tuning to make different amounts of boost at diferent rpm etc.

 

[JeremyH]

ah it all makes sense now.
thanks for the info, rep point +1 for your time at 2 in the am..

ok one more question..
The BOV is before the MAF, even though its a blow through design, now, can the BOV be vented into atmosphere, or must it be vented back into the pre-compressor intake?
this is all before the MAF so it should matter right?

EDIT: also, do you measure your vac at idle? is that what you base your spring choice on?

You can vent to atm or recirculate thats up to you. On a draw through setup (maf before the turbo) you will want to recirc as it is metered air.
On a blow through(maf near the throttle body and bov near the turbo (discharge side) you will have no problem venting to atm. recirc is more stealth and to atm makes the noise lol

Your car makes its max vac at idle at wot it goes to zero on an n/a car when crusing it sits at 5-10, idle is 20, wot is 0 etc.

 

[JeremyH]

Lol yeah im stuck at work night shift, ive been researching this stuff for awhile as i am making my own turbo kit.

 

[jroc07gt]

there are different types of bov's. some work off of boost and some work off of boost. if it is adjustable then set it as soft as you can without blow off too early. too tight will create compressor surge which you dont want. a boost control hides the signal from the wastegate so it will stay shut longer. the wastegate is designed to vent out anything over the desired boost. the one part i would make sure is quality is the wastegate.

 

[jroc07gt]

You can vent to atm or recirculate thats up to you. On a draw through setup (maf before the turbo) you will want to recirc as it is metered air.
On a blow through(maf near the throttle body and bov near the turbo (discharge side) you will have no problem venting to atm. recirc is more stealth and to atm makes the noise lol

Your car makes its max vac at idle at wot it goes to zero on an n/a car when crusing it sits at 5-10, idle is 20, wot is 0 etc.

more vac at idle generally means you have good compression across the cylinders. built low compression motors will show less vac at idle.

 

[08nastygt]

So I'm understanding right, I cannot run the bov n wastegate together to the same vaccum? I don't have a boost controller I will get one next year though. Also how would I know what size spring is in the bov. They ran 5psi on the test car n then put a 8psi spring in but I don't think they changed anything with thebov.

 

[JeremyH]

Wastegate should have a dedicated vac line the bov is fine with the gauge.

Ask on3 what spring came in their wastegate what ever the spring is, thats the minumum boost the car will make

 

[Natural1]

I have always found that it is best to bench test any wastegate using regulated compressed air. This also allows you to see when the valve starts to open, what % it is open at what pressure and when it is fully open. It's nice to know and see everything work properly.

 

[SilentScope]

good idea. then you know whats going on in it, if you have to troubleshoot it makes things easier!

 

[Natural1]

Yeah, I never have trusted that 8lb, or 12lb spring crap. The test will vary slightly from what you would see in actual service, but it will give a good indication of where you stand.

 

[08nastygt]

So where would be a good spot to tap into for thee wastegate ya think. IDK what vaccum line work for it.