Vacuum question

Rufus · 03-31-2008

I'm up and running with my turbo but need a little help with vacuum. When my kit was put on, the guys used a vacuum block on from the brake booster vacuum line. On the dyno, we immediately knew I was getting compressor surge. So the question was "is the BOV even working?" I knew it was getting some vacuum, so I switched it out and the same thing occured. Next, my ABS light came on. Clearly that line wasn't ideal for vacuum. Next I noticed that when I'm in boost, if I need to slam on the brakes, they're hard as hell for a few seconds. Obviously, I need a new vacuum source. Where do you guys pull your vacuum from?

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tfnaaf · 03-31-2008

exact same place as mine. I get some compressor surge at lite throttle/low boost

cinaibur · 03-31-2008

Rufus, is that a Full Race logo I see?

Rufus · 03-31-2008

Quote:

Originally Posted by cinaibur

Rufus, is that a Full Race logo I see?

It is. Everything is within a mile of each other down here in AZ

Rufus · 03-31-2008

Quote:

Originally Posted by tfnaaf

exact same place as mine. I get some compressor surge at lite throttle/low boost

No ABS light on? On the block bottom I have the middle 3 plugged and the far left one going to BOV and the far right one to my wastegate. Maybe I have a leak....

EDIT: I see no ABS unit on your car. lol

I still have a very hard brake pedal during boost...

I'm at 175whp on 5.2PSI

tfnaaf · 03-31-2008

ABS light came on when it was strapped to the dyno?

tfnaaf · 03-31-2008

hard pedal under boost... i bet that you/they removed the check valve in the line. And they /you shouldnt have

Rufus · 03-31-2008

Quote:

Originally Posted by tfnaaf

ABS light came on when it was strapped to the dyno?

No after driving it for a bit, just after the dyno. It went straight from the shop to the dyno (wasn't on the road at all)

Rufus · 03-31-2008

Quote:

Originally Posted by tfnaaf

hard pedal under boost... i bet that you/they removed the check valve in the line. And they /you shouldnt have

I didn't. Hell, I thought that was all internal anyway. I'll ask to see if I can get it replaced.

tfnaaf · 03-31-2008

Just a guess would be they somehow damaged awheel speed sensor or they put it into a ABS stop while on the dyno and it malfunctioned

tfnaaf · 03-31-2008

The check valve is mid way between the intake manifold and the brake booster, and its not visible from the outside. but you can feel it if you squeeze the hose

FoSho · 03-31-2008

I'm turbo, w/ abs, & I have my vac manifold just like that.

I have no abs light, turbo works fine, brake pedal is fine, & no vacuum problems?

What do you mean by compressor surge?

Rufus · 03-31-2008

I think we figured it out at lunch. You're right about the check valve. The guys suggested removing the check valve from it's current location and putting it before the vacuum block.

Rufus · 03-31-2008

Quote:

Originally Posted by FoSho

What do you mean by compressor surge?

Without enough vacuum to get the BOV to open the excess air is released back through the turbo, which can be very bad for it.

andyman97 · 03-31-2008

Yeah, you want the vac manifold sourcing vacuum directly from the intake manifold. Those guys should know that....

civic-driver · 03-31-2008

Quote:

Originally Posted by FoSho

I'm turbo, w/ abs, & I have my vac manifold just like that.

I have no abs light, turbo works fine, brake pedal is fine, & no vacuum problems?

What do you mean by compressor surge?

THe way i understood compressor surge is that when the throttlebody closes and there is to much pressure between the turbo and the TB and the pressure doesnt have anywhere to go and it tries to go back out the turbo which causes the compressor blades to spin the wrong direction. It can be bad cause when the Tb is opened again the turbo will try to spin the right direction again and it can stall the turbo and possible hurt it. Thats why you use a BOV to try and eliminate compressor surge. I think it can also be caused when the BOV is too small for the turbo and it cant release enough of the pressure. Forgive me if this isnt right its been a while since i looked this up and im still on pain killers from my surgery.

andyman97 · 04-01-2008

Quote:

Originally Posted by civic-driver

THe way i understood compressor surge is that when the throttlebody closes and there is to much pressure between the turbo and the TB and the pressure doesnt have anywhere to go and it tries to go back out the turbo which causes the compressor blades to spin the wrong direction. It can be bad cause when the Tb is opened again the turbo will try to spin the right direction again and it can stall the turbo and possible hurt it. Thats why you use a BOV to try and eliminate compressor surge. I think it can also be caused when the BOV is too small for the turbo and it cant release enough of the pressure. Forgive me if this isnt right its been a while since i looked this up and im still on pain killers from my surgery.

That's pretty much it. Boilermaker snapped his shaft from using a shitty bov.

FoSho · 04-01-2008

oh ok.....so it's the BOV not doing it's job........learn something new everyday! I'm glad dezod supplied me with an awesome BOV.....I don't think I'd ever have to upgrade

Rufus · 04-01-2008

Well I thought I'd at least try their suggestion and move the check valve to the other side of the vacuum block, although I coudn't logically think of a reason why it would work any different, and it didn't change a thing. I'm going to try Andy's suggestion and T off the vacuum line above the brake booster vacuum line on the IM.

Rufus · 04-02-2008

So the "check valve" that Honda had in there wasn't really a check valve.. I could see right through it.

We put a regular check valve in and the brake assist is back. The BOV is opening but I think it's just a shitty one. I'm ordering a Greddy.