Tial BOV issue

[Blinkwow74]

It made 620rwhp when they dyno’d it. I did the install and they said I did a perfect job. It ran for two days fine then it stopped. So that’s when I tore everything apart looking for a loose coupler ect.... until I realized that wouldn’t be my problem since all the air was coming out of the bov.
I have it t’d off the vacuum hose coming from the intake manifold going to the brake booster per the Paxton manual.
I’ve already tried just going straight from the intake manifold straight to the BOV with the same results.
Currently trying to remove the tial and installing the bov that came with the kit originally. Kinda of a pain in the a$$

 

[Blinkwow74]

Do you have another blow off valve you can swap it with to see if it repeats?


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Trying to install the original now

 

[Blinkwow74]

Nope not happening.. grrrr I’ll have to remove the radiator fan.... remove the front bumper... remove some inter cooling piping maybe partially drain radiator to get the fan out just to pull off the tial adapter flange and install the old bov grrrrr.

 

[geoffmt]

Ah that sucks! Swapping that will eliminate the bov or give you a better idea of what’s going on


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[Blinkwow74]

I’m going to place a few large washers inside that the spring rests against to put a little more tension on the spring.... I feeling that the bov is not closing fast enough before there is positive pressure in the intake manifold so the pressure from the supercharger is keeping the bov valve open.
Tial replied back and it thinking the same but he won’t be able to look into it till Monday.

 

[01yellercobra]

I'm sorry if some of what I'm about to say is redundant, but I'm still having a problem wrapping my head around everything.

The BOV is pretty simple. If it's not closing then it's seeing vacuum at all times for some reason. Adding washers isn't going to make a difference. Even if it was slow the positive pressure plus the spring pressure will overcome the boost.

What I would do is disconnect the vacuum line from the BOV then take it for a quick spin. Yes, the engine won't be happy, but it'll be quick. IIRC I was able to get about 5psi with just the spring when I was doing some leak testing. This was with a 50mm Tial BOV. So if your BOV is working correctly you should at least see a couple psi for a quick couple seconds before the boost over powers the spring. If you see boost, then the issue is elsewhere. If you don't see boost then the BOV is the issue.

Just to double check, there is only one place to hook a line up on the BOV you're running correct?

 

[Blinkwow74]

I'm sorry if some of what I'm about to say is redundant, but I'm still having a problem wrapping my head around everything.

The BOV is pretty simple. If it's not closing then it's seeing vacuum at all times for some reason. Adding washers isn't going to make a difference. Even if it was slow the positive pressure plus the spring pressure will overcome the boost.

What I would do is disconnect the vacuum line from the BOV then take it for a quick spin. Yes, the engine won't be happy, but it'll be quick. IIRC I was able to get about 5psi with just the spring when I was doing some leak testing. This was with a 50mm Tial BOV. So if your BOV is working correctly you should at least see a couple psi for a quick couple seconds before the boost over powers the spring. If you see boost, then the issue is elsewhere. If you don't see boost then the BOV is the issue.

Just to double check, there is only one place to hook a line up on the BOV you're running correct?

Well what I was thinking is that bov isn’t closing fast enough and the Paxton is keeping the blowoff valve open... so because of that it never gets a chance to make positive pressure through the vacuum line to the diaphragm of the BOV.

Yes only one place. And like I’ve mentioned before it was dyno’d and worked fine for two days after the tune. And I never raced it accept that initial pull out of the tuner garage down the street to see what it could do now.

I’ll try what you suggested.

 

[Blinkwow74]

Ok so put it back together and went to the highway to check it out. I still don’t have the throttle response I had after it was tuned.... just feels lagging....so if I floored it really quick it the vacuum went away and it started climbing to a max of 3 psi maybe no hissing until I let off the gas....

If I’m just driving normal and start to accelerate the vacuum goes to zero or almost zero then falls to negative again like really has no power. I seam to remember having better throttle acceleration when I was N/A.....

So I’ve tested the bov with out the vacuum line hooked up and yes it’s doing the same thing....but I didn’t let I run in that configuration very long I tested it at sitting no load.

So question could my intake manifold have a hairline crack? Not sure if these are the symptoms I would see....

1. Vacuum hoses are good no kinks nor cracks.
2. Tial BOV seams to be functioning properly when tested with a hand vacuum tester per tial’s tech support.
3. Brake booster isn’t a potential bad part because like I posted before I took it out of the equation. During a troubleshooting session.

So this is getting very frustrating
I want the car back that was crazy scary before this happened.

 

[Blinkwow74]

Now the car shuts off intermittently at red lights when sitting at idle hmmmm

 

[01yellercobra]

What do you mean you tested it without the vacuum line hooked up and it's doing the same thing? Did the valve stay closed or did it open up? It should have stayed closed. The fact that you saw boost means it's working and the issue is elsewhere. With it stalling there's either a vacuum leak or your throttlebody is having issues. It might be time to hand it back over to your tuner and see what they find.

 

[Blinkwow74]

yeah thinking the same thing