Tial BOV question
 

Well I installed the BOV with the 7lb spring because my vac was at around -.12 inHg while at idle and cruising. Now after the install my vac dropped to -.20 inHg and is causing the valve to stay open at idle, cruise is still at -.12 inHg. Here's the wierd thing, my afr's are pretty close to the same 14.7 at idle and cruise and the car seems to drive a lot better, no stuttering or surging. I do have a very small flutter at part throttle driving which I am assuming normal since every BOV I have tried did this. At least the Tial doesn't make the car buck like the Forge did. Also at idle when the valve is open air is being forced out of the valve but if I just touch the throttle very lightly the valve will close.


Im thinking about getting the 9lb spring. (Seems like no vendors have them in stock)

Are you venting?

The Tial will not let you recirc. Try not to get on the whole recirc/VTA thing I am running speed density.

Have you tried adjusting the valve a bit tighter with the existing 7lb spring?

Tials don't have a adjustment it's all based on the spring pressure.

So much for that theory...guess I should actually look at one before posting next time...

I have all the springs here, and from experience can tell you that it will cause your turbo to surge more with a 9 and 11lb spring. Bottom line is the Tial is made for high boost race applications where it can hold 40 psi + with no problems. So stay with the 7 psi spring.

Thats what I think Im going to do. Since the valve is only open at idle I don't really see a problem. I guess with the 7lb spring the valve is suppose to be open, at least thats what a few vendors have said. If any problems arise in the next few weeks or at all I'll be sure to post up.

So far so good.

Since you are running speed density your A/F ratios will not change due to the lost air at idle, it should stay rock steady at what ever you have it tuned for.... and it sounds like that is the case.

For me with the 7 lb spring it is open at idle, and just part open at cruise constantly cycling open and closed. This didn't bother me at all in my old 03 EVO, but in the new 05 RS with no sound deadening material the noise is anoying as hell. I will be putting in a 9 lb spring when I get around to it.

Keith

PS: Don't even try to shim the spring. You end up limiting the travel of the plunger way to much, reducing the ability of the valve to do it's job.... trust me, I tried it when I first put in the 7 lb spring.

Change to the 9lb spring. I use it with 20psi on pump and 28psi on race.

I was actually thinking about that, but thought it would be bad since no shims are available from Tial for the BOV, although I still have the forge shims but Im sure the diameter from either valves are completely different. I think the forge is a 30mm spring seat while the Tial will be larger (didn't take it apart yet).

Remeber that the air/debris you suck in at idle will be unfiltered...

You are blowing out at idle.

Even at idle the turbo is spinning (slow by on boost comparison, but it IS spinning) blowing low pressure air into the intercooler and associated pipeing.

Keith

Did you read my entire post? Or are you assuming that you know whats happening without reading? Please before more stupid posting goes on please read the entire thread, think about it a little, then post.



I see the IQ dropping in here lately

Our valve shims/washers/spacers are deffinetly not appropriate for the Tial valve. As you mentioned, the Tial valve is too large to use those components, Tial does not recommend it anyway, and your type of engine management will not have any issue with the valve being open at idle or part throttle.

Your setup is basically just like an SRT-4 to which we supply a single-diaphragm atmospheric valve that is open at idle and part throttle with no issues.

I don't have much experience with Tial valves, but I don't necessarily think that upgrading to the 9 lb. spring will be good or bad. It may be stiff enough to keep the valve closed at idle, but it may be too stiff to allow for maximum piston travel and airflow at full-boost throttle lift which can create compressor surging.

Call Tial and see what they say. They were very friendly at the PRI show when I stopped by their booth.