Tial Q 50mm bov users

[turtle m3th]

I'm about to pick up a tial q 50mm bov and was wondering what psi spring you guys have had success with? I'm looking to run 16 psi on my gt2871r.

[RalliartRsX]

http://www.tialsport.com/documents/w3_tial_qqr_sp.pdf

Search next time............

[turtle m3th]

^ I didn't ask for a chart, I asked for personal experience, but thanks for the link.

[RalliartRsX]

The chart tells you EXACTLY what spring pressure to run

If you prefer peoples "experience" over facts, you are going to have a very hard time determining the correct spring (myself, has been through 4 springs total (including shimming several in-between) before arriving at the spring the chart originally recommended.............)

One thing however: the 50mm NEEDS a dedicated 1/4" Vacuum Source from the manifold (as the chart has stated). Without it, the BOV will have some lag before BOV opens and coupled with incorrect spring pressure (which if you follow peoples experience, you WILL choose incorrectly), can cause the BOV to stay open and not operate correctly

[RalliartRsX]

I had the same issue and based my choices off peoples experience, and ended up going back to what Tial originally stated.

Also, your PSI you run has ZERO to do with the spring pressure. If you read the sheet, you would realize its based off vacuum

Again, do not go off what people say. Go by the sheet and be done! For my vacuum of 20 in, I have heard anywhere from 7-11 psi spring.

I ended up with the 11psi spring as recommended by TiAL!

IJS.............

[turtle m3th]

^Awesome! Thanks for the insight. I'm also a bit curious what my engine vac will turn out to be with my bc 264 cams. Time to search.

[RalliartRsX]

We posted the same time to reload and read my second post :)

[turtle m3th]

That's the exact spring I was considering. I'll give it a shot! Your experience came in handy, hahaha! Just needed a knowledgeable one.

[RalliartRsX]

Also, I forgot to mention

You can also shim the springs ever so slightly in the 50MM. If you feel you may be running more/less vacuum, opt for the lesser spring and you can use 1/8" "shims" to shim the BOV and increase spring stiffness. However, the limit is around 2.5-3 shims as over that amount, you have compromised the travel of the BOV diaphram and you loss the ability of the BOV to open

Do a search on google. It's on one of the DSM forums with formulas and all!

Good luck!

[omgRWDgoodness!]

FWIW I'm running the 10psi spring on my RB25 and haven't had any performance issues, although it's the QR recirculating type.

[derass]

I too have experimented with a few of the different springs and shims. In the end I just went with the recommended spring from that chart, no shims.

The Tial 50 is a race valve meant for 20+psi applications, it needs ~10psi in the system to help it open, otherwise it doesn't and you experience surge.