• We are no longer supporting TapaTalk as a mobile app for our sites. The TapaTalk App has many issues with speed on our server as well as security holes that leave us vulnerable to attacks and spammers.

BOV and vacuum - help clarify please?


VIP Member
Jan 17, 2005
Clear Lake, IA
I am on the hunt for a 2nd BOV that will go between the turbo and SC. I don't have a problem as of yet but I think with the way I chop the throttle in tight trails the way I like to, I thought it would be good to alleviate the pressure from both blowers instead of just up at the TBs post IC. Also noticed when I let off even at low boost (17psi) it really spiked the MAP so with plans of being near 28 psi on meth I figure this is a smart move to help keep boots and stuff from blowing off. I am worried about the head intake boots blowing off, I did use yamabond on them when I put the new motor in and that trick does work. The rest will have quality clamps on it and should hold up fine.

Leaning towards this one:

GenV RacePort BOV - (Black)

The Turbosmart RacePort is famous for being an amazingly small and light BOV for turbocharged competition level engines. Featuring our unique collar design and internal flow structures, it is 50% lighter and 25% smaller than the competition while flowing 330 CFM – making it the highest flowing...

Curious on the vacuum to pop it off, looking at the data logs from my sled and I only register about 20 inHG and this looks like it needs more vacuum at 18 inHG and that is the most sensitive spring you can get.

But then I look at my current BOV:

Maxflow Race Bypass Valve

Our Maxflow® Race Bypass Valves flow 320 CFM @ 8 PSIG and feature a compact design that is ideal for sport compacts and other applications with tight engine compartments

And its saying it opens at 10-11 inHG which I am not even close to (according to the data logs but maybe I am not sampling my MAP sensor fast enough to see the low numbers) and it opens just fine.

I guess I am a little confused why you wouldn't want ANY vacuum to pop it open, with the spring options on the turbosmart what am I try to prevent form it creeping open under pressure? Any thoughts? Just a little confused what I am looking for here.