any one try this again latlely??? gmht just did this and it worked awesome!!! max out blower for faster boost, set waste gate to max psi, done. Way better power band...

this is on a Centrifugal Supercharger.

i also found a old post on this but it died out with no good info..
https://www.camaroz28.com/forums/sho...d.php?t=554304

the mustang guys loved it also..

 

I don't see how this would improve anything over a BOV or BPV. If the're set up right and working correctly, once your out of vacuum into boost they should be closed and you should see no boost wasted until you let off. Can't see how you would build any more boost with a wastegate vs a BOV or BPV on a supercharged setup.

Ken R.

 

Read old post. I could see how that could work....

 

no one has done this or know any one that has done it?

 

Probably no on is making more boost than they want at high rpms.

 

If this is what I'm thinking, you pulley the head unit so you can make bigger numbers under the curve and blow off the top end so you don't kill your motor. I've heard though it causes a lot of stress on your head unit though. I've never seen a head unit fail due to this although I only know of one personally. People who do this for a living though say it's not good for the HU and they have seen them come apart.

 

yes you are right. this has nothing to do with wanting higher boost at motor max rpm this all about low and mid rang. It spools up fast to make more boost for low and mid range then when it hits your bov pressure it opens and holds what ever you have it set at..

That is the only thing i can think of that it is a little harder on the unit. i dont like the fact that it is working like hell to get to the bov pressure and than bang bov opens and most of the load is lifted.. that has to be some what hard on it...

 

I think it would work when you have a large head unit that you didn't need to spin so fast to make lots of boost. In my case, it is about maxed out (rpm wise) at my shift points and I don't want to spin it any faster, so I'm not sure how I could benefit from it. There is also the question of efficiency at the higher impeller speeds. Now might be possible to set it up to make a lot of torque down low, shift earlier, and have more average power. But if I had a huge blower that made a lot of boost down low, then I could bleed some of it up high for a steady boost level at some point. I actually have the opposite problem and make too much boost down low because I need to rework my bypass valve setup - it comes on too strong and it will blow the tires off at 40-70 mph so I need to smooth that out somehow.

 

I used two (2) Bosch Alum valves in parallel to bypass IC air.
They were about $104 each.
The springs were not correct for my FI app, so, I measured some manifold data and did an excell spread sheet to design new spings. I used a max IC pressure of 18psi to ensure a no-leak valve.

I cut and adapted springs purchased from Enco. I also calibrated the valve seat load with machined shims @ valve assembly.

Result was they work much better. Compressor boost builds very fast, and, is vented fast @ 0% TB throttle. No leaking of boost pressure from the IC around the valve seat.

I did have a problem with the vented Opti. The vent check does no work well. So, I made a ball check. On a bypass configuration, the bypass air can back-flow into the Opti vent on the compressor intake side when the valve(s) initially open. I did not consider this problem. The stock checks don't work well for FI apps.

Hope this helps. B.