my new project

[Super Bleeder!!]

Just a boost actuated valve that blocks off one scroll of a divided turbo, effectively reducing the AR of it (which we all know increases spool) until boost kicks in and it opens up allowing both scrolls to flow when at full boost.

Id like to get one but they are expensive.

It doesnt really reduce the A/R ratio does it? I thought it just blocked off a port and thus the gases get forced through the open port at a much greater speed.

[goodhart]

If gases only go through one scroll vs. two it would effectively cut the A/R in half would it not?

Edit, FP is having Holiday sales on their BB 3788 ($1700), BB 3794 ($1700, JB 4294 ($1500), and JB 4205 ($1500) turbos. All are T4.

Ball bearing (http://store.forcedperformance.net/merchant2/merchant.mvc?Screen=CTGY&Store_Code=FP&Category_Code=Holiday)

Journal bearing (http://store.forcedperformance.net/merchant2/merchant.mvc?Screen=CTGY&Store_Code=FP&Category_Code=SP)

[4seasons69]

Just a boost actuated valve that blocks off one scroll of a divided turbo, effectively reducing the AR of it (which we all know increases spool) until boost kicks in and it opens up allowing both scrolls to flow when at full boost.

Id like to get one but they are expensive.

Hmmm how well do they actually work? And how expensive lol? It might be something worth trying since I'm going to be running a 2.0l. I'll have to look into them

[Super Bleeder!!]

If gases only go through one scroll vs. two it would effectively cut the A/R in half would it not?

Hmm i spose that is what the A (cross sectional) stands for doesnt it?

Now that i think about it A/Rs on divided exhaust housing are kind of strange to compare because they realistically have a separate A/R for each scroll. Hmmm brains.

When i said what i said above i didnt have a dual scroll exhaust housing in mind. now i do!

Carry on!

[4seasons69]

Also I will probably be running a gt42 style turbo with a top mount manifold so I might run into fitment issues with the hood

[goodhart]

FWIW, a friend of mine runs a QSV on his poopra with a Comp billet 67mm. I believe he said it cut roughly 5-600 rpm off his spool time when it was setup correctly.

[4seasons69]

FWIW, a friend of mine runs a QSV on his poopra with a Comp billet 67mm. I believe he said it cut roughly 5-600 rpm off his spool time when it was setup correctly.

If I could pick up 5-600rpm that would be worth it to me but they look kind of thick so idk if fitment would work but ill look into it

[Shane@DBPerformance]

Switch to DSMLink.

[4seasons69]

Switch to DSMLink.

That is something I would really like to do. But i have no idea what all would need to be done to switch. This car has been such a headache already that I don't really want to try and deal with figuring out how to switch over right now. Plus money is starting to become a factor in what I do with it right now. So for now I will probably have to run aem still next summer and switch to link next winter

[Halon]

I've never used one first-hand, so couldn't speak on any sort of actual RPM increase. I think they are in the 300-400 dollar range.

Check out youtube videos of Sound Performance Supra's, they have some where they compare with and without QSV dyno charts.

Flopster, I think you figured it out on your own :) But if anyone else is still confused, yes you reduce the "A" by blocking off one of the scrolls. So if you're A/R was .90 (90/100), and you block off one port, you would have reduced the A (90) to a lower number say 50. So your A/R is now .50 (50/100). I am not a mechanical/math master, so I don't know if it's exactly cut in half or what. But it is significantly reduced.