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Sound Performance Quick Spool Valve (for twin scroll)

jrohner

15+ Year Contributor
2,666
10
Sep 25, 2004
Willmar, Minnesota
If it was cheap I could maybe see the point since divided manifolds are expensive, but for close to the cost of this and a cheapo open manifold you could have a good divided manifold so you could run a true twin scroll setup. I also wonder if it can handle the intense heat without any issues.
 

spoolin ddub

Proven Member
598
17
Aug 24, 2007
Chicago, Illinois
QSV on our cars are a waste of time. Especially if you run a T3 housing. Can you imagine running a .70 T3 housing with a QSV closed. That's similar to running a .35 a/r T3 housing. Our motors don't have the VE to support the gains at the rpm's the turbo would come on. We'll just surge. If you run E85 it would surge even worse.
 
Last edited:

turbo addict

Proven Member
482
1
Apr 17, 2005
Omaha, Nebraska
SPV on our cars are a waste of time. Especially if you run a T3 housing. Can you imagine running a .70 T3 housing with a SPV closed. That's similar to running a .35 a/r T3 housing. Our motors don't have the VE to support the gains at the rpm's the turbo would come on. We'll just surge. If you run E85 it would surge even worse.

yes and no it depends on the turbo and the a/r. if you are running a gt42 with a big a/r then it would be worth it. also with many of these new turbos the ported shroud helps with the surging as well.
 

ramsack

Banned Member
3,286
20
Dec 27, 2007
West Lawn, Pennsylvania
The gains of having a proper twin-entry manifold is many times that of putting a spool valve on. I don't understand how there are gains at all with part of the exhaust flow just hitting nothing. I also don't understand why someone would get a twin scroll turbo if they aren't planning on using it properly.
 

spoolin ddub

Proven Member
598
17
Aug 24, 2007
Chicago, Illinois
yes and no it depends on the turbo and the a/r. if you are running a gt42 with a big a/r then it would be worth it. also with many of these new turbos the ported shroud helps with the surging as well.
Not true. My turbo is a 42r size turbo with an anti surge housing. Big turbos have huge a/r turbines housings for a reason. Once again our motors do not have the VE to support the air flow at lower RPMs (even at lower boost). I learned the hard way. My turbo on a divided .84 T4 (on e85) spooled very fast with boost coming on at lower 3K and I was surging by 9psi. Isn't a .84 housing bigger than a 1.15 housing in half? So yes it will spool faster. But what is the point of spooling fast if it's just going to hit left of the compressor map and surge. It's not as cut and dry as people think.


The gains of having a proper twin-entry manifold is many times that of putting a spool valve on. I don't understand how there are gains at all with part of the exhaust flow just hitting nothing. I also don't understand why someone would get a twin scroll turbo if they aren't planning on using it properly.
It does work. It just doesn't work for every application. It's the equivalent of taking a housing and making it a smaller housing. You gain more torque and hit boost sooner on the half blocked housing but with the valve open at the target boost you gain the topend from the full housing. Another major factor is a QSV isn't necessary for drag racing. We use a 2-step to reach our target rpm and most likely that point is past the rpm that the QSV is really effective. I asked a worker at Sound Performance who would win a race? A supra on a 2-step or supra without a 2-step using a QSV?
 

turbo addict

Proven Member
482
1
Apr 17, 2005
Omaha, Nebraska
Not true. My turbo is a 42r size turbo with an anti surge housing. Big turbos have huge a/r turbines housings for a reason. Once again our motors do not have the VE to support the air flow at lower RPMs (even at lower boost). I learned the hard way. My turbo on a divided .84 T4 (on e85) spooled very fast with boost coming on at lower 3K and I was surging by 9psi. Isn't a .84 housing bigger than a 1.15 housing in half? So yes it will spool faster. But what is the point of spooling fast if it's just going to hit left of the compressor map and surge. It's not as cut and dry as people think.


It does work. It just doesn't work for every application. It's the equivalent of taking a housing and making it a smaller housing. You gain more torque and hit boost sooner on the half blocked housing but with the valve open at the target boost you gain the topend from the full housing. Another major factor is a QSV isn't necessary for drag racing. We use a 2-step to reach our target rpm and most likely that point is past the rpm that the QSV is really effective. I asked a worker at Sound Performance who would win a race? A supra on a 2-step or supra without a 2-step using a QSV?

what turbo did you have the wheel size has alot to do with it as well. and no you are not going to want a ton of boost really low on a big turbo, (like my gt42) but not spooling until 7000rpm is not great either. This is a ballpark range for my turbo. Also another thing that something like this will allow you to do is run a bigger a/r with the same spool up. the key feature of this is that it CHANGES the a/r where a wastegate doesn't. this allows the benefit of spooling sooner and having more topend of the bigger housing. a wastegate doesn't change the a/r and it takes a certain amount of back-pressure to do the work of turning the wheel. what this does is lowers the back-pressure once you spool and have a better pressure differential both on the turbine before and after and the boost,back-pressure.
 

slipstream808

Proven Member
773
6
Mar 2, 2005
State College, Pennsylvania
OK so I googled it and it seems to me it is working for everyone that uses it, period. No matter what vehicle it is or turbo it is. It cuts the A/R in half causing a lot faster direction of exhaust at the turbo spooling it up quicker.

Links to discussions on other forums:
Zombie's "Quick Spool" valve testing with pics and nerd like graphs - LS1TECH
Resurrecting the SpoolieJobbie - HybridZ
SoundPerformance Quick Spool Valve??? - evolutionm.net

Youtube videos on a Supra:
YouTube - Sound Performance Quick Spool Valve Results on Precision 6765 Billet!!!
YouTube - Sound Performance Quick Spool Valve testing and results!!!

Youtube video of operation:
YouTube - Sound Performance Quick Spool Valve

Now is it worth it? Entirely different question... But for us it should be able to work.
 
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