yeah something doesn't sound right, it should boost early, and keep on delivering to redline.
maybe its not opening up at the right time.

 

I got my hands on a quick spool valve. I am ready to see if it is worth the hassle of extending the dp or leave my setup alone. I will continue to research this further. I am wondering if I need to retune. I have a bw s366, divided housing on turbo and divided manifold.

Do or not to do?? Whats your thoughts?

Read my signature for the restof the mods done. I want the car to spool a little sooner.

 

You need a divided housing and un-divided manfold .

You will need a retune from a tuner that knows how the valve works, when to open it and when to close it.

By looking at your dyno chart , you need a retune regardless if you go with the qsv or not your car shouldn't be that laggy.. again a better tune will help your spool.

gl

 

100% right you have to have that combo above or it will do alot of nothing.
Once you get that combo in place, and adjust the spool valve itself to open at the right time (either mechanically via hobbs switch when on regular ecu's or electronically if you are on a standalone with extra outputs), it should get you spooling considerably faster. The point of switching over will depend on your powerband everyone's will be a little different.

 

Now this is the info I love to read about. I will continue to see if this is the route I want to do. I honestly dont feel like messing it and fixing something that isnt broke. Can you two explain why one needs undivided and the other divided in detail?

Thanks guys.

 

What do you mean by something that isn't broke?

Undivided exhaust manifold (single )not too port at the t4 flange where the turbo sits on the manifold.

Divided exhaust housing on your turbo , BW if you get the .88ar it's non divided and the .91ar is divided , so what ar do you have?

Again if you boost controller is setup properly and the Tune is on point your setup should not be laggy when you are running a stock SC4 rear end.
No way.

gl

 

I just installed a QSV on my Supra and even without optimizing the valve opening, I am getting into boost much faster. Without the controller, it starts opening at 5.5psi and fully opens by 9.5psi. This is simply seat of the pants and observing my boost gauge vs rpm. Just drove it home from the shop. I'm doing the wiring for the control myself at home, but it's winter and my SC needs much more loving LOL. Will update with results for sure.

I'm happy, but it costs a lot of money for custom work that needs to be done. It might be better to just get a smaller turbo, esp if the hp goals aren't astronomical.

As far as retune, I am doing it myself, but if your tuner built you a robust tune, only minor adjustments are necessary since your motor is getting into boost earlier than before (ie finally seeing part of the map it wasn't seeing before)

Jeremy

 

Step 1: is the twin scroll turbo (divided). This will allow you to put all of the exhaust flow into one side of the turbo, which will spool it faster at lower rpm's when there is not enough gas volume to spool both chambers at the same time (sort of makes your turbo size 1/2.. sort of).

Step 2: In order to put all of the exhaust flow into one side of the turbo, or one side of the t4 flange, you need a quick spool valve to block off the other side of the t4 fange (thats what it does).

Divided Manifold (cases major problems): If you block half the flange on a divided t4 manifold, those exhaust gasses have literally no where to go while the quick spool valve is closed, and they are not getting stuffed into the smaller open side (because they are not connected in the manifold, hence divided).

Undivided manifold (required for quick spool): Now when you block half the t4 flange off, since your manifold is undivided, all 6 runners connect to an open space before the T4 flange, so now when you block half of the flange, ALL the exhaust gasses go through the smaller side now, and spool up your turbo with twice the power you had before.

When the quickspool valve opens (a low psi amount maybe 5-10 psi), it lets the exhaust gasses into both chambers of the turbo, and that gets the already spooled turbo to rocket off to whatever its max output is.

you have lost a little bit of efficiency on the top end in not having a true setup where 3 cylinders feed each half of the turbo, which gets a little efficiency gain from the timed pulsing, but this is really not that noticeable if at all.
What is noticeable is that you have gained at least double your spooling potential at lower rpm's where a large turbo is least efficient.

There aren't that many undivided T4 manifolds out there, If you have the height for it you may be able to stack an undivided T4 flange on top of your manifold, and then the quick spool valve, but those 2 will add alot of hieght to the setup it may be worth it to have the manifold properly modified to have an undivided flange.

Sounds like its doing what its suposed to, do you know what manifold you went with and did it need modification. ge or gte? thanks.

 

Ali,

I have a GTE. My manifold is an older, Turbonetics cast that had been ported and ceramic coated. The guy who worked on my car had to also port both manifold and turbine housing in addition to fixing the downpipe, to make the QSV operate correctly (free to move).

I think the QSV is great for the beginning of the project, with a turbo that matches hp goals while trying to get it to spool a little bit faster.

Jeremy

 

any downside to this? is making the exhaust go through only half of the turbine housing going to hinder off boost performance and maybe gas mileage?

 

negligible difference

 

I have both divided and also have a .91 AR with a BS S366. My buddy is selling his off of his MKIII, and I have read a little bit about them. I say this again, very little, don't know the pros and cons. After reading this and the suggestions provided, I had better stick with what I have. I turned up the boost today to 21, and it felt like a damn rocket. I haven't turned it to that in awhile. I really don't think I need to start messing with my setup. I just thought while I had the opportunity to get a spool valve, why not. I had better leave well enough alone and just replace the bad bearing I have and ride with a smile when in boost.

 

Thanks for the info marshall2j, I had heard that porting was needed in alot of cases.
Im guessing the cast manifold is a log style, those usually come undivided so easier for QSV.

You will be getting into boost quicker so not really. we don't really talk gas mileage when talking turbo's and power, but If you can keep your foot out of boost territory can't be that much worse.

Think of it like a GTE system, except you have 1 big turbo that can act like 2 smaller turbo's, and a QSV to actuate the second turbo/half instead of a bunch of vsv's and wategates.

Like the GTE uses turbo 1 up to 4k rpm's, prespools and opens turbo 2 right at the crossing point, and then both turbos are online to redline.
You are doing the same thing with the quick spool valve except it uses boost to switch over instead of rpm, which is marginally better than the gte system.
we all know how much faster the twin turbo's will get into boost vs. a big single.

it def is alot of work, but its not that bad if you are choosing all your parts around it because once you set it up it will just do its job. its much easier to do it at the start of a build as everything has to come off. You would have to change your manifold or have it modified to undivided.
You shouldn't feel a big difference in top end, its just a trick that is done to get some crazy spool, if you feel you turbo spools fast enough, than its probably not worth the hassle/investment.

 

Yep, mine is a log style. Off boost response should be the same or better... I mean you can get to positive boost much more sooner even part throttle.