Quickspool Valve.

[GeorgesR34]

But lots of the pressure / flow engineering stuff makes no sense. Would be interested to see if any one could do a controlled run on a RB25det in Australia.

No one's more suited then your self.

[rockabilly]

hi guys, resurecting an oldish thread.

i like the idea and did some research. i have found a guy in the usa who modifies yours existing t4 twin scroll exhaust housing. so basically he cuts out the divider and fit a pivoted flap in there, similar to the spool valve. differences here are.

the valve is in the exhaust housing so you still keep the twin scroll manifold and no sandwich plate to fit, so dump pipe still fits

also the flap is at 45 degrees when closed so make a nice transcient flow of exhaust gas and creates no blockage or hotspots.

i am going to be sending my rear housing to him for mods so will try to update on the results.

i like th spool valve idea but not there design, i would imagine massive heat build up behind the closed flap where this idea eliminates this.

any thoughts on this type of design guys??.

bernie

[rockabilly]

here are the only pics i have of his device.

[Super_Dude]

It's a good idea for a road car but I bet with tracking the car or even aggressive street use it would overheat parts, warp pieces, and cause problems. Some wrc cars didn't even use twin scroll turbos as the heat and pressure would cause one side to push over and block the other side.

[rockabilly]

i thought this but you can have it in stainless or inconel....

this is an email clip from him to me.

We have two models. The standard model comes with stainless steel 304L internals, and the pro version comes with nickel 600 (Inconel) internals. The pro version provides peace of mind for those who think they will be running in very high horsepower and temperature environments. Both models come with all required bracketry and the actuator so the unit is a complete bolt-on kit.

Edited January 25, 2011 by rockabilly

[W0rp3D]

Prices?

[rockabilly]

just waiting for prices mate. will post up the two prices when i get them.. think its similar to the sp one by the time you have posted your housing there,its been modded and posted back. will update when i hear more..

i do know though that on a 3000gto with a gt42 turbo. 20psi was acheived by 4300rpm with the valve and its been on the car now 5 years no issues..

Edited January 25, 2011 by rockabilly

[BoostdR]

I like this design much better than the quick spool. Much better flow when travelling through one scroll. The quick spool presents a brick wall to 50%. At least this design directs the flow smoothly.

[rockabilly]

thats what i saw when i looked at it BoostdR.. i can see any great hotspots on this set up, he says when idling the gate is in the closed position until positive pressure is reached to the level of the spring you choose, also on gear changes as boost drops the same again, it closes and you have major instant responce. i will try it out and see how it goes. the guy works for a living and this has been a 6 year project for him, he could not find suitable people to make the valve cheap enough so he bought his own cnc milling machine and made it himself..

Edited January 26, 2011 by rockabilly

[Rolls]

anymore results people?

it looks like a ghetto variable vanye setup to me, worse backpressure than a normal vv turbo but it has to spool better there's no way about it, you are halving the usable area of the turbo, will probably pose some restriction in the top end but my thinking is it will be completely worth it.

honestly I dont think it is that dodgy at all, surely the flow couldn't be much more turbulent than a normal dodgy log manifold or unequal length aftermarket one, and even if it is, it can't increase backpressure any more than just running a stock turbo.

[Lithium]

Thats pretty cool, I approve of this method - had actually been trying to come up with a good way of achieving basically the same thing but never posted anything. It still looks a bit more whorey than what I'd like to do, but I can't really knock it too hard. Would be very interesting to see videos of it in action

The thing which makes me curious is what affect the back pressure has on engine efficiency and tuning to suit, if you are letting it build to 20psi before opening the second scroll then I'd imagine that back pressure is getting very high - then it will suddenly drop substantially when the second scroll opens. It'd be interesting to see the torque curve.

[Legionnaire]

Ditto. However backpressure changes suddenly only if you suddenly switch it from fully closed to fully open. With a proper pressure source this setup should stabilize the back pressure for some engine rev range, while the valve opens gradually, and when it's fully open, backpressure rises again.

Actually if intake manifold pressure is used as a source, gradually opening valve does not stabilize back pressure, but rather reduces its rate of rise, as you have to maintain expantion ratio in order to keep level of boost. So many variables

Edited February 16, 2011 by Legionnaire

[Lithium]

The gradual opening thing is something which worries me a little, if its tuned on a dyno there is an assumption that at any particular boost level the valve will be so far open and timing will be adjusted to optimise that.

I am prone to overthink things, but I know with swingvalves there is a bit of a delay (most people with internal wastegates get a little bit of a boost spike on gearshifts) but what if you shift at high rpm with this setup? Conceivable that if the swing valve is set to 20psi, where it hits at around 4300rpm on the dyno- but rpm drop to 5000rpm on the gear shift and shoot straight up to 26psi.... there could be a very brief moment where you have 26psi of take pressure, a gazillion psi of exhaust manifold pressure and the ignition advance to suit something with perhaps have a gazillion psi of exhaust manifold pressure.

Could make for a pretty unfriendly engine environment in a track car, though just pondering out loud really.

[Rolls]

The gradual opening thing is something which worries me a little, if its tuned on a dyno there is an assumption that at any particular boost level the valve will be so far open and timing will be adjusted to optimise that.

I am prone to overthink things, but I know with swingvalves there is a bit of a delay (most people with internal wastegates get a little bit of a boost spike on gearshifts) but what if you shift at high rpm with this setup? Conceivable that if the swing valve is set to 20psi, where it hits at around 4300rpm on the dyno- but rpm drop to 5000rpm on the gear shift and shoot straight up to 26psi.... there could be a very brief moment where you have 26psi of take pressure, a gazillion psi of exhaust manifold pressure and the ignition advance to suit something with perhaps have a gazillion psi of exhaust manifold pressure.

Could make for a pretty unfriendly engine environment in a track car, though just pondering out loud really.

may or may not be an issue, if is you'd something that takes into account rpm and boost pressure, I imagine most decent aftermarket computers could offer something like this, or if you run it with rpm only you would need a decent boost controller that can compensate for it, depends what is slower the wastegate actuator or the flap actuator, the fastest one should be doing the most control, I imagine the wastegate would be the fastest so unlikely it'd prove a huge issue.

Just means you'd need a competent tuner who can test all possible scenarios and ensure stable boost and no detonation, couldn't be too difficult.

I can't see backpressure being a huge issue, you'd just tune the gate to open slowly once full boost is it, cause if you did it too fast boost would drop/dip.

Edited February 16, 2011 by Rolls

[Legionnaire]

Lithium, Also pondering out loud, just as you are, but I wonder if track 997 porsche turbos use VGT turbines. Just as this "quick spool" valve I don't think VGTs are suitable for a track car, unless of course it uses water cooled exhaust housings.

As for extremely high backpressures in certain circumstances - just to make sure I understand - 26psi in intake due to boost overshoot because of wastegate delay and gazillion exhaust psi due to spool valve operating lag, so both wastegate and spool valve are clorsed, but throttle is fully open and rpms are high? Is this correct? Timing may not be extremely advanced as when MAP-based ECU sees 26 psi when it expects only 20, it either shifts timing right back or cuts it off temporarily, but either way reacts before backpressure rises, on AFM-controlled ECUs... hm, I have to think about this... Dunno how PFC accesses its ignition tables, in factory ECU maximum load is seen when engine torque peaks... so 26 psi is irrelevant, is flow high in these conditions you described?

Anyway, that's exaclty why I wrote about importance of choosing a proper pressure source. I think we should use exhaust manifold pressure as a reference for the swing valve instead of intake manifold pressure.

Just means you'd need a competent tuner who can test all possible scenarios and ensure stable boost and no detonation, couldn't be too difficult

The problem is that some ECUs may be unable to tell the difference between normal and dangerous operating window beacuse of the way they access load points.

Edited February 17, 2011 by Legionnaire

[Lithium]

Urk. I have a small novel forming in my head, but just a couple of points to ponder on.

1/ If a tuner tunes to cover all scenarios in this kind of situation, they have no sensor for exhaust manifold pressure - so the only way they can make it guaranteed safe for all scenarios is tuning the whole thing as though everything is flowing through a single scroll. That would be aweful, exhaust pressure would be through the roof - if it could even maintain full boost like that. There would be minimal timing at high rpm/high boost and the car may as well have a much smaller turbo.

2/ An equivalent flowing twin scroll setup tends to take noticeably more timing/make more power through the middle of the rev range than a single entry manifold. Thats comparing two efficient setups.... what happens if you turn a twin scroll into a single scroll with half the flow potential, and 3 cylinders have an exhaust flow which could either take a pair of 90 degree bends going into the turbine housing, or just go straight in - while the other side just goes straight in.

[Fat_Tony]

Hey Rolls, I know what A/R is.

If you change the cross-sectional area of a 3d object the volume will change. Quick spool valve is not changing the A/R. I'm sceptical that blowing half the turbine wheel will give quicker spool.

Anyway if quick spool valves really work go buy one and prove me wrong.

[Rolls]

Hey Rolls, I know what A/R is.

If you change the cross-sectional area of a 3d object the volume will change. Quick spool valve is not changing the A/R. I'm sceptical that blowing half the turbine wheel will give quicker spool.

Anyway if quick spool valves really work go buy one and prove me wrong.

By blowing half the turbo you are effectively changing the a/r as there is less volume.

Urk. I have a small novel forming in my head, but just a couple of points to ponder on.

1/ If a tuner tunes to cover all scenarios in this kind of situation, they have no sensor for exhaust manifold pressure - so the only way they can make it guaranteed safe for all scenarios is tuning the whole thing as though everything is flowing through a single scroll. That would be aweful, exhaust pressure would be through the roof - if it could even maintain full boost like that. There would be minimal timing at high rpm/high boost and the car may as well have a much smaller turbo.

If you jam it shut all the time (why?) it will be like running a smaller turbo as you are only utilising half the blade area, then when it opens it is like using a larger turbo.

2/ An equivalent flowing twin scroll setup tends to take noticeably more timing/make more power through the middle of the rev range than a single entry manifold. Thats comparing two efficient setups.... what happens if you turn a twin scroll into a single scroll with half the flow potential, and 3 cylinders have an exhaust flow which could either take a pair of 90 degree bends going into the turbine housing, or just go straight in - while the other side just goes straight in.

You use a standard manifold, no way in hell you use a twin scroll manifold, I imagine you'd cook 3 pistons if you tried doing that.

The concept makes sense to me, it just depends how negative the effect of turbulence is.

Edited February 17, 2011 by Rolls

[zoidbergmerc]

anti lag would work better...

But I'm skeptical about these type of devices, you might get better pulse onto the Turbine wheel but you're also only doing it on half the surface area....

it'd be like one high pressure hose squirting a water wheel as opposed to two hoses using half the pressure on the wheel. Maybe if that one hose had a better mechanical advantage over the wheel then it'd be better...

More unbiased testing is required! If someone wants to donate a twin scroll turbo I'll be more than happy to test it

Edited February 17, 2011 by zoidbergmerc

[Lithium]

If you jam it shut all the time (why?) it will be like running a smaller turbo as you are only utilising half the blade area, then when it opens it is like using a larger turbo.

I explained it. I'll try and do it slower/clearer - even though you almost answered your own question.

When anyone who has half a clue upgrades their turbo, they retune their car to suit - right? So if you are going to have a setup which alternates between a bigger or smaller turbo and there is no way the ECU knows exactly which point in the transation the flapper is at, what tune should it use?

You use a standard manifold, no way in hell you use a twin scroll manifold, I imagine you'd cook 3 pistons if you tried doing that.

FFS, I forgot why I stopped partaking in tech threads in forums for a while. I'm not going to bother with my huge speel now - thanks for saving me some time. To make what I said make sense, read the thread - specifically the posts by Rockabilly I was referring to. Its all here.

I don't get how you guys don't see that this is essentially just blocking off part of the turbo making it seem like a smaller turbo, then when the valve opens it utilises the other half of the turbo as well, eg a larger turbo. Mazda did it on their series 4 rx7s apparently and there are loads of dyno vids on youtube showing how it works

Strange how people always made their Mazdas more reliable by binning the stock turbo setups.