Spool Valves?

[VB-]

im always up for tips on how to reduce lag, and recently saw a dyno graph with a gt55 turbo on a supra which had a curve like it was a t04z.

the supra was stroked to 3.4L and some nice cams but he also mentioned that half the reason why the spool was so insane was because he had a "spool valve"

from wat i understand its basically using a split pulse manifold system and blocking off one side to force the exhaust cases through the other one. resulting in more restriction thus faster PSI buildup.

any professionals care to explain this tatic any any pros and cons?

honestly never heard about it until now

btw does anyone actually sell these in aust?

Edited April 7, 2009 by VB-

[Cjmartz2k]

I see thread pop up about this every few months on other boards. I've never actaully seen anybody use it other than that one write up with the Supra, but it requires a NON-split pulse/twin scroll manifold to work. It's interesting for sure, but I've got a split pulse manifold, so I'm not going to be a guinea pig. How much do they cost?

[VB-]

from wat i hear around 600US =[

would be definitely worth it if it it does wat they claim.

[Evan_R33]

im always up for tips on how to reduce lag, and recently saw a dyno graph with a gt55 turbo on a supra which had a curve like it was a t04z.

the supra was stroked to 3.4L and some nice cams but he also mentioned that half the reason why the spool was so insane was because he had a "spool valve"

from wat i understand its basically using a split pulse manifold system and blocking off one side to force the exhaust cases through the other one. resulting in more restriction thus faster PSI buildup.

any professionals care to explain this tatic any any pros and cons?

honestly never heard about it until now

btw does anyone actually sell these in aust?

I don't see how this would be effective at spooling a turbo any faster. Basically this would create more pressure on the manifold side of this valve as the exhaust gasses try and pass trough what is a smaller opening and as i have been taught increased pressure does not increase flow through the same sized hole.

Basically this is choking your exhaust. The best way to spool a turbo is to get as much exhaust gas onto that turbine wheel as soon as possible. Putting a restriction like this in place i can't see how it would work as you are basically halving your exhaust flow with the restriction like that in place...

use this calculator ( http://www.efunda.com/formulae/fluids/calc...iction.cfm#calc ) to see that increasing the pressure without changing the pipe diameter does not alter flow at all. change the pipe diameter however and watch the flow increase.

I wouuld say that there would be a optimal size in exhaust header diameter to keep flow and gas velocity at an optimal level.. but to my mind a contraption like this wouldn't help.

My two cents, hope it helps.

Not to mention companies like HKS/GARRETT etc probably don't make these and that would be a fairly good indication as to whether they work or not.

[zebra]

It would work by accerlating the gas flow into the turbine at low revs. so instead of having a large area of slow moving gasses they have a smaller area of high speed gasses.

I could work in theroy but without having serveral diffenent cars with it to back up the results its all hersay.

[Lithium]

The fact that they could improve spool etc definitely makes sense - its effectively like hugely tightening up the turbine a/r, though ultimately I don't like them - they would make the breathing of the engine very inconsistant and even when its open I really can't see it doing anything other than creating a restriction. All the dyno plots I have seen with hem being used seem to finish at the point the "normal" setup catches up... what happens to top end flow?

There may be a better way of doing the same kind of thing.

[VB-]

i agree with lithium, causing a restriction would basicly rack up psi way faster.

as far as top end, i dont know how this would be possible due to restriction. but they claim it gives a 25% INCREASE in top end and improved spool.

if i can get my hands on one id defiantly be interested in trying it out.

[Cjmartz2k]

It effectivly halves your a/r then opens up at a certain psi when the turbo is well on it's way to being spooled. It's kind of like a poor man's variable geometry turbo. I'd be worried about it standing up to high temps. I have no doubt it works, but how well and at what cost/pain in the butt are my questions.

And basing whether or not something works off of whether or not HKS or Garrett makes it is rediculous.

[discopotato03]

I did once see a diagram of something along those lines but I smell marketing rather than function driving this idea .

Firstly to have it work properly you'd need an open collector manifold with that thing between the manifolds mounting flange and the twin scroll turbine housing .

What it does is feed all the engines exhaust gas through one side of the divided turbine housing until the plates throttle opens up .

I image once the boost , or preferably the exhaust manifold , pressure reaches a set point the actuator opens the throttle valve .

The downside is that the throttled side won't flow as well as the open side and the open collector manifold won't work like a true twin scroll system .

I think a 3.4L 2JZ type thing should not have dramas making torque off boost or kicking a big turbo into life if the manifold/gates and the overall state of tune is on the money .

Gimmick I think , cheers A .

[T04GTR]

i will be building one,, anyone know where i can find some inconel sheeting?

[T04GTR]

oh that and they are 500usd for a t4 flange.. a guy on ebay made some the SAME for $100 but got sued by sound performance coz they have a patent pending on it...

evan though borg warner patented the concept using a valve in the actual turbine housing....lol

[Fastrotor]

Just look at the Series 4 Rx-7 .............. It had this setup from factory !

Gary

[T04GTR]

lol... sweet

[Cjmartz2k]

$500 isn't too bad if it works I guess. Holset does the same kind of thing with variable vanes in the exhaust housing effectively changing the a/r. It makes a 600rwhp turbo spool like a stock turbo, but the problem is it's electronically controlled via the factory Dodge ECU and people have yet to make it work real well in a non-OEM application.

[VB-]

i defiently think this would be the next best thing since sliced bread, but looks like its very new to the market still.

id give ti another year, thing will be selling faster then HKS BOVs

[Cjmartz2k]

It's already been around for a couple years. I think they were having some kind of "development problems" which is why they put the idea out there, but didn't sell it yet. Maybe making it last on high hp daily driven cars is still a big hurdle.

[PM-R33]

Hmm interesting idea, never come across it before. However when its fully open, surely the side with the valve in it would be at a greater restriction than the other side causing a larger pressure build up in the runners for cylinders 4, 5 and 6. This wouldn't have a slight negative effect?

[R31Nismoid]

Been around a lot longer than a couple of years

[VB-]

Hmm interesting idea, never come across it before. However when its fully open, surely the side with the valve in it would be at a greater restriction than the other side causing a larger pressure build up in the runners for cylinders 4, 5 and 6. This wouldn't have a slight negative effect?

you would think so huh?

but they claim it would ACTUALLY increase top end by 25%.......dunno how but insane if true.

[Fastrotor]

Obviously you would have to run a normal (non split pulse) manifold, and a split pulse turbine housing ....... when closed all the exhaust gas is re-directed thru one side, generally 1/2 A/R of total housing rating. So spool up would be same as a much smaller housing, and top end of the larger housing. There would be a slight restriction to the runner with the plate in it obviously, and so i would say power could be slightly lower , top end. Depends on how hard the housing is working to make the power you are at.

As i mentioned , this was a factory setup on the S4 Rx-7. It however , used a setup more akin to a wastegate flap, not a butterfly.

I wonder what materials they used, as that flap looks quite thin. You'd think there could be probs with it sticking too with the huge heat range it would be getting.

Gary