The Split Pulse Turbocharger Thread

[Dale FZ1]

It's likely that the major manufacturers DO have them under development, if not production.

The info is out there if you do a bit of searching.

But it is worth putting into another thread that deals with VNT.

[discopotato03]

With Variable Nozzle Turbine housing turbos (shortened version of VATN or variable area turbine nozzle) they want all the exhaust gas to go through the nozzle ie none wasted or bypassed around the turbine . The idea is to control boost (compressor speed) purely from variable gas speed (variable restriction) . If its possible to open the nozzle up far enough the exhaust gas velocity falls and the compressor speed becomes constant or even falls . Electronic controlls are what the manufacturers would need to stay on top of things like exhaust gas temperature and possibly to assist exhaust gas recirculation if need be . All sorts of strategies used to make NoX emissions suit the laws of the land .

I think from our point of view the complexity is too great and too limiting for the "aftermarket" .

Yes OT , I was just at Nasoic and found this in a thread I've been watching . Some interesting thoughts about T4 vs T3 flanged T4 twin scroll housings . Of no interest to those with split pulse T3 flanged manifolds but if you happened to have a T4 flanged manifold ie HKS low/cast with the T3 stud pattern and could have both T3 and T4 food for thought . Both the RB20/25 and RB26 low cast HKS manifolds have this T4 sized flange its just that the 20/25 one has smaller ports but they could be opened up ...

Cheers A .

Edit , link removed see below .

Edited June 11, 2007 by discopotato03

[discopotato03]

Sorry link doesn't work . Search New exhaust manifold by Full-Race for Subies ! Page 15 .

Cheers A .

[BHDave]

Yeah, i know, I'm a bit of topic but my thoughts tend to bounce around;

Overall, a bit of a disappointing night, but i did learn something from it; The cef only had it's cams installed the previous night and was run up on the dyno to tweak the tune and proceeded to spit out a clutch at about 270rwkw around 4-4.5k. I think he would have had me. So i have about a 2 week wait to see what he can do and the same dyno. I really wanted to see what the 71mm compressor could do in a back to back situation as it would have sealed the deal for me if it made more power with better response.

I was down by about 10rwkw when initially run up with the same setup as my last 288rwkw run. Only changes were the rb25 gearbox install, new diff center and a new set of rt215's. I'd added some octane booster to see how far i could push my current setup and see if i could break the magical 300 barrier so proceeded to add a couple of degrees timing, and made 281rwkw. Then added a touch of boost (up to about 19psi up top), and made 281rwkw, then added another 3 degrees timing gradually, and made, you guessed it, 281rwkw.

Correct me if i'm wrong here, but does this mean that i'm really not that far off having the power capped by the turbos ultimate flow capability (compressor or turbine?), rather than detonation threshold? I'm talking peak here, as there were small midrange gains made by both the addition of timing and boost. It's this mid range area i'd expect to improve with the use of the newer smaller compressor and twin scroll housing. Is this a correct assumption? That is ultimately my goal now that i know i'll never reach 300 with what i have so i'm not interested in going there as i'll lose the power down low that i really enjoy.

I suppose the other thing worth asking, is whats this saying about the turbine inlet pressure and it's effect on the whole situation if i'm only a couple of degrees timing short of ultimate peak power of the system with my current .63 turbine housing? Should a just stick with a .63 3071?

Edited June 10, 2007 by BHDave

[Dale FZ1]

I'm still backing that you will have the higher peak power numbers pretty much through the range but definitely up top. Transient on-road response might be another deal - your rotating assembly is bigger and physics should dictate it is slower to accelerate. Maybe Adrian can chime in with the impeller dimensions of your HKS T3/TO4S hybrid? I'd say that the turbine is the flow-limiting factor because your compressor should do more, and the cams are a help with efficiency.

I'm interested to see the results of your dyno battle, but more interested to hear what happens in back to back driving. Maybe the Pro-S should give good light-throttle driveability, whereas yours would need to be driven more on the throttle to get it moving?

I'd be even more interested again to hear what happens if you could also run it up against a 3071, split pulse or not. That would add an extra background dimension to whatever Full-Race Geoff comes up with.

[saliya]

http://forums.nasoic.com/forums/showthread...570&page=15

From post #368 on .

Cheers A .

Try

http://forums.nasioc.com/forums/showthread...570&page=15

Regards,

Saliya

[Cubes]

Playing around with Performance Trends Engine Analyser Pro I noticed they had a little option to select between twin and single scroll turbo's.

According to the simulator it appears the largest gains are to be had during spool, power equals out once spool is matched by the single scrol, peak power is made and then as power is falling off the twin scroll appears to hold power ever so slightly better.

Interesting. Slowly getting the hang of this engine sim. I've taken inlet, port, valve, exh and turbo measurements. :S

Spool appears to be pretty spot on with what I would expect out of a given turbo on mysetup.

Excellent program for the fiddlers out there.

[180bfj20det]

Anyway news on the full race testing disco?

[discopotato03]

Not sure , I'll ask later in the day or this evening . I have a feeling that international parts junket Seema Ceema what ever is looming so time may be short .

If I had the time I'd search through some of the Supra or Bimma forums to see what sorts of results they are getting from 2.5-3L turbo twin cam sixes . Some of the Supra crowd are pretty switched on but like everywhere some want too big too much too sick .

If I hear anything I'll pass it along , cheers A .

[PSI Parts]

I know this thread is very old, but wanted to see if this ever went ahead, as I'm just deciding on the final specs for the Twin Scroll GT3582R for our demo car.

[Lithium]

What specifically are you after? I've seen some pretty convincing results from twin scroll setups and am a total convert, my next turbo setup will definitely be a twin scroll one

[Harey]

Hi all , I've had an E mail back from Geoff Raicer to say that he read these TS type threads here . He said the only way to show the difference is to experience both because the difference is really noticable .

In about 6-8 weeks he is going to do some dyno testing in the following configs .

The engine will be a "stock" RB25DET except for the GRedy (sp ?) inlet manifold and a GT3071R turbo so .

1) Std exhaust manifold with a single scroll GT3071R , not sure which A/R housing , tune and dyno .

2) Change to Full Race manifold with same turbo , retune and dyno .

3) Change turbine housing to twin scroll , retune and dyno .

The results should be very interesting though how well the graphs relate to the real world experience is hard to say .

I'm going to ask him if he can log exhaust manifold pressure (turbine inlet pressure) and compare or overlay the numbers to the inlet manifold ones . I don't know if they'll get the chance to try a twin scroll GT3076R and GT3582R but it would certainly answer the question of can bigish (not hugeish) turbos be reasonably responsive without being restrictive on the exhaust side (ie resorting to small A/R's) .

I think also more TS turbine housings are going to be made available but no details yet .

Cheers A .

The results of this I believe is what he wants. Well its what I want anyway

[Lithium]

OK sweet, I thought so but just wanted to be sure. For what its worth - I know a couple of people who have independantly switched to twin scroll configurations using the same CHRA, just changing the manifolding to suit and have fantastic results.

One was from a .82a/r GT3582R to a 1.06TST4 GT3582R on an EVO and it gained a few hundred rpm in spool and made roughly the same peak power.

The other was going from a .96a/r single entry T04Z to a 1.00a/r twin scroll housing (on my recommendation and having issues with disappointing spool and power <gloat>) on a built VG30DET. The car also improved spool by around 400rpm, torque for a given boost level went up substantially and as such power did.

The car also wanted to take much more timing, so much so that the owner and the tuner decided to change the ECU on the car as the amount more timing it wanted seemed alarming compared to where the car previously became knock limited. They stopped tuning at around 430wkw (from 390wkw at the same boost on the .96a/r housing) and ran it up again with a G4 Link, where they ended up with 460wkw on pump gas - with far better spool and generally way better driveability.

The owner of the car did all fabrication himself, so this is not a fancy big dollar twin scroll setup

[discopotato03]

PSI this is my opinion only but to get everything out of a GT3582R you need the T4 international sized flange on the manifold and a suitably sized TS turbine housing . You need two external wastegates on the exhaust manifold as well .

ATP Turbo is the US are advertising T4 flanged TS housings machined to suit a GT3582R in 1.06 A/R and possibly 0.82 A/R .

They also do "T3" flanged housings as well but I reckon you won't get enough exhaust gas through the largest ports it's possible to fit in the smaller flange .

I think once your engines cylinders get much beyond 400-450cc you need the T4 TS flanges larger ports to vent the gas without a pressure rise in the system - this is to make serious power BTW not just tooling around power levels .

Supra people often have 3L std and they don't muck around with "T3" flanged manifolds and turbos .

I believe when you're talking about crank power levels of maybe 450 plus the T4 stuff is essential if you want the twin scroll type of system to function properly .

I agree that big single scroll T3 flanged turbine housings can go beyond that figure but they do't have the divider taking up gas path space so their maximum flow potential would be greater than a "T3" flanged TS turbine housing .

A .

[GTScotT]

What specifically are you after? I've seen some pretty convincing results from twin scroll setups and am a total convert, my next turbo setup will definitely be a twin scroll one

setup whore

[Lithium]

setup whore

I reckon broad minded person is a much more accurate term. PS, it was a coil.

[GTScotT]

I reckon broad minded person is a much more accurate term. PS, it was a coil.

fair point agreed, and thought so lol. Yargh

[JonnoHR31]

On the topic does anyone know of anywhere that sells T4 flanged twin scroll gt30 turbine housings? atp have a listing for it under housing options when buying a complete turbo but not in the serperate turbine housing lists, gonna email them when it comes time to buy but just curious who else sells them.

[juggernaut1]

deleted due to double post

Edited March 25, 2010 by juggernaut1

[juggernaut1]

Just email ATP. I've bought parts off them this way when they were not specifically listed on their webpage. Generally, they get back to you overnight with a response.

Other than that try GCG.