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  • 4 weeks later...

Shameless plug for twin scroll systems because done properly they really do work . They stand a far better chance of making a wider overall spread of torque and it makes all the difference usually in the mid range .

Feels more more like a larger capacity NA engine , yep thats what everyone says that goes down this road .

I'm going to wait and see how the Evo 10 TS TIW GT3071R's and GT3076R's go because twin integral waste gates make life so much cheaper and simpler .

Being Garrett GT30 TS TIW turbine housings you can be pretty sure the turbine/housing combo actually works .

Theres going to be a choice of (from memnory) 0.73 and 0.94 A/R sizes and once you get around the model specific Mitsy flange patterns (6 Boost ?) you've got it made .

We had to wait ages to get real Garrett IW GT30 turbine housings , the TS TIW ones should be the icing on the cake .

Congrats on a great result , cheers A .

Mine is the Garrett TS GT32 rear housing as available from ATP.

This housing can also be used for the GT35 although bored out to suit the bigger wheel as available from ATP.

http://www.atpturbo.com/Merchant2/merchant...tegory_Code=BCS

Stre8e180, on this forum, used the GT35 with T3 .78 rear on his RB26 and made nearly 400 rwkw but struck some fueling issues.

I've also been watching another build nearing completion of a Full-Race Dual Gate TS GT35 with T4 1.06 rear on a standard stroke SR - will be interesting to see the results of this.

http://www.freshalloy.com/forums/showthread.php?t=186058

However, I wonder if E85 became commercially available whether to some extent TS will become redundant as the additional timing allowed with E85 will make single scroll housings that much better. Alternatively, twin scroll and E85 may be just better again if this thread is anything to go by.......this setup used race fuel in his SR20 with T3 TS .78 3076 using 31 psi, which was reportedly reached by 3800 rpm and made 489 ft/lb torque and 573 hp on a dynojet. OK discount those figures by around say 20% and an estimated 460 dyno dynamics rwhp from stock stroke SR20 with full boost by 3800 rpm isn't shabby.

http://www.freshalloy.com/forums/showthread.php?t=190508

.

Sadly we need a few pathfinders here in Australia to demonstrate that big A/R housings (twin scroll ones) don't cause the same turbine lag as they would with with a single scroll and single collector exhaust manifold .

E85 doesn't really achieve the same thing as a twin scroll turbo system , you do get enhanced performance through better charge cooling (more fluid being squirted in and the evaporative cooling effect) and more efficient burning through timing the spark so that the cylinders pressure rise occurs when it will produce the most torque . So a higher detonation threshold and charge cooling is where apple juice is at .

Propper twin scrolling and E85 together should be very good .

I didn't chase those links far enough to see but another advantage of twin scrolling is the ability to run big cam profiles if need be .

A .

Twin scroll TIWG , your wanting ...

From where I sit the process goes like this .

Someone sits down and works out how to construct turbo manifolds and alls well .

Then one day someone asks for a pulse divided version and the fabricator pretty soon works out that a lot more time is needed to stitch it all together . On top of that to do it properly the external gates feed pipe has to be divided all the way to the valve , or two divorced gate mounts made .

Of course when the masterpiece is complete the customer often doesn't appreciate how much extra time went into making the thing and won't hear of paying what its worth .

I'd say its easier to sell a large number of single collector manifolds and thats probably the limit of what many people will pay for .

Do some homework , places like freshalloy.com are good to troll around in if your Nissan minded .

When you get used to seeing hard core results at places like Hondatech.com/Freshalloy/Evolutionm.net/NASIOC/Supraforums etc etc a certain manifold producers name keeps showing up .

In the US they don't like paying serious money for "a bunch of bends and plates welded together" any more than we do , but if they could have anything lots would have A FullRace one . Same here , if I was serious about it I wouldn't have anything else .

When divided turbine housings grow divided wastegates it will get cheaper and easier because the awkward bits been taken care of further down the line .

Point . Twin scroll systems really do work , if they didn't high performance diesels wouldn't have them and neither would the higher tech Evos and Subarus etc .

The other way to attack the problem with an RB is to make two isolated exhaust manifolds and bolt up parallel twin IW turbos . The same kind of gains for the same reasons , divide the cylinders into 2 groups of three all the way to the turbine/s and use two divorced waste gates RB26 style .

Your call .

Sadly we need a few pathfinders here in Australia to demonstrate that big A/R housings (twin scroll ones) don't cause the same turbine lag as they would with with a single scroll and single collector exhaust manifold .

Twin scroll TIWG , your wanting ...

I preach the gospel and sometimes I manage to convert: http://forums.toyspeed.org.nz/viewtopic.php?t=71870

That the results speak for themselves is something .

My bottom line is that turbocharging is generally cheaper and easier that fitting an engine of something up to double the originals capacity .

The thing that has to be remembered is that when you increase an engines power output you increase its exhaust gas output but if you have an exhaust tract that can handle the extra volume or it'll choke .

To make high power with a turbocharger means also having to increse the the exhaust throughput starting with the exhaust manifold and turbine housing .

The stumbling block is having a turbine housing that accelerates the exhaust gasses into the turbine blades without forming a restriction or pressure rise .

When you have all of the engines cylinders pulsing into a common collecter and turbine nossle you WILL get a pressure rise unless the housing A/R is quite large . This in itself is not an issue unless you want turbine response in the low or middle of an engines useful rev range .

There is no black art in any of this , no ASIO spec turbine or housing at all .

There is no other method that gives all the advantages of a properly set up and functioning TS system .

If you truely understand how the four stroke cycle works it becomes very clear that this is the only way to have good turbine response while keeping the engine happy exhaust flow wise .

All I can say is research the results and go figure .

A .

Its very easy to TALK about how good a ts set-up will be, the reality isn't nearly so simple. I was simply pointing out why bugger all people give it a try, because even if you want to, local manifold makers aren't interested and its hard to justify 4k for a fr manifold.

Once i'm back in oz I'l be giving it a crack, and will post back to back results from the same dyno.

As I said it's the cost of the manifold and wastegating thats the problem .

This is why I think the TS TIWG GT3071R/GT3076R has so much promise , granted it doesn't have the twin outlet mount flange that an RB20/25 exhaust manifold has but it would be a bonus if it did or could be adapted .

If you had to have a divided manifold made whats to stop you asking for one with the Mitsy Evo 10's mount flange in the appropriate place to plonk a GT3071R/GT3076R in ?

Won't need the two divorced external gates or mounts because the Garrett GT30 TS TIWG turbine housing does it all for you .

Granted still not ultra cheap , good performance often isn't .

A .

I preach the gospel and sometimes I manage to convert: http://forums.toyspeed.org.nz/viewtopic.php?t=71870

The comment about timing in the thread link mimic's what my tuner found also - that he was able to add more timing - scarily so - but backed it off to a level where he felt 'comfortable'.

Its very easy to TALK about how good a ts set-up will be, the reality isn't nearly so simple. I was simply pointing out why bugger all people give it a try, because even if you want to, local manifold makers aren't interested and its hard to justify 4k for a fr manifold.

I'm fully sold on twin scrolls now, and my next stage with my Skyline will have to involve one. I'm no fabricator, but I would have thought they'd to some degree be easier? A pair of 3>1 collectors must easier to find equal paths to than a single 6>1 in a tight engine bay I would have thought?

Quite some years back the feller that ran Pulse Racing/Pulse turbocharging was making them out of steam pipe and TIG welding them nicely . His collectors looked good to . I didn't see it myself but stories of making 700+ CHP from a 2L FJ , with 30 lbs boost and 30 deg of full load timing and god knows what witches brew fuel . And a big series TA45 I think .

A little birdie tells me that he's been with Plasmaman since but I haven't seen him for years .

Also don't bother trying to make the mythical equal length equal diameter 3-1 plus 3-1 spaghetti manifold .

The critical thing is having the PRESSURE DROPS equal because thats whats important not the runner length .

Playing with drop tests to equalise the pulse energy takes time and money and again trying to justify the development costs to prospective customers for small volume sales is difficult .

A .

Edited by discopotato03

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