Twin Scroll Vs Single

[discopotato03]

I don't know of any twin entry T3 , Euro T4 , GT30 turbine housings but the non gated one I see most is the GT32 plain bearin one - search for GT3267 in 0.78 AR .

The only real GT30 TS IW housings I know of are the Evo 10 ones but they have a different mounting flange .

Possibly the best response GT3076R (IMO) would be the 52 comp trim one with a 0.63 AR GT30 turbine housing .

If it were me the 0.63AR with a good smooth up job in the turbine housing and maybe exhaust manifold would be good enough . I dunno about a lot of boost at 7500 but more that enough to be a tractionless pig in a RWD car with the boost turned up .

If you could go inside the engine and fit a tad more capacity ie 26 crank and 1mm over pistons it all helps . I would touch anything under 9.3 to 9.5 static CR and Poncams don't go astray . Then just bolt a 56t GT3076R on with the 0.82 housing and tune the thing properly .

On the cheap , a std freshened up RB30 short and if you could spare the cash higher compression pistons .

My conclusion is that twin scroll systems are either too expensive or too defectable on single turbo Skylines so tried and proven single scrolls and extra cubic inches end up being easier .

A .

[GTScotT]

If you could go inside the engine and fit a tad more capacity ie 26 crank and 1mm over pistons it all helps . I would touch anything under 9.3 to 9.5 static CR and Poncams don't go astray . Then just bolt a 56t GT3076R on with the 0.82 housing and tune the thing properly .

On the cheap , a std freshened up RB30 short and if you could spare the cash higher compression pistons .

My conclusion is that twin scroll systems are either too expensive or too defectable on single turbo Skylines so tried and proven single scrolls and extra cubic inches end up being easier .

Disco, could you give me your opinion on 8cm to 10cm turbine housing with a 1:1 increase in CR? On an SR.

Am thinking would possibly make for a better driving car than not.

[nik.]

Why dont you just get a Garrett EVO9 replacement twin scroll GT3071 or 3076 with internal gate.

You will find that the 0.76AR TS GT3071 will spool about the same rate as the 0.63 GT3071 but the power will be more - ie closer to the 0.82. Twin scrolls are about broadening the torque curve.

My pick for 280rwkw with the rb25 would be the TS GTX3071 with the 0.73A/R. I would expect that power at 15psi with full boost around the 3000-3200rpm range.

Lol is this a stab in the dark? As that information is also inaccurate. Twinscroll generally makes more midrange and less topend vs openscroll.

[simpletool]

Probably the EFR 7064 will fit the bill.....if it ever gets released. The EFR 7670 seems to be between the GT30 and GT35 - so too big for you.

AND you can have either single scroll (T3) or twin scroll (T4) with internal wastegate. No need for external wastegate.

Edited July 8, 2011 by simpletool

[discopotato03]

8-10cm housing on what ?

I thing the Garrett GT28 based turbos are the go for SR20s , either the GT2860RS or any but the biggest trim GT2871R . The reason being that they use either a GT25 or GT25 BB turbo std so the GT28 ones go on easily enough .

I'm not really an SR 20 person but if I was it would have the early high inlet port non VCT head and the GTiR four throttle inlet manifold .

A

[Lithium]

Going by this dyno plot, a GT3582R with an ATP T4 1.06a/r twin scroll turbine housing will more or less hit the magical 200kw by 4000rpm mark on an RB25:

[Rolls]

Very weird looking dyno plot, looks more like a torque plot than a power one. Torque must absolutely nose dive after peak boost.

[juggernaut1]

Very weird looking dyno plot, looks more like a torque plot than a power one. Torque must absolutely nose dive after peak boost.

Solid line looks like torque....dotted line is power....albeit in PS so would read lower in KW's.

Edited August 9, 2011 by juggernaut1

[Rolls]

Ah that makes more sense, missed the dotted line before

[Lithium]

The curve is a lot less steep than some because its not a peaky power delivery It'd read less in kw, but its still at 280ps (208kw) by around 4000rpm and reaches 526ps (390ishkw) which makes for a pretty impressive spread of grunt.

[SimonR32]

Going by this dyno plot, a GT3582R with an ATP T4 1.06a/r twin scroll turbine housing will more or less hit the magical 200kw by 4000rpm mark on an RB25:

That is predicted flywheel ps and not wheel ps. So take off a fair whack of power everywhere

[SimonR32]

The curve is a lot less steep than some because its not a peaky power delivery It'd read less in kw, but its still at 280ps (208kw) by around 4000rpm and reaches 526ps (390ishkw) which makes for a pretty impressive spread of grunt.

As my above post realistic figures are probably more like 165kw by 4000rpm and 310rwkw

[Rolls]

That is predicted flywheel ps and not wheel ps. So take off a fair whack of power everywhere

So it is different from other dyno sheets? Aren't they all predicted hp?

Or do you mean theyve inflated it to give flywheel hp instead of wheel hp? What would be the purpose of that?

[Lithium]

How can you tell its inflated flywheel power? I'm not that familiar with DD dynos.

[JonnoHR31]

yer inflated to roughly give flywheel ps. some people just prefer it that way....

[D_Stirls]

So your saying that PS = BHP not WHP? Can't it be either it's just a unit of measure and the graph doesn't say where the power was measured.

PS

This unit (German: Pferdestärke = horse strength) is no longer a statutory unit, but is still commonly used in Europe, South America, Japan and India especially by the automotive and motorcycle industry. It was adopted throughout continental Europe with designations equivalent to the English horsepower, but mathematically different from the British unit.

DIN 66036 defines one horsepower to lift a mass of 75 kilograms within one second against the earth gravitation over a distance of one metre.[10] Similar definitions were already common to the time of James Watt.

The PS was adopted by the Deutsches Institut für Normung (DIN) and then by the automotive industry throughout most of Europe, under varying names. In 1992, the PS was rendered obsolete by EEC directives, when it was replaced by the kilowatt as the official power measuring unit. It is still in use for commercial and advertising purposes, in addition to the kW rating, as many customers are still not familiar with the use of kilowatts for engines.

Edited August 9, 2011 by D_Stirls

[Lithium]

Yeah that's why I assumed it was wps, I have seen DD plots using Shoot6f so figured it was standard

[Beer Baron]

yes but either way I think you've mixed up the lines. dotted line is power for sure. other line would be boost or possibly torque. it's only hitting 250ps at 4000 RPM which is around 180kw. I agree it's probably at the wheels. it's pretty good but not super awesome.

[SimonR32]

So it is different from other dyno sheets? Aren't they all predicted hp?

Or do you mean theyve inflated it to give flywheel hp instead of wheel hp? What would be the purpose of that?

If you look at the power axis you will see that it is referred to as S_PS

The "S" represents predicted flywheel. So any Dyno Dynamics graph with S_HP or S_KW etc is predicted power at the flywheel not recorded power at the wheels.

The guys from the UK tend to use it a lot... See below as an example, this is a stock RB25 turbo on a RB25 running 12psi (which would be around 270rwhp normally)

[Lithium]

yes but either way I think you've mixed up the lines. dotted line is power for sure. other line would be boost or possibly torque. it's only hitting 250ps at 4000 RPM which is around 180kw. I agree it's probably at the wheels. it's pretty good but not super awesome.

Not sure who that is directed at, I knew the dotted line was power.

The 4000rpm line is a bit hard to nail down exactly, but at 4140rpm it looks to me to be sitting at around 294ps (216kw) which is fairly stout in my books.