Full-race's new toys
The only downside of the AC setup on the 4094 is that you have to use our AC downpipe, which obviously doesnt flow quite as well as our non AC downpipe. Of course if AC is a requirement, that decision is easy, and it will still flow plenty
we just keep trying harder and harder! thanks
actually they are both 30Rs. A GT3071R is the small 30R, and the GT3076R is the big 30R. The second two numbers in the title indicate the outer diameter of the compressor wheel in mm, the 3071 is a 71mm OD and the 3076 is a 76mm OD
the 3071R has a closer turbine to compressor match indicating better response, slightly better spool, and slightly reduced backpressure. This is the turbo preferred by our time attack test driver and our drift pilots. This turbo can do just shy of 500whp
the 3076R has a larger compressor. It can make more power than the 3071R but has slightly later spool, and slightly slower response. Most of our customers (and most evo guys) actually use this turbo and are still VERY happy with the response and spool, and they can be a bit more competitive on a drag strip. It can make a bit over 530-540whp
the 3071R has a closer turbine to compressor match indicating better response, slightly better spool, and slightly reduced backpressure. This is the turbo preferred by our time attack test driver and our drift pilots. This turbo can do just shy of 500whp
the 3076R has a larger compressor. It can make more power than the 3071R but has slightly later spool, and slightly slower response. Most of our customers (and most evo guys) actually use this turbo and are still VERY happy with the response and spool, and they can be a bit more competitive on a drag strip. It can make a bit over 530-540whp
It depends on what size turbine housing one uses. I drove Drifto's car with a 3076R and .78 A/R T3 TS housing, and it felt very 'V8-ish' - surprisingly responsive and ballsy. He's since gone larger.
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From: Cypress
Stuff I wrote about Twin Scrolls in SCC a long time ago
here is a snippet of an article about turbos I wrote for SCC, probably around 8-10 years ago, so long ago I can't remember. Perhaps it can serve as a good reference for this thread.
Another interesting aspect of turbine housing design is divided housings. Divided housing originated in the long haul diesel truck industry as a way to improve turbo response and efficiency. A divided housing is exactly how it sounds; the scroll of the turbine housing is split in two. Sometimes this is called a twin scroll housing as this was old Toyota nomenclature for this sort of design.
A divided housing can increase turbine efficiency by as much as 15% in some parts of an engines operating range in 4 cylinder engines. By efficiency we are talking about the percentage of work extracted by the turbine wheel as measure by shaft power out of the available energy in the exhaust gas stream. There are studies that show that a 2% gain in turbine efficiency can offset gains of up to 25% of the turbines inertia so a 15% gain in efficiency is quite significant. A savvy tuner can use a divided housing to his advantage on an engine with few numbers of cylinders. A divided housing works best on a 4-cylinder engine with some advantages on a 6 cylinder with a properly designed manifold. Divided housings are exceedingly potent on a rotary engine.
When a divided housing is used, usually cylinders 1 and 4 are fed into one side of the scroll and cylinders 2 and 3 are fed into the other side. The cylinders fed into each side of the scroll are as far apart in the firing order as possible. This allows the turbine to be hit with 4 distinct pulses as the engine goes through its firing order. This improves turbine efficiency, sometimes to the point where up to one size larger A/R housing with it’s attendant lower backpressure can be used, either that or less turbo lag can be enjoyed with the same size A/R housing.
The divided housing can also improve volumetric efficiency by making reversion from adjacent in firing order cylinders much more difficult. This is because there is a great deal of separation in degrees of crankshaft rotation between the valve opening events of the adjacent cylinders. In order for a reversion pulse to contaminate an adjacent firing cylinder, it has to travel back through the spinning turbine blades and up the other side of the divided turbine-housing scroll to get to the adjacent cylinder. This is pretty difficult and the pulse will tend to take the path of least resistance, past the turbine to the area of lower pressure, the exhaust. With less reversion an engine can safely tuned more aggressively for more power. Cam timing can be optimized more for power with less worry about limiting overlap to avoid reversion issues.
The fewer and more discreet the pulses fed to a divided housing turbo are, the better it works. On more than 6 cylinders, the divided housing is probably not worth the effort except perhaps in a V-8 engine with a 180-degree crank in twin turbo configuration. In this case, the V-8 can be treated as two 4 cylinder engines. Even if a divided housing exhaust housing is not used, if pulse separation can be maintained all the way to the turbine inlet of a conventional turbine housing, significant gains in turbine efficiency will still be noted, sometimes in the order of 5-8 percent. For some reason, divided exhaust housings have not been exploited in the tuner market or even by OEM’s outside of the commercial diesel market. Perhaps some visionary tuner will soon take advantage of this and come out with turbo kits designed in this way.
Another interesting aspect of turbine housing design is divided housings. Divided housing originated in the long haul diesel truck industry as a way to improve turbo response and efficiency. A divided housing is exactly how it sounds; the scroll of the turbine housing is split in two. Sometimes this is called a twin scroll housing as this was old Toyota nomenclature for this sort of design.
A divided housing can increase turbine efficiency by as much as 15% in some parts of an engines operating range in 4 cylinder engines. By efficiency we are talking about the percentage of work extracted by the turbine wheel as measure by shaft power out of the available energy in the exhaust gas stream. There are studies that show that a 2% gain in turbine efficiency can offset gains of up to 25% of the turbines inertia so a 15% gain in efficiency is quite significant. A savvy tuner can use a divided housing to his advantage on an engine with few numbers of cylinders. A divided housing works best on a 4-cylinder engine with some advantages on a 6 cylinder with a properly designed manifold. Divided housings are exceedingly potent on a rotary engine.
When a divided housing is used, usually cylinders 1 and 4 are fed into one side of the scroll and cylinders 2 and 3 are fed into the other side. The cylinders fed into each side of the scroll are as far apart in the firing order as possible. This allows the turbine to be hit with 4 distinct pulses as the engine goes through its firing order. This improves turbine efficiency, sometimes to the point where up to one size larger A/R housing with it’s attendant lower backpressure can be used, either that or less turbo lag can be enjoyed with the same size A/R housing.
The divided housing can also improve volumetric efficiency by making reversion from adjacent in firing order cylinders much more difficult. This is because there is a great deal of separation in degrees of crankshaft rotation between the valve opening events of the adjacent cylinders. In order for a reversion pulse to contaminate an adjacent firing cylinder, it has to travel back through the spinning turbine blades and up the other side of the divided turbine-housing scroll to get to the adjacent cylinder. This is pretty difficult and the pulse will tend to take the path of least resistance, past the turbine to the area of lower pressure, the exhaust. With less reversion an engine can safely tuned more aggressively for more power. Cam timing can be optimized more for power with less worry about limiting overlap to avoid reversion issues.
The fewer and more discreet the pulses fed to a divided housing turbo are, the better it works. On more than 6 cylinders, the divided housing is probably not worth the effort except perhaps in a V-8 engine with a 180-degree crank in twin turbo configuration. In this case, the V-8 can be treated as two 4 cylinder engines. Even if a divided housing exhaust housing is not used, if pulse separation can be maintained all the way to the turbine inlet of a conventional turbine housing, significant gains in turbine efficiency will still be noted, sometimes in the order of 5-8 percent. For some reason, divided exhaust housings have not been exploited in the tuner market or even by OEM’s outside of the commercial diesel market. Perhaps some visionary tuner will soon take advantage of this and come out with turbo kits designed in this way.
So are they making a T4 turbine housing for that? I know you said you will never go back to a T3 turbine housing
ok..i've been reading abt the TS for far too long now and I'm desperate to jump on the TS band wagon. I just bought a used ATP3071 kit, so please tell me as to which TS exhaust housing I should get to convert my turbo to a twinscroll setup??
The ATP stealth kits for Evos use a very custom, very compromised, and very NOT twinscroll exhaust housing.
Sell the ATP kit and buy a Full Race kit.
No, if you do that, nothing else will fit. It's impractical to attempt to recycle an ATP kit into anything else. About the only things that remain usable are the turbo and WG. Trust me, I've been down that road.