ct26
- Thread starter daledoe
- Start date
alltrac have 6 fins while we get 6. they spool faster but we get a bigger opening for air and which end up with better top end. those cost more to rebuild as well cause my friend got his rebuilt for 350 while i can get mien for 300.
The supra turbo is bigger, by like .0005 of an inch or something stupid.
The Ct off the celica and mr2's have a funky turbo exhaust footprint and exhaust housing.
The Ct off the celica and mr2's have a funky turbo exhaust footprint and exhaust housing.
um, ST165's aren't dual entry. ST185 and Mr2's are dual entry. Basically, second Gen 3s-gte's only are dual entry.
daledoe said:
ST205's are a similar design, but no longer bear the CT26 name, they are ceramic turbos.
some chicken cookers (rotissaries/rotaries) had twin scrolls too.series 4 or 5 i think.Dont quote me on it.
actually st165's did come as dual entry. JDM only though. Oh and the st205's turbos also had a antilag system. never buy used St205 turbos...
i thought it was to take adv of the 4cyl exh pulsing to help it spool up.All i know is that they(mr2,gt4) have a dual wastegate flap and supras single slightly larger flap.
The dual turbine inlet housing has two major advantages over a merged collector. It reduces turbo lag and increases engine volumetric efficiency by reducing exhaust contamination.
Turbo lag:
Each half of the turbine is connected to only half the cylinders of the engine. 2 cylinders on 4's, and 3 cylinders on sixes. When the exhaust valve opens, the energy from the cylinder only has to pressurize half the exhaust runners, not the entire manifold, hence increasing the velocity through the turbine, leading to a faster spool.
Volumetric efficiency of the engine:
In a turbocharged engine a lot of back pressure is generated between the exhaust manifold and the turbine. By separating the exhaust manifold and turbocharger into two separate pathways, you have twice the time available for the exhaust to exit, prior to the next exhaust port opening. Hence the exhaust coming out of the cylinder sees less residual pressure from the previous cylinder that just vented, leaving less unburned gasses in the cylinder and more room for fresh air/fuel charge.
That's the good news. The bad news is that you need to have a completely separated exhaust manifold for this to work. The dual scroll CT26 does bolt onto the MKIII exhaust manifold, but the stock manifold isn't sealed off to separate the cylinders (1,2,3 and 4,5,6). Also the turbine side and the compressor side are a lot smaller than the Supra CT26's. Knowing how unreliable the CT26's can be once bigger wheels are used, it's probably not worth the work to try to put one on. Unfortunately if you want to gain the benefits of using an aftermarket dual scroll turbocharger, you'd have to run two wastegates and a fully divided exhaust manifold to keep the two sides separated. The dual inlet CT26 accomplishes this by using a dual pathway (flapper) single wastegate.
Turbo lag:
Each half of the turbine is connected to only half the cylinders of the engine. 2 cylinders on 4's, and 3 cylinders on sixes. When the exhaust valve opens, the energy from the cylinder only has to pressurize half the exhaust runners, not the entire manifold, hence increasing the velocity through the turbine, leading to a faster spool.
Volumetric efficiency of the engine:
In a turbocharged engine a lot of back pressure is generated between the exhaust manifold and the turbine. By separating the exhaust manifold and turbocharger into two separate pathways, you have twice the time available for the exhaust to exit, prior to the next exhaust port opening. Hence the exhaust coming out of the cylinder sees less residual pressure from the previous cylinder that just vented, leaving less unburned gasses in the cylinder and more room for fresh air/fuel charge.
That's the good news. The bad news is that you need to have a completely separated exhaust manifold for this to work. The dual scroll CT26 does bolt onto the MKIII exhaust manifold, but the stock manifold isn't sealed off to separate the cylinders (1,2,3 and 4,5,6). Also the turbine side and the compressor side are a lot smaller than the Supra CT26's. Knowing how unreliable the CT26's can be once bigger wheels are used, it's probably not worth the work to try to put one on. Unfortunately if you want to gain the benefits of using an aftermarket dual scroll turbocharger, you'd have to run two wastegates and a fully divided exhaust manifold to keep the two sides separated. The dual inlet CT26 accomplishes this by using a dual pathway (flapper) single wastegate.
Shawn: LTNS! 
I thought for split pulse to work correctly they had to be grouped per the firing order and this is why there aren't many true split pulse systems around?
(Pipes get very ugly)
I thought for split pulse to work correctly they had to be grouped per the firing order and this is why there aren't many true split pulse systems around?
(Pipes get very ugly)