Originally posted by Jun9970@Sep 17 2004, 15:01
A quick question.
The 6A12TT engine has a pair of turbo's which boost in tandem.
There are inherent limitations to the upgrading of these turbines due to the spacial contraints posed by the firewall on the 2nd turbine (closer to the driver), [not to mention gobs of lag if the turbo's r not sized correctly]
After such discussion, a fren of my posed a question, what if he were to only upgrade 1 turbine, ie the one further away from the driver, to lets say a TD04L (which he has at home from his GSR days).
Assuming there is enough fuel and spark, would there be any drawbacks? ie engine not balanced due to different loads on the exhaust side, uncontrolable boost spikes? etc..
would love to hear your opinions, guys.
p.s. For arguement sake, lets say he doesn't want to go with a customised turbo exhaust manifold. He wants to use the stock manifold.
I'm not sure if the bolt pattern on the flange is identical between the TD04L and TD02. maybe someone knows. Anyway, assuming it can be done, will it work? ie more power? more response?
I think the Efini has different sized turbo's as well. So can it work on a 6A12TT?
I'm not expert in any twin turbocharger. But it's my opinion after changing 5 turbo..
I assume you're ready for fuel, ignition and else.. Let's say the td04* turbo flange is not same as TD025. Meaning that U still have to customize it.
Power would be differ because changing of compressor size, and diffrent CFM load.
I think stock twin turbo(td02) will be faster on accelaration compare with td04.
A bit lag, ie boost kick at above present boost kick .
A good choice of turbo where it should be bigger than stock?? I think you should take the td04 twin blade.. Because I experiened it on Daihatsu L2 engine where Single blade td04 turbo put more lag compare to td04 twin blade.. and IHI RHF4 VF14 have less lag than td04 twin blade.. But Daihatsu L2 modifier usually searching for td04 diesel turbo where the turbin smaller than petrol engine.. The A/R of turbo is different.
If your thinking to make it Sequential Turbo the problem appear where there's a loop at your hp graph.. (tested on GTR).. when changing boost kick at your secondary turbo but it put a good accelaration compare to parallel turbo.
Parallel turbo would be better if you searching for better top speed or boost kick above RPM4000.
About uncontrolable boost spikes.. you need to change to external wastegate or harder actuator_bypass valve :P ie HKS actuator.. heheehe small turbo no need laa
That's my opinion