replacing a ct12b turbo with a ct16 turbo TOYOTA

[vvilly]

hey all at smoko today was talking to a few of the mechanics about changing a ct12b turbo with a ct16 turbo.

so taking the ct 12b out of the 1kz and replacing it with a ct16 out of a 1kd

i have been told that the flanges are very similar if not the same

How would you run the variable geometry, control it (electronically).


has anyone tinkered with this idea or done it


i have been googling but to no prevail


Jase

[rob-mu]

Just send your ct12b to Steve Murch and about $700+ Later you get a new turbo with a bigger billet compressor wheel

[3VILC]

Look up 'dawes valve'. Allows the vacuum supply the the VNT actuator to be regulated with a boost supply from the manifold more like a traditional turbo. Assuming they work the same way as nissan VNT turbos they are often used on late model patrols etc to take VNT control away from the ECU.

[tweake]

i think the turbo is electric stepper motor controlled.
not sure if you could convert it to vacuum or boost actuator controlled. you would have to check what linkages you could fit.

however some people overseas have made electronic controllers to control the turbo. google TD42 VNT and you should find and example.

one of the reasons for electronic control is speed. vac and boost control can be to slow and the turbo can over boost massively.

[vvilly]

what about removing the electric side of the turbo and dumbifying it lol

make a new bracket up and fit a 1kz wastgate new linkage between them, then get a turbo guru to correct the spring rate??????

[tweake]

the only major problem with changing to to boost controled ie'wastegate' is that its a bit slow and may overboost. you would have to slow the turbo down. eg set the vanes closed position is open a bit more or reduce fueling a bit.

[vvilly]

the linkage would have to be made and set pretty good but what about using a tap to govern the boost

[3VILC]

The vacuum setup I have seen uses a dawes valve to control spool up rate, and a needle valve to control max boost, so there should be no overboost since the whole idea is to prevent the overboost caused by ECU control (since nissan ecu's are dumb and don't have a boost sensor to check the turbo is actually doing what the ECU thinks it should be doing).
But then, that doesn't help you if the toyota unit is stepper motor controlled
Probably be easiest to retain the stepper motor and find a way of generating a signal for it, I havn't looked into it but I'm sure theres some info out there somewhere where some electronics savvy person like myself has tried to do it.

[tweake]

the linkage would have to be made and set pretty good but what about using a tap to govern the boost

a tap wouldn't work.
you need 'wastegate creep'. ie you need the actuator to be responding as the boost increases.

the nissan patrol turbo is all ready vac controlled. not really as issue to change the way its done. but motor controlled turbo's are a lot more precise and can be sized a bit better than a boost/vac controlled turbo.