anyone heard of putting the bigger ct20s (jdm) on a 1j with the 1j manifold? they look identical except the output flange is 3bolts on the ct12, round port. 4 bolt on the ct20, they are oval port. the ct20 is obviously bigger and upgradable to a steel shaft and to gt2528 specs. that is the reasonsing, and if they bolt with minor mods, then it's a great upgrade for the 1j

 

Its fairly a straight forward process.

Use the 1jz manifolds (port them bigger to accept the larger ct20 housing)
Drill the hole in it bigger.
then you use a 3/8 adapter to adapt the y-pipe so it all fits.

You wouls have to use the 2jz pluming.

Only down side is you have to convert the rear ct20 so that its a true parallel setup.
I do this. You make a sleeve, press it in, and then drill into the scroll so the wastegate regulates the scroll.

then just build a custom down pipe.

I take the Ct20 turbos and upgrade them to steel/inconel shaft and put GT2860RS compressor wheels up front.

Ceramic Vs Steel:



Steel shaft in:


Comparision:


Custom Downpipe to delete the sequential crap: