Will this turbo fit on my GTST?

[johnny350zr]

I have a 89 skyline GTST. i also have a set of HKS 2530 turbos sitting at home. Ive read a few posts saying that these HKS turbos bolt right up to a RB20DET without other parts upgraded. Can some of you guys confirm this? one more thing, does anyone have detailed instructions to install an apexi avcr electronic boost controller? thanks in advance. once i get decent photos, i will post a proper introduction post.

[Yellow4g63]

Nope I think those have a T25 flange on them. Stock turbo manifold uses a T3 flange.

[johnny350zr]

Is the t3 flange more rectangular than the t25? I Googled and from what I gathered, the t25 is a lot less rectangular. Almost squared. Someone on another board also mentioned that the flanges on the rb26 is t25 and the rb20 and rb25 are t3. Would it help if I posted pictures of my hks turbo?

[Yellow4g63]

They are also smaller than a T3. If you have the stock RB20 turbo off you can put them next to each other and see. Yes RB26 factory turbo's are T25 flange.

[johnny350zr]

ive beeng going back and forth on forums trying to figure out a concrete answer. some say the 2530s will bolt right up, some say no. im attaching a picture of the flange, maybe i can get a definite answer.

[Yellow4g63]

Looks like a T25 flang to me.

[johnny350zr]

Thanks yellow4g63. I guess i may have to look for a manifold.

[RRRRB]

Rb20 uses a T25 style flange, that turbo you pictured looks like a T3 flange, but hard to tell as the difference is somewhat minimal.

Measure it to see what you got.

https://encrypted-tbn2.gstatic.com/imag ... cbCOBjtfHH

[Yellow4g63]

RB20 uses the same flange as the RB25. Thus some people use to upgrade to the RB25 turbo from the 20.

[Yellow4g63]

Found some old pics of my test fit of the SC61 turbo to the stock exhaust manifold. If I shaved down one of the humps and the compressor housing it would have cleared. T3 flanged turbo.