putting rb25 turbo on rb20

[ScottKing GTS-4]

So what's the general feeling with the RB25Turbo on the RB20DET? Little laggier, doesnt come onto boost until 5,000RPM but is stronger up top? That's 2,000RPM later then the RB20Turbo - hardly seems worth it for more top end surge. 2,000RPM later seems alot for a slightly larger compressor. I would of expected it to come onto boost at about the 3,500-4,000 RPM mark at the latest?

[yogi000]

Scotty when do u get full boost in ur car in third?? should be around 3-3500rpm. an rb25 turbo will only be lagier by ~500-1000rpm and sometimes if that, depending ifu have cam gears....exhaust.....etc.......

[fane]

i have 1 forsale.... look in sig, never been boosted over 10psi.....and this sounds like a good upgrade for a rb20...

if mine doesnt sell i will just keep it because there is nothing wrong with it...and i might be getting a 32 as a dori car... i will get pics of turbo asap....it is a s1 33.

[R31 POWER]

So what's the general feeling with the RB25Turbo on the RB20DET? Little laggier, doesnt come onto boost until 5,000RPM but is stronger up top? That's 2,000RPM later then the RB20Turbo - hardly seems worth it for more top end surge. 2,000RPM later seems alot for a slightly larger compressor. I would of expected it to come onto boost at about the 3,500-4,000 RPM mark at the latest?

It is'nt that late,there is a little lag and it's hard to say when 12psi is made coz the tacko don't work!Think of it this way,it does'nt drop off boost at all and the 500rpm or so that it does come on song I reckon is worth the $350 or so dollars for a RB25 turbs.

[cul202]

Going from old RB20 turbs to RB25NEO turbs:

- lag increased by around 800rpm so it feels a far bit slower around town

- 5500-7500rpm much less breathless then before

- extra airflow & psi = messed up AFR's from 4000-5000.

Most say a new fuel pump & chipped ECU would make it a lot nicer to drive...

[ScottKing GTS-4]

Thanks for the reply guys. I didnt think the boost would come on so late and would be a harder kick in the back then the RB20 Compressor. So now the big question - where is the best place to source an RB25 Compressor in decent conidition?

[Cillham]

rsx74, yea rb25 turbo upgrade and what u mentioned just then is exactly what i plan to do ;D I've made up my mind.

[Nismo_Boy]

Whats the max cc rating on stock rb20 injectors? I've got a GTR fuel pump, and about to put on a fuel reg. Will they hold up for what should* be a 200 - 220rwkw motor?