RB20 Upgrade questions

[Linux2501]

Alright so Im curious, Im not looking for direct numbers just round about numbers and ideas on what might be possible for an rb20 so here is what im going to upgrade and you tell me what numbers I might see after a good tune.


Stock rb20, over the rocker intake
Rb25 Turbo with 10lb wastegate
Fmic


Further upgrades
GTR Injectors
aftermarket turbo manifold
Front facing manifold
Gtr Cams
Hks Fuel Rail
Nismo FPR
Q45 tb
Aftermarket pulleys
Probably going to go ahead and put a new hg and studs to go with it.

Let me know your ideal numbers for this setup.

[R_34]

I would say 220-ish rwhp with only the fmic, the rb25 turbo and a tune.

You can run this turbo safely to 14/15 lb on a rb20 netting you 250-ish rwhp.

The GTR injectos will need the gtr resistor and chewing your injectors harness. You can find some drop-in injectors, i think DW is making a set for the rb20.

The factory cast exhaust manifold is not very sexy but isn't really a bottleneck, some guys in australia pulls impresive numbers with the standard unit. Plus you can keep all the standard heatshield which is a good thing.

For the front facing plenum you can find only the upper manifold, keeping the standard runners and low end torque the rb20 lacks a lot.
Or you can replace the whole standard plenum with some short runners unit. Nice for high rpm operation (>5000 rpm), but a pain in the ass for the rest of the operating range.

The GTR cams are a no-no unless you convert your head to solid lifter. Big $ for small gains. Stick to the oem camshaft, they're good enough to pull some nice numbers. Get some poncams if you want an idle a little lumpy.

The Q45 tb isn't necessary, the factory tb is large enough to feed the tiny 2 liter engine behind it. You'll just get a twitchy engine response with small angle opening with the Q45 tb. It will fucks up the driveability and SR get very good numbers with a lot smaller tb without a problem.

Aftermarket pulleys may bring some boost response and few extra whp in the mid to high rpm. Buy a set only if you know what you're doing and have access to really measure the gains by tweaking the timing.

AFAIK the rb20 is not really subject to head lifting/blowing HG, so I don't see the point in having better stud and metal HG for such small numbers.

[Mikester]

Alright so Im curious, Im not looking for direct numbers just round about numbers and ideas on what might be possible for an rb20 so here is what im going to upgrade and you tell me what numbers I might see after a good tune.


Stock rb20, over the rocker intake
Rb25 Turbo with 10lb wastegate
Fmic


Further upgrades
GTR Injectors
aftermarket turbo manifold
Front facing manifold
Gtr Cams
Hks Fuel Rail
Nismo FPR
Q45 tb
Aftermarket pulleys
Probably going to go ahead and put a new hg and studs to go with it.

Let me know your ideal numbers for this setup.

A lot of the mods you are talking about are a complete waste if you plan to use an RB25 turbine. Save the money ;)

- The Nismo FPR is a good idea... For some reason, RB20's seem to eat regulators lol

- The pulleys are a good idea- eliminates some parasitic drag

- You can get some drop-in injectors and tune with the RB25 turbine... and call it a day... at 14-15psi, I agree with above that you should see about 250-ish to the wheels.

Aside from that, you should be concentrating on brakes & suspension... Power is useless and dangerous if you can't control or stop the car. IMHO, there is great sense in the phrase 'wheels-up build'

OR you could spend all that money you were going to waste on a fuel rail etc on a good radiator/fan combo... RB's get hot quick when being driven hard.

If you are going to pull the head and add studs & HG, you may as well go ahead do a rebuild. If that's not in the cards, drive it till something blows, THEN do a rebuild. The OEM RB20 HG is not known for being weak... With the right turbine/injector combo, you can make a pretty cool, 400hp daily driver pretty easily/economically.

You don't need cams. All they will do for what you're talking about is shrink your power band at the expense of low-end torque... with negligible power gains at best.