Rb20det swaping to Rb25det, any suggestions

[FITZY_07]

So I will be Swapping My RB20det w/ the tranny(for sale ) and I will be dropping in a Rb25Det with the tranny...

Does this seem like a good idea, what problems will I encounter?

I already know about modifying the tranny, other then that...???

What HP can the Rbdet motor ANDS tranny handle???

I want 450-500WHP... Do-able???

[lucky_cefiro]

you're going to need a new driveshaft if you use the 25 trans.

[kelaog]

Agree, new driveshaft. The motor should be able to put out 500 hp no problems. I would stay with an rb20det unless you have a lot of money to throw at the rb25.

[serega32]

you're going to need a new driveshaft if you use the 25 trans.

Why would you need different drive shaft? And what kind?

[deliberate32]

I'm no genius, but I assume that since the RB20 isn't as strong as the Rb25, it would break due to the power, and it's strength not meant for that power. So, I assume an Rb25 Drive shaft would suffice as well.

[judasentinel]

Just a thought..........why do you want to get the RB25 tranny? Your RB20 tranny will work just fine WITHOUT any mods. Yes, the RB25DET tranny has the same gear ratios (minus the final drive, I think) as the RB26DETT, but to me, you get a lot of kick by using the RB20 tranny ratios, which are more aggressive.

I am running my RB25 with the RB20 tranny WITHOUT any problems. Just thought I'd share, but your choice in the end.

[FITZY_07]

I want 450 WHP.
Rb20 tranny will NOT handle it.

[entelijint]

I want 450 WHP.
Rb20 tranny will NOT handle it.

it would be close... best to go with the rb25 trans.
the slip yokes for the rb20 and rb25 trans are completely different... thankfully a Z32 yoke fits the RB25 trans get one of those yoke welded onto your stock driveshaft (which needs to be shortened) or just get a one piece made (the route i went).

other than that, 450whp is completely do-able... i'm not using that big of a turbo and should be around 400whp *fingers crossed* on mine.

[nissan_for_life]

Just a thought..........why do you want to get the RB25 tranny? Your RB20 tranny will work just fine WITHOUT any mods. Yes, the RB25DET tranny has the same gear ratios (minus the final drive, I think) as the RB26DETT, but to me, you get a lot of kick by using the RB20 tranny ratios, which are more aggressive.

I am running my RB25 with the RB20 tranny WITHOUT any problems. Just thought I'd share, but your choice in the end.

Hey i have a rb20det and i'm looking to swap for the rb25det and try to keep my rb20det tranny so i can spend the money on a greddy plenum, injectors, and haltech ecu. for the time being I'm looking for high 300 to 400 bhp. Should i keep the 20tranny or should i purchase the rb25det with it's tranny? I own a R32 gts-t

[Supraclean]

Bump from 2007 hey. Personally I have been at this cross roads and unless your tranny needs a rebuild or is on its way out I would not buy the 25 trans. Yes it is a beefer trans but that comes a a cost /mod sensors/custom welded driveshaft. Its also how you drive your car and your shifts. Its not going to be the 300-400 hp thats gonig to kill it its how you are shifting aka is it a dragcar? or Driftcar doing shift locks.

You can always pickup a spare rb20 trans that is cheap (150-250) and if your sincros go swap it out.

[M13]

i dunno about you but I was thinking of mating a non-nissan tranny to my 20 anyways.

[Skym]

Could fit a 300ZX gearbox with custom bellhousing adaptor plate.

On Gibson GTS-R they used a Hollinger gearbox with custom bellhousing behind a Group-A RB20DET producing around 420rwhp.

[redrocket]

if you cryotreat the rb20 block 450 is dooable. i personally would pick up a nismo six speed and mate it to the rb20 bellhousing. HYBRID FTW

[Skym]

This S14 Silvia runs a 300ZX gearbox with NA Nissan V8 -

http://www.youtube.com/watch?v=9bg4OPx0wTI