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I've been thinking about the best way to go for an RB25 upgrade for my R32. I don't want to be ripped off or dissappointed so I'm just wondering...

What's the best way to go with an RB25 upgrade and what should I be paying for one?

An estimate price for a stuffed engine that needs rebuilding would be great and maybe a price for a low km engine that can go straight i would be awesome.

James

just keep an eye on the for sale section, also call around the jap wreckers to see what they charge for a complete engine to give yourself something to reference to.

http://www.skylinesaustralia.com/forums/topic/358328-real-deal-rb25-setup/page__p__5725529__hl__rb25__fromsearch__1#entry5725529

just keep an eye on the for sale section, also call around the jap wreckers to see what they charge for a complete engine to give yourself something to reference to.

http://www.skylinesa..._1#entry5725529

So his rebuilt, forged engine is going for $1700 and his rebuilt gearbox is going for $1500 and the only other things i'll need are a computer and loom.

Not too shabby. Just depends whether its worth it or not. If I can get my 32 to 300rwkw for roughly the same I won't bother aha.

You got a conversion in yours?

yea, mine has a rb25 with a gt3076. In all honesty though, i feel the turbo is a little laggy for my liking. I may end up down sizing the turbo at some stage, or maybe just hunt down an externally gated .63 housing for it.

That link was just an example, I'm not saying to buy it, I'm pretty sure I saw a a complete rb25 long motor for sale either here or boost cruising the other day for 1200, you would expect to pay anywhere from 1000-2000 for a decent condition engine. Totally worth while to have the extra cubes down low as well, much nicer to drive off boost then an rb20

yea, mine has a rb25 with a gt3076. In all honesty though, i feel the turbo is a little laggy for my liking. I may end up down sizing the turbo at some stage, or maybe just hunt down an externally gated .63 housing for it.

That link was just an example, I'm not saying to buy it, I'm pretty sure I saw a a complete rb25 long motor for sale either here or boost cruising the other day for 1200, you would expect to pay anywhere from 1000-2000 for a decent condition engine. Totally worth while to have the extra cubes down low as well, much nicer to drive off boost then an rb20

Ahhhhh I see. I had no idea they're so cheap!!! I might have to do this hey. I think it'll all be in the compressor housing dude or yeah if its more than that just research the best combination for the 25.

If I've got a lightened fly and HD clutch, will an rb20 gearbox cope with an rb25?

Edited by EXEMPT

Ahhhhh I see. I had no idea they're so cheap!!! I might have to do this hey. I think it'll all be in the compressor housing dude or yeah if its more than that just research the best combination for the 25.

If I've got a lightened fly and HD clutch, will an rb20 gearbox cope with an rb25?

Depends how you drive but likely not. I killed a couple of RB20 boxes with only 183rwkw, first one behind the RB20, second behind the RB30 (the second one died real quick.. I don't think it liked so many 2nd gear clutch drops :laugh: )

Depends how you drive but likely not. I killed a couple of RB20 boxes with only 183rwkw, first one behind the RB20, second behind the RB30 (the second one died real quick.. I don't think it liked so many 2nd gear clutch drops :laugh: )

I might have to get someone to look at my gearbox coz im pushing a fair bit more than that atm. Gearbox feels solid as all hell but I mean Murphys Law will come into play as soon as the rb25 goes in, if it does lol.

Cool. I'll have my mechanic confirm I've got an rb20 gearbox next Friday.

Is there anything that is obviously different on the outside of the two boxes that will indicate 20 or 25 box? I'm only asking because the car runs 230rwkw on 20 psi and has done for a long long timeand hasn't complained at all. Only when I le the clutch out before I complete the shift pinch.gif

Is it torque or power from the engine that wears a gearbox?

Edited by EXEMPT

Torque, power is just a function of torque and revs (and a constant).

Physically, the RB25 is SHITLOADS bigger than the RB20 box. If you have a look down the transmission tunnel and the gearbox barely fits.. it's probably an RB25 box. Couple of other things like how the slave cylinder bolts on and the speedo sender is one the bottom of the output shaft on one box, and on the top on the other.. can't remember which way round it is though..

If you need me to, send me a PM and I'll have a look under the car when I get home :)

Torque, power is just a function of torque and revs (and a constant).

Physically, the RB25 is SHITLOADS bigger than the RB20 box. If you have a look down the transmission tunnel and the gearbox barely fits.. it's probably an RB25 box. Couple of other things like how the slave cylinder bolts on and the speedo sender is one the bottom of the output shaft on one box, and on the top on the other.. can't remember which way round it is though..

If you need me to, send me a PM and I'll have a look under the car when I get home :)

Noo shit. Well that should be a fairly easy diagnosis then =) I'll be sure to check it out when I'm home in a coupla hours. If I can't make my own mind up I'll snap a pic and post it up lol.

Cheers dude.

heres how you tell which box you've got;

RB25 box on the left, RB20 box on the right.

post-13452-0-26397000-1300858744_thumb.jpg

you can tell the difference straight away. the rb20 box is noticeably smaller and it has some differences in the housing.

in your case, buy a half cut - it will be much cheaper than buying everything separately. it should cost you around $3000-$3500. i also recommend doing a leak-down and compression test before anything. if the motor is in good nik then the gearbox that is attached is more than likely to be in good nik, i.e. not abused.

heres how you tell which box you've got;

RB25 box on the left, RB20 box on the right.

post-13452-0-26397000-1300858744_thumb.jpg

you can tell the difference straight away. the rb20 box is noticeably smaller and it has some differences in the housing.

in your case, buy a half cut - it will be much cheaper than buying everything separately. it should cost you around $3000-$3500. i also recommend doing a leak-down and compression test before anything. if the motor is in good nik then the gearbox that is attached is more than likely to be in good nik, i.e. not abused.

Very nice bro thanks for your wise words also! I can see this happening in the months to come aha

Definitely buy a half cut if you don't already have a 25 box in there. People over here want $1500ish for the gearbox alone. I then had a custom 2-piece shaft made up (to handle huge torque), that along with a new slave cylinder and some miscellaneous stuff, brought the gearbox conversion to around $2500 and that's with me doing all the labour.

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