rb20 bore?

[impulse_rb20]

Can anyone help me? im wondering if a rb20 engine can be bored out from stock 78mm to a rb25 piston of 86mm? or maybe if there is an aftermarket piston kit for the rb20? any help would be great! thanks!

[JNS Performance]

No it cannot be bored out that far. Largest I have seen is 83 or 84mm

If your interested we can have CP make custom pistons for the RB20, takes about 1 month and costs $100 more than the off the selve pistons they sell.

Let me know

Regards,

Braden @ JNS

[impulse_rb20]

would it be smarter to do that? or ive been looking around for a rb25 or rb26 engine with a rb25 tranny. would it pay to build the rb20 up? or build a rb25 up?

[supguyex]

I'm currently running a 25 in my 32. Its buckets torquier than the 20 and spool up is pretty good. A major drawback is that you'd have to change your screenname. And that could become a hassle haha

[NismoS-tune]

you can get an RB20 into a RB24.

[M13]

or just drop a 26 in it.

[impulse_rb20]

haha well im not to worried about my display name haha. a 26 would require a different tranny as the 25 would also with a bigger price tag too.. roughly how much would those custom pistons be? havin a rb24 would be pretty sweet i guess.. since im already runnin a rb25 turbo and ive already got a twin plate clutch.

if i stay with the idea of boring my rb20 out ill hopefully be replacing as much of the internals as possible as well as adding an intercooler and possibly a meth injection system but that will come after.

[M13]

yeah but if your goal is to increase power, why not go with a transmission that can handle it?

I wouldn't bore the 20. It's about the only thing good about these motors. (wall thickness)

If you are so concerned about price, why would you bore a 20, then build the innards and deal with all the bs to make mediocre power when you could just drop in a 26? I've seen lots of built ones go for A LOT lower than the route you are planning to go with.

[impulse_rb20]

ahhh i see.. well if i could get some help with finding a good deal on a 25 or 26 engine it would be great but id also need the 25 tranny sooo and help would be greeaaat thanks

[M13]

i believe c unit is selling a series 2 rb25 tranny with driveshaft for r32 so that's perfect.

I would personally go with a 26 bc 25 seems less lively from my experience. Also lots of mods available for the 26 and they offer solid lifters.

[Skym]

RB20DET can be as quick as GTR up until a certain point, where hp on RB26 engine and grip is way better due to 4wd. Rwd RB26 can spin up to 3rd gear until you get traction (I know someone who had rwd RB26 R32 racecar with decent amount of rwhp and that's what he mentioned and he tried alot of things to reduce it).

Example with 600hp GTR's x 2 with laptimes at Tsukuba -

http://www.youtube.com/watch?v=mo44KAwHQMs

Then a R32 GTS-T with RB20DET running 1:01 laptime at Tsukuba with only 314hp at rear wheels (sub 400hp at engine) -

http://eyevio.jp/movie/228538

Mentions sector times and overall lap time in above link. Not bad considering the EVO was slowing him down.

Thread on that R32GTS-T and dyno chart here -

http://forums.gtrcanada.com/media/35446-400hp-rb20det-powered-r32-gts-t-tsukuba.html

Way cheaper with R32 GTS-T (probably less than 30k, going by the mods). Probably an easy 100K in those GTR's. 40K alone on RB28 engines.

[impulse_rb20]

how much is he asking for the tranny and drive shaft?

[cschepp]

A smart idea would be to get a 33 gts25 front clip, part out all the stuff besides the engine and such. You'd make alot of your money back and you would have everything needed to complete the swap. After doing the rb25 swap on my gts I feel it was a great decision compared to the 26. Mainly because I'm not going for a 800 hp car. A solid 450 is definitely enough for a dd/ track car. Plus the 26's take a little bit of modifying to fit into a gts.

[Skym]

If it had to be RB25DET, R34 RB25DET. Why, because stock R34 ECU (16 bit ECU, just like PowerFC) can be modified with Nistune and have the handy coilpack shut off feature and have solid lifter, solid cams.

[nelsonmxmarc]

81 mil overbore, sleeved, using VR6 pistons (off the shelf unit), shot peened RB26 rods, RB26 crank, RB20 head (properly gutted, decked, ported), bronze valve guides, tomei valve springs, switch to solid lifters (http://www.rawbrokerage.com/Tomei-RB...Set-163006.htm) running RB26 cams .. RB24.. mmmm wall thickness never looked so scarce! But it's epic..

One day...