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Engine Build Options Rb24Ish, Vers 26/30

Overnight Parts From Japan
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Overnight Parts From Japan Apprentice

Overnight Parts From Japan

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Hey guys I own a s13 silvia, which is fairly modded in terms of suspension, brakes and all the rest, and I have put a rb20 in it which has a high flowed turbo, front mount and a few other things like after market bov and is running 18pound. I'm at the point where i need to buy a aftermarket comp and im wondering whether i should bother, or build up a decent motor.

THese are my options; I own another rb20 block, 26 crank, rods and would buy a 26 head. I believe that because the bore is the same across the rb range, and only the stroke is different (apart from block differences,more modern as they progress) that I could buy forged rods (decrease the stroke) and dome top pistons (increase the subsequently lowered comp ratio) and get closer to a 2.5/2.6 litre that revs harder than a 26 and of course a 30 (as the 30 is limited by its stroke) and avoid the older tech of the 30 block, and get away from the oiling problems of the early 26's. By going to a twin high mount turbo set up (splitting the exhaust with firing order in mind, same as the 26). By changing the head studs to something stronger, and running a thicker metal gasket, the volume increase, and a subsequent compression loss occurs, allowing ultimately for more boost (due to the lower compression) and the twin turbo's will lend themselves to the lower comp, given that they will kick in earlier (than a large single) and make up for the lower na power prior to boost.

Essentially This first option would be a hybrid 26ish, except substituting the block for a rb20 and making up the for the volume difference in bore, stroke, and piston caps, all things that would be changed in a serious 26 or 30 build.

The second option would be to opt for a tradition 26 head and 30 block (there is something to be said for following a trend, look at the vl turbo's quarter times)

and maybe a third option would be building up a late model 26.

P.s guys i apologize for the dodgy shit, that's been going up the last few days, a mate hacked me and put up all the crap.

Overnight Parts From Japan Apprentice

Overnight Parts From Japan

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Your american arn't you...

better do a little more research mate.

Justin

Na dude, I'm australian, research with regards to what?

Edited by Overnight Parts From Japan
Overnight Parts From Japan Apprentice

Overnight Parts From Japan

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Rb bore sizes are the same for rb25/26/30

rb20's have a smaller bore champ.

Sorry my bad, just checked and your right, do you know if they are able to be bored out to 86?

Nee-san Grand Master

Nee-san

Posted
Posted

you might be able to get it out to 82, but to make the 26 head fit (if it is indeed possibl) you would have to use bore sleeves.

I like the idea mate, but being limited to the RB20 head is probably your greatest downside in this project: read: there would be expensive headwork involved in properly taking advantage of the increased output ?

what does everyone else think ?

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

Dude - search function.

Put "RB24" into it. Watch the joyus results roll in.

There are entire threads listing in detail exactly what parts you need, what needs to be done and so on.

For the price, RB25. RB24 is simply not worth the money as you'll soon see by searching and reading past threads about it. Hence there are very little.

Thanks.

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