Advice on a rb25det build - Page 3 - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Corbic · 10-19-2016, 01:35 PM

Quote:

Originally Posted by STR8 H8N

Are you an Idiot?

Yes! - Swap RB20DET
NO! - Proceed!

Do you want to go fast?

No! - Swap RB25DET or SR20DET!
Yes! - Proceed!

Do you fantasize about having a budget?

Yes! - LSX Swap!
No! - 2JZ Swap!

STR8 H8N · 10-19-2016, 01:47 PM

Quote:

Originally Posted by Corbic

Are you an Idiot?

Yes! - Swap RB20DET
NO! - Proceed!

Do you want to go fast?

No! - Swap RB25DET or SR20DET!
Yes! - Proceed!

Do you fantasize about having a budget?

Yes! - LSX Swap!
No! - 2JZ Swap!

ADIDASilvias · 10-19-2016, 03:03 PM

Ignoring all the fucktards that generally tend to shit up threads with useless information and getting back to the original topic.

I came across an interesting read regarding the oiling issue:

http://www.skylife4ever.com/2011/04/...-to-build.html

It's an RB26, but the concept is exactly the same for the RB25. Scroll down almost to the bottom of the page.

Quote:

It's info I've been sitting on for about a decade and a half. Well, the cat's out of the bag. I know I've said I never did an extra "oil return" on an RB26, and that's true. But I never said (I don't think) I never added anything for crankcase ventilation to aid oil return through the stock pasages. Semantics...

Why do I discourage people from doing this mod? BECAUSE YOU DON'T NEED IT! And, if it's done wrong, you'll end up with more problems than you've solved. Originally, this engine turned around 11,000 rpm, boosted way over 30 pounds, and made hp north of the millennium mark. The new configuration doesn't need it, but because the mod is already done to the pan, the parts are there, etc, it's going on this engine.

The following three pictures are of the additional crankcase vent. I first started doing this mod on the 26 in the mid 90’s. It’s a common mod for high rpm engines, so it was a no-brainer for the RB26. Soon thereafter, the Internet got a hold of it and speculation as to its function ran rampant. “Additional oil drain-back” became the consensus, and consensus became fact. Now it’s well known as the additional oil drain back mod… Then it became a fact that all the oil in the engine will pool in the head and the engine will blow if you don’t have it done…

Really? Let’s examine some facts. The RB26 has been lapping the Nurburgring starting years before the R32 came out in 1989. Lap after lap at full-boogie. Since then, the R33 and R34 have been lapping the same track. The N1 GT-R that races in the N1 class doesn’t have this mod done. Super Taikyu RB26’s don’t have this mod done. I can assure you that the RB26 does not have an oil drain back problem that warrants modification to implement an additional one.

On Youtube you can find some videos of the Porsche Turbo engines in a cradle that simulate a run of the Nurburgring to test the oil system. Nissan has the same thing.

I'd trust this guy more than any of the keyboard mechanics currently proving they are idiots.

Edit: FYI, the new configuration he is talking about that doesn't need the mod is a 600hp touge set-up.

ADIDASilvias · 10-19-2016, 04:05 PM

Quote:

Originally Posted by Corbic

Don't worry, I'll still pass. It's an inferior design and your still dumping money into machine time that wouldn't be needed on a 2JZ.

But if you are sending a block out for machine work, having the crank collar machined, throwing in rods, pistons and studs.... why would you not spend the extra $50 on an upgraded head-gasket?

Like I said - if he is having the head decked then go for it, otherwise the stock HG seals much better when things aren't perfectly flat, and is not a weakness at 500hp.

Also, with the 2JZ, the only way you are even coming close to the cost of the RB swap is a 2JZ from a non Supra chassis, and throwing an R154 tranny behind it. The R154 is not a bad transmission, but it is definitely the weak link in the pairing. 6-speed Getrag, get outta here, you got another 6 grand for the transmission?

And it's fine that you'll pass. Those of us who would like to keep a Nissan a Nissan can deal with that. I won't lose any sleep over it.

P.S. jared420sx needs to go smoke a fatty and forget this whole internet thing exists.

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