I've got a friend here (Japan) who wants to add a supercharger to his RB25DET. He doesn't know what it'd cost, what kind of work it'd require, where he should go, etc... I'm not good at the mechanical stuff, so I told him I'd ask here. Any thoughts on this?






And to those who know me, yes I know he drives a Nissan, but he's a good guy so I can forgive him.

 

eh?

So you're saying he wants to twincharge his car?

Or just replace the turbo with a supercharger?

 

He wants to twincharge it. Any ideas for that? I'm sure he'd also appreciate any ideas that'd be cheaper but equally powerful. Right now he thinks twin charging is the best option, but neither of us really have much of a clue what's good. Basically, we're just looking for any kind of feedback. Thanks.

 

this is not the best place...

recommend visiting:

www.skylinesdownunder.com

to get some good information on the RB motor.

 

The website doesn't really address my question. It focuses more on looks for a skyline and has some basic airflow mods. 82 views and nobody can help me out? I don't post often (as evidenced by my post count) and typically only post when I genuinely want some input, so it's not like I'm just trying to be a post ho and waste time or get attention. C'mon, I know there are some people out there who know what they're talking about, that's why I posted here.

 

alexi

From what i understand he wants to put a traditional twin screw s/c on the rb25...correct? The twin screw is a top mount which would be a little more difficult and always has trouble with belt tension and over all application. If there is an after market manifold i'm sure it could be done but, on an application that is not typically known to do this type of power adders i wouldn't. Like the Roots supercharger, the air inside a twin-screw supercharger is trapped in pockets created by the rotor lobes. But a twin-screw supercharger compresses the air inside the rotor housing. Makes it more efficient but more precision in manufacturing and tuning is required.

Personally i would recommend a centrifugal supercharger (if this application even exists for the rb25) which is pretty much a turbo with a belt attached and he still gets the wining noise he is looking for. A centrifugal supercharger powers an impeller -- a device similar to a rotor -- at very high speeds to quickly draw air into a small compressor housing. Unlike being mounted on top, makes it more efficient.

Now for the answer...it IS possible but procharger or a major company will only send you a carb/efi kit catalog and you could peice it together for a butt load of money, time, and labor. But if he decides to go this route go centrifugal.

-josh

 

Is there a reason why, or just because it'd be cool?

I'll put it this way, there's a reason why the simplest solutions are usualy the the best, less crap to go wrong, less crap to buy, less crap to break, less crap to replace, less variables to tune for, etc. In most of the twin charged set ups i've seen, (lexus is300s, legacys, etc.) it's been more of a novelty than a big power maker. I really think that a clearly thought out plan, taking what he's got, with a clear goal of what he wants, will yield a better performing and more fun car than just throwing compressers under the hood.

Plus honestly i think you'd want a positive displacement blower with a turbo rather than a set up that is going to go from no boost to huge boost. Then you have to figure out when your compressors are running at peak efficency... icky... it just gets messy. good luck.

 

^^^Agreed.

He's probably thinking it's the "Best" because he THINKS you get the advantages of both systems.

But to get the to work together is gonna be a ridiculously hard thing and by the time you're done you could've just gotten one of the typical Turbo Upgrades and saved a buttload of cash.

 

Thanks guys. That was what I was looking for.
That is exactly the case. I think he'll change his mind after he reads this.

 

Surprised that you had that much trouble with SDU....
Used to get great info from them on my RB20 questions.

I didn't want to say it...but twin charging would definately not be the best solution as everyone has already pointed out.

He should look into an RB30 bottom end with an RB25 head.