Supercharged RB25

[Shocker]

I vote compound setup.

I will be following this thread.

[abubika345]

yea the response should be insane, and the tuner for our shop is the guy who runs best1tuning.com and is one of the best around so i dont think we'll have any issues on a tuning standpoint

[krayton]

i think for ultimate response monster i'd use a blower with an electric clutch and use an rpm switch to activate it...that and a smaller blower.

this for sure. i vote for a smaller charger for mount if you want it to be a sale thing later on. i think most people can give up ac, but i wouldnt wanna do without powersteering.

but i know you guys are just trying this as is, so id like to see just supercharged alone

BEERs s15 had an awesome setup. with the clutch type supercharger to let off once the turbo took over.

a whole new ball game when you make that much hp down low *cough*ls1*cough*

[abubika345]

well like i said a guy might be buying the turbo so we might just be doing a supercharged setup. The only reason were using a charger this big is also because we had it around and wouldnt expect anybody to run a setup like this with a $4300 supercharger for their daily

and yea the power its gonna have early will be the best part....im actually throwing an lq4 (iron ls2) in my rhd hatch right now

[Andyb2637]

This is an awesome build!

+1 for compound build(i cant wait to here this thing scream)

[Coolwhip]

i've been considering compounding for mine. But you see will have a sweet setup with the SC for sure! Can't wait

[240cp]

looks cool fo sho but might be a pain in the a** to tune...course it might be a walk in the park.who knows, i say straight supercharger first then go with a turbo once a good base line is established.seeing 20+psi at the manifold around 2krpm would be insanity tho.

This is by far a very interesting build. But aint no centrifugal gone make 20 psi by 2000rpms, period. Seems to me that this is a little bit of a waste of time. I mean a centrifugal supercharger in sense is a turbo in how it delivers boost. Not much down low and then comes on strong up top. To take best advantage of twin charging or compound charging, whatever you want to call it. It would be best to use a postive type supercharger and feed it with the turbo.

Not trying to knock this build by no means but this is kinda wasteful. Now if you were to use a small turbo that would spool very quickly like a t28 or something and feed it with the supercharger, well that would a whole nother story.

[Z-tune!]

This is by far a very interesting build. But aint no centrifugal gone make 20 psi by 2000rpms, period. Seems to me that this is a little bit of a waste of time. I mean a centrifugal supercharger in sense is a turbo in how it delivers boost. Not much down low and then comes on strong up top. To take best advantage of twin charging or compound charging, whatever you want to call it. It would be best to use a postive type supercharger and feed it with the turbo.

Not trying to knock this build by no means but this is kinda wasteful. Now if you were to use a small turbo that would spool very quickly like a t28 or something and feed it with the supercharger, well that would a whole nother story.

???

A supercharger delivering 12psi pre-turbo is going to be more than 20 psi at 2000 rpm. A smaller turbo doesnt make any sense at all, it doesn't have the efficiency to compress already-compressed air. it could use a small turbo if the supercharger was after it.

[240cp]

Again, please show me a centrifugal supercharger that can deliver 12 20 or hell even 7 psi by 2000rpm. It aint gonna happen. You have a belt driven turbo that requires power to turn it and have lag to boot. No thank you.

Like i said use a postive type displacement supercharger. As in eaton, magnuson, or get fancy with the lysholm/twinscrew design of kenne bell or whipple and you have something. Until then your wasting you time.

The reason i said use a smaller turbo to be fed by the centrifugal is you have to have bottom end from somewhere. As far as the small turbo not being efficient. Do some research on compound turbo charging. You will always see that the first charger in the series is always smaller than the primary. Thats where you get the low end grunt from.

[abubika345]

Alright well if you feel that way then you do that, i started this thread to show people what we were doing. So dont come on here and tell me what were doing wrong.

[240cp]

Na man wasnt trying to be that way. Im not saying your doing anything wrong. I actually am very interested in the outcome of this. Was mearly replying to the above. I agree should be discussed some where else besides your thread.

[DrifterProdigy85]

I wonder what would happen if you took the cintriful charger and did a compound setup like the turbo setup above. Use a large 74mm turbo or something feeding into the charger, as it goes through the charger it compounds the pressure going to the intake manifold. I know it works with turbos but its just a thought with a supercharger.

[Kansei240sx]

If you wanted to compound the setup, i vote a C30 Rotrex supercharger with a Holset HX35/40. that'd be tits.

[Darius]

A smaller turbo doesnt make any sense at all, it doesn't have the efficiency to compress already-compressed air. it could use a small turbo if the supercharger was after it.

^This is incorrect. Please do not post this kind of thing if you aren't 100% sure of what you are talking about because it will mislead others.

Do you think a turbo knows whether it is pumping air from 1 atm or 3 atm? It will increase the pressure the same amount relative to the intake charge pressure. So, if the SC is providing 7 psi to the stock RB turbo that most agree 12-14 psi is the reasonable max boost, the intake manifold would be seeing 19-21 psi minus the losses between the chargers and the turbo and TB. This is a good reason why pressure ratio is the vertical axis unit on compressor maps.

Back on topic, the roots-type twin charging has been done on the RB25 in australia. There's a thread on it on SAU, but it is pretty old. I haven't seen centrifugal-type twin charging on the RB25 before, but it would be a step down in efficiency from the turbo setup. Keep it up though, I think we'd all like to see you guys follow thru with this setup/project!


Modified by Darius at 12:50 PM 7/13/2009

[abubika345]

well someone actually bought the twinscroll manifold we had so were going to do just supercharged for right now and then prolly do twincharged later so we can see how both perform

[Carl H]

a guy on sau did an rb30 twin charger (roots blower and turbo) and it had like 10psi in 1st gear using some gt40 based turbo.it was silly...found info on it.http://www.performanceforums.c...arged

and a vid!

http://www.youtube.com/watch?v=yzRpz9c-t_o

[Darius]

Yep StockyMcStock on SAU.

[240cp]

Ive seen that before and is quite nice. But i cant seem to find any info on what that blower came off of. Looks like a eaton m62, but what off i wonder.

[Carl H]

looks a hell of a lot like a blower off of a jaguar xjr (95-97 car)...only reason i know that is my dad has one.

[l0nestar]

rupdates?

[abubika345]

No updates really, the car belonged to a guy that worked atthe shop with me and he ended up stealing s*** and was fired, last I heard he sold the car and the motor.

Sorry I was excited about the build too but I do still have the supercharger, anybody wanna buy it and try to do it?

[Justin Duncklee]

lol how much for the supercharger and adapter plate you made?

[abubika345]

Now I can't find that damn plate anywhere, the supercharger has just been sitting on a shelf tho, make a reasonable offer and well go from there, were busy right now but we might be able to fab up a plate for it if we have extra material

[J14cm7]

Threads like this are so informative. I know debating like that is thread jacking but i wish ppl would do more of it. That mark guys video blew my mind. Im still trying to comprehend it. (new to turbo set ups just have a stock s14 sr20det but would like to learn more)

[BigJuiceSr20]

"Ive seen that before and is quite nice. But i cant seem to find any info on what that blower came off of. Looks like a eaton m62, but what off i wonder. "

StockyMcStock used an M90 Eaton (found on mid to late 90's GM cars like supercharged GTP and Grand Prix). Roots and twin screw (positive displacement) will have no lag, the centrifugal will have lag like a turbo, but not as much. If you want to see a nice twin turbo setup that has virtually no lag check out Opel's twin turbo setup. 212 HP from a 1.9L diesel with no lag! Can you imagine that on a gas powered motor?http://www.worldcarfans.com/10...ology

Anyhow, I'm not dissing the twin turbo compound setups. That is a sweet setup. There's a VW diesel ruunning low 10's with the compound turbo setup, but that will have some lag as well but the Opel's setup is great if you don't want lag.

StockyMcStock's RB30 twin charged setup has the turbo feeding into the supercharger. It provides no lag and added benefit of a very low exhaust backpressure because he uses a very large exhaust backhousing ( like a 1.12 A/r or larger) and still get full boost by 2500 to 3000 RPM. The intake pressure will also be greater than exhaust backpressure under boost, so you can run a nice overlap on the cam setup and not have any residual exhaust pressure reversing into the chamber under boost.

I got a Whipple and Gt40 setup ready for my built SR and adaptive engine management.
Modified by BigJuiceSr20 at 12:06 PM 3/9/2010