how much? . . .RB30DET with a GT30 at about 10-12 PSI

[Tenchuu]

So i was thinking i need a new goal, but don't want something completely un streetable. was wondering if anyonw knew the approximate numbers that i could expect out of a RB30DET with a GT30 at around 10-12 PSI.

just wondering if my new goal was going to be unreasonable for street use, maybe get a RB30 with a smaller snail.


and before you say it, yes the RB30DET exists as a hybrid motor, RB25DET head on a RB30 NA block from aussie, and yes this would be a far out goal probibly after i finish school, but i could probably swing the RB30 Block in the next year and a fresh rebuild for it. This is a goal, i am getting a little tired of the RB25, as my buddies worked STI still makes my car feel slow.

discuss, hopefully some decent answers come out of this, if you don't have something useful to add, feel free not to add anything.

[GSXRJJordan]

"GT30" is an old designation - there's so many "GT30s" now that you have to be more specific :) The GT3071 .63 is a very streetable turbo on the VQ35, so I'd imagine the RB30 would spool it about the same. Stick with that.

Don't set a target boost level. If anything, set a target power level. If you choose the motor and choose the turbo characteristics (RB30, streetable = good torque around 2.5k-3k) then choose boost while you're tuning. Put in some pump gas, tune till you're comfy, then put in some race gas and get a number that Steve Shadows would be proud of.

I don't think the RB30 is "far out". Yes some people haven't heard of it, but it's not actually that much work. The long and short of it, though, is that it's more work than it's worth (RB25, stock internals + GT3071 = 400rwhp, no prob).

[Z U L8R]

rb30 = waste of money imho

Dave

[WagDatto]

Yeah, but they sound so good..... What's the point of NOT having something unnecessary? Plus, you'll be one of the few who have one in your car...

PS. Starting your burnout in 4th gear is baller status unto itself.

http://www.youtube.com/watch?v=Note-i7zcNA

I say shoot for the moon, just do it right! It's an unusual swap because it's more reasonable to swap an RB25, but hey. Like I said, you'll be doing something uncommon, which is fucking rad.

[gotta240]

With half of the money you put into an rb30 you can redue the rb25 to rape your friends car.

If it aint broke, modify it!

[Tenchuu]

I'm just toying with the idea right now. not sure but was thinking i need to up the power level on the 25 or switch to a LS, and the extra .5l plus more boost seems like it might do the trick.

yeah i know it's not too obscure, but i knew someone would com in asking about it so i tossed that up front.

why you think it is a waste of money Z U? thinking for a mild build (350-400 whp) that i could up the wick on at a later time for track fun, but the stock RB is making a decent commuter/ weekend track car right now.

i hear that you might have some good advice for riding for me gxxr ( as i recently picked up a motorcycle) PM me with anything that might help me as i am self learning to ride due to lack of timely courses available and no one i know that rides can spare time to sho me a thing or two.

[Z U L8R]

because the benefit of a tiny bit more of low end torque at the loss of revability + the money, time, spent in sourcing parts + machine work is not worth it

you could make a 600hp rb25 with the same time/energy

although i produced my sig with only a commetic hg and arp head studs (+the bolt ons obviously) i would strongly recommend pistons & arp rod bolts when exceeding 350hp.

fwiw, i was making 350ft lb @ 3500rpm with my set up at the time. if low end torque is the goal in which u seek :D

gl man, we're here to help
Dave =]

[GSXRJJordan]

Dave, you hit the nail right on the head - it's a time/money trade off, and a built RB25 will outperform a stock RB30 anytime. Also, as a preference, I love the rev-ability of the Rb25, and wouldn't want to give that up :)

Riding tip of the day: keep the rubber side DOWN.

[sr20boostn20]

for a street car, whats wrong wiht a built rb25.

instead of going for a new block, im sayin you just build the 25 block.

then put a gt3582r even, that on pump gas 15psi youll have plenty of power.

and if you want more power after that add in some race gas, pull some timing, and add some more psi.

RB30 would be OG tho

[Devil Man]

also have you looked into the price of an rb30 block too... it wouldnt be worth it. all the money that you will spend on just making the rb30 you could have a sweet rb25.

[MTalon]

how about you put your boost controller on, turn up the boost and realize that the rb25 isn't as slow as you think.. hell, 5 more psi makes the car feel like a whole different monster

[s13coupedrfter]

Since your setup is stock with the exception of basic bolt on's there is no reasond you can't tune it to stomp your buddies STI. I just installed 550cc injectors and a power FC in my rb25 and it feels great. Next up will be a head gasket and a gt3071r. I plan to run 14 lbs of boost and should be around 300-350 whp. Stick with it and the money you would put in a rb30 you could have you rb25 scream.

[Tenchuu]

right now i am just running a stock 25 with a front mount. going to yank it out and do a rebuild before i get too crazy with it, and figured that that would be the time to swap out blocks if i was going to do it. could have something to do with the fact i am currently living at 4000 ft and running 8PSI that it feels slow. and i do have a dual stage boost controler jsut sitting in a box ready to install.... once i freshen up the motor.

[lazierhobo]

with all the after market options for the rb25, you can make so much better power for less money, but if you want to shoot for something unique then go for the 30 for sure. at 3 liters tho, a gt30 series turbo starts to get pretty small, def consider something in the gt35 family or bigger...its all a matter of choosing how far you want to go

[McRussellPants]

lol at GT30R on RB30.

get serious.

[S14DB]

RB30 is kinda a jank block. Get a RB26 stroker kit instead.

LoL at the GT30 being street-able. At least get a GT35R.

[Z U L8R]

borg warner s262 > gt35r

, the 30/76 is a great turbo, but i also would have liked to go 35r instead.

rb28 > rb30

Dave =]

[S14DB]

borg warner s262 > gt35r

, the 30/76 is a great turbo, but i also would have liked to go 35r instead.

rb28 > rb30

Dave =]

You are the only person I know of that likes BW. Seems like all the VW guys dump them for Garrets.

[Z U L8R]

i have yet to put one on my car, but my ka26det datsun 510 will be getting a bw s262 instead of a gt35r. from what i've heard they spool faster and make more power without even being ball bearing. the 35r has a 61mm inducer whereas the s262 has a 62mm inducer. i'm going to try it for myself, but i want 600rwhp+ spray on top of that for the little Datsun 510

Dave =]

[S14DB]

Is the S262 even on the market yet? I can't find it for sale, only "coming soon." Searching for s262 comes up with posts by you on Google. If he's wanting something street-able, I wouldn't recommend anything but a BB center section.

[spanishricer]

Here's a comparison between the Garrett GT3076R and BW S256 with extended tip technology.

The GT30R used a .82 a/r turbine housing while the S256 used a .70 a/r turbine housing. C16 was used in both runs with boost spiking at 24psi then tapering off to 22-23psi.

http://www.synapseturbo.com/gallery/cache/93aa7a054bb0d4ae84034460785e327f011d894d_800.jpg


As you can see, it appears the Garrett unit still spools faster than the Borg Warner, while the Borg Warner makes a few more ponies at higher boost levels.

A pretty fair comparison between the two turbos. Thread can be found HERE (http://www.honda-tech.com/zerothread?id=2220363).

[spanishricer]

And as far as the original poster is concerned, I would stay with the RB25 and build it for more boost. I don't think he ever mentioned what his horsepower goals were, but a built RB25 with a GT35R at 19-20psi should be over 500whp and still fun to drive.

[Z U L8R]

since i will have nitrous on it as well as headwork and fully built top and bottom i may even opt for a t4 frame turbo. i have absolutely no qualms at all with the garrett gt series turbo's. they've been good to me. my original intent was a 35r for the 510 but when i heard there was something that spools faster yet makes more power than it, it got my attention.

the ka will have all brian crower shit, oversized valves, cams, springs, retainers, head port. for the power i want to make with the ka i would have to do pistons and rods anyways so the only extra part i'm buying would be the stroker crank. in it's defense it is a FULLY COUNTERWEIGHTED crankshaft, aside from more displacement that is the other reason for going with the stroker.

back to the OP

rb25'll make your 350-400hp goal no problem, at low boost i was making [email protected]

for that hp goal it's not necessarily needed, but what i've found is many many many people are overlooking headwork aka getting the engine to flow more efficiently, and just throwing bigger turbo's and turning up the boost.

in the back of our minds we all would like our shit to last. therefore wouldn't it be in our best interest to be able to make the same power at lower boost because our motor's flow much more efficiently?

after having a long talk with our machinist. my opinion is anything over 14psi and you are greatly reducing the life of the motor. his words "if you could see what's happening on the inside of your engine from 8psi to 12psi let alone 14psi it'd shock you. anything over 14psi and now you have a "race motor" it may last through a season or two but you can't be surprised if it doesn't"

another conversation went along the lines of

"boost is simply a measured RESTRICTION. it is what the motor cannot ingest. it is pressure backed up in the intake manifold. basically if you had a 350 and put on an 8psi superchager kit that would make the motor produce 500hp , the motor would make 500 hp and run 8psi of boost. if you take the same exact kit and put it on a 350 that makes 900hp naturally aspirated. the motor wouldn't make 900+500, it would still make 500hp and it wouldn't make 8psi, it would make 0 boost. because the motor would flow more than the supercharger could produce, thus the supercharger would be a restriction and not a benefit."

the moral of the story is, if an rb25 can make [email protected] on pump gas with a gt35r (which they can), wouldn't it be in your best interest to be able to make 500rwhp @ 12-14psi. not only would u be running less boost, but since your motor flows that much better, you would have quicker spool, better power band and not put so much stress on the engine.

the facts are, you CAN make power by going bigger turbo and running more boost. but the other side of the coin is, you can do the same thing more efficiently,reliably and make more power at the same boost levels by increasing the efficiency of your motor's brain aka the head.

good head is a terrible thing to waste lol

to put the cherry on top. once a motor flows at 100% efficiency....the rest comes down to cubic inches.

take care =]
Dave

[S14DB]

dyno comparison at 20psi GT30r is the solid line BW 256 is dotted.

http://www.synapseturbo.com/gallery/cache/285afb1e4acb37ea4b7e45d343bc376301212e22_800.jpg

[Z U L8R]

good graph @ spanish. i'll read that whole thread when i get a minute.

from the graph comparison, it's like a trade off between 2 different cams. you lose here to gain here.

from the graph it looks like the bw spools ~500rpm later, but makes ~25 more hp from 6k to redline where they end up making about the same peak numbers. but also the torque from the bw is better through out the power band.

the spool is relative to because from the graph it's taking the motor 5k to even spool the 35r. so imo these turbos are a tad big for my liking for the application in the first place.

based on the graphs though. i would rather have the bw than the garrett if that were my car.

on s14db's post, the gt is better than the bw. very interesting.

now i'm intrigued on finding out if the s262 is truly better than a 35r. keep it comin :)

my overall conclusion from these 2 graphs is the bw's more efficient passed 22+psi than the 30r but at 20psi the 30r is more efficient than the bw.

so the next question. is there a better comparison between a bw turbo and a garrett turbo where both turbo's are running the same psi and in the same % efficiency. then how big is the garrett's housings in comparison to the bw's. because another factor is fitting the turbo somewhere in the engine bay.

we're toatally thread jacking lol sorry op
Dave =]

[Tenchuu]

lol at GT30R on RB30.

get serious.

lol @ anything smaller than a GT30. i'll get right on a typhoon intake or a K03 from a VW golf and crank it up to 50 PSI?

not what i am looking for. Z U later is not the first person to strap a 30 series turbo onto a RB with good results.

thanks fro the great response.

but i am looking for opinions here, just most of them have a sold base one way or the other. not random one liners.

[GSXRJJordan]

McRussell was no doubt commenting that the turbo is too small, not too big. GT3071's are small for that motor, but we were talking about streetability. Spooling past 4k isn't ideal for the street.

Dave, you hit the nail right on the head. Efficiency is always good, and getting the motor past about 95% efficient is great, but not easy. Bigger valves/porting let the head flow more, but port velocity is almost as important as total flow - bigger valves/porting drop intake velocity and hurt efficiency lower in the powerband, and don't necessarily guarantee better hp numbers up top... which is why most SR's don't use oversized valves.

You're absolutely right about boost being a measurement for restriction, but the real equalizer is CFM. Given correct tuning/fuel, Airflow x Efficiency = HP, so yeah a blower set for 500cfm will not make 900hp under any circumstances.

OP, build the RB25, get a big turbo, then tune and decide. You can always sell a built RB25 if you want to go bigger.

[McRussellPants]

lol @ anything smaller than a GT30. i'll get right on a typhoon intake or a K03 from a VW golf and crank it up to 50 PSI?

not what i am looking for. Z U later is not the first person to strap a 30 series turbo onto a RB with good results.

thanks fro the great response.

but i am looking for opinions here, just most of them have a sold base one way or the other. not random one liners.

Yeah, 57mm on a 3 liter. I was totally making fun of you for choosing too big of a turbo.

61mm bare minimum, 67 for the big kids.

lol at people hoping and dreaming that the Borg Warner is gonna be some snake oil magic.

If you're not running 30ish PSI, stick with the Garrett.

[WagDatto]

I kind of already spoke my mind the other day. The RB25 is a great motor with SO much potential. The REASONABLE choice would be to say screw it, and stick with the 25. The more controversial and probably more expensive and difficult way would be to go to the dark side and go with the 30.

Honestly, either way you're a winner. Neither motor is necessarily COMMON in the US, so you've got something different regardless of which you decide on.

Plus, a straight 6 gives ME a straight six....

[Tenchuu]

i could care less about different. I live in Oregon so my car is built for the sole purpose of being a fun road car on all the twisties we have around here while takin it on long trips. track is nice, but i am working the balance of being able to drive 200-250 miles between towns to get gas and have the power i need to pass anywhere i want. right now 3rd ends me around 90mph ish, but i need faster response than that to pass someone going 50 in the short passing lanes i deal with on a regular basis. I don't encourage reckless driving, but i do not believe in slowing down for corners below twice the posted speed limit, so i do what is nessairy to meet that goal. That includes not getting to big, or too small, a turbo to keep with my driving needs.

hence the larger displacement motor with the mid size turbo on it.

I'm airing at a road car, not a auto x killer, not a drift star, not a dyno queen, not a drag monster. no emissions and no regulations.
I ditched the AC as it is not that warm around here, am working on putting the cruise control back in, and plan to strip as much weight as possible while keeping a full interior in it.

now that i have made it clear where this project is heading, I know that allot of this broad will no agree with me, or have the same goals as me, but that is cool.

I see what your saying McRussle, most people think that a 30 is too big, so i was assuming that you were of the same mindset. i won't go bigger due to fuel issues, i have to be able to cruise long stretches between fill ups due to the geography of the state i live in.

[MTalon]

Ken, im going to sneak a boost controller into your car, up the boost to 1 bar.. and when you drive it next you will be like.. wow, maybe my rb isn't so slow!!!!

Dont waste your money with a rb30, just spend 2k on a new turbo, injectors and a tune.. You will be inlove with your car after that trust me!!!

p.s. i don't remember where i put that 11mm wrench you brought back to me