Turbo decision need help

[420_240]

I need help specificially from the guys that have already replaced your stock turbos...I'm debating on getting an HKS GT-RS turbine kit for my rb25 .... supplies everything necassary to be a bolt-on affair....or the ol' t3/t4 (no idea what a/r trim etc. to get either). I have read that the internally gated t3/t4 will bolt right up without any other accessories necessary, lines, fittings, gaskets, whatever... and the externally gated turbo requires a spacer with an extra flange for the wastegate.Only reason I'd prefer the t3/t4 over the HKS is because it's cheaper

As far as horsepower goals and plan for my car... i want a streetable 300hp with an occasional 350hp for tracks... I don't know if i'll see any real drift/autox because of where i live... but it's very possible i'll take this down a strip just for sh!ts and giggles

again thanx for your guidance fellas

[krayton]

id go with internal t3/t4

but when i tried to bolt my t3/t4 up, it seems like you need a small spacer to push it out. the housing hit the exhaust manifold.

mines a .48ar exhaust (tiny) and i think when i push it to its max, i should be near the 350 mark.

[BoostFab]

i have a 60-1 turbo here, brand new 0-mile, it has a A/R .68 P-trim on the turbine housing so lag wont be an issue. stage 3, 360 bearing, it support up to about 30psi of boost and rated to ~600hp. let me know if you're interested. it's perfect for the RB25. I'm moving on with a T66 for my power goal.

my friend have this same turbo on his FC RX7 and he put down 450 at the wheel at about 18psi

[eh?]

I used a t3 flange to space a interal WG t3/t4. I also had to get a new DP and i welded the stock compressor elbow to the new housing. I wonder if the stock turbine housing would bolt to a new t3/t4, if so it would save making a new dp.

[Sil240]

I was just looking in the Turbonetics catalogand for a 2.5 liter for 400HP (guessing at the Flywheel)TO4B H wheel - CompressorStage III wheel .63 AR- Turbine

But i was talking to the guy from turboneticsand he said for my RB20 that i could go with a T3/T4 BB, Oil/Water, Big ShaftT04B H wheelT3 Stage III .48 AR

Check out their web-site they have a little compressor chart to help you

[BoostFab]

i suggest A/R .60 for the rb20--better top end

[WDRacing]

Boost, are you talking about a TO4 with a 60-1 compressor?? Cause a T3 with a 60-1 I thought would be a T3/T4 hybrid.

Edit* nm, I found it, it is the T4 60-1 compressor bolted to a T3.

With Garret I believe the AR for the exhaust housing is .63 and .48 for the smaller version. The .48 is to small IMO.

I'd opt for a T3/TO4E in 50 trim with a .63 AR exhaust housing and a stg 3 wheel. This turbo should have very little lag and flows enough volume for 450WHP+.

[420_240]

I posted this same question on an aussie forum and they're telling me to go with the GT-RS... they were saying something like if i went with the t3/t4 it could be a little bit of guess work and since the gt-rs has been tested and proven i should know how much power to expect....damnit i can't make up my mind

[eh?]

What is your budget? That's the bottom line.

[420_240]

I've got enough to cover the gt-rs, power fc, powerfc boost controller, 555cc injectors, tune, and possibly an oil coolerEven tho the gt-rs isn't as practical... it's more convenient knowing it comes with everything necessary to get the job done.

[BoostFab]

Boost, are you talking about a TO4 with a 60-1 compressor?? Cause a T3 with a 60-1 I thought would be a T3/T4 hybrid.

the one i have is a full size T04 60-1, with a T4 flange, not a hybrid. it's about size of the Turbonetics T61 or T62. P-trim, for the big boys

GT series turbo are nice and all, but if you have around $1500 budget for a turbo.

[SeVa-S13]

I've been debating this for awhile, the whole .48 vs .63 A/R thing and seeing as I don't have both turbos to play with, I can't know for sure how big the difference will really be. With the .63 A/R 50 trim (which btw is indeed the best straight t3/t4 as you've been saying, Carl H can tell you how much research and compressor map plotting I've done) I'm thinking maybe I'll starts seeing decent boost at what? 3500-ish? full tilt at 4k? I'm wondering how much sooner I'd be seeing usable power with the .48 and how much it would truely limit my top end, seeing as I'll probly stay below 8k.

Oh, and I'll have 256dur 8.8mm lift HKS cams to help the top end flow. I just don't wanna be disappointed with a Honda powerband.

This is on a 20 by the way...
Modified by SeVa-S13 at 8:51 PM 5/12/2005

[BoostFab]

honestly stay away from the A/R .48 for the RB...it's about the size of the stock turbo's turbine. go with the A/R .63... even the 4-banger b16 honda guys spools quickly on the .63.

[WDRacing]

.48 is a quicker spooling turbo, but very inefficient for any good numbers. I say quicker spooling, but it's only 500-700 rpm quicker, I've driven with very similar setups on the S14 KAt and the .63 was just a tad behind the .48 but the .63 generated a noticeable difference.

420-240, the T3/TO4 in 50 trim has the broadest efficiency window out of almost any turbo I've ever plotted. I'd use a GT30 GT35 if I were to go with a GTspec turbo.

WD

[BoostFab]

the GT35 is definately a perfect match for the RB, ball bearing also get you boost sooner.

[krayton]

.48ar from comparing the two was smaller then my stock turbo!

i was planning on going with WDs specs, but this deal came up i couldnt pass. i was hoping to squeeze only 300 out of it, but everyone seems to be getting a lot more. everyone tells me that i can get 350ish, but we'll have to see.

anyways my .48ar gets 10lbs at around 3500. probably a little bit higher then that. i was also suprised it actually holds that 10lbs all the way till redline. as soon as i get my aem and probably some injectors, ill be pushing it till the little turbo cant push anymore.

[420_240]

Is anyone in here running an oil cooler? sydneykid from skylinesaustralia.com recommended i run one with a bigger turbo