GT25 or GT28RS

[GT4 20]

Okay, I know I have a few different threads, but want to keep each subject seperate
I'm stiill trying to decide which turbo to go with when I upgrade. I'm split between a GT25 and a GT28RS. The former is rated at 320bhp and the latter at 350bhp.
I'm after low down/mid range rather than all out top end power - it is a road car after all I'll be getting the head gas flowed and a tubular exhaust manifold made up and *probably* running around 18 - 20psi boost max. Which one do you guys think would be best suited to the 3S-GTE?
Gary

[1598cc]

either will go fine, but id go with the 28.

[QikStarlie]

i'd go for the gt28rs or somthing bigger... 400/440hp version gt28
i use one on my 5e (1500) and gets full boost at around 4500, so should be pretty good on a 3s

[Al]

Street Brawler 46 trim 0.63 a/r t3/t4 over those turbos.

http://www.koracing.net/img/DynoRunGen3SB50PumpGas.jpg

[Adamal]

I'm after low down/mid range rather than all out top end power

The keywords here are low down/mid range people. Keep that in mind

If thats what you're after, I'd go for a twin screw supercharger. Full boost by ~1800RPM and keep going til the redline! Just expect to fork over your arm, leg and first born. Maybe second too

[GT4 20]

Thanks Adamal

Not interested in something that doesn't spool up fully until 4500rpm. Pretty pointless on a road car IMHO.

Al. Do you have any further info on this turbo? [EDIT- Just found the answer - http://www.koracing.net/products.html]
Gary

[Lloyd]

Bear in mind that spooling at 4500 was done on a 1.5L 5E rather than a 3S-GTE. Couldn't comment on which would be better for your application but if you cant find what you need then get the GT25 and see how you go. If its not doing what you want them play around with the inside bits

[Adamal]

Given a volume increase of 33%, you'd probably look at full boost at about ~3400RPM....

[Twolitre]

I personally would not go with anything smaller than a GT28RS as you might be dissapointed with the gain over what you already have, your ct20b should be able to achieve 200kW @ wheels with an aftermarket ecu which I would have thought would be enough for a daily driver no? or are you actually trying to achieve better response than the stock turbo?
Anyway I've always found http://www.atpturbo.com/ to be an awesome site, you could read through the archives and research which turbo attained certain results on certain engines especially as they seem to do a lot of research on 2l 4 cyl engines might give you some more ideas.

[GT4 20]

I'd like better response than what the CT20B has to offer. I was thinking that the GT25 may be too small and the GT30 too big which is why I also considered the 28RS. Out of interets, what sort of boost does the GT28RS max out at - anyone know as I can't seem to find that out oanywhere?
Gary

[Akane]

hahaha Gary, what happened to your 450hp aim?

[GT4 20]

hahaha Gary, what happened to your 450hp aim?

Aren't the TRD stickers I'm putting on worth an extra 100bhp?
Gary

[Al]

Have a search for Gen3 and street brawler on http://www.mr2oc.com for some insight of peoples thoughts on the 46 trim t3/t4.

[Akane]

I think you're better off with the ct20b.
The GT28RS kit would cost around $3k to put in your car. This is based on the average of about $1300 USD for the turbo, then the shipping, which excludes everything. You'll need a custom dp to suit your car, adapter plate made up, oil feed and return lines you're looking at $300 NZD, then the work to put in it.

So:

Turbo: $2000 shipped (or you can buy locally for $2300 IIRC)
Hoses: $300
Adapter: $ 150
downpipe: $400

$2850 without labour.
the GT28RS does have an edge over the ct20b in terms of power and spool, but I don't see the bang / buck here Gary.

Maybe you can pick up one of those popular t3/t4 kit as Al have said.
Still, my favourate choice of turbo is the GReddy TD06 turbo, I'd trade this GT28RS I have now for a TD06 any time of the fukkin day of the damn week in this crap year. Don't get me wrong, the GT28RS is cool, but just that there are better bang / buck options out there, I am willing to trade some spool time for that tad more power... for now.

[GT4 20]

Not sure where you've been looking on the net, but I can get a GT28RS for a lot less than NZ$2000! I've seen them in Oz going for AUS$1600 and I can get it here for nowt.
I understand what you're saying, but I'm having the motor rebuilt by Lyn Rogers so see little point in 'skimping' on something as important as the turbo.

[Akane]

Well, I guess if you can get "hookups" then that's cool.
Looking forward for your car to be finished, have fun.

[Malcolm]

i wonder if on a heavier car like your's, if you might be better off trading a bit of spool up for more power, especially since the exceptionally short and straight intake path of the gt4 (keeping the stock ic?) will give you a bit less lag than people report with the same turbos on mr2's. Since you're going to the trouble and expense of getting the head gas-flowed and presumably some aftermarket cams installed, a turbo with a bit more lag but more flow capacity might be a wiser choice?
just my 2c anyway

[GT4 20]

OE WAI is staying, though I will be getting a tubular manifold made up. Hade a chat with Turbo Vehicles today and they recommended a GT25 with a .60 AR Comp and .86 AR Exh. Pretty much the same as the GT2871R I've seen. May well be a better option than the GT28RS. So may different trims of turbos out there it gets so damn confusing
Ideally, I'd like something like the WRC motors. 300bhp but torque for Africa
Gary

[Malcolm]

get an intake restrictor (38mm is it?) and antilag and you could see similar results....

[Twolitre]

Not sure where you've been looking on the net, but I can get a GT28RS for a lot less than NZ$2000! I've seen them in Oz going for AUS$1600 and I can get it here for nowt.

I agree, have a look at the following site and you'll see that AU$1430 will get you one of these puppies landed to yourdoorstep within Australia so can't be a hell of a lot more than that to get one here.
http://www.horsepowerinabox.com/HPIAB2/category12_1.htm