Stock T25 ---> GTiR T28 Review

[AmoebAssassin]

I just installed this turbo on my car after fabricating a wastegate actuator bracket, and rectifying a wastegate flapper issue (flapper wasn't being tensioned shut, was a little open and spoolup sucked, but that's fixed now). Here is a quick review of it.

Specs:

60 Trim BCI-1 compressor wheel in a T3 housing.86 A/R, 79 trimTurbine side w/higher flowing 10-vane turbine wheelJournal Bearing CHRA

Installation went smoothly. The compressor housing needs to be clocked so that the compressor outlet elbow lines up with the hot pipe. The CHRA needs to be clocked so that the oil return pipe will line up with the stock return hose. You need to fabricate a wastegate actuator bracket so that the wastegate actuator hat doesn't interfere with the compressor outlet elbow. You need to bend the stock T25 hard lines a little to fit--I didn't want to deal with this hassle so I went with Taka stainless steel braided lines. I used the stock manifold and turbine outlet elbow; they bolt right up. In the future I will upgrade to a tubular manifold (or ported/extrudehoned/thermal coated stock cast manifold), and a larger turbine outlet elbow to increase spoolup and power. The stock compressor inlet needs to be cut and rewelded so that it won't point into the manifold, and will align with the stock rubber intake tube.

The first thing you notice coming from a T25 is a slight decrease in response. With my T25, I'd spool at 2700rpm and make full boost almost right away, by 2900 to 3000rpm. The GTiR T28 will begin it's spool at about 2900-3000rpm, and reach full wastegate boost (looks like 8 or 9psi on my boost gauge) by about 3700 or 3800rpm.

The next thing you notice is that the powerband is considerably wider with the GTiR T28 than the stock T25. With the stock T25, the boost would come on nicely but then fall off drastically by 6000-6250rpm, making it worthless to stay in gear past 6500rpm or so. The GTiR T28 is a whole different animal. Once the turbine is spinning, it will continue to flow until redline. I've found myself banging off the rev limiter more often because the car has so much more top end now.

Power is fantastic coming from a T25, even at stock GTiR boost. At 12psi, the T25 was making about ~220whp on the butt dyno. At 8psi creeping to 9psi or so, the GTiR T28 makes a good bit more power! It made about 260whp @10psi on some KA-T, so it's probably at about 240 or so whp @ 9psi on an SR. I can't wait to turn it up -- it apparently starts to leave it's efficiency range at 16-18psi and is good for 300+whp.

I will be hunting for 325whp with this turbo. I plan on this setup:

GTiR T28Z32 MAFTubular Manifold, or ported, extrudehoned, and thermal coated stock manifoldGReddy (or GReddy knockoff) turbine outletSTi 550cc/min injectorsHome-tuned ROM ecu (I will be soldering on my own daughterboard, and tuning my own map using a Mine's .bin file for Z32 MAF and 550cc/min injectors as a base map)264int/264exh Cam setup (HKS, BC, or JWT -- haven't done too much research yet)

If you have any questions on this turbo, I'll be happy to help you out. Contact me on AIM or e-mail me.

[efrain240sx]

sounds like you been having some fun with youre new turbo. keep us posted on the HP #'s good luck

[ILikeMy240sx]

sounds good. I didnt know the T-28s can flow to support 320 RWHP. I hope you have lots of fun!!

[SR20Monster]

Im doing the exact same thing.. You've got IM

[S13FASTBACKSR]

a kid down where i live had his gti-r t28 compressor housing ported and is making a good 350rwhp at 20psi iirc..just around there atleast..my skyline t28 made 305rwhp at 18psi but it has been rebuilt with higher a flowing fan...so i guess the factory gti-r is capable of 300hp more than any other factory t28...by the way i have a set of hks 264 step 1's for sale if you are interested in them..very nice condition. they were used for about 2 months and the car is not drove often..let me know

[adrianfromthecastle]

nice... youve answered pretty much all the questions ive had in my head about the gtir t28s.... me likes what me sees

[oki_bum]

my friend had a GTi-R turbo on his 180...dam good power

[AmoebAssassin]

Well my STi 550cc injectors are on their way (105 shipped on nasioc), so I'm about 200 bucks out on my setup (Z32 MAF and the daughterboard + rom burning board). I'll let you guys know how it feels at 16-18psi in a month or so.

[IDriveFords]

Damn; how much can you pick one of these up for? Eventually I wanna try and run a comfortable 250hp on the car which for the most part will be a daily driver. Keep us posted on how this turns out.

[SR20Monster]

if you get lucky, you can pick one up for like 300-400.. sometimes 500.. but brand new 700-800..

[AmoebAssassin]

I paid 350 shipped for mine with under 20k miles on it, in freakin rockstar awesome condition.

[n00b240]

nm just figgered it out
Modified by n00b240 at 4:37 PM 6/2/2009

[240FOREVER]

HEY THIS IS MY FIRST SR20DET SWAP FOR MY S14 AND I HAVE A LOT OF QUESTION TO ASK YOU PRO PEOPLE. WHAT TYPE OF MOTOR MOUNT DO I NEED TO FIT INTO THE THE ENGINE BAY FOR THE THE SR20DET

[virus77]

wow, what a first post you poped in here with lol, I sugget searching alot before asking the most obvoius of questions but Ill answer this one for you. SR20s and KA share the same mounts so it pretty much bolts in, add some piping, a few wires here and there and they start right up

[Chuvy]

since your mentioning the t25 i take it that this is on an s13 sr, no? what would be the difference on my s14 sr?

[racemydatsun]

who the hell bumped a 2 year old post?!?!?!