Your Turbo

[mRodiek]

ive been readin about peoples turbos & their setups as well as the numbers they put down but i havent seen too many people put a t28 on a redtop. this is probably partially due to the fact that you could just buy a newer SR and use that

has anyone done this? i wouldnt think you would need any supportin mods would you?

im also curious if you wanna list your turbo setup on your SR's just to see how you like them, not necessarily the numbers your produce

[MastaYu]

i have seen alot of people put a t28 on a redtop

[X-MAN510]

Everyone uses those turbos.....

[mRodiek]

no required mods? just bolt it on to tthe stock mani n go? lol

[Koshin]

no required mods? just bolt it on to tthe stock mani n go? lol

search or gtfo....

[mRodiek]

search or gtfo....

wow thanks for your help! it sure does mean alot!because yanno i didnt try that

[Kalypso]

type t28 and hit search

[mRodiek]

type t28 and hit search

i guess the keyword is important lolthanks dude.especially for not being a d!ck

[Clawhammer]

A t28 is the most common turbo upgrade for an S13 SR lol.

[Neil]

When I think of "T28" I think of a stock S14 turbo, which is basically a ball bearing version of a T25 with a slightly improved exhaust turbine. The combined differences result in improved reliability and less lag, but since it's got the same compressor it's not much of an upgrade over a T25. In my opinion not worth the effort unless your t25 is fully blown and there's a t28 available to you for under $300.

also the compressor inlet & outlet are clocked differently, as well as the oil/coolant lines so you'd need another ~$250 worth of adapters and flex lines to even install it. But no you wouldn't need injectors and tuning or anything like that.

The GT28RS, however, is a different story. There's actually a bunch of turbo's in the GT28 family but obviously the S15 Spec-R came with the GT2860, aka GT28RS, aka Disco Potato, which is probably what most people think of when you say "T28"... and i'd argue to be the most common upgrade.
Modified by Neil at 2:39 AM 12/8/2008

[mRodiek]

thanks Neil, i was unsure of the differences and figured i could use one off of a S14 but instead i looked around a lil..

the T28 im lookin at is the SPEC R from an S15. i did some more research on here & elsewhere to find that for a complete drop in kit with gaskets & all hardware will run me about $470, plus $710 for the turboputing me @ $1150 for 300hpamazing!

is the spec R the famous disco potato?! lol ive heard people talk about it but only recently did i really learn about turbo trims A/R etc

[Neil]

Yes, the Spec-R's turbo is a Garrett GT2860 'disco potato'.

It's a much more efficient compressor than a T25, so you need to watch your boost levels or you can easily overtax the fuel system. At 12psi it probably flows as much CFM's as a T25 does at 15psi. I wouldn't run more than 12 on the stock fuel system.

To get 300whp you'd need to run about 18psi. To do that you need 550cc injectors and probably a Z32 maf, and for either of those you need tuning. So add another $1000 to your estimate. (an s15 has 450cc injectors, compared to red/blacktops 370cc injectors)

[mRodiek]

well you ruined my excite... lol but you sound like you have run this setup before?not sure if youll know but how much hp could i expect from 12psi?

thanks for the advice my friend!

[Clawhammer]

The S15 turbo is commonly called a GT28R, not to be mistaken with the "Disco Potato" RS.

The S15 turbo is actually a GT2560R (yes, the gt25 family), see Garretts catalog for the S15 Turbo: http://www.turbobygarrett.com/...4.htm

The Disco Potato: http://www.turbobygarrett.com/...1.htm

Notice the difference in the specs, such as A/R and trim.

They are NOT the same.

Now that that's cleared up...

Take a look at this thread of mine: zerothread?id=362808

Everything you need to know is in there.

I ran the S15 turbo at 6psi for a couple months, because melting pistons is not cool and it wasn't worth the risk to up the boost. Honestly, I wouldn't go over 10, even though you'll hear reports of success at the max without supporting upgrades.

I now run the S15 turbo, 550cc's, z32 maf, enthalpy ecu, and I got the Greddy intake kit for the turbo mentioned in that thread...it's amazing. And all SS braided lines. Running 15psi right now and it's awesome. Dyno coming soon.

P.S. Next time search. All of this info is READILY available. And learning for yourself is better than someone giving you misinfo...can you even trust what I say?

[Neil]

edit: if claw is correct then i'm sorry, i never intended to spread misinformation. I was just going by what I had read in the past.

i haven't run this exact setup but mine's similar, just substitute the disco potato for a gt2871r.

im not exactly sure how much power it'd make at 12psi. 100% duty out of 370cc injectors usually puts people just under 220hp at the wheels, though. I would not recommend trying to push max duty out of the injectors all the time, however, since you can't measure it for yourself without getting on a dyno.

Be warned that I don't claim my psi / cfm figure to be anywhere near accurate. its just a generic example to explain one of its differences. To be perfectly honest that turbo could possibly very easily max out the fuel system at even 10psi. If you install the turbo and then wait to get injectors and tuning, i'd do a few test runs with a wideband O2 sensor so you know at what boost levels you start to lean out at. then stay below that level.

[mRodiek]

thanks clawhammer, when i asked about the disco potato i was asking out of curiosity, i hadnt started researching seriously quite yet about the gt28R. i simply asked because he had already answered some of my questionsi saw the thread & it helps a ton, i wrote in their as well but thanks again isnt that the point of forums? gettin others advice/experience togetther and then make your own decision?

[Z28ricer]

A lot of what Neil posted earlier was quite backwards, and just about upside down.

The T28 on the S14's and S15's, as Clawhammer posted is the GT2560RThe compressor side is actually larger, and the turbine side the same.

S13 T25: 56MM exducer 60 Trim compressor wheel 53.0 MM 62 Trim Exhaust in .64 Housing

S14/15 T28: 60MM Exducer 60 Trim Compressor wheel in a T04 housing53.0MM 62 Trim Exhaust .64 housing

The GT28RS is the "disco potato" not the S14/15 GT28R

GT28RS is different than both of those with these specs:60MM 62 Trim compressor 53.8MM 76 Trim exhaust, .64 and .86 housings available.

You will want to limit yourself preferribly to 10 PSI on the GT28R with your stock injectors and MAF, your out of flow on both at about that point, the bright side is that when you upgrade those, you'll be good for an 80 HP jump approx.

When you install you'll need to either buy adapters to reclock the outlet and inlet pipes, or cut and weld them, or you can buy the Greddy S13 kit meant for the install.

You'll really at the minimum want to replace the coolant hardline from the block to turbo with a rubber hose, the stock T25 hardline doesnt clear the compressor housing on the T28, and I didnt see a feaseable way of bending it to fit as I was doing the install with the engine in the car, maybe with things out its possible, but for the $30 I spent on the two barb'd banjo fittings, it solved a big headache.