Help W/ Picking A Turbo

[jameson is dope]

i have decided to go with a t3/t4 turbo and have already purchased a manifold. i am looking for a setup that will maxout around 350hp on my sr i dont know how much boost this will require but what ever it takes im shooting for a tune that lays down 300whp. i want the turbo to spool as fast as possible (like most peple) so i need to know what sizes/trim to run on the housings and the wheels. PLEASE HELP CAUSE I NEED IT!!!!!

[dj_lennon_franz]

300 is acheivable with smaller turbos (ie:GT25r GT28rs or GT28r) the larger the turbo the more lag you will gain...with those smaller turbos yer lag wont increase much (espeically with ballbearing turbos) im not sure if anyone makes a ballbearing T3/T4

start by finding the turbo, some 550cc (or larger) injectors, a SAFCII, a Z32 MAFS, a nice FMIC kit (something a bit large), a nice 3-3.25inch exhaust kit, downpipe, youve already got the manifold covered, try working on a greddy intake mani, thicker head gasget (this is a must), and maybe a nice head package from tomei or JUN....that should get u where u wanna be (reliability for the power)

[msaskin]

For that amount of power, as lennon said, it'll be way easier to use a bottom-mount turbo.

I'd suggest one of the following:GT28RS "disco potato" - maxes out at about 320hp with cames and intake manifoldGT2871R - like the GT28RS, but with the NS111 compressor wheel (same as the GT series turbos). should max out at 350hp or so with cams, good tune, etc.GT25R - the smaller AR (.64) should be able to hit 350hp without cams, higher with cams, manifold, etc. The bigger AR (.82, or .86, i can't remember) will max out around 400hp after cams, etc.

All the horsepower figures I listed are RWHP. If you've got any more questions, let me know. I'm aiming for 350rwhp on pump gas, so I'm in the process of making all these decisions

~matt

[bootman]

What do you have done to your car now make sure you get ALL THE SUPPORT MODS.300-350whp it not hard to get but hard to keep before you get a bigger turbo maybe you sould replace bearings & headgaskest & oil pump&water pump and etc.Look at all the small things your motor (red top) is at least 10 years old.Not being a *sshole just dont wont anyone to forget about the small things that make reliable power.I will get back to you on the t3/t4 i mam in the works of looking for one .

[dj_lennon_franz]

the oil pump should last a LONG time....the headgasget i mentioned to replace...the water pump is no big deal (these are commonly replaced at 100k miles) and its irrelevant to making 350 reliable horsepower...the bearings in the motor are fine stock...the STOCK bottom end on the SR can handle 500+hp...unless yer out EVERYDAY beating the holy hell outta the motor then you will be fine...all the parts you listed bootman arent big deals...and most of em cept for the headgasget and water pump should last the life span of the motor...350hp isnt a TON of power to make on the SR...if we were talking 500-700hp then yes thats when you would want to start looking for those parts that can handle that power...but 350hp is a pretty low number....ill be making close to 300 to the crank with just bolt ons (im already producing about 250 now...205-210 to the ground...dyno proven)

[jameson is dope]

thanks for all the concerns but i simply asked for what turbo to run (oh and **** u quincy a.k.a. bootman) nobody knows what i have, have done, or am planning(not even u quins). the motor is on the engine stand and i am taking all the necessary step to do what i need to do to not have future problems. hate to sound like an *** but i just want help picking the specs for the t3/t4 that i am gonna run!!

[VitaminT]

I think you received your answer...don't use a t3/t4. It is really not worth the effort and expense to use a top mount t3/t4 for the power levels you wish to achieve.

For 300whp I am conviced that there is not a better turbo than the S15 GT28. It will spool the quickest of any 300whp turbo I know and will make the requested goal. Best of all it is relatively cheap and bolts up with much hassle.

Sorry if this is not what you want to hear, but IMO it truely is your best option.

[Trigger]

50 trim with a stage 3 wheel will make that with not to much problems. That is what i have for my CA and a couple others are using that same one and seeing very good numbers. hope that helps a little man

[240SXer]

I've got a .86 AR GT25R, my goal is 350whp on pump gas, and 400whp on racegas. I'm shooting for 11s on slicks and racegas

Looks like you've got a top mount.. Just get a good ball bearing turbo. My GT25R takes longer to spool, but low rpm driving is still a lot easyier before it spools. (i.e. daily driving is easier, since you rarely have to spool driving around town, but to reach full boost it takes a bit longer than the t25).

[Phax]

For 300whp I am conviced that there is not a better turbo than the S15 GT28. It will spool the quickest of any 300whp turbo I know and will make the requested goal. Best of all it is relatively cheap and bolts up with much hassle.

How many PSI do you need to run the GT28 to get 300whp? Will it hold that boost until 8000 RPM?

[VitaminT]

"the S-15 turbo car is a car i tuned. RWD s13 SR 299 HP @ 16 psi, stock block, stock cams, stock headgasket. OBX style manifold, Stock Cat, stock intake manifold." Scott @ secretservices (well was I think).

Anyway that was on his romtune and peak power was at 6K. You will need some cams if you are going to rev to 8K. Probably stage 1 264 or something like that.

If you are going to be revving that high I wonder if the GT2871 would be a better choice or maybe a GT-RS. I have some calculations in a spreadsheet and it shows the SR off the compressor map of the GT28R @16psi and 8K.

Granted that paper math dosen't always add up in the real world. Especially since Scott said the car I quoted was tuned conservatively due to the stock head gasket.

Basically you could probably run it, but based on the compressor flow your effincency would suck around the 60-50% range.

[240SXer]

It's odd with different turbos. I keep hitting the rev limitor because i'm used to the power going away at the high RPMs so I know when to shift. the power stays on till redline now. Shiftlight time? humm.. Big turbos rock though.