stangs400

iTrader: (5)

Hey guys im doing a turbo swap into my 71 Trans am. car weighs about 4000 with all the sound deading in it. Car is mainly a daily driver which rarely ever sees the track. My problem is im on a serious budget and am stuck on which turbo to go with. I recently purchased a quick spool valve that uses a t6 flange. Now I figure it would be best to use a turbo that uses a t6 flange, or i could make an adapter to go from a t6 to a t4 turbo.

Im using 6.0 lq4, bosch 65lb injectors, ls6 manifold, slight port and polish on 317 heads, ls9 gaskets, head studs, upgraded springs and pushrods, cam specs - TFS 228/230 .588/.588 112 CAM, so not to wild or anything, and looking to make around 600rwhp. This will be mated to a built t56 with a 12 bolt and 3:73 gears or 3:30 gears.

But I was looking at a few turbos on ebay. But also entertained a couple Borg Warner S475 turbo, with a/r above 1.1 because I do have the quick spool valve... But still thinking of going with something like this with an adapter:

Godspeed t88
Intake :5 inch
Outlet: 107mm outter diameter, 82.35 inner diameter
Compressor trim: .70 ar (anti- surge)
Compressor Wheel diameter: 74.80 /102.40 (big wheel)
Turbine wheel diameter : 75.35 / 81.70
Exhaust trim: 1.05ar
Turbine flange type: t4 flange ( twin scroll )
Downpipe flange type : 6 bolt type

Which route would be best for daily driving and making 600ish rwhp? Sponsors?

denmah

iTrader: (2)

s475 is a great turbo, but i love trying ones i never have.

the gt45(t4) is similarly sized to that one you posted and its Vband downpipe not junky bolt up

turbocamaro125

iTrader: (3)

s475 s480 or ebay gt45

DrTurbo

iTrader: (3)

You can run the S475 on a T4 housing which will make more power, better built and actual parts made/available in the USA

a4ls2goat

Im running a gt45 with my lq4 with a ls9 cam. I'll let you know how it works out.

Camaro9969

iTrader: (12)

S480 seems good just large I like the t6 also with the race cover but dr Turbo I'm sure knows this answer

Fbodyjunkie06

iTrader: (10)

S475 hands down. T6 1.32 hotside 650 brand new from Dr. Turbo

stangs400

iTrader: (5)

As much as I would like to run the ebay gt45 turbo, the turbine wheels just seems way too small. I think it will be choked out or running at maximum efficiency? Am I correct in thinking that? I am running a quick spool valve after all, so spool up time is going to be fairly fast as it is, so I could afford to go to a higher a/r and be more efficient on the top end while acting as if I had a small a/r when the valve is closed under low boost pressure.

Will the GT45 ebay turbo be capable of producing 600ish rwhp without being maxed out, or would it be more wise to go with the BW475?

stock48

iTrader: (17)

For less than 800 HP I wouldn't go near that 96mm exh 1.32 AR. The BW S475/83mm/1.10 would be plenty.

Fbodyjunkie06

iTrader: (10)

I don't know why some are afraid of a T6 turbo.

There are 5.3's and 5.4 mod motors that spool those S475 T6's all the time. It's a 364 cubic inch motor, and with the proper EVO event in the cam timing it will light that thing off like a 67mm T3/T4.

If you want the most performance out of it, and don't want to have to swap to a different housing one day use the T4 92mm turbine wheel exclusive to Dr. Turbo, because with a turbo you always end up upgrading and anyone that has owned or owns a turbo car knows what I am talking about, the turbo always ends up bigger one day.

Hank Peabody

iTrader: (2)

96mm turbine with a manual trans and 6.0 is a terrible idea for a street car.

Fbodyjunkie06

iTrader: (10)

It's a 364 cubic inch motor.

With the right EVO it would work all day.

There will be a 5.3 here soon with a T56, blow through, and a S480 and a cam I spec'd spooling one just fine.

Hank Peabody

iTrader: (2)

Define "work all day" and "spool one just fine"...5psi at 4000rpm sucks with a street car using a clutch.

stangs400

iTrader: (5)

The thing is, my quick spool valve is using a t6 bracket. So i would like to keep the t6 housing so I wouldnt have to use an adapter. But seems like the t4 GT45 EBay turbo might be the way to go with for a street car, especially if I want to keep the engine more reliable and under 14lbs of boost. Will I see any trouble reducing from a t6 housing to a t4? Also there is a "t88 ebay turbo" for like 440.00 shipped which specs more like an actual T76, specs:
Inlet Size 5"
Outlet Size 107mm outter/ 82.35mm inner
Type of Bearing WET FLOAT BEARINGS
Maximum PSI Capacity 30 PSI
Compressor .60 AR Compressor
Compressor Wheel

Exducer: 102.4 mm, Inducer: 74.8 mm
Turbine 1.05 AR Turbine
Turbine Wheel Inducer: 81.7 mm , Exducer: 75.35mm
Type of Flange T4 (Twin scroll turbine housing)
Type of Down Pipe Flange 6 BOLT

There are adapter to go from the 6 blot exhaust flange to a v-band flange, then again after buying all these adapter to make this thing work, Im right up near that 600.00 range and might as well go with a BW475 from on of the sponsors, right?

So i guess Im deciding between the ebay GT45, and a BW475 on a T6 housing. Is it going to be worth the extra 300.00 and go with the BW turbo for more reliability and efficiency? Also which sponsors should I talk to?

93camaro_zzz

iTrader: (13)

I agree with this! Even with a manual trans.

Fbodyjunkie06

iTrader: (10)

I dunno how else to put it?

The cam that is going in that car will be 235/242 .617/.592 114+4. This cam would work just as well in this application as both motors (5.3 vs. 6.0) have the same stroke. Even though the displacement is different torque output will be similar due to the same stroke just at a lower rpm and because the 75mm wheel will limit power that is able to be made at a higher rpm by taking the compressor out of it's efficiency range at higher boost levels.

I really don't know how else to tell you that if you advance the exhaust timing it puts more volume in the turbine housing for the turbine to spool and drive the compressor wheel.

OP I wouldn't be afraid of an S475 T6 at all. If you feel like you're getting pressured to not run the T6 and absolutely feel the need to go with a T4 because of it, get the S475 with the 92mm turbine and 1.10 housing exclusive to Dr. Turbo and if you really somehow get roped in or talked into something smaller do the 87mm turbine, but I wouldn't put that on a 6.0. You will only want more later.

Hank Peabody

iTrader: (2)

Forget all the theory and tech, around what rpm will it hit 5psi in top gear rolling down the freeway?

MUSTANGBRKR02

iTrader: (91)

I just don't see how you can be choosing between the eBay and BW unit and be stumped.

Fbodyjunkie06

iTrader: (10)

I don't have a crystal ball if that's what you're asking.

I would say if it cruises in the 2300-2500rpm range it should see full boost by 3500rpm maybe slightly higher. I wouldn't doubt that you would have full boost by your 4000rpm threshold.

Hank Peabody

iTrader: (2)

That would be quite a cam then, a 96mm turbine S400 on a 5.3 and full boost by 3500, even single T4 5.7/6.0/6.2 setups don't hit full boost quite that fast with a manual trans.