69-chvl

iTrader: (11)

Going to do a turbo 96 'stang with either a 4.8/5.3, PG or TH400, and a GT rear with low 3.xx gears. I'd like to use either truck or F body exh manifolds, completely stock engine except for springs, and the Holley EFI system

Can you guys size the turbo(s), trans, and gear to make an exceptionally responsive street car that can still run low 10's and maybe even dip into the high 9's?

Hank Peabody

iTrader: (2)

Great to see you back in the turbo world Vince!

Loose converter and something like that t4 S400 would spool instantly. I had a regular $450 PTC turbo converter and it spooled instantly, come to find out it was running on 7 cylinders the whole time. I had PTC tighten it up while still unknowingly on 7 cylinders and the spool time was longer, kind of removed some of the fun of the car, but I didnt miss the CVT like shift of the looser converter, but just comes with the territory. I put a T10 in the car and the spool got even worse even on 8 cylinders once figured out. Some people will tell you they can spool twin PT91s on a stock 4.8 with a clutch but neither of us had much luck with more reasonable combos and a clutch.

Interesting thing on the cheaper PTC turbo converters, one was very loose and the other quite a bit tighter, but they both cruised on the freeway very very tight. Only when you put your foot down could you notice a difference in "looseness"

x275radial

iTrader: (1)

how loose of a converter 3600 4500 5000 just curious thanks

Hank Peabody

iTrader: (2)

The loose converter was right around 4600 and the tighter one was 3100. I told them when I sent the 4600 one back to tighten it way up and they did.

ls1curt

iTrader: (31)

truck manifolds, 2" hotpipes, precision 76gts or the new tc76/78 , th400 with 3.42 gear and a tight converter is what i'd do.

jridenour31

Depends on what your definition of exceptionally responsive is. A 6768 or 7168 would make instant boost with a tight converter and be very fun on the street. It's not going to take much power to go 9's in an sn95 with any some weight pulled out and a good 60'. A 7675 would be my choice. They're capable of low 9's in a full-weight car and will still spool plenty fast.

chiaj144

iTrader: (4)

5.3 or 4.8 and a little mpt 70 on 14lbs and you've met your goals and them some. My 5.3 with the mpt 70 ran a 10.50 @133 the second time out on 9lbs. I'm running a PTC 10" converter and 3.08 gears with a th400. I haven't even started to lean on it yet.
PS- I'm also running the Holley, you'll love it.

69-chvl

iTrader: (11)

Hey Frank how's it going? You know how it is, once you go turbo there's no going back (unless you have a stout BBC )

I do like the s475 t4 I had, but not sure how it would act on a 4.8/5.3. I'll get whatever engine I can get cheaper cause this is a budget build (as usual). Going to try and spend the money where it counts though - convertor/trans, efi ecu, etc. What trans an gear were you running?

Kinda where I'm leaning. I used 2.25 hot's on the last build with the 6.0l I did, so I guess 2" would be fine. Think a 3.08/3.23 gear would work? Reason I ask, is I'm looking for a take-out 8.8 GT rear and most have 3.23 from what I;ve seen. But then again, maybe a 4.8 would need more gear??? If that's the case, might as we'll get more motor to pull the 3.23's cause gear changes aint cheap!


Thanks. How would the s475 t4 compare? Their about 1000.00, and only like 650 for the t6 version. I can only imagine the 7675 is probably alot more.


Great info thanks!!!!

burbalanche

iTrader: (3)

The t4 is not 1000 call jose at fi.

Hank Peabody

iTrader: (2)

Dead on, for a 5.3 or 4.8 you'd think an mpt 70 is perfect for a very fast street car. The mpt 70s are so expenisive now though you can also get a TC70 or TC72 with the original little exhaust wheel for the same price. That t4 S400 you had would spool instantly with a loose converter, both wheels are within one mm of a 76gts/PT7675, maybe the shaft is a hair bigger/heavier, not enough to make a difference. But that turbo is more than you need even if you're only shooting for high 9s in a light car.

Vince, my car has a th350 and 2.41 rear gear and 27" tires(255 drag radials). I look at it as a powerglide with an overdrive with that super tall gear. I'd choose 2.73 or 3.08 gears and a th400 for your car if you run 27" or 28" tires.

LS1NOVA

iTrader: (12)

I had a PT7675 on my 5.3 and loved how it performed on the street and dipped into the 9's. $1400 turbo but performs very well!

67Firebird455

iTrader: (27)

I have a rebuilt MP T-70, .68 (great for a 4.8, in fact that's what I planned on using) with a polished compressor cover I'd sell for $450 shipped. I'm fabbing my setup from the beginning with a T6 for my S480 with race cover going on the 370. Pics are of the actual turbo, compare it to an S475 lol.

jridenour31

The 3.08's or 3.27's that come in the 8.8's would work great with either motor. The 2.73's are steeper than what I would run but even they would work. 8.8's are very cheap to build anyway. At least pull the trac-lok out and rebuild it with new clutches and one extra friction on each side.

69-chvl

iTrader: (11)

Thanks for the tip!!!

Hank Peabody

iTrader: (2)

Thats what she said

69-chvl

iTrader: (11)

You guys think a th350 is up for the job or is this th400 territory?

Hank Peabody

iTrader: (2)

Replace the intermediate sprag race and a shift kit and it is!