T2SLS1

iTrader: (2)

I'm having a 408 built. It was origanaly built for nos, but i came cross a deal on 2 turbonetics t70 turbos i could not pass up on.. but i only want to run one.. Whats the smallest turbo i can use on my 408 then later go up to a 80-100mm turbo after i set the car up,fuel,suspension etc. my goals for now are med to low 10's for now.

ninetres

iTrader: (35)

Way to small to feed a 408. Use both.

CamaroSS19

iTrader: (24)

Thats what I was going to say IMO a 70 is too small for a 346

Pat-Man

iTrader: (3)

I would say a 76 is the smallest you can run on a 408. Any smaller and its way too much of a restriction on the motor.

topend

I say run the single t-70. good for about 800 hp.....

T2SLS1

iTrader: (2)

Now that this his been solved twin t70 or sell for a larger turbo! i purchased a set of tfs 240cc heads are these over killed for a turbo car, should i just use l92 with carb intake and out money back into motor are turbo build?

rubbersdown

iTrader: (1)

run the twin t-70's that would be a pretty nice setup.

pozesd99'

iTrader: (3)

sell both turbos and buy a y2k hp-88... there are plenty of guys running an 88mm on a 402 set up with over 1000rwhp...
or get a st80 or sn91.. all great choices

MonochromeSS

iTrader: (1)

70 is too small for a single on a 408, 76 is pretty much the limit for those cubes.

DrTurbo

iTrader: (3)

70mm would choke a 408 like a rock. Also would probably have a headgasket failure from the excessive backpressure.

hellbents10

iTrader: (10)

Agreed, go with a smallish t6 unit if at all possible to get you buy. If cost is an issue you can get a s400 for $600ish.

Mike 01WS6

I'd go with an 88 bare minimum on a 408. You're just asking for problems if you go any smaller.

Shawn @ VA Speed

iTrader: (3)

you def need to go with and 88mm or bigger with a t6 flange,anything smaller is asking for trouble

TURBO383WS6

iTrader: (2)

these guys know what they're talking about. i had a T76GTS on 383ci and it was way too small. an 88 should spool quite nicely on 408ci. i'm in the process of swapping to a GT4788 right now and i'll get back to you on the difference.

DrTurbo

iTrader: (3)

Correct....also Garrett now has a line of Budget units. From 76 to 88mm . Under 1200 bucks.....GT47 comp, 94mm Turbine...T6 frame...etc..etc.

Pat-Man

iTrader: (3)

what kind of problems would you start seeing? You guys are getting me worried now with my 408 and T76....

DrTurbo

iTrader: (3)

Backpressure through the roof and head lifting. All a part of running a small charger on a big engine. If you are shooting for big #'s, you will have nothing but headaches.

Pat-Man

iTrader: (3)

IC...I'm only running 3 - 4 lbs now (trying to save tranny). Plan on running 15 lbs for maybe 750 to the wheels. Eventually will run something bigger (88) as money allows me.

Thanks.

T2SLS1

iTrader: (2)

how much more extra to run twin t70, a ball park i know pipeing but what about waste gate,blow off etc? and any word on the tfs240 heads for my turbo build is it over kill and should I go l92 with carb intake and put extra cash into my turbo build?

67Firebird455

iTrader: (27)

Shoot, what about a GT45 turbo? How much bigger (physically) is a GT45 vs a T70?