mtb989s

iTrader: (1)

I have a 76mm turbo with a large housing (something like a 96mm with a t6 flange). I am having a forged 408 built for it. What kind of HP would I get through a ported ls2 and a large fuel system. 96# injector, twin bosch pumps, etc...

I am wanting something close to 1000 hp. Is it possible with this setup? I've been told this turbo would make a lot of power because of the larger housing size and the t6 flange. What kind of boost do I need to run to get the numbers?

Thanks for the input.

sr71

iTrader: (17)

a standard t76 is a little small for a 408 cube engine. especially if you are trying to get 1000 hp. a t76 is rated at 950 hp. but that is at around 30psi. you will be off the map with a 408 at @ 1000hp. I would look at something a little bigger. like maybe an 88. better yet, talk to Jose at forcedinductions.com. he can hook you up with the best turbo for your combo.

Boostaholic

iTrader: (4)

I also think that turbo is too small for your application. If that 76 is new you should probabaly sell it.

engineermike

I think it will work well. A good T76 compressor will flow enough air for 1100+ hp. A built 408 will make 1100 hp at 15-17 psi. Sure, at 100 lb/min and 2/1 Pr, it isn't the most efficient turbo, but it will support the air flow required. It will work especially well with the T6 exhaust side.

Mike

sr71

iTrader: (17)

I could be wrong, Mike. but my compressor map shows 100 lbs/min not even hitting the map. 90 lbs/min barely hits the edge of the choke line. but I'm no expert. that's for sure.

King James

iTrader: (13)

I'd look at the something more along the lines of the GT55

mtb989s

iTrader: (1)

Thanks guys, I'm new to FI so all this information is welcome.

mtb989s

iTrader: (1)

Thanks guys, I'm new to FI so all this information is welcome.

RealQuick

iTrader: (14)

I am pretty sure the compressor map is for a standard T76 (something like a Q trim). The GTS will produce 150hp more than the q trim version and if he has a GT42-76 with a T6 housing (sounds like he does) then it should support 1200fwhp.

ddnspider

iTrader: (26)

i was gonna say i thought standard T76's were a T4 flange,you dont get into a T6 flange until you go with a large GT42-76 in which case it'd support the airflow and work pretty well.

Toonz

iTrader: (6)

The GT42-76mm we had on my little bro's car couldn't support his 370 cu in block. I'd upgrade to the 88 if possible.

ddnspider

iTrader: (26)

you serious?i thought that turbo was good to like 1300fwhp???now im afraid im going to max the hell outta my 76gts on my 383

edit...Jer?give us an update on your car

parish8

iTrader: (6)

i had the basic t76q trim on a 408. best i could do was 640rwhp. i do have a lot of driveline losses. the basic t76 is fun on a 408, it spools real fast but it's too small if you want to push it to 1000rwhp. i dont really know what compresor you are talking about up top.

DrTurbo

iTrader: (3)

You need to go with an S76. Its probably the most powerful 76mm unit on the market. Uses T6 flange, big turbine....etc.

stang90gt50

iTrader: (6)

Ditto, from everything I see the S76 is the only 76mm turbo on the market that can make the kind of power he is looking for on a 408", other than that you need to move to a 88mm turbo to make it work well on a big inch motor...

NA$TY-TA

iTrader: (21)

yep yep.... its not going to work very well.....
14-15 psi was all we could muster out of the ol GT42-76 and the intake temps were in the 200+ degree area also... not a good idea...... i have a 370 so a 408 is a wayyyy NO NO. Sorry.

Kyle

engineermike

I did 680 rwhp with a T76GTS on a 383 with lots of inefficiencies. Peak hp was 5800, but my converter is way too loose because it flashes to 5400 (no lockup). I made that hp with a Vortech Aftercooler, 3/8" diameter boost leak, 52 mm TB, log header, and restrictive muffler. I later figured out how to drop the backpressure from 48 psi down to 34 psi with the boost at 20 psi.

After a cratered motor, I destroked down to 363 cid based on peoples' advice that 383 is too many cid for a T76GTS. It never performed as well as the 383, even with a bigger intercooler, no boost leaks, and bigger throttle body. After cratering the 363, I'm going back with cubes. This one will be a 388 and I can't wait to see the results.

Mike

SSilverSSurfer

iTrader: (8)

88 for the win

mtb989s

iTrader: (1)

I've decided the 88 might be a better option for me. I'll keep you guys posted.

2000 Tran Zam

iTrader: (2)

Good choice