hangslo

I am planning of putting a turbo on my big block dually, but am unsure of what size or A/R I should run. I am not looking to make a ton of power, so my initial thought was a T76, but I have been told so many times that it would be too small for a big block ... the only thing is that a t76 should be good for at least 8-900 flywheel horsepower, and I dont need any more than that (if even that). I am not overly concerned with choking the engine a little on the top end since that is not where I am primarily concerned with making power, but I dont want to choke it so bad that I have excessive EGT's and reduced power either.

I am also most likely looking to mount the turbo under the bed just behind the cab.

Should I be looking toward a large A/R T4 turbine or step up to a larger frame turbo with a smaller A/R? Could I possibly use an S400 larger frame with a 1.08 or 1.32?

Once again, I am not looking to make 1k rwhp, but I would like to be somewhere in the 600-700 range turned up, but be able to keep it turned down most of the time.

ScorpionT

What are the specs on your motor?

1fast bird

iTrader: (22)

I would say a t6 flanged turbo with a 1.32 exhaust would be the ticket. Assuming it's a GM with the 8.1 in it.

hangslo

Its currently a 7.4, but I am planning of building either a 496 or 540 to put in it, most likely a 496. I was kinda leaning towards a large frame 76-80mm Schwitzer S400 with a 1.32, but I can get it with a 1.08 for a few extra bucks. I was just unsure as to whether it would be too big or not, and not spool till too high in the range.

Who knows, I may put it on the stock 454 for now and be much more impressed and satisfied than I expected.

1fast bird

iTrader: (22)

I think a 454 with an s480 would be perfect! Might wanna ask forced induction .com what would spool the best on the street without backpressure issues.

CarsandWomen

iTrader: (19)

Ive seen several sponsors say in the past that 400 cid is a good stepping point, once your over 400 go to the large frame turbo. It has more to do with the volume of exhaust accross the rpm range, Def go with the T6 flange.

1fast bird

iTrader: (22)

Definately a t-6 flanged turbo but the exhaust housing size I'm not too sure about....I know for my 402 they told me to use a 1.32 housing, but that was for more of a race setup.

hangslo

Well, even if I dont build a larger engine, if the 1.32 is good enough for a 402, then a 454 ought to spin it up nicely. I will have to call Jose and ask for his opinion and see if it would still work on a 496 for down the road.

hangslo

I stopped by the local shop that sells the turbo that I was talking about and it is definitely a 74 mm T6 frame with a 1.32 A/R exhaust. Nothing special about it ... not a ball bearing turbo, and it originally was used on Kenworth and Peterbuilt semis. The price brand new is $725 out the door.

I dont think the price is too outrageous, but does anyone know of anything out there that is better for a rear (mid) mount for a 454 - 496 big block?

I never got the chance to call Jose at Forced Inductions because my hard drive crashed and I just got it replaced and my computer up and running last night.