I'm about to order on3 turbo kit for my 03 2500hd 6.0 that gets used as a work truck that hauls and a toy. I can't decide between their 76 or 78. Ive researched this a ton and there is several debates about small or large turbine for a truck gets used for work? I'm leaning towards the 78, would that work? I want grunt down low but not consistently in boost

 

Get the larger turbine in my opinion.

 

Either would perform just fine as you aren't going for all out power.

Even the 70mm turbo would be a great jump in performance over stock.

 

Do you think the 78 would be a dog off the line?
Idk if matters about mods but I have a 220r cam and 243 heads

 

7875 On3 on my 5.3 with a 4L80E and stock convertor and 3.42 gears and it's a dog off the line and picks up after about 2500-3000 RPM ... getting a 3200 stall shipped currently.

6865 Precision before with a 4L60E and stall was a beast amd put down 520 rwhp

6.0 may help it spool a bit earlier.

 

I have a 70mm in mine with the 1.05A/R housing. it builds boost nice while cruising and while WOT turbo lag is about 2800-3000 then its a rocket. at 10lbs truck made 523rwhp and I have a 5.3l.

 

Yea I think the ar for the on3 70 and 76 has a .81 ar. My trucks already a dog down low I just don't wanna choke it with the small 65 turbine.

 

double check that AR. I thought they were 70/65 with .96 AR. I have the exact specd turbo and it lights off once i touch the throttle with my 5.3

 

I run the VS Racing 7875/.96 on my black truck and had the same results when i had the 5.3 in it. it was instant spool when touching the throttle.

 

Your right, they all have .96. so ita matter of turbine size I guess. So you both have a 78/75 and it lights quickly?