Turbo options
 

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?

Think the stock bottom end can handle this turbo? I don't plan to spin past 6400

You are out of camshaft way before 6400 anyway, stick to the stockish rpm's to keep you in the power band. Would be pointless to go that high if it can't flow good there.

Stock bottom end should hold 500hp just fine.

I just said that cause that's my rev limiter. Shifts at 59-6k. Is that turbo gonna put me at about that at like 8-10lbs

I feel like this turbo is gonna end up putting me at like 600, I.hope it can handle it

I don't see it being anywhere near that with a stock cam.

Maybe 450-500 is a better ball park. Doing a cam upgrade will open up way more horsepower.

I do have a cam, a 220r

You're pretty good at providing info so I assumed it's all stock based on your posts.

Just be aware that your long block does not have the better connecting rods so you'll want to be careful on your horsepower goals.

Still expect are around a 450-500 to the tire with a good tune, going alot higher could get into the danger zone. And at that power level it's going to destory the tires on the street anyway at lower speeds. It should be plenty fun still.

Yeah 450-500 is all I want. I mentioned my mods half way down. Also have 243 heads