06 8.1L Vortec Tuning
- Thread starter Bdsankey
- Start date
The 8.1 will out tow a 6.0 gas motor every day of the week and get better mileage doing it.
We drove my buddies 03 8.1L Extended cab long bed 4x4, Hauling my SS truck from California to Texas to the new owner and then up to Michigan to pick up another truck for me and back to California.
We averaged between 10-11 MPG every fill up the whole trip. We also where not easy on it. I personally beat it like it owed me money. Raced a few diesels and even a hopped up Semi.
It's only Tuned By him on both the engine and trans, It's also modified to Run E85. Says it gets about 5-6 MPG towing his 5th wheel camper on E85 Vs. 10-11 MPG on Regular 87 octane. No other modifications.
I recently modified an intake manifold for him, I also found him some older Raylar Aluminum heads locally that needed a little work as well as a set of used stainless works headers. He is planning to also add a small cam.
He also picked up a complete 6 Speed with wiring harness and trans ECU from an 06 so he is planning that swap as well.
We drove my buddies 03 8.1L Extended cab long bed 4x4, Hauling my SS truck from California to Texas to the new owner and then up to Michigan to pick up another truck for me and back to California.
We averaged between 10-11 MPG every fill up the whole trip. We also where not easy on it. I personally beat it like it owed me money. Raced a few diesels and even a hopped up Semi.
It's only Tuned By him on both the engine and trans, It's also modified to Run E85. Says it gets about 5-6 MPG towing his 5th wheel camper on E85 Vs. 10-11 MPG on Regular 87 octane. No other modifications.
I recently modified an intake manifold for him, I also found him some older Raylar Aluminum heads locally that needed a little work as well as a set of used stainless works headers. He is planning to also add a small cam.
He also picked up a complete 6 Speed with wiring harness and trans ECU from an 06 so he is planning that swap as well.
They hold up better than Vortec 454’s and we ran a 98 454 with a whipper 2.1 on it and other mods at 450rwhp towing a 40ft trailer for years. My dad was a bad influence on my “tow with big hp” addiction.
If you want all out high rpm performance, get a 6.0. If you want towing performance, the 6.0 doesn’t hold a candle to it mod for mod.
I've ran across a couple guys running 8.1/Allison in hotshots some car haulers some flatbed freight all under 36k gross.. couple of them were north of 300k on the trucks with nothing major engine wise done..
I had one and preferred it much over a 6.0 for farm and towing work, the biggest problem is they are choked from heads, intake, exhaust. But if you get those right, the bottom end is weak as well, pistons will grenade if you try to put anything over 6psi into them. That being said they are a solid reliable platform just kinda thirsty.
I absolutely love my 8.1 / ZF6 combo. It's a reg cab dually. 10 mpg loaded or unloaded with 255/85's
Unless you are looking to swap cams or other pertinent hard parts leave the tune alone. Check the spark plugs and gap should be .045 IIRC, get 180* tstat. I noticed the biggest difference on hot summer days after sitting in traffic with the 180 tstat.
You are not buying an 8.1 for "economy or mileage" its a truck. Get over the cost of fuel as a cost of doing business or get a Volt for commuting.
Unless you are looking to swap cams or other pertinent hard parts leave the tune alone. Check the spark plugs and gap should be .045 IIRC, get 180* tstat. I noticed the biggest difference on hot summer days after sitting in traffic with the 180 tstat.
You are not buying an 8.1 for "economy or mileage" its a truck. Get over the cost of fuel as a cost of doing business or get a Volt for commuting.
For sure on the economy side, just didn't know if there was anything left on the table in the tuning side of things.
As of now the plan is for a cat back since its rusted through in the muffler as well as changing/gapping plugs, change all fluids etc.
Thanks for the tip on the 180f thermostat!
Trying to compare a gasser running on E and gasoline for mileage is like trying to compare propane vs hydrogen. E is always way lower, but so is the cost.... And you don't see much gains on E unless it's boosted.
I for one would like to see if any meaningful milage tunes could be made. I know these things generally suck for mpg but could that be helped with tuning? Kind of like a holden tune?
How lean can these run without damage? What if you just optimized the spark map, could that help any over GMs map without changing fueling?
How lean can these run without damage? What if you just optimized the spark map, could that help any over GMs map without changing fueling?
I've got a friend that has one in a drag car that sprays N2O and runs 9's in a 3500lb car. All stock short block and it's been going for many years of abuse. Good bottom end in them, factory stroker engine. I like them.
Allison was standard on 8.1.
8.1, up until LBZ, put out the same power/tq as a duramax.
I thought they were 500ft-lbs, my error. Looks like they were 330-345hp/440-455ft-lbs.
LB7 was 235-300hp/500-520ft-lbs
LLY was 310hp/520 ft-lbs
Above numbers are according to duramax hub.
They are good at what they were designed for, low rpm torque. They are not LS motors, they are not very accepting of many power adders. I have never heard of someone blowing nitrous thru them, appears to work. I just know that they hate boost, rpm and don't respond to tuning all that well.
Well I'll have to disagree with that. Dad looked at a brand new 3500 dually back in 04-05, had the "hd" 4 speed option
Interesting. My Mitchell Works repair info only shows an allusion. Wonder if there is an error there.