Replace My 6.0 To 8.1 In 1500hd

panheadsully · January 12, 2009

Hello,

I'm considering swapping out my 6.0 Gas Hog, underperformance engine to an 8.1 liter big block. I have a 1500HD. I know that tranny I have will bolt up, but what about the engine mounts, ECM and Fuel Rail.

Has anybody considered this? Any other suggestions as to expected issues?

Thanks

dewfpo · January 12, 2009

The tranny you will need is a 4L85E. It's a beefed up version of the 4L80E you currently have with your 6.0L to survive behind the 8.1L.

DEWFPO

merlin5577 · January 12, 2009

Hello,
I'm considering swapping out my 6.0 Gas Hog, underperformance engine to an 8.1 liter big block. I have a 1500HD. I know that tranny I have will bolt up, but what about the engine mounts, ECM and Fuel Rail.

Has anybody considered this? Any other suggestions as to expected issues?

Thanks

Sully, welcome to the site. Always nice to run into members from other sites. This is what I replied to your post from the other site;

The 8.1L came with the allison 1000 5speed. The 6.0 came with the 4L80-E. I do not beleive it will bolt up. You most likely need to buy an adaptor plate. You will need a new torque converter, PCM/ECM, motor mounts, and transmission controller. Not to mention the suspension modifications. IMO you would be much better off selling the truck and just buying one with an 8.1L. Or, modifying the 6.0 for more power.

Kodiak450 · January 12, 2009

Hey great idea! Swap out that 6.0 "Gas Hog" and put in a fuel efficient 8.1 big block, oh the money you will save at the pump.

panheadsully · January 12, 2009

Hey great idea! Swap out that 6.0 "Gas Hog" and put in a fuel efficient 8.1 big block, oh the money you will save at the pump.

It seems the 6.0 is working so hard to move the 1500hd. A larger engine, less work, better fuel economy?

panheadsully · January 12, 2009

Hey great idea! Swap out that 6.0 "Gas Hog" and put in a fuel efficient 8.1 big block, oh the money you will save at the pump.

It seems the 6.0 is working so hard to move the 1500hd. A larger engine, less work, better fuel economy?

Anything is better than 11MPG at 70 MPH. If your going to get terrible fuel economy you may as well have some decent HP? The 6.0 seems doggish.

Kodiak450 · January 12, 2009

Hey great idea! Swap out that 6.0 "Gas Hog" and put in a fuel efficient 8.1 big block, oh the money you will save at the pump.

It seems the 6.0 is working so hard to move the 1500hd. A larger engine, less work, better fuel economy?

Anything is better than 11MPG at 70 MPH. If your going to get terrible fuel economy you may as well have some decent HP? The 6.0 seems doggish.

What are you pulling?

panheadsully · January 13, 2009

Hey great idea! Swap out that 6.0 "Gas Hog" and put in a fuel efficient 8.1 big block, oh the money you will save at the pump.

It seems the 6.0 is working so hard to move the 1500hd. A larger engine, less work, better fuel economy?

Anything is better than 11MPG at 70 MPH. If your going to get terrible fuel economy you may as well have some decent HP? The 6.0 seems doggish.

What are you pulling?

I'm not pulling anything at 11MPG. That is the truck alone. Driving it easy! The rig is an 06 with 30K

Kodiak450 · January 13, 2009

So you are not pulling anything, and feel under powered? What octane are you using? If you use 87, you will not be getting good results. GM has one of the finest knock control sensors out there, and even though you do not hear a knocking, it is retarding spark and giving you poor performance. With a 6.0 in a 1500HD, you should have plenty of power. Do you have 4:10's by any chance? Checked your plugs lately? You should have plenty of power, and depending on your driving habits, not sure if you are a lead foot, you should be getting better then 11. Did you have a prior truck with a bigger engine before the 1500HD? If so, you would be used to power from bigger engine.

Riverjet502 · January 13, 2009

Here's a tranny for ya, http://www.transmissioncenter.net/4L80E.htm I believe someone posted several months back on swaping out their 6.0L for a 8.1 crate motor. I believe it was in a new 3/4 ton tho and they were having the dealer do the work. Heck how about a ZZ502/502 567 ft lbs at 4200 rpm's That'll pull a trailer...

gave20 · January 13, 2009

The 8.1 will not be more efficient, it's a heavy motor, with more power and a pure gas hog. You'll be lucky to get the same mileage you're seeing now. I don't have an issue getting around 14MPG with my 6.0 with in town driving averaging 40 MPH. Highway mileage I'm around 16-17 and the 6.0 is more than enough power to get my truck moving. It's not going to accelerate like a vette, it's a 6,000 pound brick.

panheadsully · January 13, 2009

The 8.1 will not be more efficient, it's a heavy motor, with more power and a pure gas hog. You'll be lucky to get the same mileage you're seeing now. I don't have an issue getting around 14MPG with my 6.0 with in town driving averaging 40 MPH. Highway mileage I'm around 16-17 and the 6.0 is more than enough power to get my truck moving. It's not going to accelerate like a vette, it's a 6,000 pound brick.

Obviously, there must be something wrong with the engine in my pickup. At 70 miles p/h, no load, I drove 120 miles and put 10.6 Gallons of fuel in it. That equates to 11.3 MPG. This is completely unacceptable. I will be selling this PIG ASAP!

The Duramax Diesel is looking much much better. Even if it gets a little better Gas mileage, the power will be available when needed.

No disrespect to those that have the 6.0, but mine must not be right according to what the other people have posted.

I have had a diesel before, I guess I must be used to the power from those engines. I thought gas would be a better idea due to fuel costs, but I'm definently unhappy with the 6.0

Riverjet502 · January 13, 2009

My 2 cents worth here. I drove a Dodge Cummins for 16yrs. Luved the way it pulled for me. Excellerated with authority. Smooth power and very seldom every left 4 gear pulling a steep grade. Ended up selling for a good offer. I then ended up buying a very low milage 1 ton silverado with a 6.0L for a very good price. I too was very, very disapointed in the fact that this truck couldn't get out of it's own way. (Yes I know I was used to a torque'r power band) But still !!! I ended up having Justin from Blackbear retune my PCM and change my trannies shifting points. Just removing the GM "Nannies" made a huge difference alone! I haven't pulled with the truck yet since it winter, but the 400 miles I have driven it since the "tune" is night and day difference in how it excellerates now! This may be another possibility you may want to think about. A lot cheaper then a swap. But I have always been a big fan of the big block too!

66nova · January 13, 2009

My 2 cents worth here. I drove a Dodge Cummins for 16yrs. Luved the way it pulled for me. Excellerated with authority. Smooth power and very seldom every left 4 gear pulling a steep grade. Ended up selling for a good offer. I then ended up buying a very low milage 1 ton silverado with a 6.0L for a very good price. I too was very, very disapointed in the fact that this truck couldn't get out of it's own way. (Yes I know I was used to a torque'r power band) But still !!! I ended up having Justin from Blackbear retune my PCM and change my trannies shifting points. Just removing the GM "Nannies" made a huge difference alone! I haven't pulled with the truck yet since it winter, but the 400 miles I have driven it since the "tune" is night and day difference in how it excellerates now! This may be another possibility you may want to think about. A lot cheaper then a swap. But I have always been a big fan of the big block too!

+1

I think you would be pleasantly surprised by a custom tune. For the money, you cannot beat it.

I have the 6.0 in my 1/2ton and I too was disappointed with the performance. The difference is unreal after Justin (Blackbear Performance) finished with it. I absolutely love it. I fully understand that we have different trucks, but from what I understand, the 6.0 in the HD trucks are even further detuned from the factory and you make a ton of improvement with a tune.

My point, I think it would be worth your time to have the truck tuned before you trade it off or change motors. It's not going to be a tuned diesel, but I bet you will be surprised and the cost won't set you back like a diesel either.

www.blackbearperformance.com take a peek.