8.1L BBC, need tune for MPG.

[GM Guy]

hey all,

A buddy of dad's just purchased a 8.1L Allison ECLB 3500 DRW chevy. IIRC its an 04? definitely 5 speed ally.

He is scared of how bad the MPG might be.

He has also had many rather underpowered rigs over the years, and AFAIK his only long distance tow rig is a fully restored 2xx cubic inch powered Ford F5 two ton truck out of the 60s with a 5 and a 2. so needless to say, he wont need a single HP more, and would likely be willing to trade off some HP for some MPG. hauling antique tractors to shows is the main thing that will be done with it.

SO I ask you folks, who has the best MPG tunes for the 8.1L?

I have heard that Blackbear Performance makes a good one.

through some google searching, I have also read the EFI live is able to work on the 8.1L. Is this true?

Do 8.1Ls have EGR, and can this be disabled?

any info appreciated,
Thanks!

 

[Mad Maxx]

I remember back when I bought my Avalanche, they had a 2500 8.1L Model there. I wanted it just for the Big Block, but after talking to some people that had one, they said on a GOOD Day, they got 8-9 MPG.

So the same should go for a Pickup.

Shockingly enough though, and I don't see how it's possible, a few of them said they actually got better MPG when Towing.

 

[btfarm]

I ran my '03 8.1/A for 58k before I traded it for an '05 LLY and I got 11-12 mpg no matter what I was driving like. I never went away from the stock tune though. They tend to use at least a quart in 1000 miles

Sent from my SCH-I535

 

[trouttrooper]

No tune is going to give any real mpg increases that would offset the cost of the tune, unless you drove a ton of miles. As much as I've looked into getting a tune I've never done it. I'd like to disable the torque management but not going to spend the $$ just for that.

With the dually setup it's most likely got 4:10 rear end, which is what I've got. Biggest thing is just don't put the skinny pedal to the floor. You can look at my fuelly page and see my average for the life of my truck is right around 10. Fully loaded and dealing with the mountains of N Idaho I would drop to 8. Climbing the hills though I'm not one to try to maintain 65mph no matter what the consequences. I let the truck find it's "happy place" and keep it there. The one time I "abused" mine was a road trip from N. Idaho to Las Vegas and back with a horse trailer. I was not happy about the trip and wanted it over asap. Going down was empty, coming home was loaded with household crap. I pushed her to maintain 75 the whole way and got 6mpg on that trip.

Frankly don't know about the EGR system other than there is no PCV valve. Expect to burn a little oil. Mine tends to use 1 quart/3,500 miles. Oh, and if he uses the tow/haul button have him take it off for a couple seconds once up to highway speed. It won't shift to OD unless you're going about 70, but it's got plenty of torque to purr along at 55 in OD on the flats.

 

[WarWagon]

Likely has EGR and don't mess with gas engine EGR. They use the EGR for knock control as well as emissions. Not the same soot dump the diesel EGR is.
Money is better spent for MPG improvement on a less restrictive exhaust and that will mess with EGR via back-pressure change enough as it is.

at: I was reminded a couple weeks ago what towing with any gas engine is like. (Wind it or go slow and fuel gauge quickly on E.)

 

[tanman_2006]

Our 8.1 uses the typical 1qt/1k or more while towing.

8mpg loaded moderately, 10-12 normal mpg.

Black bear tunes are EFI Live

They actually recommend a cooler tstat to slow oil consumption.

Otherwise ours has 290k of farm use and a lot of abuse. 3 radiators, 2 Allison rebuilds and 2 t cases have been killed by the beast on a stock tune.