I'm debating which engine to get in a Suburban.


I would get the Dmax if it was offered.


Can anybody give me real world MPG figures for both engines?


I keep hearing that the 8.1 gets about the same mileage as the 6.0 but with the benefits of better power and torque. Is this true? The 8.1 is exempt from EPA certification so no official figure. I'm not sure about the 6.0.


Is the 6.0 truly a "thirsty" smallblock and the 8.1 an efficient big block like I keep hearing? Why would Chevy even offer the 6.0 if it's so inefficient? I understand the 8.1 might level the field when towing since it's not towing as hard but what about when empty?


Anybody with towing experience with either or both engines would be greatly appreciated.


TIA

I had a 6.0 in my 01. Just sold it as I have a D/A coming in May. Around the farm I would get 11.5, not towing, running to town, checking cattle etc. Pulling my 24ft flat bed gooseneck with a sand rail and 3 atvs down the highway would be 8. That was not a real heavy load too. The best I saw was just over 13 and that was running 70 down the interstate. I would have to work to get better than 250 miles before I had to gas up. Hated that, tanks to small! Modes where throttle body spacer, K&N, exhaust, and hyper tech to see if I could get better milage. None of it worked. My 83 3/4ton with a 350 could out perform it, just wasn't as comfortable or as prettyhttp://www.dieselplace.com/forum/smileys/Embarrased.gif

The wife only gets 8-9 MPG in the Yukon XL with the 8.1. http://www.dieselplace.com/forum/smileys/Cry.gif

I get 9-10 in my truck, I'm usually pulling a trailer though. Doesn't vary on the highway much usually still about 10mpg


2002 2500HD 8.1L with 305/70/16's.

With the 8.1 you will get about 8-10 depending on how you drive and what you pull. With the 6.0 you should get anywhere from 10-16. Some people will call BS but I had a 2002 HD with a 6.0L on 38's and I was getting 14 most of the time. Sometimes 12 if I drove over 80 mph long distance. Pulling a trailer was a steady 11. Never got below that.

I've got a 2001 Silverado 3500 cab and chassis with a custom built 11' plumbing utility box on it I get on an average 7-8mpg. This truck weighs in at 10,500lbs.The best I ever got was 11-12mpg and this was total highway driving. However, I was doing 70mph with an 18' bayliner ski boat behind it. The engine is a true work horse, I believe. I was doing 75mph up the Grapevine, and a Cummins with an empty horse trailer, couldn't keep up with me.


Best bet is to get the Duramax. I will never go back to gas engines again after owning a Durmax. My Duramax play truck, with a Hypertech & K&N, gets an average of about 17mpg.Edited by: Pure Diesel

My wife drives an '04 Suburban 2500 LT 4x4 w/6.0L and 3.73 gears, it gets about 13.8mpg around town slightly better on the highway.


JPEdited by: Heartbeat Hauler

My 6.0 in the Yukon XL gets a little over 15 empty...But I think its got more hp an tq than the 6.0 in the pickups. I did get the 4.10 gears for towing so I hope it tows well....this weekend will be the first test towing a 8000 lb trailer.

Ave 9.5 over my time with it. This thing is a blast for a 5500 lb truck! LOTSA gas motor (underated), love the Allison... I towed my 12000 lb. boat 700 mi and got a consistant 7.5 mpg pulling/working that load 70+ mph give or take a couple. I have 3.73 gear and 265 tire. My effective final drive ratio on the ground is closer to 3.55 and it still goes down the road, and even up mild grades with the boat in tow 70+ in OD (tow/haul on) without losing alot of speed! I drove the 6.0's was not impressed! The way I drive, the 6.0 was hunting in and out of O.D. unloaded just pulling the weight of the truck. Get the big gasser, you'll love the choice for a measly 8-900 bucks (+ the price of the Allison)! http://www.dieselplace.com/forum/smileys/Wink.gif I love this big gas guzzling rig and would keep it no problem...other than the stupid deal I'm getting on the new D-MAX truck (see sig). Edited by: Rippem

In a Suburban..... 8.1 in a Heartbeat.

In a pickup, just between the gassers...I'd say go for the 6.0.

Why?

Transmissions.

In the Burb with the 8.1 you'll get the 4L80E, in a pickup, you MUST get the Allison.

Get 4.10's if you can. I'll make around town milage BETTER. That Burb is heavy, and any help in gearing to get it moving is a big help! These gassers like to spin too!


Heartbeat Hauler,

How big of a block of wood did you put under your Wife's gas pedal? 13.8 around town? Thats AMAZING! She must really putt around and baby it. Best I've got is 11.2 in my 6.0 pickup around town. But then around town by me, and around town in Indianna could be totally different.

I know this is 8.1 vs. 6.0 but the 7.4l 454 I have get's 10 around town and 13 highway. It's a vortec engine too.

Get the 8.1,your better off because of added hp and torque,and about the same mileage. I run a 2001 GMC 2500HD,8.1,allison,4:10 out back and pull a 12000 5er and ave.9 mpg towing,solo is 15 mpg. But of course i'm not heavy on the throttle and run 65 mph. While towing in the hills the mpg drops to 8. Life is full of sacrifices, I need to tow,I need the power, gas is secondary.


http://dieselplace.com/forum/smileys/Embarrased.gifhttp://dieselplace.com/forum/smileys/Embarrased.gif

I had the 2500 HD with the 8.1, got 11 -12 mpg. A guy around here put a super chip in his, say's he gets 16.5

Lawnboy, the 2500 "Burb" that has an 8.1 will have 4L85E transmission. It is very similar to the 4L80E............. just a little different in the planetarie and gasket department. 4L85E is a stronger trans. All you should ever need is a good converter and a trans-go kit................no problems after that.http://www.dieselplace.com/forum/smileys/Big Smile.gif


Mine gets about 9.5 since we changed to a K&N filter. I think I'm going to put the OEM back in shortly. Road tripps @ 75 MPH yeild about 14 MPG. That's real world driving ... not babying.

Saguaro... if you're buddy can document 16.5 mpg with an 8.1 I'm buying a superchip tomorrow.... not being mean but honest... ask him if he runs in normal mode or T/H most of the time. Reason I'm wondering is that we had a traveling salesman in our shop with 01 8.1/ally and claimed 21 hwy in T/H mode.... we pulled the waders on real quick as it was getting DEEP... I get 13 hwy and 10 towing... 3.73's and 35 inch tires... even 1.5 mpg will pay for chip. Was thinking bout diesel but I'm beyond the halfway point with my payments and not too keen on another 5 yrs rental pmts. to GMAC

Ohh forgot.... get the 8.1... Dad has 04 ecsb 4x4 with 6.0... he gets 13 also but I have twice the engine but 3 times the tranny(IMHO)

........... My burb has 4:10's. I don't know if that makes a difference. However, I am running slightly larger tires. I would guess that 4:10's and 265 or 285 tire would be just right...just guessing.

In a Suburban..... 8.1 in a Heartbeat.

In a pickup, just between the gassers...I'd say go for the 6.0.

Why?

Transmissions.

In the Burb with the 8.1 you'll get the 4L80E, in a pickup, you MUST get the Allison.

Get 4.10's if you can. I'll make around town milage BETTER. That Burb is heavy, and any help in gearing to get it moving is a big help! These gassers like to spin too!


Heartbeat Hauler,

How big of a block of wood did you put under your Wife's gas pedal? 13.8 around town? Thats AMAZING! She must really putt around and baby it. Best I've got is 11.2 in my 6.0 pickup around town. But then around town by me, and around town in Indianna could be totally different.



Just for reference, you get the 4L80E in the 3/4 ton Suburban and can get the optional 4.10 gears as well.

*


* Lawnboy, the 2500 "Burb" that has an 8.1 will have 4L85E transmission.* It is very similar to the 4L80E............. just a little different in the planetarie and*gasket department.* 4L85E is a stronger trans

Not sure this is correct. There is an MT8 (SPID code) with the 4L80E is mated to the 8.1L in the Suburban, but I am unsure that it is a 4L85E. All sales info states clearly 4L80E on both the 8.1 and the 6.0 when dropped into a 3/4 ton Suburban. MT1 is the SPID code for the 4L80E trans that is mated to the 6.0L Suburban 3/4 ton. If it isn't a 3/4 ton (like some of the Yukon XLs) it's a 4L60E.

With only 400 miles on our 6.0L 3/4 ton Suburban we are getting 11.8-12mpg around town so far with stock everything and 4.10 gears.Edited by: Silvertwinkie

additionally, according to Chevy, they do eventually plan on adding a version of the Duramax/Allison into the 3/4 ton Suburbans at some point. When that will be is anyone's guess as there have been several rumors abound as to why it isn't done already. The one that I believe is that the body/frame area does not have enough room to fit a full size Allison and that possibly a different Allison would find it's way into the Suburban. I can see this since looking at the 2500HD and 2500 Suburban, one can clearly see differences in the frame configs. Keep in mind that you also are now talking about a $60k truck (Suburban) approx if you get the LT package and some toys inside.

If you have kids and want the power, it's a good plan. If not, and you are an empty nester, or just don't need the enclosed space, my .02 would be to stick with a Duramax/Allison pickup crew cab as it could be thousands and thousands less than a Duramax/Allison powered Suburban.

Of course only time will tell what it really costs. :)Edited by: Silvertwinkie

In a Suburban..... 8.1 in a Heartbeat.

In a pickup, just between the gassers...I'd say go for the 6.0.

Why?

Transmissions.

In the Burb with the 8.1 you'll get the 4L80E, in a pickup, you MUST get the Allison.

Get 4.10's if you can. I'll make around town milage BETTER. That Burb is heavy, and any help in gearing to get it moving is a big help! These gassers like to spin too!


Heartbeat Hauler,

How big of a block of wood did you put under your Wife's gas pedal? 13.8 around town? Thats AMAZING! She must really putt around and baby it. Best I've got is 11.2 in my 6.0 pickup around town. But then around town by me, and around town in Indianna could be totally different.




Yeah, she just drives it back & forth to work...15 miles round trip. I actually think it would do better with the 4.10s (around town anyway). It doesn't do that much better on the highway Maybe 15.5mpg), mostly because we run it about 70 -75mph. If we would slow down to about 60 or 65 we could gain another 1 -2 mpg.


JP

worst ive gotten is 12 pulling 6800 lbs from nc to oklahoma and back. i get about 14.3 average around town.

first full tank on my 6.0 and i got just under 14 (13.8) in town driving. havent travelled highway or towed with it yet. guy i work with has an 8.1 and he has never seen over 10 mpg

How you use your foot has a LOT to do with MPG be it gas or diesel.

I am still having a lot of trouble with properly using the gas pedal. This is the first "drive by wire" throttle I've used every day.

I find that my foot floats on the pedal WAY too easily. I'm used to a cable in there "modulating" things a bit.

And my 6.0 is VERY touchy with the first 1/8 travel of the pedal. As if 1/4 throttle is all by WOT.....Crazy.

Plus with the 4L80, if your cruising at say 50 mph in OD with the TC locked, if you lift the throttle, the TC disengages http://www.dieselplace.com/forum/smileys/Angry.gif

Then upon reapply it revs and then locks again. Why's this? Not only is it annoying, it seems like a LOT of locking and unlocking. This cant be good.

Plus with the 4L80, if your cruising at say 50 mph in OD with the TC locked, if you lift the throttle, the TC disengages http://www.dieselplace.com/forum/smileys/Angry.gif

Then upon reapply it revs and then locks again. Why's this? Not only is it annoying, it seems like a LOT of locking and unlocking. This cant be good.

This is normal operation. It really does not hurt anything but it can be annoying. It has done this long before there was drive by wire.

Recently traded in a 2001 2500HD long box crew cab with the 8.1. It would get 14 mpg + or - a few tenths on the hwy at 70 mph without a tow. Didn't matter much if bed was empty or carrying a moderate load. Towed a Nissan Maxima on a dolly across county a few times and it averaged 13 mpg. In city driving it would get 7 to 8 mpg. Had the 3.73 rear end. Just bought a 2004, same model as the 2001 but with the LLY Diesel. City mileage about double that of the 8.1. On the hwy getting 17 to 18 mpg at 70 mph without a tow.

With a 2000 K3500 SRW and a 5.7, I get about 12 to 13 in town with A/C (I never shut it off) and 16 to 17mpg on highway. During winter when I plow snow withh it carry about a ton of salt on average I usually average about 9 to 10 mpg overall by odometer readings which is quite acceptable to me.