So, how can I improve MPG in my 8.1L Suburban?

greywolf2112 · December 2, 2006

Just picked up my 2004 Suburban 2500, with 8.1L engine, and 3:73 axle. Will use it primarily for towing an 8000 lb. travel trailer, with the occasional long road trip where we aren't hauling a trailer.

Everything is stock and it has the Autoride suspension.

Could you tell me what I should do to maximize my MPG but still be able to tow well? I already drive at or under 65 MPH and don't do jackrabbit starts.

Should I get a new muffler, and if so where should I get it (order it online and get someone to install? What brand? About how much would I pay and what sort of MPG increase are we talking?)

Should I get the Wait4me chip or chip tuneup, and if so what would that cost and what sort of MPG increase?

Cold Air intake? I read good and bad about these - some say it is a waste of money, others say different. Seem to be about $250

Different filter? K&N is $50, but some research I did show no change (or even worse performance) from that filter vs. the standard AC/DELCO stock one.

Any other ideas or suggestions would really help. Keep in mind I am a TOTAL noob when it comes to trucks and SUVs, so be gentle and I hope I don't annoy you with what may seem like simple and ignorant questions.

Thanks!

pm26 · December 2, 2006

Just picked up my 2004 Suburban 2500, with 8.1L engine, and 3:73 axle. Will use it primarily for towing an 8000 lb. travel trailer, with the occasional long road trip where we aren't hauling a trailer.

Everything is stock and it has the Autoride suspension.

Could you tell me what I should do to maximize my MPG but still be able to tow well? I already drive at or under 65 MPH and don't do jackrabbit starts.

Should I get a new muffler, and if so where should I get it (order it online and get someone to install? What brand? About how much would I pay and what sort of MPG increase are we talking?)

Should I get the Wait4me chip or chip tuneup, and if so what would that cost and what sort of MPG increase?

Cold Air intake? I read good and bad about these - some say it is a waste of money, others say different. Seem to be about $250

Different filter? K&N is $50, but some research I did show no change (or even worse performance) from that filter vs. the standard AC/DELCO stock one.

Any other ideas or suggestions would really help. Keep in mind I am a TOTAL noob when it comes to trucks and SUVs, so be gentle and I hope I don't annoy you with what may seem like simple and ignorant questions.

Thanks!

<{POST_SNAPBACK}>

When towing your trailer, use only 93 octane. The reason is that the engine management system can advance the ignition timing to its maximum without knocking and that will result in better fuel economy and more power. These trucks get better mileage and have better towing power with premium fuel when pulling heavy trailers.

bry21317 · December 2, 2006

Skip the CAI, I got one for my 5.3 Burban and it was sent back, for the $250 it acdtually harmed my towing ability. I lost my low end torque that I needed. So I went back to the Drop in K+N Filter in the Stock Air box and got all my torque back. The CAI also made and annoying noise on the HWY, it was fine around town and sounded cool, but on trips it really got old.

I would go with the Wait4MeTune, this cost me $158.10, with them sending me the new computer, so I have the stock one in the trunk, for emergencies. This was the best Addon I have ever done to any car. I got about 2mpg better, but also started to really drive it harder as its so much more fun to drive. I did the tune for 87-89 Octane and told him I wanted better gas mileage. I think I might send itt back and get him to give me the hot tune he has to get more power, lol. Thats what the tune does to you, it teases you to want more. I could only imagine how much power you have in that monster 8.1 engine. My Little 5.3 will make that big thing move out, but that bigger motor, I bet would make it really fly.

Have fun with it.

Bryan

Elwood 2000 · December 2, 2006

I would not worry about milage out of an 8.1. So what if you only gain 1-2 mpg? That is all you will gain, at best and spend around a grand to get it. Just sit down, push the pedal and smile. Enjoy the power you just bought and don't worry about the pump. That is part of big block ownership!

We still need pictures to drool over by the way! ;)

greywolf2112 · December 3, 2006

Skip the CAI, I got one for my 5.3 Burban and it was sent back, for the $250 it acdtually harmed my towing ability. I lost my low end torque that I needed. So I went back to the Drop in K+N Filter in the Stock Air box and got all my torque back. The CAI also made and annoying noise on the HWY, it was fine around town and sounded cool, but on trips it really got old.

I would go with the Wait4MeTune, this cost me $158.10, with them sending me the new computer, so I have the stock one in the trunk, for emergencies. This was the best Addon I have ever done to any car. I got about 2mpg better, but also started to really drive it harder as its so much more fun to drive. I did the tune for 87-89 Octane and told him I wanted better gas mileage. I think I might send itt back and get him to give me the hot tune he has to get more power, lol. Thats what the tune does to you, it teases you to want more. I could only imagine how much power you have in that monster 8.1 engine. My Little 5.3 will make that big thing move out, but that bigger motor, I bet would make it really fly.

Have fun with it.

Bryan

<{POST_SNAPBACK}>

Bry - thanks for the info! I sent him an email and may call him if I don't hear back for a while. I was thinking of going with the extra chip as well so I can keep the stock one just in case. I really don't care too much about "More Power - argh argh argh (said in best Tim Allen voice)", but am most interested in better MPG, especially while towing.

Do you think that there is a way to get that while still being able to use 87 octane, or do I really need to start using at least 89 octane, even though it is more expensive?

MyFirstV8 · December 3, 2006

I've got no experience with a vehicle this big, but first I'd make sure that the tires are aired up to the proper pressure. Low pressure causes bad mpg. I'd also go with Synthetic oil in the engine. The price isn't too bad when you do your own oil changes and it seems like it can only help.

Also, check or replace normal things like fluids, spark plugs, wires, etc.

Does the truck come with a clutch fan? If so you might go ahead and switch to electric.

If your exhaust has pretty good stock bends from the factory then maybe go with a replacement muffler. I'd choose a Gibson because they don't seem too annoying at highway speeds.

greywolf2112 · December 3, 2006

I would not worry about milage out of an 8.1. So what if you only gain 1-2 mpg? That is all you will gain, at best and spend around a grand to get it. Just sit down, push the pedal and smile. Enjoy the power you just bought and don't worry about the pump. That is part of big block ownership!

We still need pictures to drool over by the way! ;)

<{POST_SNAPBACK}>

greywolf2112 · December 3, 2006

Loomis462 · December 3, 2006

sharp ride, wish i could go without 4x4 and get something that nice for the price you paid!

svensk · December 3, 2006

Awwww God I was afraid you were gonna ask that one next Greywolf...

I'll put it this way..you bought a 3/4 ton burb with an 8.1.

Don't even think about the milage...you bought an 8.1

You drive around town you get 11mpg. you pull an 8k lb. trailer you get 11mpg.

got it?

pm26 · December 3, 2006

somebody I know had an Avalanche 2500 4X4 which comes standard with the 8.1 V8. This vehicle is actually lighter than this Suburban and the guy was getting about 9 MPG in town. So 11 MPG may be pretty optimistic. Again, instantaneous mileage displays by the DIC is meaningless. Your mileage is miles driven/divided by fuel used as determned by refilling the tank. I have driven BMW 750 iL with an MPG economy gauge and when coasting the gauge would indicate 40 MPG. The average MPG is about 17.

Loomis462 · December 3, 2006

any money you throw into improving your fuel mileage will not benefit you in the next 10 years unless you drive that thing 25000 miles a year, just drive it and have fun.

Schmids5.3l · December 3, 2006

Agreed with most of the above posters. Big block + truck = pumpin gas and haulin ass. To be honest, if I had a 8.1l I'd supercharge it, just because the mileage blows already If your gonna get 10mpg you might as well get some rediculous power doing it.

greywolf2112 · December 3, 2006

UNCLE! UNCLE! LOL - ok, I guess I should have figured that if Detroit had figured out a way to give us that much HP and improve the MPG they would have done it already. So I'll stop trying to re-make the wheel and just enjoy the ride.

Though I'm still intrigued by the wait4me chip - I figure if it DOES improve my MPG by even 1 mpg, then it pays for itself within 4000 miles.

But, at this time I will check and replace the air filter if need-be with a normal AC Delco one, get the oil changed out with synthetic, make sure the tires are aligned, balanced, and inflated properly, and not lead-foot it.

BTW - I calculated my MPG driving the 'burb back from Orlando - about 15% of it driving in the city, and stopping three times (gas, groceries, and rest stop).

I got 14.5 MPG! I guess that is pretty good, eh?

Elwood 2000 · December 3, 2006

Excellent milage out of an 8.1 and thanks for the pictures. That is a VERY sharp rig, you should be proud of it and feel guilty for stealing it from the seller! LOL