8.1 gasser with allison trans

[Montana_2842]

Hello everyone,
Kinda new about this although I have been a member for awhile ,just watching and reading, kinda in the learning process , anyway, My question is:
I have a 2002 chevy 2500HD with 8.1 and allison trans...Love it too...but does anyone know of anything I can do or buy to improve my gas mileage? Kinda figure what I'm getting is probably it but who knows....lot of you out there and maybe someone has some ideas.
Am pulling a 335 mountainer and love it too....
Not complaining about the truck because I got it for what it will do.
Has anyone used the mach. that plugs into your sys. and changes different things and if so did it help...anyway I'm watching and listening......enjoy you all and happy camping

[Montana_1424]

I have never used anything that pluged in (computers, chips, etc) to enhance mileage. I have heard good and bad things from people that have used them. Best thing I can say is to make sure any modifcations do not void your factory warantee. Now, what I can say is try switching to synthetic oil. I use AMS OIL. When I switched, withen the first week, I noticed I was getting 1-2 MPG better, and it may even be higher by now. Whats nice about this oil too, is it is change every 10k miles, and the filter every5K. My old truck was a HEMI (Gas, as I have a diesel now), and I switched to a K & N High Performance air filter, and that too increased ,my mileage, along with Horse power as well. That is a lifetime filter too, get the cleaning kit and clean it once a year, and your good to go.

Thats about all I can offer, other than driving speeds, obviously driving 65 instead of 70 while towing will give you better mileage.

Good Luck in your search, and hope I was able to help out a little.

[rames14]

Don't know about the gasser, but I know the Diesel Silverado is very speed sensitive. About 1-2 mpg for each 5 mph above 60. At 70, I get just under 20 mpg with just the truck. When I drop to 60 - 65, I get about 22 mpg.

[Jeff Heiser]

I have a 1999 Vortec 454 and have done the following:
Throttle Body Spacer
Dual Exhaust (two completely seperate pipes with seperate Cat Converters and RV mufflers)
Chip Programmer
High Volumn Cold Air Intake

I can tell you it added about 2 to 5 mpg or more depending on speed both towing and not. I also can tell you the above mods have given my truck unbelievalbe power when towing or just running around town.

Jeff Heiser
Merritt Island Florida

[Montana Sky]

You also might want to look into purchasing a tailgate that is made for the fifth wheels. I purchased a Custom Flow with the slats in to allow airflow, and noticed approx. 1 - 2mpg increase while on the highway. That is empy of course, I never really cared too much while towing as I have it for the convience of not having to drop the original tailgate to hook up. Just another thought.

[azstar]

Hello poprtee,

We too have the 335RLBS and tow with a gasser V10. As you can see in our sig. I use the K&N air filter to help with the breathing and Synthetics in the motor and rear diff. That having been said, after doing these things I believe it gets very hard to get the return on the investments, on things like a Banks exhaust or intake system.

You didn't say what mileage your getting. I have monitored my towing MPG and over the last 10,000 mi or so I,m getting 8.55 avg. Sometimes as low as 6 and sometimes as high as 10 all towing. I can live with these numbers. I should add I have almost 1000 lbs. of Motorcycle in the bed of the Truck, so a little extra weight there.

I drive at 65/70 Fwy.

Happy camping

[Montana_1631]

I haven't gone anything to my duramax because I checked with the local chevy dealer and about anything I wanted to do and that was to go to a 4" exhaust all the way and the power chips and I was informed that those would void my warrenty. I have found that my duramax which is a 3500 dually gets its best mileage at 63 mph. I have gone up to about 70 and it drops down to about 19 and down around 63 I get 20-22 mpg and that is where I set my cruise control and leave it their. I tell you this unit pulls so good that I haven't give much more thought to modify anything on the truck for power and gas mileage.

puzzie pigpen
3500 duramax dually
3685 montana

[Jeff Heiser]

Puzzie,
You know I have owned a great deal of trucks and to each I have added many different types of after market products. Not once has my warrenty been voided due to the after market products being added. Now granted they have been on a gasser but...most where Chevys, the last was a CK3500 and the last had the most added. The additions included large completely dual high flow exhaust with high flow cat convertors, throttle body spacer, high volumn cold air intake, chip programmer and a few other goodies. I always took it to the dealer for service and the dealership loved the mods and the way the truck ran. Never did any of the service techs mention any of the enhancements would void the warrenty or void the extended warrenty. In fact when purchasing some of the products it is plainly stated on the product documentation that it will not void the warrenty. You might want to check around at some of the other local dealerships where you are at and with the after market vendor. I have been told by a few dealerships that the changes would void this and that but not one of them could show me in writting. What I have found is that so long as the after market product does not degrade the preformance of the vehicle it will not void anything. Now if the after market product such as the exhaust goes belly up the dearlership will not cover it but they will continue to cover the rest of the vehicle so long as it is under warrenty. Example: You put high flow exhaust on your truck...the cat converts plug up and require changing...the dealership will most times not change them because of the upgraded exhaust system even though they are the original convertors but...say you change the exhaust and you start recieving a check engine light and the code is for something engine related...they will cover that if you are still under warrenty. Believe me dont let the dealer tell you different. Call Chevy Headquarters and asked if you feel the dealer is not being up front about it. Chevy Headquarters has the last say on warrenty issues.

Jeff Heiser
Merritt Island Florida

[Montana_1631]

Jeff thanks for the info. I checked with a muffler shop here locally and according to his paper work his exhaust system will not void the factory warrenty. He is wanting to put a 4" exhaust all the way back from the turbo and do away with the "cat" and then use a high flow muffler. He came up with all the things that his system is suppose to do as far as power, gas mileage, torque but I can't prove any of his percentage's nor can I disprove them. I found one chip that is $395.00 and it is suppose to give me added HP and torque but I can't remember how much. The only other thing I haven't checked into yet was the KN filter system. The thing I question is when you add all these items for more power does it lower or increase fuel mileage? I feel that when you add power it requires more fuel which in turn lower's the mileage.

Puzzie Pigpen
3500 Duramax
3685FL Montana

[richfaa]

The warrenty issue is a complex one indeed..I did call Ford Warranty..not the dealer or did I ask the muffler guy..and Ford said..do not do anything while the truck is in the warranty period..The proof of weather the warranty will be voided or not is to make the modifications then actually have to use the warranty..If someone has modified during the warranty then had to use the warranty..tell us how it went..I would love to do a few things to my F350..but I can not afford to take the chance....