exhaust/mpg

[Mike_0521]

1. I have an 03 2500. Has no cat just had muffler. Took that out. Now running straight. The factory pipe has cracked so i got that welded. I put 285 70 17's on. Those are the olny two mods i have done that would have anything to do with my fuel milage. I did have a new lift pump put in but i had it checked by a diffrent dealer and they said it checks out. I average 15. 8 to 16. 6 mpg city and highway combined. When i first got the truck i averaged 17. 8 to 19. 5-ish. Around 589 miles per tank now im lucky to get 450 out of a tank. I need help/advice. This stinks. On top of it all there are no diesel shops here . The truck is a 2003 Dodge 2500 4x4 Reg. cab long bed. 47re automatic. Standard output. 83,000 miles. 2. Would a diffrent exhaust be better for my truck or does it matter?



Thanks all.

-Mike

 

[jelag]

Mike
My 04 3500 dually with the 4:10 6 speed has been pulling a trailer up until a few weeks ago... with the 22k lb trailer it got 10-12 and now with the bed removed and a flat bed installed we've just made a 800 mile trip with it at 72-74 mph... we had a total weight of about 13,300 GVW... . and it got between 17-18 mpg on that trip... ... the truck is stock... . your numbers sound right... .

 

[Mike_0521]

I am thinking of going with MBRP. 4inch.

 

[CStraface]

I wouldn't waste your money on a new exhaust system. I am running just a cat, no muffler right now, and I get 15-16 city and 20-22 freeway. So I think your numbers sound ok. I was going to remove my cat and put a muffler in it's place thinking that would help my MPG, at least it couldn't hurt.

 

[Mike_0521]

I get about 15 maybe 16 highway.

 

[michaelsmith]

OOOK I have an 04. 5 600 2wd quad cab 6speed 373 rear and the best I have ever got is 19 and hit on 20 twice I keep a log of all of my fill ups and all are hand cal numbers. What i have learned is their is a sweet spot in these engines any thing over 2200 and it drops like a rock. so run it up to 2K and shift. I am waiting for the ext warr to expire then everything is going in the dump CAT MUFF TURBO SLIENCER RING everything!!!!

IF YOU CANT HAVE FUN WHY WAIST YOUR TIME !!!!!!!!!

 

[Mike_0521]

Very true! Thanks for the reply all!

 

[DocDetonancour]

Would the drop in mpg be the 285's?

 

[Vaughn MacKenzie]

Cummins47 it could be something like injector or CP3 wear that is causing the MPG decline over time. Have you been using fuel additive reguarly? Maybe give it an extra strong dose of Stanadyne or Power Service on your next fillup. Some guys say they've seen improvement in drivability and slight MPG improvement running a can of Sea Foam through the tank.

 

[DBentley]

Those 285 tires will put the spedo off around 7 percent so your really going 7 percent more than 450 mi on a tank full ?

 

[CStraface]

Cummins47 it could be something like injector or CP3 wear that is causing the MPG decline over time. Have you been using fuel additive reguarly? Maybe give it an extra strong dose of Stanadyne or Power Service on your next fillup. Some guys say they've seen improvement in drivability and slight MPG improvement running a can of Sea Foam through the tank.

I thought Sea Foam was bad? Thought I remember reading that on here somewhere????