BLACKDODOGE

I know I have bigger tires, but crap! My question is, I hear people talking about adding a muffler brought back loss power and mpg from the stright pipe exhaust, is that my problem? I removed the muffler with a piece of 4", love the sound, but only want mods that will benefit the mpg and power. I don't think we need back pressure. I just can't decide if I should get a cat back muffler system or leave it alone.

displacedtexan

What is your MPG? And I have never heard of an increase with a muffler.

runamuk

What kind of intake improvements have you done?

How many miles are on it?


Rick

BLACKDODOGE

i'm only getting about 10 around town. It only has about 7k miles, but so does my buddies and he's getting about 17. Stock intake for now. I just wanna make sure its not my straight piped exhaust(no muffler).

bigwheels94

Back pressure is bad.I have a 5" turbo back exh.& I get about 17 mpg.combined city/hwy.You might try getting the white smoke/milage reflash.Might help.

gitchesum

How are you determining your mileage? Has your speedo been re-calibrated for the larger tires?

Do not trust the overhead mpg calculator. Mine is ALWAYS 1.5-2.0 mpg off. With bigger tires, your's will be off even more.

There's a 12.6% difference in the stock tires and the 35's. You have to figure that in.

Col.

Hello,My New Truck got 10mpg -avg 70mph, On my First trip With Her ! (sucks) Pulled a Trailer Back 6x24 No load , And Got 7mpg (65-70mph) At 3 bucks Plus a gal down Here Looking for my ford i Traded in ! I have had Dodge 3500 Before back in 1999 She got around 18-20 mpg ! I Forgot To Say i Did Run a Bully programmer On The trip 1/2 on 1/2 off No Diff On MPG ,But had More power with it on . Also Running a good air filter, long rider motor oil. did not help ? So It Looks like I'm In The Same Boat with You.

Regards,
Col.

Sevir

There is your problem, along with your 35" tires. your truck is still breaking in. you need to wait at least 15k miles until you start seeing a sinifigant impovement. But you need to relize that those tires are going to kill your mileage. theres a saying on these boards, "If you play you pay" You can do a few things to had a little better mileage to your truck, but your never going to get the 20-24mpg that I get from my truck.
1. Programmer - this is debatable weither the cost of the programmer is worth the 1mpg better fuel economy.
2. Air intake - get rid of that restrictive airbox you have, in this months diesel power magazine, they are testing 5 of the best air intakes for diesels, pick up a copy and do a search on these boards, everyone has their own opinion on which air intake.
3. You dont have to run no muffler, just replace your stock muffler with a straight threw muffler.
4. Rokktech sensor, supposably it helps with city MPG. to me, it was worth the $60 for it. if it does work then good, that $60 well spent. If not, oh well i am out $60 no big deal.
5. Your best MPG saver is taking it easy on the skinny pedal on the right side. If you know you have to stop for a red light or making a turn soon...just coast there, no need to keep on the gas if your going to stop. And if you **** someone off slowing down to stop then tuff. what are they going to do?
6. dont go above 3k RPM on the highway, i keep my truck no more then 65MPH (2700RPM) and on a good day with the conditions right i get 24MPG

runamuk

I never got much mileage benefit until I hit 15k probably due to synthetic motor oil since 5,000 miles new.

These motors are not like Chevys or Fords diesels they take a few miles to break in! 30k miles now on the ticker.

Currently I'm at 20.5 mpg cruise set at 70mph unloaded. I get 18.3 towing my 7X16 Carson enclosed trailer,(5k-6k lbs) flatlands.

The 4.10 gears hurt on the flatlands but shine in them there hills!!!

Rick

marlbroman

i do a lot of towing, driving, commuting in my truck.80k miles in 2 1/2 years.i cant seem to break 11mpg.truck is stock.

runamuk

Marlbroman,

You would benefit from a mileage reflash and a boatload of our chapter #21 guys who can help! I'm sure we can do better than 11mpg out of a Cummins!!

Rick

Thenewguy

Hey Sevir what's this rokktech sensor you're talking about? City driving seems to kill the mileage in these things.

rdc

WOW You are running at 2700 rpms at only 65 mph? Your sig doesn't say what gears you have but I wouldn't think even 4:10's would tach that would they?????

I tach 2300 rpms at 70 mph with 3:73 gears.

05CTDN8

Same here, I run 75-80 and dont top 2400 or there around! If your turning those rpm's at those speeds wow....you have 4.56 or 5.11 rears.....ouch!

Sevir

maybe its dont go above 2k RPM, and i run 1700 at 65. Sorry i am over here in the middle east and havnt driven my truck in about 4 months so i am probably wrong. so to correct myself, dont go above 2000RPM on the highway.

The Rokktech sensor replaces a stock sensor that advances your timing and is suppose to give you better city fuel mileage. I really couldnt tell you where to get one because its been so long since i bought mine, but i am pretty sure if you do a search on these boards, or even a web based search you can find it. It only takes 5 mins to install and the instructions are almost dummy proof. Well worth the $60