[slapdaddy]

I just added a mbrp 4 inch cat back pro series exhaust to my truck a week ago. I have lost 2.5 mpg from 15.0 to 12.5. I really thought I did my homework on this and totally did not expect it. I really thought my mileage would improve. Does anyone have any suggestions or thoughts on this. I see on the site where running the 285's may be throwing my milage readings off. My data is strickly from the info displayed on the dash.

 

[SmokeShow]

Do to the new found and joyous sound, are you possibly hot rodding it a little more so you can hear it more?

Yes, your miles are off by about 8 - 10% also so that'll effect it some. Did you get new tires at the same time you got the exhaust?

Possible bad batch of fuel? Possibly got some ULSD whereas you might have been getting the old LSD? Would be odd but maybe they are just switching over to winter blend fuel?


Just thinking out loud and throwing some ideas out there.

 

[jonesport]

I have had the same system on for about a week and my mileage is about the same. I am adding stanadyne as well but the mileage is about the same as stock.

 

[bogger]

you're mileage won't increase in my opinion unless you have a tuner or box added with it along with an intake. these three things work well all together but alone are useless

 

[maty111]

yea i just installed the mbrp turbo back on my '06 and lost 1.5mpg. im really babying it trying to stretch the fuel. im really disappointed, i might switch back to stock. after a couple years this is going to me a very expensive system. it sounds awsome, like a jet taking off. also running the ppe programmer on the 70hp setting.

matt

 

[Turbobruce]

You can't lose mpg by adding an exhaust. Once you lay off the throttle you will see that you are right back where you were.

 

[noproblem]

I have a tuner, CAI and MBRP duals and my MPG sucks. I think mine has alot to do with the remote start, 10-15 minute idle before I get in and never turning the truck off at the store and such.

12.5 is bad though even I get better than that. Sorry for the bad luck, try a tuner before and intake.

 

[EricJS]

You can't lose mpg by adding an exhaust. Once you lay off the throttle you will see that you are right back where you were.

:exactly:I agree. I have been "playing" with the fuel mileage since I bought my truck and the way I drive it makes a LOT of MPG difference. One other thing to consider: there is big difference in mpg between warm weather and cold weather.

Just a thought. Hope it lends an answer.

 

[hemisareslow]

i have a tuner, cai and mbrp duals and my mpg sucks. I think mine has alot to do with the remote start, 10-15 minute idle before i get in and never turning the truck off at the store and such. 12.5 is bad though even i get better than that. Sorry for the bad luck, try a tuner before and intake.

a big rig burns 1.25 gallons per hour on average when at an idle...letting your truck idle 10-15 min a day should not make a huge impact on your mpg...considering a big rig gets 1.25 per hour with an engine with much more displacement....and x3 on your exhaust having little or nothing to do with your mpg...but rather you foot being the culprit...

 

[Forced Induction]

I agree completely, you cannot lose MPG w/ an exhaust. And I agree w/ the right foot theory on the loud pedal also!!

Do you idle on high idle? When I high idle every morning for a week I'll bet I lose an avg. of 2-3 mpg. Just my experience.

 

[BoiseRob]

Who did the install? If you had a shop do it, did they weld the pipe connections or use the supplied clamps? If they welded the pipes they may have disconnected the neg. battery terminals so they wouldn't fry the computer. If so your computer was reset.

BoiseRob

 

[slapdaddy]

Thanks everyone for your input on this. Some great points have been raised. The weather here has dropped from the very unseasonable fifties back to the low to high twenties and the high idle has been on in the mornings. I have reset the average fuel economy button a few times and drove the way I normally drive back and forth to work. I hope it is just a cold weather thing. I got only 11.0 mpg today and reset right after I idled down.

 

[slapdaddy]

I did the install and used the supplied clamps.

thanks

 

[Turbobruce]

This kinda thing also happens when installing a tuner. I too thought I would get better mpg. The problem was that my damn right foot swelled up and gained weight and I couldn't stay off the gas. In reality, I found out that I really did not see an increase in mpg even after I started driving like a grandpa for 15+ tanks of fuel.


I average right a 14 combined city/hwy with 75% of my driving in the city. I have seen as high as 19 all hwy mileage. Enjoy the truck and forget about mpg numbers. It will just drive you nuts, trust me. The first year I owned my truck I stared at the dic more than the road! Also remember that those 285s are taking at least 2mpg from you. I lost almost 2mpg from my 265s.

 

[LWATSON]

My 03 lost milage and power with a turbo back system. I put the stock front pipe that had no cat, back on with the 4" muffler and tail pipe and power and milage went back to normal. If you are convinced the 4" exhaust is the cause of your bad milage I would suggest trying what I did before you remove the whole system.

 

[Turbobruce]

My 03 lost milage and power with a turbo back system. I put the stock front pipe that had no cat, back on with the 4" muffler and tail pipe and power and milage went back to normal. If you are convinced the 4" exhaust is the cause of your bad milage I would suggest trying what I did before you remove the whole system.

It is not possible on a turbo motor. It does not rely on backpressure.

 

[newduramaxguy]

[/quote]
I average right a 14 combined city/hwy with 75% of my driving in the city. I have seen as high as 19 all hwy mileage. Enjoy the truck and forget about mpg numbers. It will just drive you nuts, trust me. The first year I owned my truck I stared at the dic more than the road! Also remember that those 285s are taking at least 2mpg from you. I lost almost 2mpg from my 265s.[/quote]


Yeah!! do what he says! it will drive you nuts I quit lookin after I got 17.4 mpg's with my lly about 60/40 highway/city and i was workin my a$$/right foot off tryin to get the best i could just to see what the truck could get! coastin down hills letting off a 1/4 mile b4 red lights etc...after that i just drove like i wanted... mashin' and cruisin' havin' fun layin rubber etc : .. and got 15.0 mpg's(no bs). So be a gauge watcher= 17.4 v.s. 15.0 for havin fun driving your awsome truck...to me it's easy, Just have fun and don't worry about mpg's ...besides they will get better over time. for the record with the lbz i get 13.8 driving like a gramma and 13.3 like a MAN! no tuner or exhaust yet like my lly tho.