cat mpg opinions and advice - Page 3 - Truckers' Trucking Forum

550hpW900L · **^ Top** #21 2 Weeks Ago

First things first is get rid of them oxycats under that truck, theres 2 of them on a KW and those are your biggest killers. If you get 5.8mpg running west over the rockies then dont complain, even with a 6NZ ecm i doubt you will see a big difference maybe 2-3 tenths increase, but the engine will run and pull much smoother.

MBN is not designed to be lugged to 1100rpm, neither is a 6NZ for that matter, i wouldnt lug anything that low EVER , the person telling you this needs to go back to truck driving school, 9.75mpg? Get real, not even pulling an empty trailer.

morph · **^ Top** #22 2 Weeks Ago

what do you mean oxycats?

550, is there anything i can do with this motor that will get me better fuel mileage? any and all options.

if there isnt, would i be better gettin a whole different truck with a bigger motor for more hp?

Quote:

Originally Posted by 550hpW900L

First things first is get rid of them oxycats under that truck, theres 2 of them on a KW and those are your biggest killers. If you get 5.8mpg running west over the rockies then dont complain, even with a 6NZ ecm i doubt you will see a big difference maybe 2-3 tenths increase, but the engine will run and pull much smoother.

MBN is not designed to be lugged to 1100rpm, neither is a 6NZ for that matter, i wouldnt lug anything that low EVER , the person telling you this needs to go back to truck driving school, 9.75mpg? Get real, not even pulling an empty trailer.

550hpW900L · **^ Top** #23 2 Weeks Ago

Catalytic converters in the mufflers that are on the truck, yours being a T6 they're probably vertical behind the sleeper. You will see a difference in fuel millage with a 6NZ ecm but dont think you are going to go from 5.8 to 7.5mpg, i would do a straight 550hp program, yank the mufflers, and drive the hell out of it.

morph · **^ Top** #24 2 Weeks Ago

i have a single stack, the "trash can" muffler is under the cab beside the fuel tank. so that needs to go. if i go with a 6nz ecm such as one from pittsburgh power, but gettin a better turbo to match the ecm program wouldnt help?

Quote:

Originally Posted by 550hpW900L

Catalytic converters in the mufflers that are on the truck, yours being a T6 they're probably vertical behind the sleeper. You will see a difference in fuel millage with a 6NZ ecm but dont think you are going to go from 5.8 to 7.5mpg, i would do a straight 550hp program, yank the mufflers, and drive the hell out of it.

550hpW900L · **^ Top** #25 2 Weeks Ago

Depends what turbo is on there now, get the part number off of it. Just get in touch with DDS he can re flash your ecm to a 6NZ file. Dont waste your time with PP and their overpriced junk.

MedicineMan · **^ Top** #26 2 Weeks Ago

Quote:

Originally Posted by morph

question, you say 5.93 on all miles, is that before or after? did you gain any mpg by swapping from 22.5 to 24.5?
im not sure on tires and stuff but i understand the rpms would go down, but you would also have more to turn, there is more resistance on a 24.5 then a 22.5, but more rpms on 22.5 then 24.5's.

i probably got a slot or 2 i can slide the trailer closer to the cab.

24.5's are les fuel effiecient then 22.5's, tall rubber (in either size) is less effiecient then low profile rubber.

now that is considering the truck is setup properly for the tire size.

the gentalman who is saying he picked up fuel mileage from putting tall rubber on obviously had a truck that was not set up properly for the work he was doing because he was turning way too high of rpm's. his fix was to put tall rubber on lowering the RPM, if he would have swaped rear end gears to get the same rpm out of the low profile tires then he would have gotten even better fuel milage improvements. However you have to justify the cost of the upgrade and he may have already been due for tires.

Frenzy · **^ Top** #27 2 Weeks Ago

Quote:

Originally Posted by 550hpW900L

First things first is get rid of them oxycats under that truck, theres 2 of them on a KW and those are your biggest killers. If you get 5.8mpg running west over the rockies then dont complain, even with a 6NZ ecm i doubt you will see a big difference maybe 2-3 tenths increase, but the engine will run and pull much smoother.

MBN is not designed to be lugged to 1100rpm, neither is a 6NZ for that matter, i wouldnt lug anything that low EVER , the person telling you this needs to go back to truck driving school, 9.75mpg? Get real, not even pulling an empty trailer.

:bigg rin_25522:

:biggrin_2 5522:

:bigg rin_25522:

I wish I could do that on every run. Loaded miles, but probably a 10k or less load.

Ken

550hpW900L · **^ Top** #28 2 Weeks Ago

Or bobtail and you just cleared it. Either that or that thing is way more off then 25%.

Rat · **^ Top** #29 2 Weeks Ago

Never trust an on board computer for actual milage. Cat says my truck is averaging 6+ mpg yet my calculator shows that I am averaging under 4 mpg.

Oh and as 550 said. Don't run a c15 at less then 1400 rpm loaded. It won't pull it in top gear.

Reason why people get better economy at lower rpms is because they are going much slower thus there is alot less wind drag.

morph · **^ Top** #30 2 Weeks Ago

i looked all over the turbo and cannot fine a number on it. its yellow, so im assuming its the stock turbo from cat.
as for re flashing my ecm, is that really possible? i thought there were too many passwords in it to where you basically needed a new ecm. if DDS can do that how do i get ahold of him or them?

Quote:

Originally Posted by 550hpW900L

Depends what turbo is on there now, get the part number off of it. Just get in touch with DDS he can re flash your ecm to a 6NZ file. Dont waste your time with PP and their overpriced junk.

Thread Tools
Show Printable Version Email this Page
Display Modes	Rate This Thread
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode	Rate This Thread:

Similar Threads
Thread	Thread Starter	Trucker Forum	Replies	Last Post
Advice for a Old hand getting back into the truck	redfang	Questions From New Drivers	10	05.21.2008 06.09 PM
Your Advice and Opinions Wanted	rndixon1960	Questions From New Drivers	16	12.26.2007 10.37 AM
I need some advice about US Xpress	Justlivin	Questions From New Drivers	4	06.22.2007 10.03 PM

Truckers' Trucking Forum/Message Board - The Premiere Truck Driver Forum

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)