What a difference in Fuel Economy!!

[jimnance]

My '03 4X4 CTD SRW was averaging 18 MPG, better on the highway. My new '05 4X4 CTD DRW is only averaging 14 MPG. My foot isn't any heavier than before, so can 4 MPG be attributed to it being a DRW???



BTW, see classifieds about my '03. Steve, I hope I haven't violated any rules.

 

[mberry]

Jim,



There are several reasons for the difference in fuel economy, mostly related to the programming in the ECM for emissions reasons and the fact that it's newer and hasn't broken in yet. (Seems strange that to get cleaner air we have to burn more fuel, but that is another story. )



Get yourself a box that does timing or that cam sensor mentioned in another thread to change timing. That should help some with the fuel economy. After that it's a tighter TC, cam, air and exhaust etc. for better economy.

 

[jimnance]

So do you think the Edge Attitude would help?

 

[67guzzler]

Wait -- We're comparing a 6 speed to a 48RE -- the king of too high of a stall torque converters? That thing lets the engine go up to 1800 rpm and just sits there and waits for the truck to catch up. There is a big loss of efficiency around town between a 48RE and a 6 speed. That along with the programming with the extra injection for burning up emissions makes it pretty inefficient compared to your 2003.

 

[Phaeton]

My MPG went up after I hit 8000 miles.

 

[05mxdiesel]

Phaeton is right, give i some miles and it will go up. I have 12k on my 05 and I am seeing around 19-21 unloaded with TST on 2/2 on highway. Breakin the diff and go and tow to seat the rings.

 

[TheBigSgt]

I have the HOT JUICE with Attidude. I'm getting better milage and teh power is unreal!

 

[dmurdock]

Jim, I just did the opposite switch you did (03 auto to 05 6 spd). The highway mileage is about the same but in town mileage absolutely sucks with the 48re. You just have to drive it real gentle to keep a good avg. I am looking hard at the crank sensor by rokktech. Pretty cheap, no wiring, and should do just what I want ( a little timing advance to improve mileage and give a little on the low end).

 

[mberry]

So do you think the Edge Attitude would help?

Yes I do. I personally think timing is the real key for quick fuel economy improvement. Towing heavy helps immensely along with more miles. I have had a steady increase in mileage with the miles. I mostly drive in town and get around 16. 5 in town. The TC is another thing that will hurt your fuel mileage like others have said.

 

[DPKetchum]

A dually gets less then a SRW any day.

 

[JCotte]

Thanks to Rokktech.com

Oo. Oo. Oo. The Timing Advance from the modified crankshaft position sensor has given me close to 3MPG. Back over 20 MPG and close to 21 again.

 

[Hoefler]

I found the biggest improvement when the cat went awol. Changed the air filter to an Airaid. The turbo spools up quicker and the power increase is quite noticable.

 

[Sled Dog]

Advance your timing 2 degrees, and find 1. 5 to 3 more mpg's.

 

[jimnance]

Jim, I just did the opposite switch you did (03 auto to 05 6 spd). The highway mileage is about the same but in town mileage absolutely sucks with the 48re. You just have to drive it real gentle to keep a good avg. I am looking hard at the crank sensor by rokktech. Pretty cheap, no wiring, and should do just what I want ( a little timing advance to improve mileage and give a little on the low end).

I'm looking for a link for the crank sensor you mentioned and I can't find. Aslo, if the timing is advanced two degrees what will happen to my EGT's?

 

[SRadke]

Also, if the timing is advanced two degrees what will happen to my EGT's?

They should be slightly lower at higher rpm.



-Scott

 

[JCotte]

the site is www.rokktech.com and it drops your EGT about 100-150 degrees

 

[Sled Dog]

the site is www.rokktech.com and it drops your EGT about 100-150 degrees

Best of all, Rokktech crank sensor Works.

Installed mine a week ago, immediate improvement in MPG's. Oo. Oo.

 

[MMeier]

How does this thing work in conjunction with a TST PMCR box? I'm sure one of you guys have tried it with one !

 

[JPereira]

Can the Rokktech be used with other bombs? If a TST is already adjusting timing would this rokktech help or hurt? I run a TST on 4x4 for my best MPG as long as I go easy with my right foot.

Thanks, Jeff

 

[dmurdock]

Look on rokktech's site. They have a list of boxes it will and will not work with. Basically, if your box already does timing you shouldn't use the rokktech part because the timing will be advanced to much. Look at their site for clarification.