optimum milage RPM - LB7

bbltop · Post by **bbltop** » Thu Aug 14, 2008 10:16 pm

Anyone ever do a check to see if there was an RPM that yields best fuel milage? I've got a 900 - 1000 mile trip coming up this weekend to pick up a 3000 lb. trailer, and plan to run out on the 65 hp tune, and come back on the 40 hp tow tune (FWIW).

I did put a 4" turbo back exhaust (w/no cat) on recently, so I'll be interested to see if it makes the 1 1/2 to 2 mpg improvement it says it will. My typical highway rpm is usually around 2100 (64-66 mph), and best mpg was 20.0

All comments/suggestions welcome.

Thanx all.....

Steve

BTW - just filled up in NH for $4.29/gal

MAXPOWER · Post by **MAXPOWER** » Tue Oct 28, 2008 10:21 am

I wonder why you didn't get any feedback. The original post was August? Anyway, I'd like to know the results of your trip. How did you you do with milage and what truck do you have? I do about 70mph at 2100rpm in my '03 duallie with 40k miles on it. It's stock except for the K&N intake and the tuner(set on 65) I want put exhaust but don't which one is best. Duals, single, 4" or 5" I did upsize my tires and adjusted accordingly. I also check my spped with my Garmin GPS and it's right there. By the way, I do real good if drive it easy (under 68mph) It reads 16.7mpg with the 65 tune setting.

MAXPOWER · Post by **MAXPOWER** » Tue Oct 28, 2008 10:22 am

I wonder why you didn't get any feedback. The original post was August? Anyway, I'd like to know the results of your trip. How did you you do with milage and what truck do you have? I do about 70mph at 2100rpm in my '03 duallie with 40k miles on it. It's stock except for the K&N intake and the tuner(set on 65) I want put exhaust but don't which one is best. Duals, single, 4" or 5" I did upsize my tires and adjusted accordingly. I also check my spped with my Garmin GPS and it's right there. By the way, I do real good if drive it easy (under 68mph) It reads 16.7mpg with the 65 tune setting.

bbltop · Post by **bbltop** » Tue Oct 28, 2008 4:13 pm

we ended up not going on the trip, and bought the trailer elsewhere, but did have the opportunity to do a couple of 200+ milers that ended up giving me just about as advertised - 21.5 to 22+ mpg. I just passed 80K miles and have 265-75 15 tires w/the K&N filter only in the stock air box. I've never driven w/the 80 hp tune, but I've seen a few posts that said that it did as well or better on milage as the 60? hp tune. The truck is a 2004 LB7, 2wd, king cab long bed w/a cap.

The exhaust is not too loud, but sounds decent. It's a stainless by ?AFE? I think, and I purchased it on Ebay for $345. My speed of 65-66 at 2100 rpm checks out as well w/the GPS.

I also just made a couple of passes down our local 1/4 mile this weekend with the 60? hp tune in, and it ran a 15.49 @ 89 mph. Then towed the trailer home w/the race car in it using the same tune. I haven't checked it for milage yet towing, but it's looking like somewhere in the 14 mpg area.