SO whats the deal with 12.5-13MPG?

[robertk]

Ok well it seems liek some here think there 7.3 gets over 20MPG? I am lucky with no load to get 13 MPG with about 50-50 hwy / city.

I have a 01 7.3 2wd auto 35" tire, regeared (4.10) back to bring it back to stock final output ratio, that was about all and was getting the 13max.

installed 4" complete turbo back, new aem or something cold air box/filter, hypertech max mpg programmer, new fuel filter, and alignment. no real change maybe .25mpg.

had the CPS recall done about 4 months ago (the previous owner didnt ever have it done) and that raised it maybe 1mpg.

so what causes such bad MPG? It doesnt smoke at all when cruising and when you floor it, it will smoke some, but nothing like then I had the DP tuner or other diesels. Idles slightly rough but doesnt seem to miss a beat and for a huge diesel motor I figure its typical.

I take MPG by filling up till I can see the fuel level in the filler neck at max. then when its close to empty I refill to same location. Taking the total miles I have since last fill up and dividing by total gals I just filled up with.

the only thing I can think of is that the gearing if back at stock would use more of the enourmos torque this motor has for dead stop accel. and cruising speeds the motor would work less. but the finial drive ratio is back at stock.

The speedo has been calibrated using the hypertec programmer, so the miles part of the MPG is right.

So whats the deal? how do some claim over 20mpg and typ like 18 for some? is that BS or do I have something wrong?

If I have a issue where do I start? I have a killer ext warranty, but I have to call in the issue I am having first and diag is not covered if the repair item isnt covered or they dont find something wrong. Which is why I dont just take it in. You know ford will tell me aww its fine. or that its this little hose that isnt covered.

But if I can get some things to check and I can find out how to check them, I will take it to a local here and have him repair it and it will be covered. its a game with even the best ext warr's...

thanks
oh I do drive somewhat agressive but not overly. I typically will use about 2100-2300rpm (about 7-9psi) till about 25mph then down to 1700rpm (3-5psi) or so till speed limit is reached.

[caryt]

Some trucks will get great MPG but don't belive everything you read on the net. A custom chip would be better than what you have..get a TW chip. But IMO you will never see 18

[01excursion7.3]

55mph, taching around 1600rpm, I averaged 24.8 from florida to maine. (pretty much flat land till washington area) Thats the last test I've done. Since then I've just driven the ex, and mostly the wife driving, and thats 85% in town driving, we're averaging 16.5mpg.

I EASILY will average 22mpg with 90% highway driving.

I really can't tell you what would kill your mileage. My truck is stock tire size, 3.73 gears, and stock suspension. No chip or anything, just a built tranny, exhaust, and intake. Mind you I picked up 2-3 mpg with the new tranny.

[RRonning1984]

My truck got over 20 on cruise when it was completely stock. You should get better then 13!

[Daddys_Limousine99]

well, mine is completely stock with 3.73s and my 3 mile commute everyday yields me 16-17mpg average. I took a trip from here (Georgia) to Arizona last year and got 21 on the freeway averaging 70mphish the whole way. IDK...but I think you should get better than 13...maybe it's the gearing, do you have bigger tires?

[jamstoyz]

def your gear and tire size. and most people who get 20 mpg or better keep the rpms under 2000 or drive 55 to 60mph. i get average of 15 to 17 with my truck cause of my 4.30 gear. my truck is only around 5500 pds

[robertk]

Originally Posted by jamstoyz

def your gear and tire size. and most people who get 20 mpg or better keep the rpms under 2000 or drive 55 to 60mph. i get average of 15 to 17 with my truck cause of my 4.30 gear. my truck is only around 5500 pds

Well I regeared thinking that the stock drive ratio (31" tire with 3.73 = close to my 35" tire with 4.10) would be better that way. now I wonder if the faster tire speed with the 3.73's woudl ahve been better.

and the weight really does help you I think also. I know my Ex is in the 7500-7650lbs range. I had to weight my buddy and after we were all said and done thats what we came up with for the tow rig.

[robertk]

Originally Posted by caryt

get a TW chip.

I tried a DP and was told the TW design and such was the same (yeah tuning might be slight bit different) and with the DP I was having major PATS issues. after 2 or maybe 3 (I forget but it was over a period of 4 months) I tried and they tried to get it right and just couldnt. It was overly embaressing to try and explain to those at the car wash, valet parking, dealer, friends, wife, etc. that it wont start when you try and you have to cycle the key fast or slow and hope that the theft light goes out, then you can start it. not to mention my top of the line Viper alarm would not auto start or turbo time.

[scagmanf350]

Do you hand calculate the mileage or are you relying on the Lie-0-meter? My truck is completely stock and I average 16. I have done 20+ on the highway but I usually on get 16 so it beats me why your getting such poor mileage.

[robertk]

Well I did explain how I calc'd it, and I did list tire size for the guy that asked tire size..