2015 F250 MPG Change Stock to 2" Level

cmiddleton · Jan 2, 2017

I just put a 2” level kit on my 2015 F250 6.7. Also changed from stock rims & tires (Michelin tires 275/65R20) to TOYO Open County RT’s 35/12.5R20. Normally I would get 17.5 mpg HWY and 15.5 City. When I was pulling my boat I would get 10 mpg HWY.

Needless to say I have about 45k miles on the stock tires, so I wanted to get some aftermarket rims and tires. But did I just shoot myself in the foot when it comes to MPG’s??? I was getting 17.5 mpg on HWY, now I’m getting 12 mpg!! What is causing the dramatic loss in MPG’s? 2” level or the large TOYO RT tires? Also wanted to post this information in case anybody else was looking to go from stock to 2" level kit and aftermarket rims tires.

Stock Truck 275/65R20 = 17.5 mpg HWY & 15.5 City
2” Level with 35/12.5R20 Toyo RT’s = 12 mpg HWY!! & 13 City (Note: As I drive more, it appears 12 mpg could go lower… 

Any input is greatly appreciated.

bigrpowr · Jan 2, 2017

cmiddleton said:
I just put a 2” level kit on my 2015 F250 6.7. Also changed from stock rims & tires (Michelin tires 275/65R20) to TOYO Open County RT’s 35/12.5R20. Normally I would get 17.5 mpg HWY and 15.5 City. When I was pulling my boat I would get 10 mpg HWY.
Needless to say I have about 45k miles on the stock tires, so I wanted to get some aftermarket rims and tires. But did I just shoot myself in the foot when it comes to MPG’s??? I was getting 17.5 mpg on HWY, now I’m getting 12 mpg!! What is causing the dramatic loss in MPG’s? 2” level or the large TOYO RT tires? Also wanted to post this information in case anybody else was looking to go from stock to 2" level kit and aftermarket rims tires.

Stock Truck 275/65R20 = 17.5 mpg HWY & 15.5 City
2” Level with 35/12.5R20 Toyo RT’s = 12 mpg HWY!! & 13 City (Note: As I drive more, it appears 12 mpg could go lower… 

Any input is greatly appreciated.

it's the gear ratio. it gets killed with 35's and running over 70 . a weight loss plan for the exhaust etc, will get you 2 or so and an intake will add another .5 - 1 mpg . let me know if i can help !

Brian22 · Jan 3, 2017

bigrpowr said:
it's the gear ratio. it gets killed with 35's and running over 70

X2. The engine has to work alot harder to turn those 35's especially if you have 3.55s or 3.31's. Plus your truck sits higher, wheels and tires that stick out well past the fenders and is about as aerodynamic as a brick house. For 35" tires you really should be running a 4.10 or at least a 3.73.

mikeeg02 · Jan 3, 2017

Probably a combination of both. The front valence being so low in Stock firm helps mileage too.

TLyons90 · Jan 3, 2017

Dealing with a similar issue on my 13...

Just ******d it with tuning and still getting the exact same fuel mileage I was before ********

Stroke250 · Jan 3, 2017

TLyons90 said:
Dealing with a similar issue on my 13...

Just ******d it with tuning and still getting the exact same fuel mileage I was before ********

I agree. Well, comparing to my old LML Duramax, the 6.7s don't get the mileage increase like those do when going on weight loss.

Brian22 · Jan 3, 2017

TLyons90 said:
Dealing with a similar issue on my 13...

Just ******d it with tuning and still getting the exact same fuel mileage I was before ********

Everything I have read on the various Powerstroke forums indicates the 6.7's see little to no improvements in MPG from dumping the EG.R & DP.F. Your MPG's break down to weight, wind resistance and keeping your foot off that pedal.

TLyons90 · Jan 3, 2017

Stroke250 said:
I agree. Well, comparing to my old LML Duramax, the 6.7s don't get the mileage increase like those do when going on weight loss.

Guess I should of stuck with my LML

oke:

Brian22 said:
Everything I have read on the various Powerstroke forums indicates the 6.7's see little to no improvements in MPG from dumping the EG.R & DP.F. Your MPG's break down to weight, wind resistance and keeping your foot off that pedal.

That really stinks. Not only did I go on weight loss for the simple fact of drivability, performance, and better for my engine. I was really hoping for better than 12MPG...

Brian22 · Jan 3, 2017

TLyons90 said:
That really stinks. Not only did I go on weight loss for the simple fact of drivability, performance, and better for my engine. I was really hoping for better than 12MPG...

I still say that both the DP.F & EG.R should be removed. There is no benefit to removing the EG.R performance wise. You are eliminating a useless engine component that has proven time and again that it is prone to failure and causes very expensive engine repairs due to the other systems it can harm when it fails.

Removing the DP.F is about removing one more restriction holding your truck back from its true potential.

Looking at your signature, your MPG issue is certainly not helped by your wheels/tires and a 4.5" lift.

Edit: you should have seen a small jump in MPGs from the diet. But I wouldn't expect anything more than a 2mpg increase. The 6.7's are pretty efficient and don't see drastic increases like the 6.4 does. These trucks weigh upwards or 8-9,000lbs depending on options equipped.

TLyons90 · Jan 4, 2017

Brian22 said:
I still say that both the DP.F & EG.R should be removed. There is no benefit to removing the EG.R performance wise. You are eliminating a useless engine component that has proven time and again that it is prone to failure and causes very expensive engine repairs due to the other systems it can harm when it fails.

Removing the DP.F is about removing one more restriction holding your truck back from its true potential.

Looking at your signature, your MPG issue is certainly not helped by your wheels/tires and a 4.5" lift.

Edit: you should have seen a small jump in MPGs from the diet. But I wouldn't expect anything more than a 2mpg increase. The 6.7's are pretty efficient and don't see drastic increases like the 6.4 does. These trucks weigh upwards or 8-9,000lbs depending on options equipped.

I completely agree! Like you said wheels/tires/lift definitely does not help my situation but honestly was hoping for 2mpg increase. Ill see if things hopefully change over some time with mileage. Just under 300 miles so far since the weight loss.

JRLott · Jan 4, 2017

Factory for the first 5,085 miles of its life, my '15 got 13.97 with a best of 16.5 highway.
Post weight watchers for the last 22,000 miles it has gotten 15.25 with a beat of 17.9 highway. Now highway is in the 16.5-17.5 range since level and NL intake. Town now is typically in the 15-15.5 range.