View Full Version : 5.4?

07-21-2009, 10:13 AM
I was wondering if anyone knows the diffrence in the 5.4 that are in the 350s and the ones in the 150s. y 350s gas milage sucks,the power does to,and slow as a snail. he 150s are not that way a buddy of mine just bought one and is getting like 17-18 mpg towing 2 small ztrs. And not really a dog like mine. I know it can't be the weigh because his gets be mpg with mowers than mine does empty.Any ideas?

07-21-2009, 10:21 AM
That is a good question. I have noticed the same. I have a friend that has both a F-150 and a F-350 with the 5.4 in both and the F-150 has a ton more power and does way better on fuel. Maybe it is the weight and larger tranny, axle, tires ect. that the F-350 has that really kills the power of the 5.4.

Hawg City Lawns
07-21-2009, 12:40 PM
the 350 5.4 prolly has a different torque curve

07-21-2009, 11:24 PM
1 ton versus half ton...quite a bit of weight difference. Has different gears most likely. The engines however are pretty identical. Its alot bigger truck, longer wheel base...theres a whole lotta difference between a 1 ton and a half ton man.

07-21-2009, 11:40 PM
My F-150 has the 5.4 and it has great power and torque, it averages about 16mpg and 12-13 when towing a good load. The larger trucks have to have different torque ratings and shift points that affect MPG's. I personally think if you are going into a larger truck a diesel is the way to go.

07-22-2009, 12:54 AM
Should be a different cam. possibly even differences in rotating mass between the two. I don't think you'll ever get the hd motor to perform like the light duty one. It should definitely outlast it though.