Question 3:55 gears and 3 in. down pipe

[big bear]

can anyone tell me if a 3 in. down pipe is better than 4 in. from turbo* on? i remember somewher in one of my deisel mag's that a 3 in. dp gave better mpg and better torque. anybody know anything about this or can shed some ligth on this?* also i been thinking about going to 3:55 gears thinking that i would lower the rpm's* down and save some gas at the same time anyn thoughts on this or info would be highly appreciated. thanks

 

[Zookie400]

what truck/engine is this?

i have a 97 7.3, with 3"dp and 3.55, i can get 18 highway, and usually get 17 driving to work (stop and go, 30-40 mph). i also have a low stall torque converter that helped my city mileage by 2mpg. (previously got 15 driving to work)

also, you may get more help if you post it in the appropriate forum.

 

[MBRPCrazyford]

what truck/engine is this?

i have a 97 7.3, with 3"dp and 3.55, i can get 18 highway, and usually get 17 driving to work (stop and go, 30-40 mph). i also have a low stall torque converter that helped my city mileage by 2mpg. (previously got 15 driving to work)

also, you may get more help if you post it in the appropriate forum.

X2.....