performance

topherg87 · July 16, 2005

i was wondering what everyone would suggest for a ecsb with 4.10 305/70/R17 and a 4" lift to make the gas milage improve and the hp a lot more, thanks...

camel · July 17, 2005

from what i have read so far, adding an aftermarket intake, headers and a computer tune should help your milage. and corrrect your speedo if its off because of your tire size.

haulin1500HD · July 17, 2005

Were the 4.10 gears in your axles before you installed the larger tires? If so I would highly suggest changing to 4.56. I happen to have a new gearset of 4.56 for a GM 10-bolt late model axle. I ended up ordering two sets by mistake and my two-year old decided to open the package, cusing me to not be able to ship back for a refund. New corrected gear size will help maintain your cruising RPM and inturn maintain your gas milage.

The larger tires will always cause a loss in performance and milage. I would also resommend a new air intake, re-tune of the PCM, and even an after-cat exhaust system (air in, air out). If you haven't reetuned the PCM yet you could really be hurting the vehicles components, the shift points need to be reworked with the change in tires and possibly gears. If you don't have the PCM re-tuned than at least get a transmission unit from JET performance to help your tranny out.

I had 38.5 tires on my last truck with 4.56 gears and it worked great, I miss that truck my my 5' tall wife had problems getting in it when she was pregnant with #2.

Good luck and god speed!