To Regear Or Not To Regear, That Is The Question.

[firedog]

I have an 00 Silverado 5.3 4x4. I have a 6" suspension lift, 3" body lift and 315/75/16 BFG's. I have a cat back dual exhaust (2.5" i think) with no muffler. I have a true flow Cold Air.I also have the hypertech III programmer. It has 3.73's. I currently get around 11.5 to 12.5 mpg. My question is if I went with a 4.11 will that help with the gas mileage, because that is my concern. I understand the process of lowering the overall ratio with the 35's. The truck runs great. Its in need of a tune up whats the consensous for the best plugs and wires for my truck.

 

thanks for any positive input

[cmoore74]

A bigger gear will most likely have little benefit to milage IMO. Those tires are killing the mileage (higher rolling mass and aggressive tread) and the lift isn't helping either (additional drag). A shorter 4.11 gear will get you a bit better acceleration as the 35" tires are giving you an effective gear ratio of roughly 3.4. You may even want to consider 4.56 gears if you plan on staying with that size tire and off-roading is your thing.

 

As far as a tune up AC Delco or Taylor (cool red color and low resistance) wires. For plugs I'd go AC Delco or NGK.

[firedog]

Its 99% street. I was just wondering if going to a 411 , because of the tire size would put the engine back into the stock rpm range and benefit me with a little better fuel mileage. I understand the size ht and wd and the lift effect it all. guess its hard to have your cake and eat it too. lol

 

which ngk's i saw a post on here for the tr-55's, is this the best plug to go with?

anyone else want to chime in on the wires?

[omegafiler]

You could see better mileage around town, but cruising on the highway, you'd lose a bit since you'll be at a higher RPM. But if I were going to re-gear from 3.73's since they weren't getting the job done, I'd just skip the 4.10's and go straight for the 4.56's. And when you have a big truck with a lift and large tires, mileage shouldn't be the concern here since that is the last thing you do to gain mileage. You just need to get your power/acceleration back and reduce strain on the rest of your drivetrain. Then ignore your MPG and enjoy the truck for what it is.

[chakis24]

how do you have a dual exhaust? im just curious. i know on my truck i have dual cats stock that merge into a y-pipe and goes into the muffler. but you have no muffler. so how does your truck work? is there only one cat? or do you have 2 cats that you kept seperated the whole way, therefore a true dual exhaust?

[cambo]

how do you have a dual exhaust? im just curious. i know on my truck i have dual cats stock that merge into a y-pipe and goes into the muffler. but you have no muffler. so how does your truck work? is there only one cat? or do you have 2 cats that you kept seperated the whole way, therefore a true dual exhaust?

Sorry to jack the thread, but this needs to be answered by a guy that has this setup.

 

I have true duals from the cats. All they do it run the pipes off both cats, off both headers obviously, then they will just run two pipes out the back. Or in my case you will weld in an H-pipe to help even things out when they exit the tips. It's not that hard of a concept.

 

And I will need to remember this about taking my truck from 3.73 to 4.56 when I install my lift.