Gas milage help!!!

[Cesardajr]

Are you running a tuner/programmer to help recalibrate the gear ratio for the new tire size?
If not that will help, just make sure you find a tuner that can tune for the 40" tires.

[adamw89_2000]

Should I just get high flow cats or should I try and get some of those 02 sensor simulator things?? Ian not running a tuner at the moment.. U think that will help? Who makes one capable programming for a tire that big? I've though about gettin s custom time done rather than a hand held but not sure which would b better overall now.

[HUMTECH]

Simulators work good, have them on my 98 truck. If they are available for the 6l def would. If they are not available you need some cats. Ive never sourced them for a 6l so i honestly cant make that call. Google is your friend...

[tyler1bo]

Wouldn't a regear help? Like 4.88's?

[DeLH2]

I'm getting 13 on the highway and 10 in the city with lift and 37" tires. Wonder why yours is so low?

[LoJac963]

from what I read real quick the LQ4 is pretty identical to the LS2. I know when I had my GTO there were quite a few guys running O2 sims without any issues what so ever. Give the sims a shot and see if the MPG changed.

[[__--MUD--__]]

Originally Posted by tyler1bo

Wouldn't a regear help? Like 4.88's?

4.88 will be less gear than stock ratio setup, 5.13 would be a little more. It would make a major improvement. I'm sure it feels like a lazy pig right now.

Honestly this rig in question is going to need $6000-10000 in additional parts to get it to drive as stock or better. Gears are $1000, Install for gears runs anywhere from $800-2000. Although not mentioned, there is no way that truck brakes now like it should now. Big Brake kits on all 4 corners start at $5000 if you get lucky. No way any of the stock steering is going to hold up for any decent amount of time. At a minumum, $1500 in steering components. To do everything your around $3500.

I really think that anyone that sells/installs lift kits should thourghly go through w/ the buyer all the additional work that will need to be done after the kits are installed. The lift kit ends up being the cheap part when you have to upgrade all these other components.

Im in the middle of putting 5.13's in my rig and im currently running 37" tires.

[Humdingah]

Originally Posted by [__--MUD--__]

4.88 will be less gear than stock ratio setup, 5.13 would be a little more. It would make a major improvement. I'm sure it feels like a lazy pig right now.

Actually going from a stock 35" tire with 4.10s to a 40" tire would require a 4.69 ratio to keep the stock ratio. Since they don't make a 4.69 you could use a 4.56 (shorter than stock) or a 4.88 (taller than stock). A 5.13 would be way taller than stock gearing...and crazy tall running 37"s.

Originally Posted by [__--MUD--__]

Big Brake kits on all 4 corners start at $5000 if you get lucky.

You can find AP Racing BBKs for roughly $4,500 front and rear if you look...and APs are just as good, if not better, than Brembos. It's the route I'm going when I put the 10-12" Cognito and 42"s on mine. But as you've mentioned previously, any lift that uses a new steering knuckle may require some creativity to mount.

Originally Posted by [__--MUD--__]

No way any of the stock steering is going to hold up for any decent amount of time. At a minumum, $1500 in steering components. To do everything your around $3500.

Agreed...$700 for the Kryptonite steering link and tie rods, $225 for the Cognito pitman and idler support brackets, $215 for the Cognito idler pivot kit and it'd be wise to upgrade the steering box and pump as 'OrangeCrush' did to his truck. An easy $1,500 to do it right provided you can do your own labor.

Originally Posted by [__--MUD--__]

I really think that anyone that sells/installs lift kits should thourghly go through w/ the buyer all the additional work that will need to be done after the kits are installed. The lift kit ends up being the cheap part when you have to upgrade all these other components.

Agreed...if you want to do it right.

Originally Posted by [__--MUD--__]

Im in the middle of putting 5.13's in my rig and im currently running 37" tires.

That's some steep-ass gearing...but not a bad idea if you plan on running bigger tires at some point.

All in all, some good advice for anyone considering lifting their truck and thinking they can bolt on a lift to the tune of $5-6,000 and be done with it. A whole lot of other things to do that most people never even give a second thought to.

[[__--MUD--__]]

[quote=Humdingah]Actually going from a stock 35" tire with 4.10s to a 40" tire would require a 4.69 ratio to keep the stock ratio. Since they don't make a 4.69 you could use a 4.56 (shorter than stock) or a 4.88 (taller than stock). A 5.13 would be way taller than stock gearing...and crazy tall running 37"s.

I already had 4.56 gears in my truck when I bought it w stock wheels/tires. Maybe thats why I felt so much of a loss jumping up to 37's. I'm hoping w/ the extra torque I'll need less throttle which should keep it in overdrive more on the highway.