improved gas millage... now what??

so everyones first reaction to poor gas millage as result of bigger tires is gear gears and gears...
Well i geared it, 35's with 4.56R&P due to the 8.25 rear axle
im hoping to improve my gas millage
so i figured i add some ponies while i was at it
would a TB spacer
and later down the line a bigger TB improve gas millage
how about getting rid of the cat-converter i already have a flowmaster

by the way i have the 4.0 and automatic tranny
6in lift and 35's with 4.56 gears

any sugestions will help
my wallet just been looking a little empty lately

cas

I would have gone with 4.88's with 35's.

What kind of miliage are you getting now and did you change the speedometer gear before calculating milage?

one thing I can't understand is someone spending the money on a lift, tires, rims etc etc and then complaining about milege hurting the pocket book. I don't mean to be rude or ignorant, just my opinion.

as for the TB spacer, you won't see much help with that mod me thinks. a bigger TB may help with power, but not sure if it would help milege much. not sure about your cat. losing may help milege but hurt in fines if your caught (depending where you are)

if you haven't already get a cold air kit... something cheap like rusty's airtube with the K&N filter isn't expensive and helps power and maybe milege abit too.

I can tell you removing the cat is not the way to go. I smashed mine wheeling this month, and it was plugging up, so i took it off and emptied it out till i can get the new on installed (should be here tomorrow) and i lost almost 5 miles a gallon with the cat emptied out. On our last wheeling trip, i used over a 1/4 tank more gas than a anouther guy that was with me, and i know he is not making any millage.

I have noticed a big loss of power as well.
After doing some searching on here, i see that EVERYONE says that you MUST run a cat to have any power at all with the 4.0 due to the back pressure it provides.

If you dont believe me, take it off gently, and run a tank through it. Runs like crap, and just guzzles the gas.

i guess i'll keep that cat on their
as far as going 4.88 gears
i decided to run the 8.25 and so the lowest i could go was 4.56

as far as a cold air intake i simply removed my air box and just stuck a rice burner air filter in the end.....
seems to work good....i think?!?!

i just see so many people buying the TB spacer i was just wondering if theres a good power difference. or gas millage improvement..

cas

PS if i wanted to save money yeah i guess i could just drive a honda but a lifted jeep is just so much more fun

cassio said:

PS if i wanted to save money yeah i guess i could just drive a honda but a lifted jeep is just so much more fun

Click to expand...

I hear ya on that one. I can see myself getting a little car for summer and sunny weather times and keepin the Jeep for winter and offroad fun.

as for the filter... cone I take it?
if you just put it on the end of the stock hose it may be very close to the engine, and without a heat shield it is probably sucking up nice warm air... nice for us, but not as nice for the engine, colder the better. check out some of the homebrew cold air intakes on here, and the heat shielding mods along with that.

I have a TB spacer, a new intake and air filter, and exhaust. I get about 2-4 MPG more now. I still think 4.88's with 35's would be better. Leave the cat on!!!

ok so i'll probably spend some money on some pvc and push my filter out away from the engine a bit
and save some cash on the side for the TB spacer.

thanks guys

ps i wish i got 4.88 but the 8.25 stoped that
maybe in the future when i win the lottery

Stay away from the K&N filters. They improve air flow, but at to high a price in my book. I went that way once then pulled the filter one day and noticed some very fine grit on the inside of my air piping. Then I switched back to the stock and gave the K&N away.

I am not saying all cone or round filters are bad, just the cotton with wire mesh types like K&N.

I just got the new issue of Jp mag and there is an article of Air filter comparison. Also check out the website Bob is the oil guy for his research on air filters. Interesting reads, both. I agree with beakie, use a heat shield of some sort so that you benefit from the incoming colder and denser air. I made one from a sheet of aluminum flashing and that silver bubblewrap used for insulating. I notched it around the water and power steering lines, zip tied it to the mount where the factory air box was. Nothing high tech, just keeping the hot manifold in a different air current.