Fram air filter for TJ-poor mpg

matt · 2005-02-01T15:47:59+00:00

About 2 weeks ago, I put new plugs and a new air filter in my 03 sport.I used the stock champion plugs. It has about 45k on it. Oh yeah, itis a 5-speed, 6cyl, all stock, etc.No problem with the plugs. It was the air filter.I bought a fram, which I usually wouldn't do, but...The air filter had a 3/8" block of black foam glued on the bottom ofit. I've replaced the filter before, and never seen this.My mileage instantly went from about 17mpg down to 14.5mpg. this wenton for 3 tanks of gas. My tire press. was ok.the only thing I could think of was that strange piece of foam looselyglued on. So I took that piece off. To say the least, it was barelyglued on.And my mileage went right back to 17.So when did they start gluing blocks of foam to their air filters?And why, especially if it's going to kill your mileage. It's the samedimensions, pleating and all, as a stock filter.matt

Feb 01, 2005 23 Replies

Rate this thread:

Mike Romain 21 years ago

I think the larger tire gets slightly better highway mileage because it rolls farther per revolution, but this is directly offset by the extra air drag of being higher up into the flow with more of the undercarriage exposed.

In other words, I think I get exactly the same mileage with 31's as I now get with 33's taking the difference in odometer readings in account.

I have a regular 200 mile run that I get to check gas brands and octanes out on. Different brands of 'fuel' make up to 10 mpg difference in my CJ7!

My speedometer and odometer are exact with 33's on her according to many GPS checks.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Ken Knapp wrote:

Vote

L.W.( Ãill ) Hughes III 21 years ago

Vote

Lee Ayrton 21 years ago

Heh. Big tires as overdrive. Hadn't even thought of that, thanks.

Vote

SteveBrady 21 years ago

Well, it takes more engine torque to get those big meats turning....but that just might put your RPM's in the advanced range, so it would make much difference!

Vote

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required