Air box restrictor

Your better off putting that back.

It's a venturi and designed to create the vacuum necessary to evacuate the emissions canister. without that, the canister will become saturated and die an early (and expensive) death. A properly designed venturi doesn't restrict much and the actual restriction is the air turbulence caused by the bellows.

There is no appreciable gains from removing the venturi. (tested it myself) You can get a tiny gain from a larger diameter air tube, but the problem with venting the canister remains.

However, take careful measurements of your fuel economy and see if there is a difference. If there was on my ZJ (and I tested it over a year) I certainly couldn't see it.

Thanks, Doug. There was certainly no mention of that in the write- up. I think I'll leave 'em out for a while to see if there's any difference - if not, I'll put 'em back. You didn't happen to do a write-up on your site, did you?

Long time back. Don't know if it's still in my collection. Nope, that was back when I was on a different ISP. Basically I track my milage every fillup (got a excel spreadsheet to do it) over about a year I didn't see any difference, and my 1/4 mile and 0-60 times didn't change by anything I could detect.

The only thing I did notice was more of a gas smell from the engine. Turned out that was the evaporative canister maxing out. Soon after I put the venturi back and the smell slowly went away.

Later I put in the supercharger and didn't even think about it again till your post.

I've been without it for seven or eight years, excellent fuel mileage, no gas smell yet...

Earle

Dunno.. that's what happened with me.

It's got one of those CCV things.

Earle

Haven't had a problem, don't have an air cleaner with a bunch of weird gizmos stuck to it and don't have a carburetor, but thanks anyway. I owe it all to regular oil changes, warming the Jeep to operating temperature nearly every time I start it up and living in sunny dry Colorado. There are some advantages to living fifty miles from the grocery store I guess. IMHO, the CCV will clog if and only if you have a bunch of gunk in your engine that you shouldn't have there.

Earle

At expiration of warranty, 36,000 miles:

A) Defeated evaporative canister to eliminate raw gas fumes entering engine.

B) Removed venturi from inlet hose, not needed after "A".

C) Removed metal block off plate in front of Air Box inlet to allow cool air to enter.

D) Enlarged opening in Air Box to match opening created after "C".

E) Removed Catalytic Convertor, Muffler and 1 7/8" Tailpipe.

F) Replaced "E" above with Straight Pipe, Turbo Muffler and 2 1/4" Tailpipe.

Power from 3,500rpm to Redline is amazing, and Fuel Economy improved an average of 2 MPG. Jeep now has 240,000 miles and has had NO major repairs and runs same as at 40,000 miles. Mobil-1 in Engine, Mobil-1 ATF in Transmission and Transfer, Royal Purple in both Differentials and none of them have had any repairs.