Has anyone upgraded their catalitic converter on their 3.8l v6 jk wrangler and if so what did you find?
I'm currently running 16-17L per 100 km which I believe is way too high for my JKUR with 285/70/R17 Maxxis Bighorns, a saffari snorkel with air ram, and a stock steel bumper with winch and lights. I found running the soft top is better on fuel but only 1L per 100km. I'm also running 98 octane fuel.

Will it run better with a high flow cat?

Are they prone to blockage as stock?

Other suggestions for fuel savings?

Is another fuel octane better for our jeeps?

 

I DONT believe that changing your catalic converter Will increase your fuel average , might increase your power by little as 2 or 3 HP
ANY ELSE ITS JUST NOT TRUE..
where are you getting 98 octane gas????
If you read your JEEP MANUAL tells that with UNLEADED youll run just fine.
Thats just my personal opinion ........

 

Clean cats and fresh O2 sensors can improve mpg. Especially if you've burned coolant through your engine at some point. Coolant will gunk up cats. 98 octane is a waste for sure without a tune and other goodies. You could run a fresh set of ripp headers that reduce from 4 cats to 2 or get a magnaflow oem replacement set. My jk with bumpers, winch and heavy toyo m/t's is getting 13.5-14L/100km. That can depend on mechanical condition of your jeep, altitude and driving habits. My jeep is in near perfect condition, at sea level and i try my best to drive nicely DD. Regear can help too.

 

Just adding some hi-flow cats won't gain you any real measurable gains in mileage or power. The intake (manifold, filter, TB - all of it, not just a CAI), engine (heads, cam, etc...), and exhaust (manifolds, cat, pipes, suitcase) are a system. Opening up one piece, or in the case of hi-flow cats just a piece of a piece, without opening up the rest doesn't do much most of the time. That all assumes the system is bottlenecked to begin with, which it isn't really in stock form. You get better gas mileage for less money running shallower gears and staying off the skinny pedal.
Good luck!

 

Did you mean 89 oct. fuel? Yes it will breathe easier w/high flow cats. but prob. not enough to offset the costs. If its in your area, buy pure gas(100%) w/out corn. It has more energy & will improve the performance of your vehicle.

 

I think he meant 98 ron as he is in Australia.... That's about 93 octane in North America. How fast are you driving and how much stop and go driving do you do op? I know when I'm around town doing short hauls less then 5 mins my fuel gets up to those numbers too. But when driving longer distances and keeping it below 100km/h on the highway I can squeeze out 9-11 L/100km with 35"a and front and rear steel bumpers and 3.5" lift. All on 87 octane (91 Ron). All stock exhaust system. Try running some seafoam or similar additive through your tank and see if that helps. The stock cats are fairly efficient if you wanted just remove the second set to release some back pressure.

 

Yea I'm running the 98 octane I do I bit of stop start driving in the jeep but even on the highway I'm getting 16.3 L/100 km at 100km/h. Air filters in good condition and I'm now running 91 octane fuel in her(no corn/ethanol)
I'll have to sort out the oxy sensors and check the plugs. I'll check them on Monday.

No coolant through the system so I'll check everything else.

And I'll run some injector cleaner through too.

Any other ideas?

 

WHY THE HELL ARE YOU RUNNING 98 OCT? Do you know the point of grades of OCT?It means the burn rate. Engines are designed for certain burn rates/temp. higher compression, higher HP also require to you to increase your OCT to decrease the chance of pre Detonation. 98 wont give you any better MPG. it will burn slower, longer and as a result much hotter burning out your valves and other components NOT rated for that Temp. unless your added a programmer, intake, FULL exhaust that requires you to bump it up as high as 93 that should be the max. you are destroying your jeep. yea there are a few other things but im not trying to get in full technical about octane ratings, engines or this will just get to long. just stop running 98 ok.

 

Did you not read any of the previous posters?

 

I might have to look at my Jeep, I run about 18L/100km