Ca. legal cats, and back pressure

[maxyedor]

Time for some new exhaust on the Rover and I need new cats, while I'm sure I could pass smog with 49state cats I'd rather just get the legal ones. I searched the usual places, Jegs, Summit and eBay, and found dozens of brands, but couldn't figure out which where good and bad. What do you guys reccomend for a decent, inexpensive cat, need 2 of them, they need to be 2.25 inlet and outlet and are for a 4L V-8 if that matters.

Also I've always been told that you need a muffler to create back-pressure or you'll have no torque. I'm thinking that I'll make the muffler bolt-in so I can take it off and get an extra couple feet per gallon when I'm in Baja or otherwise away from people who would whine about it being too noisy. Will running 1 cats into a Y-pipe and about 3.5ft of tubing after that give me enough back pressure to develope torque, or will I need that muffler in order to have the beans for pulling stuck race-trucks out of silt?

[philofab]

The only difference in cats is the amount of precious metal in them. Some cars are more picky about how clean the exhaust is (such as new GM vehicles). You'll pay a little more for them to be 50 state legal.

You'll be surprised on how quiet your truck is without the muffler and just cats (they muffle the noise quite a bit) but with a proper muffler you'll get better mileage than without. If your vehicle is stock you will see a performance improvement from newer cats and a aftermarket muffler. Backpressure does create a little smother torque curve and makes the vehicle drive a little better but if you could pull a truck out before you will still be able to.

You never mentioned what year the truck is?

[maxyedor]

Sorry the truck in question is a '98 Land Rover so it's ODB2. I've driven it with cats and no muffler before, and it's a tad on the loud side, not too bad really, but just loud enough tp really annoy the neighbors when I leave the house at 5:30.

[philofab]

If i was smart I would have read your sig.

I wouldn't worry about which cats to use. Even the low line 49 state legal cats are better quality then the ones that thing had in 98.

[maxyedor]

If i was smart I would have read your sig.

I wouldn't worry about which cats to use. Even the low line 49 state legal cats are better quality then the ones that thing had in 98.

If I was smart I would have caught all the spelling mistakes in my post and put info about the truck in the post, so I guess we're even.:D

Thank's for the info, even with the stock cats with 120k miles on them I passed my last smog with flying colors, so I think you're right, 49 state cats should do the trick. Thanks for the help.

[JONES PERFORMANCE]

you most liely wont pass smog with a obd1 cat on it. the 49 state cat you are talking about is essentially a obd1 cat. the obd2 cats reduces the emissions alot more than the obd1 cats do.

[1wayne]

I can get you OBD 2 Cats. made by Magna Flow they are very good quailty and flow very well. They will be legal for vehicle. PM me if intrested.

[Beat98TJ]

I have run my 4.0L jeep without a muffler after the cat a few times, and with glasspacks that have no glass. The only difference I notice in performance, fuel economy, etc. is noise. I get a headache much faster without them.

I really don't feel you are going to notice the extra flow unless you have changed to a low restriction air filter and possibly the program in the ecu.