I looks as though my 86 f-150 w/302 efi has two catalytic converters. From what I've heard that it helps in the way of horsepower in opening up the engine if I remove them. Is this legal if I live in a non DEQ area. Would it really make a difference to remove them and then just run like a flowmaster 40 series. Thanks. I really need someones educated experience. I don't want to ruin my engine.

 

The first cat is the main and the second cat is the pre cat. Dont know why they have two cats. I have a 95f-150 and it had the same thing. I cut the silly things off and put a true dual exhaust with glasspacks and it made a good difference in sound and power because it doesnt have to go through all those honey comb shaped holes and flows way better. If you have inspections there and dont want to cut them off just replace the tw0 with a dual in dual out high flow cat and it would still make a difference or if theres no tests cut them off.

 

I remember reading somewhere that the first cat helps heat up the gases to burn cleaner in the second cat. I recently had my exhaust redone on my 86' Bronco and they replace the 2 (one was bad) with a single heavy duty cat. The place said there books show it could have either 2 cats or 1. Haven't been to the emissions place yet so who knows if that's true.

 

I have the "2 cats" also. The one closest to the headers is a resonator and does heatup the exaust. I am planning on cuttng them both off and running a 40 series flowmaster out back.

henry
94' f-150 302 4x4
rockford fosgate 1200 watt system
k&n system

 

I don't believe that it is legal to remove cats regardless of emissions testing or not.

 

I live in mass with some pretty harsh emissions tests. I have a 95 F-150 300/6. Looking to open up the exhaust a little more. I have put on a Gibson cat back system and was wondering that if i take the Y pipe off and get rid of the two cats that you guys were talking about, get new Y and have it go into one high flow cat and then into the muffler and out if it would pass emissions or not, anyone know?

95 F-150 Eddie Bauer 2WD
4" Superlift Suspension
MSD 6A ignition, Ram Air Hood
K&N Filter, Gibson Cat Back
32 BFG All Terrains

 

Mustang221:

This isn't going to answer your question as directly as you'd probably like, but...... it depends. The best advice I can offer is to ask several emissions testing stations what they're looking for, and whether their guidelines would allow what you want to do.

There have been guys who've posted that they passed emissions with flying colors with true dual exhausts fitted with one cat per pipe, which is illegal by the letter of the law. Others haven't been as lucky.

I recently ordered a high-performance Y-Pipe for my 302, which came with a high-flow cat installed. This replaced my stock Y-Pipe, which originally had the pre-cat and after-cat. When I questioned this, I was advised that "the regulations provided that my truck should have single exhaust and at least one catalytic converter." And, considering that the manufacturer is advertising the product as "50 State Emissions Legal", and that the exhaust shop installed it, I asked no further questions. While I don't have to pass emissions in my state, though, who's to say that if I ever move I won't run into some tester who won't like that I have replaced my exhaust with something aftermarket? You'll get as many different answers as there are different people who've had differing experiences, but the bottom line will be the guy at the station signing off your truck. And just for good measure, I'd ask several to see if they are consistent with their interpretation of the regs.

 

Thanks for the advice.