Help with 90 302 exhaust

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Bubba

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I was wondering if anyone had any suggestions about what I should do with my exhaust. I was thinking 3" duals with flowmaster and no cats. Also on my 81 bronco with a 302 I ran without cats and it didn't hurt anything, but since the 90 is all computerized would running without cats hurt anything? Such as gas mileage, power, or turn on any warning lights. Any suggestions would be appreciated.

 

Shadow_D

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First thing I would do is check your State's laws. I know in NY if the vehicle came with a cat, it has to be there to pass inspection.

As far as I know it won't hurt anything to "remove" them.

 

Justshootme84

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The best and legal solution I've found is to replace the stock cats with an aftermarket one, using the stock y-pipe with the stock manifolds or shorty headers. Then just run a single pipe from a Flowmaster muffler to exit behind the right-rear tire. three inch tubing is rather large and reduces the backpressure, so I suggest staying with 2.5" throughout.

 

Seabronc

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If it were a 60 - 87 with a carb and you were eliminating the EGR, I wouldn't worry about back pressure. Of course that legally makes your truck an off road only vehicle in most states. However, EFI engines require the EGR and therefore require back pressure in order to function properly and to prevent damage to the engine. The reason being that the engineers made use of a side effect of the EGR which reduced the combustion chamber temperatures which allowed them to write more aggressive timing programs. They make a lot of nice high flow CATs and exhaust systems that will give some performance increases. I think I'd go with Justshootme84's suggestion.

Good luck,

:)>-

 
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oldtimer

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you can hack off the cat then ru 2 1/4 pipses along the passenger side then split them up whe they go over the rear axle then poit them out the sides or where ever you what them thats what i did

hope you have a pipe bend

weld the seams all of them except for the mufflers

 

rebel33382

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my 95 has no cats and with 2 flowmasters, with tips coming out from behind the tires. They sound very deep. I have no CEL (thanks to my tomato soup can vacuum canister.) I also live in LA where they rulz are very laxed.

 
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Bubba

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I know it's not legal to run without cats but in Oregon we don't have inspections. I'm gonna do duals, either true dual or just split the single pipe. I'll most likely have the exhaust dump in front of the rear tires, I know it will make my wheels dirty but I plan on having them muddy most of the time anyways. So I guess my new question is Should I go with true duals with cats and flowmasters or single exhaust with a cat and flowmaster and then have it split off. Or I could go with dual in dual out cats and mufflers. And so far eveyone saying 2.5" so if no one else thinks I should go with a different size I'll go with 2.5" and just get tips.

 

Seabronc

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I believe that your answer is contained in the above posts. Reread some of the suggestions. It's your truck and you need to make up your own mind on which way to go.

God luck,

:)>-

 

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