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Reverting from Dual cats with 2-1/4" piping to single cat 3" pipes,will i lose power?

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Old 03-04-2014, 11:20 AM
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Car: 88 Firebird Formula
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Transmission: 700R4
Axle/Gears: 2.73 stock rear end
Reverting from Dual cats with 2-1/4" piping to single cat 3" pipes,will i lose power?

Hey all so im getting ready to redo my exhaust as im in communist california and ive lost all my hot smog communications & need to rip off my non CA approved Jegs tubular headers. I got these things cheap brand new back when i first bought the car. I was 17 year old high school kid with a tiny check so dont laugh at me lol. Back then (2009) i think they were cheaper than now, like $105 now there like $149, weird..... there CRAP. at that same time i redid my exhaust as well. I was once again a 17 year old kid and bought two "high flow" cats off another teenager in high school, his cats were off a 04 mustang (4.6L) , im not sure the brand, but there TINY. I havent actually measured my piping but im quite sure its 2-1/4" because its small. Any ways point of my life story is that i was a dumb kid not thinking about smog and just throwing any parts on i could get my hands on with the little cash i had, but for a kid i did make it work at that time, . I ran it back to some cheapo muffler a shop sold me when i put it all together.The shop actually created me a if you want to call it a y pipe lol a y-pipe.The shop did a really crappy job, alot of unnecessary weld locations and add-on piping, which resulted in ALOT of exhaust leaks all down my exhaust. Its BOGUS. One of the main reasons i want to go with hooker 2055 is because of the great Y-pipe!!! Im really pumped to actually get a exhaust job done correctly lol. So now im ready to re-do my exhaust, but am i going to lose power?

I was able to get 2 hot smogs in a row (4 years) and now i need to get passed a damn visual to even get my car on the machine, im going to be going with Hooker 2055, with Y pipe. I made my choice on this magnaflow 3" cat http://www.summitracing.com/parts/mpe-36019 and then 3" piping all the way back to still not sure on my muffler setup. (open to opinion's/advice!!) Basically what im wondering is going from a dual cat setup with 2-1/4" piping to a y pipe (after cats) , which looks tiny if anything 2-1/2 (no way 3") and back to i dont even know what kind of muffler, and dual tips, will i lose power/flow? Consider that the shop i did get my original exhaust job at did a good job, would i lose power/flow? Ive read by kevin91 says that dual 2.5piping is as good as single 3.5piping, so is dual 2.25 as good as 3"? This exhaust job is going to be done at a reputable shop so i know it will be done correctly. Also they wont be supplying alot of pipe as i will be supplying most of the items. (muffler, cat & y-pipe). So do you think i'll lose power?

If anyone has a good catback system to recommend im open to it!!!!!!!!!!!!!!!!!!!!!!!!!!!! Never used one so im new to the exhaust world, open to vid samples, audio samples or what ever!! Thanks all
Old 03-04-2014, 11:26 AM
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Re: Reverting from Dual cats with 2-1/4" piping to single cat 3" pipes,will i lose po

If its an '88 with a TBI you're going to have to switch back to single cat, because you wont pass the visual with dual cats, they only came on 89-92 TPI cars.

As far as power loss? It probably might even seem better because you're going from a crappy cobbled-together setup to a much better designed 3" system.
Old 03-04-2014, 05:15 PM
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Car: 88 Firebird Formula
Engine: LO5 5.7 TBI/Ebl Flash
Transmission: 700R4
Axle/Gears: 2.73 stock rear end
Re: Reverting from Dual cats with 2-1/4" piping to single cat 3" pipes,will i lose po

Originally Posted by Kevin91Z
If its an '88 with a TBI you're going to have to switch back to single cat, because you wont pass the visual with dual cats, they only came on 89-92 TPI cars.

As far as power loss? It probably might even seem better because you're going from a crappy cobbled-together setup to a much better designed 3" system.
ops yeah it is, i forgot to mention that in my original post. Thats kinda why im heading back to single cat as i just want to have my exhaust legal, but i dont want to lose any power/flow. Thats what i was thinking, but i just wanted to make sure that they 'flow' at the same rating. Should dual 2-1/4" piping flow as good/close to 3" single piping? Also does anyone know the CFM rating on that Cat? I know you take cfm & divide by 2.2 to get maximum horsepower its good up till, but i cant find any numbers, and i have a mild/moderate built 350.
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