exhuast pipe diameters?

nervekiler

Registered User
i need to know what the stock exhuast pipe diameters are on a 1990 supercoupe. where it goes into one pipe, is that a 3 inch diameter? what about right after the cats, what is the diameter on those pipes? the pipes that go into the stock resognator, are those dual 2.5 inch in and then one 3 inch out?

i was thinkin those were the sizes, but when looking on supercoupeperformance.com at the high flow cats it said something like 2 1/4 inch diameter.

i would just like to know what the correct sizes are. my plan is to put in a magnaflow resognator, high flow cats, and to delete my mufflers (i read this gives a very nice sound). but i would just like to know what the exhuast pipe diameters are so i can be sure to get the right size pipes. thanks.
 
Stock isn't even remotely that large in diameter. I didn't measure, but I'd say that after the cat's is less that 2", the center pipe still 2" or less. And crimped up in several places. Stock does not have mandrel bends, if you see it off the car it's pretty funky looking and very uneven at an kind of bend.
 
The stock exhaust is 2" from the manifolds to the resonator. Then the mid-section is 2 1/2"....and where it Y's off in the back is 2 1/4" I believe.
 
ok so we have established that the exhuast is super small. way smaller than the openings will be on the resognator i am buying.

so how do i make the 2" pipe fit into a 2.5" opening? do they make special parts that are like a funnel that i will need to stop by a muffler shop and buy before i have my buddy weld it up?

id rather ask on here and look stupid than ask someone who does muffler stuff for a living and have him laugh in my face.

thanks
 
Just had my SC up in the air today to tighten sub-frame, i was studying just the parts you are talking about and there are definitely some adapter type parts you will need . I wish i could be more specific but i would just get the car up in the air and make a list of diamaters that already exist on your car and a list of what diameters you need to adapt into the resonator, and if your not going with muffs ,then get the longest res that you can fit.
 
ok thanks. ill be sure to get a nice long resognator. ill probably just let the shop weld in the new resognator... they can deal with having to make it perfect and deal with the different diameters. lol
 
Thanks mike ! reducer is what i was thinking ! It is easier to let the exhaust dudes handle it...got a quote of 105.00 for a Magnaflow installed.

Jeff
 
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