Exhaust piping for 93 SC400

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im trying to have a custom exhaust made for my 1993 SC400, and i was planning on using 2.5" piping with two megan mufflers out back. the problem i have is that all the shops out here use pipe bending, how much will that hinder the performance of the exhaust, and does anybody have suggestions of if i should remove the cats or place one cat in the y pipe?

 

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also, does anybody know the stock exhaust diameter for the 93?

 

[JBrady]

Read through my previous posts for your information. If you still have questions ask again.

 

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well, the posts were informative, but im still at a loss.

i was planning on having a shop like midas or meinike make my exhaust, and they use pipe bending, im just afraid that might pinch off flow a bit too much.

also, i was planning on running 2.25" piping into the Y, then removing the center cat and running 2.5" pipes from the straight section all the way out to the split and the mufflers. i will be using a pair of Megan racing N1 mufflers. i just wanted to know if this would be a viable system or if i should revise my logic here. i dont want to lose any low end torque, but i want a good sound.

 

[JBrady]

Go with 2.25" from cats to either (Y pipe, 2.5" center, Y pipe) or (2.25x2.25 X pipe). 2.25" duals to mufflers. If system is too loud you can add resonators in the center pipe between the Y pipes and or between second Y or X pipe and the mufflers.

I would buy a selection of mandrel pipes from JCWhitney and have the shop cut swage and weld as needed.
http://www.jcwhitneyusa.com/autoparts/ProductDisplay/s-10101/p-1020/c-10101

Here is an inexpensive X pipe that can be cut to make dual Y pipes.
http://www.exhaustproslinc.com/humaxpiass.html

 

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would it be ok to have the Y pipe setup and have it expand to 2.5" at the very end just to accomadate the mufflers?

 

[JBrady]

would it be ok to have the Y pipe setup and have it expand to 2.5" at the very end just to accomadate the mufflers?

That would be ok. If I did that I would make an expansion fitting that went over the 2.25 pipe and filled the gap. The 2.25 would be cut off blunt and a little bit into the muffler so that there would be a one way "step" as it went into the muffler... just a little anti reversion engineering. If you have a smooth transition the intersection will flow well backwards between pulses (not recommended).

To visuallize pulsing, place a straw in a glass of water and puff and release and watch the water rush back up and out of the straw. This happens with air pressure also and does impact low speed exhaust flow.

 

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ok, i have the mufflers and i have a shop lined up to do the work, just one last question that might sound a bit stupid...

is the 2.25" the inside or the outside diameter?

 

[JBrady]

ok, i have the mufflers and i have a shop lined up to do the work, just one last question that might sound a bit stupid...

is the 2.25" the inside or the outside diameter?

outside diameter

 

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how would it sound if i removed all 3 resonators? too loud?