Anyone running 2-1/4" true dual exhaust?

[kustomkyle]

I have a '86 Regal that I have been considering putting true dual exhaust on. It is a 307 VIN Y. The main thing that is holding me back is the intermediate pipes. I have a pair of dual side exit (442/Grand National) tailpipes but as everyone knows forward of that it gets a bit tricky as the floorpan design doesn't provide much ground clearance. I do have a new dual exhaust transmission crossmember to install when the time comes, I just really need some input on this part.

I was thinking about getting a factory replacement (VIN 9) cat-back y/intermediate-pipe and modifying, but that still doesn't solve how to route over/around the floor pans. I do intend to run headers and dual cats if possible.

Again, any input would be appreciated, it's time to get rolling again with the old girl.

 

[-83MONTESS-]

I havent seen 2 1/4" but I have a 2 1/2" true dual setup on mine. Not sure if that helps or not :lol:

 

[86 Grand prix]

X2 on the 2.5". got mine from Jegs, whole kit.

 

[pontiacgp]

I have 2.5" SS custom system on my car, got it done at a muffler shop who sponsors late models. They say they could have put a 3" but it's tricky to get it over the axle

 

[kustomkyle]

Yes it appears most people go to 2-1/2". I'm wondering though, if using a 2-1/2" intermediate pipe (stepping down from 3" header collector/cats) would work well. I've looked into that too but haven't found anyone who sells just the intermediate section. Any out there, or do any of you guys have pictures of how they were routed? I could always use generic pipe but it seems like there is never a correct contour where you need it. I don't think there are any pipe bending places around here...that gives me an idea, but that's another topic for another day.

 

[MrLightning]

[ if using a 2-1/2" intermediate pipe (stepping down from 3" header collector/cats) would work well.

your engine isn't making enough HP (140) or torque to need to worry about diminished performance by stepping down to 2 1/2 from 3". If for no other reason, unless you intend to put a Olds 350 in it sometime in the future, you don't need to go any bigger than 2", because you still need to have good back pressure. Don't you have a Midas muffler shop around close by, most of the time you can have them do some custom stuff when they are slow and looking for something to do.

 

[oldmansmonte]

I run 2 1/2 on my Monte with GMPP 350. Even the Muffler shop I brought it to said 3" would be overkill and might actually reduce power.

 

[MightyCarlo86]

x2 that, I am running 2 1/2" dual exhaust with my ZZ4 the 2 1/4" should be more than enough and you shouldn't have any problems.

 

[565bbchevy]

They say they could have put a 3" but it's tricky to get it over the axle

What was "tricky" was when I made my 4" tailpipes for over the axle on my Monte with no clearance issues.
http://youtu.be/EkXhFbqZ4UY

 

[pontiacgp]

What was "tricky" was when I made my 4" tailpipes for over the axle on my Monte with no clearance issue

I don't think I seen a nicer set up, or heard one....

[youtube]EkXhFbqZ4UY[/youtube]