downpipe connect to headers [Archive] - GrandAmGT.com Forum

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burgett2103
02-26-2011, 05:45 PM
Are the pacesetter headers a direct bolt on to stock downpipe?

and

Will the pacesetter headers bolt onto the milzymotorsport aftermarket downpipe?

AaronGTR
02-26-2011, 06:46 PM
No and no.


No aftermarket headers will bolt up to the stock DP. That is because the stock manifolds stop up by the block so the DP bolts to it way up there. With headers you have longer primaries and a longer cross-over, so they go down towards the bottom of the car and usually have a flange that sits right above the sub-frame height. The headers basically replace most of the "down" section of the down pipe. Same thing with the Milzy DP since it is made to replace the stock DP. You need to either cut the stock DP and have a flex pipe and flange welded on to connect to the headers, or make a new custom center section with a high flow cat.

Since headers will dramatically increase the exhaust flow and most have a 2.5" outlet and the stock DP/cat converter is only 2.25"... I would go with the second option. That's what I did. I made a custom center section with a flange, a short leg 30 degree bend with an O2 sensor bung in it, a short section of flex pipe, an electric cutout, and a high flow cat, then another flange to connect to the rest of the exhaust. All done in 2.5" stainless steel. An decent exhaust shop should be able to make you something similar.

G.I.Ceo
02-26-2011, 07:21 PM
No it will not work. The MilzyMotorSport one is designed for a direct replacement for a stock down pipe. Like Aaron said you can have a shop build you one for a reasonable price. I had to have my down pipe cut down when I installed my S&S headers and it wasn't that much of a cost. SO just call around to your local muffler shops and get some quotes on have a 2.5" high flow down pipe built for you.

burgett2103
02-26-2011, 07:34 PM
alright thanks boys, just checkin things out