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Does anyone have the difference in length between a Z06 exhaust manifold and down pipe versus stock C6 exhaust manifold and down pipe as they sit installed in the car?
Does anyone have the difference in length between a Z06 exhaust manifold and down pipe versus stock C6 exhaust manifold and down pipe as they sit installed in the car?
The actual length, I never measured, but they are very similar in length. However, the design is completely different. The Z06 exhaust manifold consist of four hydroformed 309 stainless steel tubes that meet at the collector and covered with a stainless steel jacket vs base cast iron manifold where the tubes join in pairs prior to the collector. GM carefully designed the shape of the stainless steel tubes to reduce exhaust restriction. The Z06 collector is larger oval shape vs base smaller and round shape. The Z06 downpipes w/cats are 3" pipe vs base with 2 1/2" pipes. The Z06 exhaust manifold will only work with the Z06 downpipes, no mix and matching with the base downpipes.
Last edited by Mike's LS3; Apr 20, 2019 at 12:41 PM.
Mike ...thanks for your response. My question and thoughts surround with what would be required to take the Z06 midpipe with converter and neck/ reduce the outlet down to meet to the 2.5 inch ls3 X pipe. I really believe most of the horsepower increases derived from the Z06 exhaust occur with the exhaust manifold + down pipe before entering the mid pipe to mufflers.
Mike ...thanks for your response. My question and thoughts surround with what would be required to take the Z06 midpipe with converter and neck/ reduce the outlet down to meet to the 2.5 inch ls3 X pipe. I really believe most of the horsepower increases derived from the Z06 exhaust occur with the exhaust manifold + down pipe before entering the mid pipe to mufflers.
You would also benefit with a Z06 mid pipe, then use reducers for the 2 1/2" axle back mufflers. This is the way most people do the swap if they want to retain the 2 1/2" axle back mufflers. If the "X" pipe is desired you can look for ZR1 mid pipe, 2011+ mid pipe or aftermarket replacement. The "X" mid pipe with converters started in 2012 for both ZR1 and Z06. Personally, I would find a mid pipe w/out converters since they are not monitored by the ECM.
Last edited by Mike's LS3; Apr 20, 2019 at 06:51 PM.
I quess the best way to put this is that I am trying to avoid using the Z06 X pipe as I would have to modify it anyway as the car is a 2008 A6 and would rather attach and neck down the exhaust at the junction between the Z06 downpipe and LS3 X pipe.
I quess the best way to put this is that I am trying to avoid using the Z06 X pipe as I would have to modify it anyway as the car is a 2008 A6 and would rather attach and neck down the exhaust at the junction between the Z06 downpipe and LS3 X pipe.
If you're trying to extract the most power by using a combination of Z06 exhaust and base components, the point of pipe diameter reduction is relatively close to the mid-point hanger. You need to think in terms of temperature, velocity, volume, and rate of change. Since using mostly GM stock parts for economy reasons or CA rules, a 3" to 2.5" reducer is the least costly method to accommodate the rate of change. You can also eliminate welding by using clamps on the reducer to save that cost too. Because the hanger is at the same point on all C6 Vettes, simply cut the Z06 X or H pipe off prior to the hanger and your 2.5" X or H pipe at the same distance. Then shorten either the Z06 3" pipe or the 2.5" pipe by the distance to insert the reducer and clamp the new assembly together. That effectively creates a X or H pipe that starts at 3" and ends at 2.5" with the hanger in the correct location. Your OEM or any aftermarket pipes from that point to the tips will always match.
BTW, I keep mentioning X or H pipes for anyone else who reads this. The Z06 H pipe is far more available because of the volume produced. Also, the 2012-13's with the additional cats will cause more turbulence, so avoid those unless you need to meet CA regs.
I just did this project a few weeks ago. You would be better off modifying the X or H pipe at the axle/ transmission end. You might be able to modify the down pipe to fit the 2.5in connection but it will be more work which will cost more. As you can see it's not that much work to get around the A6.
