If you've followed me for a while, you know I dislike the light throttle torque loss associated with the addition of headers, particularly big tube headers. I have been working on a cost effective way to get the torque back. I have hit on a system / formula that works, and won't cost much money or any peak HP.
Please read the instructions to the end.
1) Source an automotive exhaust reducer that has an entrance OD of 2.375" or entrance ID of 2.25" and an exit side OD of 1.875" or ID of 1.750" . You can find this easily at many auto parts stores, or order online at Rock Auto, Jegs, etc etc. You can order an AP exhaust reducer # 8931 and it will fit the bill. Usually about 5-6.00 dollars.
2) Cut 1.125" off the entrance end (large diameter end) Clean the cut with a file, die grinder, etc.
3) If there's any crimps or metal around the exit, (1.750" end) clean it with a file or die grinder.
4) We're going to be inserting this into the adapter pipe just after the header collector. We want it snug in the pipe. You can test fit it per the pic below, but an easy way to make it snug is to go down the INSIDE about 1/4" from the leading edge the large end, where you cut, and using a hammer / punch, punch 3 or 4 divots from the INSIDE of the pipe towards the outside. this will make little high spots on the outside of the reducer that will prevent it from slipping in the adapter pipe. If you flatten the "roundness" a little when punching, round it back out with a peaning hammer. If you're doing this mod, I don't need to tell you how to use your tools.
5) Insert the reducer into the adapter pipe as per the pic below. You should have to tap it to be flush with the leading edge of the adapter. It's a good idea to bevel the internal "lead in" edge, so there's not a sharp edge for the exhaust to impact.
6) Reassemble the exhaust and go ride your bike!
7) Many thanks to Justin Bowman for creating the graphic!
8) All the information you need is here. I'm not going to get sucked down the internet wormhole answering questions. This modification will cost you 30 minutes and less than 10 dollars. It works. It works with any flash, it works with no flash. Do it, don't hit me with the ordinary 10,000 questions. Do it, and then post up about it. Remember, this will help your throttle response and torque just ordinary riding, and not take anything away from WOT performance.
9) Yes, I've already done this for the Black Widow header. I will post up about that soon, I'm trying to source an adapter that I like a little better, just for convenience sake. DO NOT hit me with the posts about "what about the Black Widow" ... I'va already answered this.
10) If someone with an area p pipe is interested, post up and PM me. You will need to do some measurements. I'll see if I can find a reducer for it, too. BTW, IF someone posts up that they will measure the area p header, that's it, everyone else can relax, I don't need 50 PM's.
Enjoy!
Steve
Please read the instructions to the end.
1) Source an automotive exhaust reducer that has an entrance OD of 2.375" or entrance ID of 2.25" and an exit side OD of 1.875" or ID of 1.750" . You can find this easily at many auto parts stores, or order online at Rock Auto, Jegs, etc etc. You can order an AP exhaust reducer # 8931 and it will fit the bill. Usually about 5-6.00 dollars.
2) Cut 1.125" off the entrance end (large diameter end) Clean the cut with a file, die grinder, etc.
3) If there's any crimps or metal around the exit, (1.750" end) clean it with a file or die grinder.
4) We're going to be inserting this into the adapter pipe just after the header collector. We want it snug in the pipe. You can test fit it per the pic below, but an easy way to make it snug is to go down the INSIDE about 1/4" from the leading edge the large end, where you cut, and using a hammer / punch, punch 3 or 4 divots from the INSIDE of the pipe towards the outside. this will make little high spots on the outside of the reducer that will prevent it from slipping in the adapter pipe. If you flatten the "roundness" a little when punching, round it back out with a peaning hammer. If you're doing this mod, I don't need to tell you how to use your tools.
5) Insert the reducer into the adapter pipe as per the pic below. You should have to tap it to be flush with the leading edge of the adapter. It's a good idea to bevel the internal "lead in" edge, so there's not a sharp edge for the exhaust to impact.
6) Reassemble the exhaust and go ride your bike!
7) Many thanks to Justin Bowman for creating the graphic!
8) All the information you need is here. I'm not going to get sucked down the internet wormhole answering questions. This modification will cost you 30 minutes and less than 10 dollars. It works. It works with any flash, it works with no flash. Do it, don't hit me with the ordinary 10,000 questions. Do it, and then post up about it. Remember, this will help your throttle response and torque just ordinary riding, and not take anything away from WOT performance.
9) Yes, I've already done this for the Black Widow header. I will post up about that soon, I'm trying to source an adapter that I like a little better, just for convenience sake. DO NOT hit me with the posts about "what about the Black Widow" ... I'va already answered this.
10) If someone with an area p pipe is interested, post up and PM me. You will need to do some measurements. I'll see if I can find a reducer for it, too. BTW, IF someone posts up that they will measure the area p header, that's it, everyone else can relax, I don't need 50 PM's.
Enjoy!
Steve
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