which header?
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Road Master
Joined: Aug 2010
Posts: 859
Likes: 43
From: Upstate NY
which header?
After upgrading to a S and S 475 c cam, S and S mk 45 mufflers, SE breather, FP-3 tuner with a decatted stock header ( I tried to save some money 
) , it feels like I lost a bunch of torque. After tinkering with the FP-3 with the help of a good friend, turns out the dealer just put a basic stock flash on my bike. We redid the flash and I am going to take it out tomorrow for a test ride to see if that helped. I am however now considering a different head pipe to help with the torque as well. I hear that the V and H power duals (1.75" pipe) are better for that than the (2.5 " pipe) Jackpot 2/1/2. Any thoughts? Other pipes I should look at? Also am probably going to go down to 4" mufflers from the 4.5" ones. Thanks.
) , it feels like I lost a bunch of torque. After tinkering with the FP-3 with the help of a good friend, turns out the dealer just put a basic stock flash on my bike. We redid the flash and I am going to take it out tomorrow for a test ride to see if that helped. I am however now considering a different head pipe to help with the torque as well. I hear that the V and H power duals (1.75" pipe) are better for that than the (2.5 " pipe) Jackpot 2/1/2. Any thoughts? Other pipes I should look at? Also am probably going to go down to 4" mufflers from the 4.5" ones. Thanks.
Ultimate HDF Member
Joined: Oct 2016
Posts: 5,063
Likes: 2,582
From: On my bike!
A good dyno tune would probably get it like you want. I would personally spend the money on that first and go from there. The decatted stock header is actually not that bad. The FP3 is not a popular tuner for dyno guys so I would check around to see if anyone in your area dynos with it. Good luck sir!
Last edited by Quik; Mar 25, 2020 at 05:57 AM.
Stellar HDF Member
Joined: Jul 2013
Posts: 2,341
Likes: 982
From: Trinity NC
It is most like an opportunity with the tune and not the exhaust set up. The MK-45s with the DB reducers installed are go to mufflers for many builds. The decatted stock header also seems to perform well on builds like yours. To get the most out of your build find a good tuner in your area and have them put it on the dyno and dial it in. I ride with another member that has the same set up as your, except he has a Fuel Moto headpipe, and a good dyno tune. The bike sounds really good and runs very strong.
Road Warrior
Joined: Apr 2015
Posts: 1,535
Likes: 780
From: Manitoba
I had exact same setup on my Road King last summer and could never seem to get it dialed in proper with the FP3. This winter I took it to a Tuner and they wanted nothing to do with the FP3 so I just paid the DynoJet license and had them Dyno it. It's still winter in my part of the world but I'm confident it'll run much better. I'll let you know once I get out hopefully within the week. In my opinion the FP3 is a great Stage 1 tuner not so much with Stage 2 and up. Lots on this forum have been suggesting this for years but I didn't listen LOL.
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With your combination there is not going to be large gains swapping head pipes if you are already running a de-catted head pipe, and the MK45 mufflers you are running perform really well. You are going to want to make sure with the S&S 475 cam you run the inserts in these mufflers as removing them will greatly affect low RPM performance, response, and tunability. Getting the bike tuned properly is going to be the biggest consideration with your combination. Most of the FP3 tunes have been derived by setting up tune parameters (specifically cam ivo/ovc) in the FP3 base maps then require the end user to develop the tune using the Auto Tune application. Whether or not the FP3 base tune is close can be open to interpretation, however it is going to require fairly comprehensive tuning.
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Jamie Long / Fuel Moto USA
The USA's Leader V-Twin EFI & Performance www.fuelmotousa.com
Contact 920-423-3309
Email jamie@fuelmotousa.com
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Thread Starter
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Road Master
Joined: Aug 2010
Posts: 859
Likes: 43
From: Upstate NY
Thanks to those who responded. Took it out for a long ride yesterday with the new canned map my friend suggested and it ran somewhat better. He ( owns his own independent shop on the other side of the country) believes the FP-3 is just fine to tune a stage II setup. (It will need a lot of tweaking though) Already paid for it so might as well give it a go. I also hear many different opinions on weather the stock head pipe without the cat is ok. Some say it is, some say the chamber where the cat was is just a big plenum now and will kill some of the back pressure compared to a V and H power dual set up. I wish there were more readily available charts to compare head pipes other than just the manufacturers claims. Ride safe all.
Last edited by kanelakos; Mar 27, 2020 at 06:58 AM.
Thread Starter
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Road Master
Joined: Aug 2010
Posts: 859
Likes: 43
From: Upstate NY
With your combination there is not going to be large gains swapping head pipes if you are already running a de-catted head pipe, and the MK45 mufflers you are running perform really well. You are going to want to make sure with the S&S 475 cam you run the inserts in these mufflers as removing them will greatly affect low RPM performance, response, and tunability. Getting the bike tuned properly is going to be the biggest consideration with your combination. Most of the FP3 tunes have been derived by setting up tune parameters (specifically cam ivo/ovc) in the FP3 base maps then require the end user to develop the tune using the Auto Tune application. Whether or not the FP3 base tune is close can be open to interpretation, however it is going to require fairly comprehensive tuning.