Exhaust/Crossover Question...
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Road Master
Joined: Aug 2010
Posts: 1,205
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From: SE Michigan
Exhaust/Crossover Question...
I'm at the point where I need new exhaust header pipes on my '91 FLHS as the flange on the rightside pipe is cracked off and the muffler rattles despite my best efforts to "Jerry Rig" it. The pre 1995 header pipes have flanges on the muffler end that the muffler flange butts up to and all is secured with a wrap around clamp type fitting. I have the option of going with the "crossover" style I have now, "true duals" ( no crossover pipe from rear cylinder), or a "two into one" with one muffler. What I'm wondering is what is the function of the crossover design which HD still uses on up to at least the 2006 Bagger? Will I experience performance differences with the "true duals" or "two into one" set up?? Will I have to rejet my S&S carb if I change the configuration, etc.? I really like the idea of the "true duals" ( cheapest fix btw also) as it gets rid of a hot pipe near the transmission and makes access easier to the starter area too. Any ideas, info would be greatly appreciated. Thanks. 
Road Captain
Joined: Apr 2005
Posts: 535
Likes: 14
From: Highspire Pa
I am no expert but read many posts that claim the 2 into 1 is the best for overall performance, and the stock setup is a little better than true duals, but some fellows say differently.
If everything else is OK, you can saw off the flange and the slip on mufflers for newer models will work OK with your existing headers. I did that for a couple years on our '90 flhtcu to try various slip on mufflers. I found used mufflers for as low as $40.00, good enough to try. I had true duals for a short time and may try them again, some day. Currently I am using the headers from an '08 touring bike and the 4" CVO mufflers for an '06 with 1.75 fullsac baffles. Overall it's pretty quiet. I have read the Supermeg 2 into 1 gives good power and is pretty quiet and may try that some day as well. I use an oxygen sensor and a air/fuel ratio gauge in the front header so I need the newer style headers with O2 bungs. You can fit newer, maybe up to '08 headers on your bike.
If everything else is OK, you can saw off the flange and the slip on mufflers for newer models will work OK with your existing headers. I did that for a couple years on our '90 flhtcu to try various slip on mufflers. I found used mufflers for as low as $40.00, good enough to try. I had true duals for a short time and may try them again, some day. Currently I am using the headers from an '08 touring bike and the 4" CVO mufflers for an '06 with 1.75 fullsac baffles. Overall it's pretty quiet. I have read the Supermeg 2 into 1 gives good power and is pretty quiet and may try that some day as well. I use an oxygen sensor and a air/fuel ratio gauge in the front header so I need the newer style headers with O2 bungs. You can fit newer, maybe up to '08 headers on your bike.
Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
A further alternative I have used in the past is a Fulsac conversion kit, which will turn your current system into a true dual set-up. Cheaper than buying new pipes, especially if there is life in the rest of your current system.
If you have the original style pipes with flared ends you will find it difficult to get replacements, but you can fit the later style pipes with suitable slip-ons.
I have later spec Samson true dual pipes on my S&S 107 (with S&S oval mufflers) and get slightly better performance than they claim I should, so TDs haven't hurt my bike! There is no doubt that a good 2-into-1 will give best performance, but IMHO that will really only happen with a tuned motor. For near stock I reckon there is little in the performance of the various options we have. Restrictive mufflers will have a bigger affect.
If you have the original style pipes with flared ends you will find it difficult to get replacements, but you can fit the later style pipes with suitable slip-ons.
I have later spec Samson true dual pipes on my S&S 107 (with S&S oval mufflers) and get slightly better performance than they claim I should, so TDs haven't hurt my bike! There is no doubt that a good 2-into-1 will give best performance, but IMHO that will really only happen with a tuned motor. For near stock I reckon there is little in the performance of the various options we have. Restrictive mufflers will have a bigger affect.
Tourer
Joined: Apr 2010
Posts: 293
Likes: 7
Making power and noise is fairly easy.
Making a lot of power, and not making a lot of noise is not so easy.
Supermegs do it fairly well.
Some think it is not a classic HD note, and look elsewhere.
The stock crossover pipe is typically 1-3 HP better than not having the crossover.
Making a lot of power, and not making a lot of noise is not so easy.
Supermegs do it fairly well.
Some think it is not a classic HD note, and look elsewhere.
The stock crossover pipe is typically 1-3 HP better than not having the crossover.
Tourer
Joined: Sep 2009
Posts: 309
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From: Tegucigalpa
What I've always read is that 2to1 are the best, performance wise but don't seem to like the look on baggers IMO, true duals look sweet but theres the "less restrictive" factor that happens, sort of running with baffleless pipes. I read somewhere (trying to remember where) that the crossover pipe acts on giving some negative pressure on the cylinder, thus creating a bit more torque on the low end, that's why touring bikes still come with crossover pipes I suppose. Heavier bikes like more low end torque. HP wise... haven't read or heard any comments about it
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Road Master
Joined: Aug 2010
Posts: 1,205
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From: SE Michigan
Thanks all and great info and insight!! I'll let you all know what I go with. I'm leaning towards just matching what I have now as Paughco ( wierd spelling no?) still offers them and I won't have to buy new mufflers as I have very expensive Super Trapps on her now and she runs like a r*ped ape. If those flanges ever break again I'll use Pajoe's info and cut them off and go to new slip ons I'm thinking.
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Tourer
Joined: Sep 2009
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From: Tegucigalpa
check this out
http://www.harley-performance.com/harley-exhaust.html
it explains it better than I did
http://www.harley-performance.com/harley-exhaust.html
it explains it better than I did
Tourer
Joined: Sep 2009
Posts: 309
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From: Tegucigalpa