No Baffles?
Fcsallan, thanks. That was valuable information.
I forgot to mention I bought the V&H fuel pack. I also installed the Ness Big-Sucker just now. I'm not even worried about the baffles, it sounds just awesome the way it is. Honestly there isn't much of a difference between the sound, except it just sounds a little deeper now. Given it has baffles now though, that makes sense.
It has a little bit of a Ping to it now though. Which sucks, cause I don't know if it has the stg 1 or not and that's though only thing keeping me from putting on the Fuel Pack.
Thanks everyone for the input.
Cruiser
Joined: Jul 2011
Posts: 210
Likes: 1
From: Pacific Northwest
Fattened up to compensate for the "wrong" pipes?
Losing torque permanently?
There sure is a lot of confusion and misinformation on the issue of exhaust "back-pressure". Many performance-minded people who are otherwise somewhat knowledgeable still cling to the myth.... "You need more back-pressure for better performance."
For virtually all high performance purposes, backpressure in an exhaust system increases engine-pumping losses and decreases available engine power. It is true that some engines are mechanically tuned to "X" amount of backpressure and can show a loss of low-end torque when that backpressure is reduced. It is also true that the same engine that lost low-end torque with reduced back-pressure can be mechanically re-tuned to show an increase of low-end torque with the same reduction of back-pressure. More importantly, maximum mid-to-high RPM power will be achieved with the lowest possible backpressure. Period.
Less back pressure leads to higher O2 saturation in the final mixture. In performance terms, higher O2 saturation is ALWAYS better than lower O2 levels. More O2 in the mixture means more fuel is needed to maintain the correct ratio, so if you reduce back pressure a significant amount you need to re-jet / remap to get the fuel mixture correct (EFI systems with O2 sensors will automatically adjust for proper mixture when changing pipes). And yes, running lean IS hard on an engine and causes higher head temperatures.
Losing torque permanently?
There sure is a lot of confusion and misinformation on the issue of exhaust "back-pressure". Many performance-minded people who are otherwise somewhat knowledgeable still cling to the myth.... "You need more back-pressure for better performance."
For virtually all high performance purposes, backpressure in an exhaust system increases engine-pumping losses and decreases available engine power. It is true that some engines are mechanically tuned to "X" amount of backpressure and can show a loss of low-end torque when that backpressure is reduced. It is also true that the same engine that lost low-end torque with reduced back-pressure can be mechanically re-tuned to show an increase of low-end torque with the same reduction of back-pressure. More importantly, maximum mid-to-high RPM power will be achieved with the lowest possible backpressure. Period.
Less back pressure leads to higher O2 saturation in the final mixture. In performance terms, higher O2 saturation is ALWAYS better than lower O2 levels. More O2 in the mixture means more fuel is needed to maintain the correct ratio, so if you reduce back pressure a significant amount you need to re-jet / remap to get the fuel mixture correct (EFI systems with O2 sensors will automatically adjust for proper mixture when changing pipes). And yes, running lean IS hard on an engine and causes higher head temperatures.
Last edited by pnw_hd_rider; Aug 27, 2011 at 02:42 PM.
Seasoned HDF Member
Joined: Mar 2010
Posts: 38,292
Likes: 6,322
From: Honah Lee
Dang GRF, that's kinda harsh, no? Just about all of my neighbors have Harley's, and don't have an issue with it. I'm glad I keep it in the garage at all times when I'm home. Haha. As far as the noise goes, to each his own. I haven't had any one say anything negative thus far, everyone has all said it sounds awesome.
Last edited by Jackie Paper; Aug 27, 2011 at 12:47 PM.
Stage II
Joined: Jan 2015
Posts: 2
Likes: 0
From: Tampa
I've been running open stock shorty pipes (took slip on mufflers off) since day 1 of owning my 2014 streetbob 103 and love it. Mpgs did go down noticeably but it's a motorcycle that cost 7 bux to fill up so who gives a **** about Mpgs . Probly does run more lean then stock but bike has alot more power in my opinion. Much more torque then stock. Put stock mufflers back on for services at harley dealer to not void warranty and bike feels half as powerful with stock mufflers. There's absolutely no backpressure. Loud as *****. Cars know I'm close. Saved my *** a few times. Turns heads. Love it. If I run Hess gas I get alot of decel pop which sounds bad *** imo. Could care less about my neighbors. Hope they move! Have plans on adding k&n intake and v&h sideshots with Harleys Dyno tune but I will not be running baffles on the new exhaust either. RIDE SAFE. BE HEARD.
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