Drags, Baffles, Sound and Performance
#1
02-02-2008 | 10:33 AM
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Road Master
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Drags, Baffles, Sound and Performance
Just a little opnion on my latest venture with drag pipes on a Sportster 883 upgraded to a 1200. (carb'ed bikes)
I purchased a bike that had been upgraded to a 1200 and had the 1.5 drag pipes installed. Nice ride but loud and the low end torque seemed to me to be a little starved (no back pressure I was thinking). They sounded great however but not deep and hollow like you can get on the larger dia drags or slip-on muffs.
Because what I thought about the low end torques I purchased and installed some 4" baffles.. Well they did seem to sharpen the torque issue (to a point) but I had to increase the idle setting to keep the bike from chocking down and stopping. (back pressure)
Also the baffles quieted the sound but sound. The thinner sound is not what I really expected.Best discribed as "tinnie"... Guess that's because there is no hollow "sound chamber" as slip-on's would have provided.
The final issue is the cold starts as it seems to take more time for the bike to warm up and there's a little popping and cracking through the exhaust.. but once warmed up everything seem OK.... Carb will caugh a little also but it also stops doing that after a complete warm up.
My next move will be to remove the baffles and flatten down some of the restriction tabs and reduce some of the back pressure (guess you could call it tuning the baffles).
My summary would be to say: Back pressuremeans more pressure for the exhaust valve to overcome and the exhausted burntgas is a little more compressed between the engine and baffle. Drag pipe restriction with baffles "muffles" the sound ofexhausted gases, (like the potato in the tailpipe trick) and my requirecarb adjustments for idle settings.
Don't know how all this would work out on the newer FI bikes. Anyway all this is just my opnion and observation and provided FYI.
I purchased a bike that had been upgraded to a 1200 and had the 1.5 drag pipes installed. Nice ride but loud and the low end torque seemed to me to be a little starved (no back pressure I was thinking). They sounded great however but not deep and hollow like you can get on the larger dia drags or slip-on muffs.
Because what I thought about the low end torques I purchased and installed some 4" baffles.. Well they did seem to sharpen the torque issue (to a point) but I had to increase the idle setting to keep the bike from chocking down and stopping. (back pressure)
Also the baffles quieted the sound but sound. The thinner sound is not what I really expected.Best discribed as "tinnie"... Guess that's because there is no hollow "sound chamber" as slip-on's would have provided.
The final issue is the cold starts as it seems to take more time for the bike to warm up and there's a little popping and cracking through the exhaust.. but once warmed up everything seem OK.... Carb will caugh a little also but it also stops doing that after a complete warm up.
My next move will be to remove the baffles and flatten down some of the restriction tabs and reduce some of the back pressure (guess you could call it tuning the baffles).
My summary would be to say: Back pressuremeans more pressure for the exhaust valve to overcome and the exhausted burntgas is a little more compressed between the engine and baffle. Drag pipe restriction with baffles "muffles" the sound ofexhausted gases, (like the potato in the tailpipe trick) and my requirecarb adjustments for idle settings.
Don't know how all this would work out on the newer FI bikes. Anyway all this is just my opnion and observation and provided FYI.
#2
02-02-2008 | 11:00 AM
Ultimate HDF Member
Joined: Sep 2005
Posts: 8,641
Likes: 24
From: Ozark Country
RE: Drags, Baffles, Sound and Performance
I might be different from most, but whenever I change/modify the exhaust system on any of my carb'd bikes I also have the bike either dyno-tuned, or at the least have gauges hooked up to set the correct air/fuel ratio throughout the operating range.
I've found that just 'reading plugs' or changing the jetting based on a combination that works for someone else isn't accurate enough. What's right for one bike might not be right for another.
My Shovelhead has been running open drag pipes since day one, and it now has over 85,000 miles. My EVO Dyna WideGlide has been running open drag pipes for at least the past 30,000 miles.
When the EVO WideGlide went from pipes with internal baffels to open 'stepped tuned' drag pipes the low end performance felt a little 'sluggish', even through we rejetted, checked plug color, and had the bike where it felt like the carb was set correctly.
Finally gave up and had a 'carb guru' hook up some gauges to verify the air/fuel ratio throughout the operating range... Needless to say, it wasn't set quite as "perfectly" as we thought. With the equipment hooked up he messed with the carb to optimize the a/f, and the end result was very impressive, in low end, mid range, and top end performance.
I guess the bottom line is that it doesn't take much (either on the intake or exhaust side of carb'd bikes) to throw off your a/f ratio, and the bike can be running slightly lean, or rich, without it being obvious...
I've found that just 'reading plugs' or changing the jetting based on a combination that works for someone else isn't accurate enough. What's right for one bike might not be right for another.
My Shovelhead has been running open drag pipes since day one, and it now has over 85,000 miles. My EVO Dyna WideGlide has been running open drag pipes for at least the past 30,000 miles.
When the EVO WideGlide went from pipes with internal baffels to open 'stepped tuned' drag pipes the low end performance felt a little 'sluggish', even through we rejetted, checked plug color, and had the bike where it felt like the carb was set correctly.
Finally gave up and had a 'carb guru' hook up some gauges to verify the air/fuel ratio throughout the operating range... Needless to say, it wasn't set quite as "perfectly" as we thought. With the equipment hooked up he messed with the carb to optimize the a/f, and the end result was very impressive, in low end, mid range, and top end performance.
I guess the bottom line is that it doesn't take much (either on the intake or exhaust side of carb'd bikes) to throw off your a/f ratio, and the bike can be running slightly lean, or rich, without it being obvious...
#3
02-02-2008 | 08:19 PM
Elite HDF Member
Joined: Sep 2007
Posts: 4,085
Likes: 11
From: Boise Idaho
RE: Drags, Baffles, Sound and Performance
Get rid of those pieces of crap!! It's been known for 30 years that they DESTROY the performance of ANYTHING they are put on unless you have a Top Fuel bike that only needs to make HP in a very narrow range.
Get a differant exhaust system; any exhaust system will be a step up.
Get a differant exhaust system; any exhaust system will be a step up.
#4
02-02-2008 | 08:53 PM
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Road Master
Joined: Sep 2007
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RE: Drags, Baffles, Sound and Performance
ORIGINAL: jag1886
Get rid of those pieces of crap!! It's been known for 30 years that they DESTROY the performance of ANYTHING they are put on unless you have a Top Fuel bike that only needs to make HP in a very narrow range.
Get a differant exhaust system; any exhaust system will be a step up.
Get rid of those pieces of crap!! It's been known for 30 years that they DESTROY the performance of ANYTHING they are put on unless you have a Top Fuel bike that only needs to make HP in a very narrow range.
Get a differant exhaust system; any exhaust system will be a step up.
#5
02-02-2008 | 09:47 PM
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Joined: Jul 2007
Posts: 2,192
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From: Metro Milwaukee, WI
RE: Drags, Baffles, Sound and Performance
ORIGINAL: Doug45601
When I got the bike it had the drags on it... was also given the stock pipes and mufflers... So would you say the stock pipes with some SE's would be better??
ORIGINAL: jag1886
Get rid of those pieces of crap!! It's been known for 30 years that they DESTROY the performance of ANYTHING they are put on unless you have a Top Fuel bike that only needs to make HP in a very narrow range.
Get a differant exhaust system; any exhaust system will be a step up.
Get rid of those pieces of crap!! It's been known for 30 years that they DESTROY the performance of ANYTHING they are put on unless you have a Top Fuel bike that only needs to make HP in a very narrow range.
Get a differant exhaust system; any exhaust system will be a step up.
#6
02-02-2008 | 10:25 PM
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Road Master
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#7
02-03-2008 | 12:29 AM
Outstanding HDF Member
Joined: Aug 2007
Posts: 2,225
Likes: 4
From: fegfsg
RE: Drags, Baffles, Sound and Performance
ORIGINAL: Doug45601
UGGHHH..... I don't like the factory cross-over pipe... Looks like a bathroom curtain rod.. Why not just cut off the cross-over pipe and weld the hole shut and go from there?? I really don't understand what it's really doing anyway.
UGGHHH..... I don't like the factory cross-over pipe... Looks like a bathroom curtain rod.. Why not just cut off the cross-over pipe and weld the hole shut and go from there?? I really don't understand what it's really doing anyway.
I dont like it either, but I'm painting the chrome cover on it flat black so its much less noticable. No point to cut it off, wont gain anything.
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#8
02-03-2008 | 12:43 AM
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Joined: Jul 2007
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From: Metro Milwaukee, WI
RE: Drags, Baffles, Sound and Performance
Well Doug, it balances the exhaust pulses between the front and rear pipes. Helps prevent power robbing exhaust gas reversion.
Cross-over Tube
By joining the two mufflers, the crossover tube reduces the resistance the exhaust gases must overcome, and allows the exhaust already moving down the pipe to suck the exhaust gases out of the cylinder whose valve has just opened. Both of these are Good Things. This is why the best performing aftermarket pipes for any type of motorcycle join the exhaust tubes.
Removing it by only replacing the stock headers will cause a power loss.
Why drag pipes aren't the best...
Unless you have had some engine modifications to allow for it, you will be down on power (maybe more power than the stock, but less than if you used "tuned" pipes). Engines are built to compensate for a certain amount of back-pressure (i.e. the valves opening a little earlier), and if you remove the backpressure, the valves will be opening too early, letting some still-burning fuel into the headers. ... because of this, you can suffer (in extreme cases) from burnt exhaust valves if you hammer it too hard..."
Recommendations
The following is a list of replacement exhaust systems, listed in order of performance as rated by r.m.h conventional wisdom. It is important to note that there is not a great deal separating the 1st four and that by far the slip-ons are considered the best value.
Bub Bad Dogs -- I used these on my Dyna and really liked them. My dynometer tests didn't show near the HP gains advertised but what else is new? One unexpected benefit is the greatly reduced vibration due to the reduced weight.
Python II -- Good mid and high range, though down on torque at low RPM
Cycle Shack
Supertrapp -- Quality control problems reported, tunable
Thunderheader -- Lots of power with lots of noise, especially @ high rpm. You'll either love or hate the distinctive way they look. Black or chrome.
SE Slip-on mufflers --
[blockquote]
"It appears that the MoFoMoCo has taken steps to reduce the noise level produced by their prodigy. I believe that if you order a new set from the Stealer you will not get the the old "Cycle Shack" "Python" flap style baffled muffler. You will get a glass packed piece of **** with a penny sized hole in it for the exhaust to exit. I believe that the MoCo no longer sells the good mufflers under the SE flag" -Rick B.
[/blockquote]
V&H Pro Pipe HS -- This is a 2 into 1 performance pipe that V&H states is their best performing. V&H often gets excellent reviews on their fit and finish. Plus they are one of the few companies who include heat shields in the pipe's price.
This info came from http://rmhfaq.com/pipes.htm and I only copied and pasted the most (seemingly) important and understandable parts for you.
You can click the link to see the whole article if needed.
Hope this helps a little.
Cross-over Tube
By joining the two mufflers, the crossover tube reduces the resistance the exhaust gases must overcome, and allows the exhaust already moving down the pipe to suck the exhaust gases out of the cylinder whose valve has just opened. Both of these are Good Things. This is why the best performing aftermarket pipes for any type of motorcycle join the exhaust tubes.
Removing it by only replacing the stock headers will cause a power loss.
Why drag pipes aren't the best...
Unless you have had some engine modifications to allow for it, you will be down on power (maybe more power than the stock, but less than if you used "tuned" pipes). Engines are built to compensate for a certain amount of back-pressure (i.e. the valves opening a little earlier), and if you remove the backpressure, the valves will be opening too early, letting some still-burning fuel into the headers. ... because of this, you can suffer (in extreme cases) from burnt exhaust valves if you hammer it too hard..."
Recommendations
The following is a list of replacement exhaust systems, listed in order of performance as rated by r.m.h conventional wisdom. It is important to note that there is not a great deal separating the 1st four and that by far the slip-ons are considered the best value.
Bub Bad Dogs -- I used these on my Dyna and really liked them. My dynometer tests didn't show near the HP gains advertised but what else is new? One unexpected benefit is the greatly reduced vibration due to the reduced weight.
Python II -- Good mid and high range, though down on torque at low RPM
Cycle Shack
Supertrapp -- Quality control problems reported, tunable
Thunderheader -- Lots of power with lots of noise, especially @ high rpm. You'll either love or hate the distinctive way they look. Black or chrome.
SE Slip-on mufflers --
[blockquote]
"It appears that the MoFoMoCo has taken steps to reduce the noise level produced by their prodigy. I believe that if you order a new set from the Stealer you will not get the the old "Cycle Shack" "Python" flap style baffled muffler. You will get a glass packed piece of **** with a penny sized hole in it for the exhaust to exit. I believe that the MoCo no longer sells the good mufflers under the SE flag" -Rick B.
[/blockquote]
V&H Pro Pipe HS -- This is a 2 into 1 performance pipe that V&H states is their best performing. V&H often gets excellent reviews on their fit and finish. Plus they are one of the few companies who include heat shields in the pipe's price.
This info came from http://rmhfaq.com/pipes.htm and I only copied and pasted the most (seemingly) important and understandable parts for you.
You can click the link to see the whole article if needed.
Hope this helps a little.
#9
02-03-2008 | 09:30 AM
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Road Master
Joined: Sep 2007
Posts: 976
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RE: Drags, Baffles, Sound and Performance
Hay thanks for the super great info and eduication... The pipes on the bike now appear to be nothing more then just the pipes they sell on ebay for 49.00 with the stock chrome shield (front and back) stuck over them to cover the blueing. In fact the chrome has ripple looking "cheap".. Guess I'll be upgrading now.. Thanks for the help guys..
#10
02-03-2008 | 01:02 PM
Road Captain
Joined: Apr 2007
Posts: 573
Likes: 2
From: Central, Wisconsin
RE: Drags, Baffles, Sound and Performance
ORIGINAL: Biker Trash
Well Doug, it balances the exhaust pulses between the front and rear pipes. Helps prevent power robbing exhaust gas reversion.
Cross-over Tube
By joining the two mufflers, the crossover tube reduces the resistance the exhaust gases must overcome, and allows the exhaust already moving down the pipe to suck the exhaust gases out of the cylinder whose valve has just opened. Both of these are Good Things. This is why the best performing aftermarket pipes for any type of motorcycle join the exhaust tubes.
Removing it by only replacing the stock headers will cause a power loss.
Why drag pipes aren't the best...
Unless you have had some engine modifications to allow for it, you will be down on power (maybe more power than the stock, but less than if you used "tuned" pipes). Engines are built to compensate for a certain amount of back-pressure (i.e. the valves opening a little earlier), and if you remove the backpressure, the valves will be opening too early, letting some still-burning fuel into the headers. ... because of this, you can suffer (in extreme cases) from burnt exhaust valves if you hammer it too hard..."
Recommendations
The following is a list of replacement exhaust systems, listed in order of performance as rated by r.m.h conventional wisdom. It is important to note that there is not a great deal separating the 1st four and that by far the slip-ons are considered the best value.
Bub Bad Dogs -- I used these on my Dyna and really liked them. My dynometer tests didn't show near the HP gains advertised but what else is new? One unexpected benefit is the greatly reduced vibration due to the reduced weight.
Python II -- Good mid and high range, though down on torque at low RPM
Cycle Shack
Supertrapp -- Quality control problems reported, tunable
Thunderheader -- Lots of power with lots of noise, especially @ high rpm. You'll either love or hate the distinctive way they look. Black or chrome.
SE Slip-on mufflers --
[blockquote]
"It appears that the MoFoMoCo has taken steps to reduce the noise level produced by their prodigy. I believe that if you order a new set from the Stealer you will not get the the old "Cycle Shack" "Python" flap style baffled muffler. You will get a glass packed piece of **** with a penny sized hole in it for the exhaust to exit. I believe that the MoCo no longer sells the good mufflers under the SE flag" -Rick B.
[/blockquote]
V&H Pro Pipe HS -- This is a 2 into 1 performance pipe that V&H states is their best performing. V&H often gets excellent reviews on their fit and finish. Plus they are one of the few companies who include heat shields in the pipe's price.
This info came from http://rmhfaq.com/pipes.htm and I only copied and pasted the most (seemingly) important and understandable parts for you.
You can click the link to see the whole article if needed.
Hope this helps a little.
Well Doug, it balances the exhaust pulses between the front and rear pipes. Helps prevent power robbing exhaust gas reversion.
Cross-over Tube
By joining the two mufflers, the crossover tube reduces the resistance the exhaust gases must overcome, and allows the exhaust already moving down the pipe to suck the exhaust gases out of the cylinder whose valve has just opened. Both of these are Good Things. This is why the best performing aftermarket pipes for any type of motorcycle join the exhaust tubes.
Removing it by only replacing the stock headers will cause a power loss.
Why drag pipes aren't the best...
Unless you have had some engine modifications to allow for it, you will be down on power (maybe more power than the stock, but less than if you used "tuned" pipes). Engines are built to compensate for a certain amount of back-pressure (i.e. the valves opening a little earlier), and if you remove the backpressure, the valves will be opening too early, letting some still-burning fuel into the headers. ... because of this, you can suffer (in extreme cases) from burnt exhaust valves if you hammer it too hard..."
Recommendations
The following is a list of replacement exhaust systems, listed in order of performance as rated by r.m.h conventional wisdom. It is important to note that there is not a great deal separating the 1st four and that by far the slip-ons are considered the best value.
Bub Bad Dogs -- I used these on my Dyna and really liked them. My dynometer tests didn't show near the HP gains advertised but what else is new? One unexpected benefit is the greatly reduced vibration due to the reduced weight.
Python II -- Good mid and high range, though down on torque at low RPM
Cycle Shack
Supertrapp -- Quality control problems reported, tunable
Thunderheader -- Lots of power with lots of noise, especially @ high rpm. You'll either love or hate the distinctive way they look. Black or chrome.
SE Slip-on mufflers --
[blockquote]
"It appears that the MoFoMoCo has taken steps to reduce the noise level produced by their prodigy. I believe that if you order a new set from the Stealer you will not get the the old "Cycle Shack" "Python" flap style baffled muffler. You will get a glass packed piece of **** with a penny sized hole in it for the exhaust to exit. I believe that the MoCo no longer sells the good mufflers under the SE flag" -Rick B.
[/blockquote]
V&H Pro Pipe HS -- This is a 2 into 1 performance pipe that V&H states is their best performing. V&H often gets excellent reviews on their fit and finish. Plus they are one of the few companies who include heat shields in the pipe's price.
This info came from http://rmhfaq.com/pipes.htm and I only copied and pasted the most (seemingly) important and understandable parts for you.
You can click the link to see the whole article if needed.
Hope this helps a little.