Removing Baffels
- Thread starter Softail
- Start date
2002UltraClassic
Member
Thanks for the question bro....was wonder the very same thing! My Ultra has the same thing with Stage II, been wondering that for a while now.
NO back pressure and a noisy scoot ! ( I.M.O.!!!!) And if you did take them out , would it run right without some more mapping and such!??
Other issues come into play here with no baffles. There's reversion in the exhaust without a restriction (baffles) which is a sound wave that travels back up the exhaust that can do some strange things as far as exhaust and fuel delivery. Do a search for "exhaust reversion" and you'll find more info than you could read.
I was reading in your self-help and there are a couple of other threads on here about this very thing. It's kinda funny, some bikes you just tweak a couple of jets and tighten a few bolts and your good to go ! And some take a computer to "line it out" to run right!!! :cheers
Flashback
Active Member
open pipes work great in a drag racing application where you have a highly modified engine that needs to intake and exhaust as much fuel and air as possible in a brief period of time. But for the street in an EPA engine any benefit you could gain (and it's debateable whether there would be any) would be in an RPM range that normally you would never use. For anyone considering open piped also keep in mind that besides probably a performance loss in low and mid range RPM's that you can also damage your engine if not configured right. I beleive if I remember correctly (and I may be wrong) that you need a minimum of 22" pipe length or chance warping the valves at shutdown due to cold air rushing back in to the head up the pipe. At least with the old ironheads that was the rule couldn't swear to it with the new stuff.
SamHayne
New Member
Not to say you guys are wrong, but it does sound like a few of you work right for Harley. Yes you need back pressure. Most dealers would cut your baffles for you before all the EPA Laws for 2006 & after.
My bike is a 2001 & I have no clue what pipes are on it as I was not the original owner. I removed the baffles & stuck some Big City Thunders in their place. My bike is much louder & as far as performance, it was Dyno'd. It got much better results then any stock bike. Really your bike should have as many horsepower as your cubic inches of the engine. Mine is 88" & I have 86 HP. A stock 88" would have about 20 HP less. Besides the pipes I just have a high flow air cleaner. If I gun it up to about 80 & then release the throttle, I will get some backfiring. No big deal because I am not usually trying to get to 80 as fast as I can & then letting off the throttle anyway.
The main problem is, you have a 2007, so that will change everything. Most dealers won't do alot to it because of the EPA laws now. My wife has a 2006 Sportster 883L & it had some engine issues. The dealer wouldn't do to much because they were afraid it may cause issues with the EPA. I told them, sorry, it is a 2006, the law is 2006 & earlier are not included, & it is still a choke not fuel injection, so it for sure is not included.
Here is a good link to Exhaust Reversion
Understanding Exhaust
Here is part of it about "back pressure" which is NOT as important as alot of people want you to believe.
"Much controversy (and apparent confusion) surrounds the issue of exhaust "back-pressure". Many performance-minded people who are otherwise knowledgeable still cling tenaciously to the old school concept.... "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."
My bike is a 2001 & I have no clue what pipes are on it as I was not the original owner. I removed the baffles & stuck some Big City Thunders in their place. My bike is much louder & as far as performance, it was Dyno'd. It got much better results then any stock bike. Really your bike should have as many horsepower as your cubic inches of the engine. Mine is 88" & I have 86 HP. A stock 88" would have about 20 HP less. Besides the pipes I just have a high flow air cleaner. If I gun it up to about 80 & then release the throttle, I will get some backfiring. No big deal because I am not usually trying to get to 80 as fast as I can & then letting off the throttle anyway.
The main problem is, you have a 2007, so that will change everything. Most dealers won't do alot to it because of the EPA laws now. My wife has a 2006 Sportster 883L & it had some engine issues. The dealer wouldn't do to much because they were afraid it may cause issues with the EPA. I told them, sorry, it is a 2006, the law is 2006 & earlier are not included, & it is still a choke not fuel injection, so it for sure is not included.
Here is a good link to Exhaust Reversion
Understanding Exhaust
Here is part of it about "back pressure" which is NOT as important as alot of people want you to believe.
"Much controversy (and apparent confusion) surrounds the issue of exhaust "back-pressure". Many performance-minded people who are otherwise knowledgeable still cling tenaciously to the old school concept.... "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."
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fatboywayno
New Member
have the fp3 and it has a map for running 3 inch slip ons with no baffles. was wondering if this mapping would take care of all the issues I have read in these threads
D
dbmg
Guest
At best it would be a compromise. With no baffles you are critically changing the necessary back pressure that the engine needs for proper operation....