Thoughts on Cat being restrictive......
Road Master
Joined: Apr 2010
Posts: 795
Likes: 1
What size baffles do you have in the slip-ons? I recommend a properly tuned fuel management system anytime the head pipes are changed. In most situations it's required for proper operation.
A stage 1 flash of the ECM will most likely not be enough when upgrading headpipes. Since 2008 all it really does is increase the fuel at wide open throttle by 3-5% and will never richen it beyond 14.7. On most models it will slightly advance the timing and raise the rev limiter by 500.
Ryan
A stage 1 flash of the ECM will most likely not be enough when upgrading headpipes. Since 2008 all it really does is increase the fuel at wide open throttle by 3-5% and will never richen it beyond 14.7. On most models it will slightly advance the timing and raise the rev limiter by 500.
Ryan
In open loop such as wide open throttle the stock HD ECM will go as rich as 12.5 from 13.9. It is closed loop which is epa mandated and which 14.6 is used for emission reduction. Intake is what is most affected in which recalibration or tune is needed - not exhaust unless poorly designed allowing reversion which plays havoc with the o2 sensors.
-Ryan
Seasoned HDF Member
Joined: Jun 2005
Posts: 12,946
Likes: 32
From: Colorado Springs, CO
The only real undesireable characteristic of the catalyst is the additional heat the rider feels, and the fact that it makes the exhaust system quieter is considered undesireable by the loud pipes crowd. Whether or not they suck is a matter of opinion, mostly influenced by myth and misinformation. Cats don't create heat, they just absorb and harness the existing exhaust gas heat and utilize it to carry out the chemical conversion processes. The catalyst area of the headpipe does radiate more heat than a similar pipe without a catalyst would, but it doesn't make its own heat and it doesn't cause the engine to get hotter, causing it to ping, retarding the timing, and lose power. Please explain what manner of transference you believe the catalyst uses to "pass heat back into the engine" and cause it to get hotter?
If a pipe gets red hot, and is bolted to something, then the heat will pass on to the attached point (engine). I have ceramic coating on the headers of my Mustang precisely to keep heat down.
Again, like I said, if a guy likes them GREAT.......how come Rush doesn't sell pipes with cats in them?
~Joe
Last edited by traveler; May 22, 2012 at 04:03 PM.
Outstanding HDF Member
Joined: Jan 2010
Posts: 2,916
Likes: 31
From: earth
Maybe because........
(fine print extract from the Rush catalog)
"Mufflers and Systems offered for sale in this catalog may not meet with EPA emissions and noise guidelines and may be restricted to off-road useonly. Removal of catalyst exhaust systems is a violation of state and federal regulations. Contact your municipal, state, or federal agency forspecific guidelines."
(fine print extract from the Rush catalog)
"Mufflers and Systems offered for sale in this catalog may not meet with EPA emissions and noise guidelines and may be restricted to off-road useonly. Removal of catalyst exhaust systems is a violation of state and federal regulations. Contact your municipal, state, or federal agency forspecific guidelines."
They are playing the aftermarket exhaust legal dfisclaimer game just like everybody else.
Outstanding HDF Member
Joined: Jan 2010
Posts: 2,916
Likes: 31
From: earth
with no other changes, my bike ran 20 degrees cooler with the cat removed.
If a pipe gets red hot, and is bolted to something, then the heat will pass on to the attached point (engine). I have ceramic coating on the headers of my Mustang precisely to keep heat down.
Again, like I said, if a guy likes them GREAT.......how come Rush doesn't sell pipes with cats in them?
~Joe
If a pipe gets red hot, and is bolted to something, then the heat will pass on to the attached point (engine). I have ceramic coating on the headers of my Mustang precisely to keep heat down.
Again, like I said, if a guy likes them GREAT.......how come Rush doesn't sell pipes with cats in them?
~Joe
Seasoned HDF Member
Joined: Jun 2005
Posts: 12,946
Likes: 32
From: Colorado Springs, CO
Sorry I negelected the first part, The pipe is the pipe, and the cat is the cat lets keep our heat arguments segregated. All pipes bolt to the heads and they all get just as hot, and they are insulated from direct contact with the head via the gasket. Ceramic coating in an automotive application reduces underhood temps contributing to a colder intake charge.
Tourer
Joined: Oct 2006
Posts: 466
Likes: 2
From: Bothell, WA
I just replaced my stock exhaust ('11 Limited) with V&H Power Duals and SE Fatshots (50 state compliant). It is the sound I'm looking for (deeper and only slightly louder than stock) and THE HEAT IS GONE. That's what I wanted. Next is to put my high flow AC and get it dyno'ed.
Outstanding HDF Member
Joined: Jan 2010
Posts: 2,916
Likes: 31
From: earth
Humble appologies for asserting my opinion to the point that I've encroached on your comfort zone, just trying to stay focused on the root of the topic and help shed some light on the whole cat restriction myth. Perception is reality so you must be right, my mistake.
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Tourer
Joined: Oct 2010
Posts: 465
Likes: 1
OK guys, I consider myself a layman and have just enough knowledge to be dangerous to myself. So I'm asking a question, not asserting an opinion.
I have a FM catless headpipe on order for my otherwise stock 2012 Trike. Since I have become convinced by the scholarly opinions in this thread that doing this will only reduce heat, not increase HP, would my money be better spent by leaving the cat pipe as it is and instead going with a set of quality slip ons?
If I only do one or the other of either catless headpipe or slipons, can I get by without re-tuning? What if I do both? I have heard several people whose authority seems credible say the stock ECM will adapt to both these exhaust changes as long as you don't open up the A/C. One of these sources actually told me that the stock A/C isn't overly restrictive anyway, and any gains from opening it up would likely only come at 3500+ rpms anyway.
I suppose my ultimate "going cheap" plan would be the catless headpipe, leave mufflers stock and maybe go with a more open A/C and XIEDs to cover the A/C. But since a cheap solution would not be a good idea if you subsequently holed a piston, what do you guys think about this idea?
Thoughts would be appreciated. It's difficult to know what's best to do when opinions vary so widely. And don't mention dealers! My dealer thinks you need a tuner and $800. in dyno time if you change out your seat...
I have a FM catless headpipe on order for my otherwise stock 2012 Trike. Since I have become convinced by the scholarly opinions in this thread that doing this will only reduce heat, not increase HP, would my money be better spent by leaving the cat pipe as it is and instead going with a set of quality slip ons?
If I only do one or the other of either catless headpipe or slipons, can I get by without re-tuning? What if I do both? I have heard several people whose authority seems credible say the stock ECM will adapt to both these exhaust changes as long as you don't open up the A/C. One of these sources actually told me that the stock A/C isn't overly restrictive anyway, and any gains from opening it up would likely only come at 3500+ rpms anyway.
I suppose my ultimate "going cheap" plan would be the catless headpipe, leave mufflers stock and maybe go with a more open A/C and XIEDs to cover the A/C. But since a cheap solution would not be a good idea if you subsequently holed a piston, what do you guys think about this idea?
Thoughts would be appreciated. It's difficult to know what's best to do when opinions vary so widely. And don't mention dealers! My dealer thinks you need a tuner and $800. in dyno time if you change out your seat...
