exhaust question
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Road Warrior
Joined: Oct 2006
Posts: 1,853
Likes: 21
From: central florida
exhaust question
i guess im having a hard time understanding WHY i have to replace the A/F and us e a fuel management system just to put some pipes/mufflers on my bike to get a nicer sound?
my exp has been with cars -incl 10 yrs with Midas.never had to go to that trouble on a car. is there a short answer thats a little north of "it be's that way?"
my exp has been with cars -incl 10 yrs with Midas.never had to go to that trouble on a car. is there a short answer thats a little north of "it be's that way?"
Tourer
Joined: Jul 2007
Posts: 497
Likes: 8
From: New Egypt, NJ
RE: exhaust question
This is a suspicion: Probably because the engine is so much smaller, and the intake and exhaust conduits are so much shorter than in a car the "small" change to a car is much bigger to a bike, in relative terms. I can tell you that knocking the freeze plug out of the mufflers on my wife's Dyna without changing anything else made it sound absolutely fantastic, but it vibrated MUCH more than stock, and sputtered and ran lean. I put the plugs back in. Exhaust changes DO have a dramatic effect on running condition.
Extreme HDF Member
Joined: Sep 2006
Posts: 10,920
Likes: 6
From: Upstate New York
RE: exhaust question
relli,,,, you can just add mufflers,,,, just make sure they are not ones with like 2" = or bigger baffles,
good ones to look at are Vance n hines ovals, supertrapps, rush 1.75,,
good ones to look at are Vance n hines ovals, supertrapps, rush 1.75,,
Road Warrior
Joined: Jun 2007
Posts: 1,539
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Outstanding HDF Member
Joined: Jul 2007
Posts: 2,609
Likes: 1
From: Indy area
RE: exhaust question
I spent most of a tank yesterday with the stock airbox and mufflers back on to reset the AFV. Then I put the 2" Rushes back on and rode it pretty hard today. When I get very deep into the throttle in higher gears I can make it ping a time or two. Other than that I'm quite confident that the Delphi does an admirable job handling the situation. It's lean, yes, but not too lean. It's good and crisp. I wouldn't give it a second thought for just mufflers if they're reasonable. The suggestion for 1¾" Rushes is a good one, the 2" baffles have got to be right on the edge. Maybe even the Fullsac duals conversion would work well enough without further expense (beyond a good pair of mufflers, which you're getting anyway).
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Road Captain
Joined: Jul 2007
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RE: exhaust question
Cars have wide-band 02 sensors.Most (V-8`s)have 4 total. 2 pre-cat and 2 post-cat. The PCM`s have the ability to adjust the AFR according to 02 feedback. The auto PCM has adaptive AFR plotting capabilitis base on PROM calibrations that bikes do not have.
The auto PCM`s havelarge table values available.
The bikes have narrow band 02 sensors with an ECM that haslimitedAFR adjustment. Most are from 14.1 to 15.1
This is why you must change the fuel control to stop it from leaning out. Fixed ECM`s with narrow band 02 sensors are designed to run an AFR@ 14.7 That's Stoichiometeric. The leanest and cleanest burn with lowest emissions. Thanks EPA.[8D]
The auto PCM`s havelarge table values available.
The bikes have narrow band 02 sensors with an ECM that haslimitedAFR adjustment. Most are from 14.1 to 15.1
This is why you must change the fuel control to stop it from leaning out. Fixed ECM`s with narrow band 02 sensors are designed to run an AFR@ 14.7 That's Stoichiometeric. The leanest and cleanest burn with lowest emissions. Thanks EPA.[8D]