Change Exhaust *Only* on '08 RG ?

Discussion in 'Engine, Fuel and Exhaust' started by LtDan1, Dec 7, 2010.

  1. LtDan1

    LtDan1 Member

    Hi all,

    Have looked here enough to have learned that I should probably change exhaust, fuel, and air all together, or pretty much not at all.

    I have a stage 1 air cleaner standing by, but know not to install it until I'm ready to do the fuel along with it. But I don't have the fueler yet.

    Wondering if I can get by with changing exhaust only for a short time and maybe as much as 2,000 miles, then changing the air cleaner and fueler together at the same time. The exhaust I have in mind is the D&D Fat Cat, regular baffle.

    Or should I ***really, really*** just wait and do it all together? That won't kill me - - but when I change the exhaust, I can also change the clutch cable, then I can tilt back the handlebars I already changed (but can't adjust the way I want until I have more clutch cable) - - - etc. So it's about more than just being in a big hurry for some more noise. But having had 3 drivers shift over into my lane in less than 6,000 miles -- I'm ready for some more noise, too.
  2. TripleJ

    TripleJ Senior Member

    Go for it, changing just the exhaust for now you will be fine. Just don't get tempted to do the A/C while you are at it because you know you will want to:D

    For doing both at the same time I would definitely wait for the fueler. I think your choice for exhaust will be a good one, enjoy....................
  3. Iceman24

    Iceman24 Well-Known Member

    LtDan1; guess you're not blessed w/cold weather & winter bike hibernation like us a little farther North...this makes plenty of time for winter projects...;)

    I'd say you're probably fine w/the pipe swap 1st & others later - bike will run a little lean, but ECM can adjust a bit. Is there any reason for waiting on air & tuner? A/C & tuner are pretty simple installs - hardest part is lifting tank w/o damaging. I'd get all three & UG in one swoop so then everything's complete. Would be nice weekend PM project...good luck!
  4. Dr. Dolittle

    Dr. Dolittle Experienced Member Staff Member Moderator Contributor

    I'm not trying to start a "loud pipes" debate but I think folks in your situation should seriously consider upgrading from the wimpy stock horn if you haven't already done it.
  5. Hoople

    Hoople Account Removed

    Like Smitty says, you won't melt down but I myself would not do it.

    I would wait till I got the fueler. You have an 2008. The a/f tables were set up for none E10 fuel. Now using E10 fuel, the ecm can not adjust for pipes because any window that was left is now taken up by the fuel (.3 a/f needed for E10). I promise you that your front cylinder is screaming lean already. Pipes alone will increase VE.

    For me it would be like riding with a quart low on oil. It won't cause the engine to cease up but the entire time I would be very uncomfortable.:)
  6. Hoople

    Hoople Account Removed

    Smitty, What you say is true. People won't watch a meltdown happen in front of their eyes. You are absolutely correct that no 1 change will hurt an engine. What I am going by is the accumulation of several factors which when added together will add up to enough change that would cause a person like myself to be very uncomfortable.

    These are some of the reasons why I feel the way I do. Some are actual Facts and some are just very strong beliefs that I base on experience.

    1) Even a 2008 bike (OP's model) has a factory tune (map calibration) to meet EPA standards at the time it was built. It was a closed loop tune and the A/F calibration was done with fuels of that day which were not E10 fuels.

    2) The oxygen sensors used on our bike is a narrow band sensor that can only read a/f ratios in the range of + .3 to- .3 of stoich which for non- alky fuel is ~14.5:1. Therefore the window limit of adjustment for a narrow band sensor is absolute tops => 14.1 to 14.9. Pure ethanol is something like 9:0 stoich so when we run E10 fuels we must recalibrate our A/F ratio by .3 of 1 point.
    What all that means is our stoich is now 14.2 and no longer 14.5 when we run E10 fuels. Just from the E10 fuel ALONE, we have reach the adjustment limit of our closed loop system. Everyone keeps saying "it will adjust", "it will adjust". But it can't adjust anymore than it has due to the E10 fuel .

    3) Look at any HD VE map. The Front VE look up tables on our bikes are close to 10% lower than the rear cylinder VE tables. At any given time the front cylinder is running leaner than the rear cylinder by a bunch. HD can get away with it because the front cylinder gets better cooling so they push that cylinder to the limit to get the bike to pass with a factory calibration.

    4) Looking at an A/F ratio on a Dyno pull is meaningless because it was done during wide open throttle. During WOT the O2 sensors are not even looked at and the A/F is based on a RICH set of "look up tables" only. Under WOT condition the A/F ratio should be in the 12's not 13's. Under part throttle 13's would be fine but not for under WOT conditions. That dotted line on the bottom of ALL dyno pull charts is the "allowable" maximum not the optimum A/F ratio.
    What all this means is don't base you cruise A/F ratio on what you see at the bottom of a dyno pull. The dyno pull was done at WOT while in open loop mode. Therefore it is meaningless unless you ride all day at WOT. Why doesn't anyone ever look at that beautiful flat A/F line at the bottom of the Dyno pull sheet and say "13.5 a/f at WOT is lean. It should be in the 12's"? It seems like all they focus on is the Torque curve.

    5) Pipes alone without an air cleaner will substantially increase your VE at PART throttle. The side by side comparison of a stock Air cleaner VS a Stage 1 air cleaner under WOT conditions will show a BIG difference in flow. BUT when used at 50% of throttle body opening, I would bet they are pretty close in the amount of CFM each can and will pass. It is not until a throttle body opening of 50% or more, does the stage 1 A/C really kick in. Therefore unless you ride all the time at butterfly opening of 50% or more I would bet (theory) that both air cleaners will pass about the same amount of air.
    What does all this mean? I am not saying that from 0-50% of throttle the stock A/C does not restrict flow to some degree. I sure it does to *some* degree. What I am saying is that a Stage 1 A/C was really designed around WOT air flow. At PART throttle (cruise) the VE of the engine is almost the same regardless of which A/C you have on the bike but the pipes increase VE all the time. Therefore it is my belief that running "just pipes" at cruise speeds requires the same ECM calibration tune as having pipes AND an A/C.

    So does any of the above really mean anything in the real world. Heck, I don't really know. The Fact remains there are thousands of guys & gals riding with no problems at all and they could not care less about any of the above.
    With that said there is one statement I can always quot as FACT.... I have been known to overthink a topic. If I rode my bike as much as I tinkered with it, the tires would be bald! :) So I guess it just boils down to each persons own comfort level.
  7. Jack Klarich

    Jack Klarich Expert Member

    After my bike got wrecked, the dealer put on cycle shack turn outs full system, I improved on the small( Baffles) to give a bit more back pressure with no ill effects, that was 13k miles ago JMO
  8. LtDan1

    LtDan1 Member

    Thank you to all who responded on this topic! This place is great. I can't tell you how many times/issues I've come and looked up and found what I needed without having to bother anybody. A real treasure trove we all have here.

    To answer the question "Why not do it all now?" I'd love to, but it's a money thing -- with Christmas and all. Also, though it is warm enough to ride way down south here, it isn't always warm enough to ride with my regular mesh jacket & summer gloves, so some colder weather gear has been in order -- more $$. And then there's the pending back tire, and the battery that sounded a little faint one cooler morning last week, and . . . Well, you get it. Stuff Happens. Being able to maybe sell the takeoff slip-ons might help the fueler happen more quickly, and they probably sell better off the bike -- which means with the new pipes on it or the bike is standing in the meantime. So that's all part of the rationale here.

    Thanks again for all the informative replies.
  9. LtDan1

    LtDan1 Member

    I did spend a fair chunk of change on an air horn that I'm not impressed with. 2 of the 3 drivers heard it and responded well -- one had his stereo thumping so loudly he never heard the horn right at his door. I guess people like that won't hear louder pipes either -- but maybe louder pipes will reduce the # of times I have to rediscover the horn button. If I was riding a scooter in a 3rd world city, I'd ride around with my thumb on the horn button all day because I'd be using it 2-3 times a minute -- But a Harley on U.S. Highways -- I just don't stay that familiar with where the darn thing is. Seems I usually end up evading first and finding the horn button later, mainly to let them know I'm not happy about having to find it again.