slip on mufflers on new dyna - do I need a download from the dealer?

[berms]

Just looking for some advice here with regard to the "downloads" you get from the dealer when you change exhaust or intake.

The only thing I want to do at this stage is put a set of V&H 3" slash mufflers on a totally stock brand new street bob - do I need a download??  is the download any good?? 

I don't really want to go down the route of getting a tuning device (PV or SEPST) until I have done a good few thousand miles down the track and then I will be doing intake and cams and will definitely get the tuner and a good dyno tune.  So for now I just want to put on the slip-ons and enjoy the ride.

Thanks for any advice.

[Bolo Ocho]

What size is the baffle? The OL put Rush slip-ons with 1.75 baffle on her Heritage with no tuner- her spark plugs say it is actually running richer than it did stock ( maybe something to do with losing the Cat in the mufflers, less heat, lower exhaust velocity?)

[ckwizard]

I say no.
Yer still running the stock air cleaner so it is still sucking the same amount of air so no need for the download.
Cheers

[Admiral Akbar]

I say no.
Yer still running the stock air cleaner so it is still sucking the same amount of air so no need for the download.
Cheers

Yeah but it's easier for the motor to push that nasty old burnt stuff out of the cylinder.. The less that remains there leaves more room for the fresh air..

Something to think about. 

Max

[berms]

I say no.
Yer still running the stock air cleaner so it is still sucking the same amount of air so no need for the download.
Cheers

Yeah but it's easier for the motor to push that nasty old burnt stuff out of the cylinder.. The less that remains there leaves more room for the fresh air..

Something to think about. 

Max

Yeah, this is what I am concerned about.  Is there even a download for just slip on mufflers??

[HV]

To answer part of your question... NO there is not a flash for just slip ons of any kind ..the HD flash is for AC only... now that being said...slip ons and no AC still will run a bit lean from stock... if it was mine and I didn't want to buy a tuner..I would at least do the HD Flash and it would help with the fuel mixture changes ...not perfect but closer

[strokerjlk]

Just looking for some advice here with regard to the "downloads" you get from the dealer when you change exhaust or intake.

The only thing I want to do at this stage is put a set of V&H 3" slash mufflers on a totally stock brand new street bob - do I need a download??  is the download any good?? 

I don't really want to go down the route of getting a tuning device (PV or SEPST) until I have done a good few thousand miles down the track and then I will be doing intake and cams and will definitely get the tuner and a good dyno tune.  So for now I just want to put on the slip-ons and enjoy the ride.

Thanks for any advice.

Leave it stock until you decide to buy a tuner.
Anything that changes how the motor breaths will require a tune .
The stock a/c is capable of breathing better when you change exhaust. The breather isn't the bottle neck on a stock bike. Will the bike run down the road if you don't ? Sure it will. Will it be lean? Sure it will.
Two of the biggest myths on the Internet .
If I don't change my a/c and add better sounding exhaust I don't need to retune.
The stock sensors will adjust for just an exhaust change if you don't change the a/c.

[berms]

Just looking for some advice here with regard to the "downloads" you get from the dealer when you change exhaust or intake.

The only thing I want to do at this stage is put a set of V&H 3" slash mufflers on a totally stock brand new street bob - do I need a download??  is the download any good?? 

I don't really want to go down the route of getting a tuning device (PV or SEPST) until I have done a good few thousand miles down the track and then I will be doing intake and cams and will definitely get the tuner and a good dyno tune.  So for now I just want to put on the slip-ons and enjoy the ride.

Thanks for any advice.

Leave it stock until you decide to buy a tuner.
Anything that changes how the motor breaths will require a tune .
The stock a/c is capable of breathing better when you change exhaust. The breather isn't the bottle neck on a stock bike. Will the bike run down the road if you don't ? Sure it will. Will it be lean? Sure it will.
Two of the biggest myths on the Internet .
If I don't change my a/c and add better sounding exhaust I don't need to retune.
The stock sensors will adjust for just an exhaust change if you don't change the a/c.

Thanks for clearing that up stroker... I will leave it stock until I do the a/c and add a tuner.

[Bolo Ocho]

Leave it stock until you decide to buy a tuner.
Anything that changes how the motor breaths will require a tune .
The stock a/c is capable of breathing better when you change exhaust. The breather isn't the bottle neck on a stock bike. Will the bike run down the road if you don't ? Sure it will. Will it be lean? Sure it will.
Two of the biggest myths on the Internet .
If I don't change my a/c and add better sounding exhaust I don't need to retune.
The stock sensors will adjust for just an exhaust change if you don't change the a/c.

Please don't take this the wrong way, not intended to argue or disrespect your knowledge and experience. I've read, here and other places, that the Delphi ECU is capable of self-adjusting about 5% either way ( although still relatively lean regardless). Also, just reporting what I've seen on the 2 Delphi Twin Cams in our garage: re-baffled my Dyna with 1 7/8" Screaming Eagle II type baffle- scary lean; OL's Softail with the Rush muff, like said, actually  appears to be running richer than stock, plugs tan in color, before they were white, and no symptoms of running lean like surging or backfiring, etc. Don't understand, her stock Softail AC is bigger in surface area than the football AC on my Dyna

[Admiral Akbar]

appears to be running richer than stock, plugs tan in color, before they were white,

Generally they should be off white.. If tan, you may be burning some oil.. Additives??  Today's gas don't color the plugs..

Max

[rbabos]

Leave it stock until you decide to buy a tuner.
Anything that changes how the motor breaths will require a tune .
The stock a/c is capable of breathing better when you change exhaust. The breather isn't the bottle neck on a stock bike. Will the bike run down the road if you don't ? Sure it will. Will it be lean? Sure it will.
Two of the biggest myths on the Internet .
If I don't change my a/c and add better sounding exhaust I don't need to retune.
The stock sensors will adjust for just an exhaust change if you don't change the a/c.

Please don't take this the wrong way, not intended to argue or disrespect your knowledge and experience. I've read, here and other places, that the Delphi ECU is capable of self-adjusting about 5% either way ( although still relatively lean regardless). Also, just reporting what I've seen on the 2 Delphi Twin Cams in our garage: re-baffled my Dyna with 1 7/8" Screaming Eagle II type baffle- scary lean; OL's Softail with the Rush muff, like said, actually  appears to be running richer than stock, plugs tan in color, before they were white, and no symptoms of running lean like surging or backfiring, etc. Don't understand, her stock Softail AC is bigger in surface area than the football AC on my Dyna

5% is an extremely low amount of change. Playing with back yard tuning myself 10%+ seems to give some noticable effect.
Ron

[Bolo Ocho]

No additives, she ran Torco SRS until deciding $16.99 per quart was a bit much. Talked her into Schaeffers v-twin synthetic, and that's what she's run the last 5K. Maybe breather blow-by coloring the plugs then? Did notice a lot of black in the intake tract last time I cleaned her AC.   

[FLTRI]

Leave it stock until you decide to buy a tuner.
Anything that changes how the motor breaths will require a tune .
The stock a/c is capable of breathing better when you change exhaust. The breather isn't the bottle neck on a stock bike. Will the bike run down the road if you don't ? Sure it will. Will it be lean? Sure it will.
Two of the biggest myths on the Internet .
If I don't change my a/c and add better sounding exhaust I don't need to retune.
The stock sensors will adjust for just an exhaust change if you don't change the a/c.

Bob

[Bolo Ocho]

5% is an extremely low amount of change. Playing with back yard tuning myself 10%+ seems to give some noticable effect.
Ron

Yes, I see your point, particularly when I think about the stage 1 download- read somewhere that there are slight changes to the voltage table for O2 sensors, amounts to changing 14.7 to 14.5 AFR; less than 5%, no wonder many who get the download can't feel much change. I would think the changes to the timing tables and VEs in the open loop portion of the map are more significant. Backyard tuning: well I can read forever, but until actually trying my hand at some of it, it's just intellectual knowledge. Screwing around with the exhaust and intake has really brought home how sensitive to small changes these bikes can be ( hopefully haven't screwed my bike up, didn't run it more than around the block without something to add more fuel whan I re-baffled it). I've been after the OL to get some kind of tuner/fueler since she got her scoot, if for nothing else than too cool it down a bit, but she's stubborn. Her bike does seem to run good though, and certainly isn't using enough oil to to require adding any between changes.

[Gderkac2]

I ran an 2007 FLHT with Doherty Power Pack air cleaner and V&H Monster ovals and I just added some XIED from Nightrider.
Ran great no backfiring and plugs lokked good. Stock Delphi can adjust somewhat and the XIED's changed the A/F Ratio to
13.8 to 1. Didn't really notice a decrease in gas mileage.

[wurk_truk]

Leave it stock until you decide to buy a tuner.
Anything that changes how the motor breaths will require a tune .
The stock a/c is capable of breathing better when you change exhaust. The breather isn't the bottle neck on a stock bike. Will the bike run down the road if you don't ? Sure it will. Will it be lean? Sure it will.
Two of the biggest myths on the Internet .
If I don't change my a/c and add better sounding exhaust I don't need to retune.
The stock sensors will adjust for just an exhaust change if you don't change the a/c.

I ran an 2007 FLHT with Doherty Power Pack air cleaner and V&H Monster ovals and I just added some XIED from Nightrider.
Ran great no backfiring and plugs lokked good. Stock Delphi can adjust somewhat and the XIED's changed the A/F Ratio to
13.8 to 1. Didn't really notice a decrease in gas mileage.

How do you KNOW it ran great?  Most likely the ONLY bike you rode and could NOT compare it to what a nicely tuned bike can feel like.  This ain't HDF here.  Stock ECM can NOT adjust how you dudes over there think like.  Stcick around and learn the TRUTH here on HTT, as all of these guys have actual DYNOS and are NOT playing with the 'money effect"...  you know just like YOU did...  "I bought it with MY money, so it MUST be good".  We, here on HTT, call BS on that kind of crap.  How do YOU know the AFR was changed to 13.8:1?  WHat kind of AFR meter did you hook up and test with?  Surely you didn't depend on someone selling a product ONLY, right?

THAT, my friend is the difference between THIS forum and all the rest...  we LIKE facts and NOT fiction.

Welcome to the forum.

[Tattoo]

Just looking for some advice here with regard to the "downloads" you get from the dealer when you change exhaust or intake.

The only thing I want to do at this stage is put a set of V&H 3" slash mufflers on a totally stock brand new street bob - do I need a download??  is the download any good?? 

I don't really want to go down the route of getting a tuning device (PV or SEPST) until I have done a good few thousand miles down the track and then I will be doing intake and cams and will definitely get the tuner and a good dyno tune.  So for now I just want to put on the slip-ons and enjoy the ride.

Thanks for any advice.

Leave it stock until you decide to buy a tuner.
Anything that changes how the motor breaths will require a tune .
The stock a/c is capable of breathing better when you change exhaust. The breather isn't the bottle neck on a stock bike. Will the bike run down the road if you don't ? Sure it will. Will it be lean? Sure it will.
Two of the biggest myths on the Internet .
If I don't change my a/c and add better sounding exhaust I don't need to retune.
The stock sensors will adjust for just an exhaust change if you don't change the a/c.

we very seldom do a download.....

[Gderkac2]

Could you please explain why the O2 sensors are there if the stock ECM can't adjust for minor changes. There would be no point in having them check AFR if they couldn't control
the AFR in closed loop mode. I know they do nothing in open loop mode but I believe in closed loop mode they have to be able to make adjustments to the AFR to keep it at 14.6
to 1. Please let me know if this is incorrect.
Thanks

[strokerjlk]

The theory is ... The 02 sensors will keep the Afr at stoich, adjusting for diff fuel.
Very small window of change. Making changes to the way the motor breaths, is beyond the ability of the system to adapt .

[hd06myway]

Any HD '07 on up, with the closed loop system doesn't need a reflash due ot AC or pipe change... simple answer NO..

[FLTRI]

The purpose of O2 sensors in OEM applications is to alter tuning parameters (fuel and timing) for changes in fuel quality ie: with/without ethanol, percentage of ethanol, variances in additive packages, octane variances, etc.

The system was never intended to use as a tuning strategy for changes in the way an engine breathes...any changes...including exhaust systems different in design than the original.

NOTE: Closed Loop Learning (AFV) for fuel variances is reset each time the bike is refilled. the system assumes you got refilled with good fuel and do not need the adjustments learned from the last tank of poor quality fuel.
So, if the sensors were used to learn AFR offsets (AFV) due to modifications to the engine's breathing the relearning process must be repeated each fill up.

These bikes come tuned "open loop" on the ragged edge of "too lean" right from the factory.
This means a starting point of lean/hot will only get leaner and hotter by adding free flowing exhaust which allows more air to go through the engine yet no more fuel.

While narrow band sensors are very precise and can make up to 10-20% change while in closed loop (cruise) the issue is in the open loop (higher rpm/load than cruise) where the engine really needs a richer, not leaner AFR.

This is one reason customers notice such an improvement after a proper recalibration of AFR and timing on even bone stock bikes with just a pipe and a/c.

HTH,
Bob

[berms]

The purpose of O2 sensors in OEM applications is to alter tuning parameters (fuel and timing) for changes in fuel quality ie: with/without ethanol, percentage of ethanol, variances in additive packages, octane variances, etc.

The system was never intended to use as a tuning strategy for changes in the way an engine breathes...any changes...including exhaust systems different in design than the original.

NOTE: Closed Loop Learning (AFV) for fuel variances is reset each time the bike is refilled. the system assumes you got refilled with good fuel and do not need the adjustments learned from the last tank of poor quality fuel.
So, if the sensors were used to learn AFR offsets (AFV) due to modifications to the engine's breathing the relearning process must be repeated each fill up.

These bikes come tuned "open loop" on the ragged edge of "too lean" right from the factory.
This means a starting point of lean/hot will only get leaner and hotter by adding free flowing exhaust which allows more air to go through the engine yet no more fuel.

While narrow band sensors are very precise and can make up to 10-20% change while in closed loop (cruise) the issue is in the open loop (higher rpm/load than cruise) where the engine really needs a richer, not leaner AFR.

This is one reason customers notice such an improvement after a proper recalibration of AFR and timing on even bone stock bikes with just a pipe and a/c.

HTH,
Bob

Thanks again for taking the time to post up that info Bob, much appreciated.

[cycleman11]

02 sensors provide readings to the ECM all the time, but they only affect the tables stored in the ECM during closed loop operation which is everything after idle up to about 3/4 throttle.  Everything before and after this is in open loop and is normally richer than the standard 14.6.1 that a standard stock EFI engine runs in closed loop mode.

It takes a bit of time for the 02 sensors to get up to speed ( so to speak ) when you first start the engine the ECM will run the bike based on information it is receiving from the other sensors, information stored in its memory and then once the engine is up to temp etc, the 02 sensor information is received by the ECM.  The 02 sensors convert the gas reading to an electronic signal ( voltage ) that the based on the tables in the ECM it either adds or subtracts fuel. The XIED's merely change this voltage reading which affects how much fuel the injectors will add during closed loop mode.

The XIED's add more fuel in the closed loop area, but if you want full control of the fuel mapping/timing then you would need something else. Their are many on the market. 

For what they are the XIED's do improve drive ability, reduce some of the heat and for those of us with stock bikes they coupled with NGK Iridium plugs make the engine run seat of the pants better.   For what they are, ( not a lot of money ) people shouldn't be afraid to try this combination, you will be pleasantly surprised.  I use this combination in my 08 Heritage Softail and like it and in my case no change in gas mileage.

I have no intention to knock full blown mods, cams, bigger engines etc, each to their own, but there is a fair number of us out here that just want to get better drive ability with our bikes.  I would love to see an actual dyno run of the above combination, I've seen dyno runs of the Iridium plugs but not in combination with the XIED's.

[1FSTRK]

So it adjusts the fuel but gets the exact same gas mileage. 

[Templar2]

Having been down this road more times than I will admit to, plan your mods and then do them all at once, if you can't then just live with the bike until you can.  Add ons will only become take offs once you get serious about making the bike run better.  I just want better perfromance than stock from '07 FLSTC so went with Rush Slip on's (1 3/4), Andrews 37h and a SE A/C.  The final piece of the puzzle was adding the PowerVision to the mix and so far it has worked out well, I actually used one of those add one tuners as a trade in for the PV!