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[Occam]

Hello Sage Ones,

As you can tell, I have a 2009 FXDFSE.
I swapped the headpipes to those from a mere mortal 96" donor, used those muffler cans as well (gutted), and put Big City Thunder baffles in the ends of the headpipes.
I like the sound, but I've been told that there is not enough backpressure to allow the o2 sensors to work right. Remember, they are located near the cylinders on the '09s, before the BCT baffles.

Thoughts, opinions?

It is not that I don't trust the info I've received, I seek knowledge and options.
I like my current sound level which is pretty much a "split the pavement and set off car alarms a block away" kinda loud.
If that's not sustainable, I'll dial back to whatever won't kill the motor - if that's at issue.

[dave29]

I installed Fulsac 1 3/4" baffles, an Xied plug in, enrichener and catless 09 headpipes on my 2009 CVE SEUC. No fault codes and runs great!!!

[grc]

Who told you they wouldn't work right, someone trying to sell you something different?

Here's an idea, find yourself someone with an exhaust gas analyzer, or put the bike on a dyno, and see where your AFR's are versus where your map says they should be in closed loop operation.  I think you will find that the O² sensors work just fine without all that "backpressure".

btw, you didn't mention if you're running with the stock map or if you've had the bike tuned.  If you haven't had it tuned, you really should.  The O² sensors don't work outside of a certain range of AFR's, and they don't control open loop operation (high rpm, high load, medium and higher throttle, etc.).  So if you've radically changed the air flow through the engine and didn't change the tune, you could in fact be running very lean.


Jerry

[Occam]

Sorry, I was being sparse with info because I have respect (as do many, many ppl here) for the source of opinion.
I'd rather not say without their consent, out of common and professional courtesy.

If I had the cash for dyno time, I'd have simply bought slipons to look like eveyone else, and plugged in the map from the TTS I bought.
I am in fact using a map purported to be close enough to serve as a base map for my V-Tuning. This process precipitated the Q&A that led me here.

I am merely asking for opinions on my setup and alternative options that don't involve a pair of slip-on mufflers for ~$500. For that cash they better make me an f-ing sammich and keep me warm at night. Plus, you can't ride without seeing the same damn thing bolted on someone elses bike.

[Steve Cole]

On most stock head pipes there are very few O2 issues but the aftermarket one's are another story. The lower the restriction of the muffler the more chances your going to get reversion at low engine speeds. Since yours is stock you most likely will not get into trouble but it is possible. Just keep an eye on things as you tune and if they start looking funny at engine speeds below 1800 you may have reversion issues due to lack of back pressure.

[SIX38]

Nice to know that we can count on Steve Cole for keeping us out of trouble with his expert knowledge. You have taught us much.
Thanks!
Tom P.

[Occam]

On most stock head pipes there are very few O2 issues but the aftermarket one's are another story. The lower the restriction of the muffler the more chances your going to get reversion at low engine speeds. Since yours is stock you most likely will not get into trouble but it is possible. Just keep an eye on things as you tune and if they start looking funny at engine speeds below 1800 you may have reversion issues due to lack of back pressure.

It is possible Steve, that the other party was referring to kinetic waves and the anti-reversion properties I took such liberty with. I was led to believe however, it had strictly to do with the lack of backpressure interfering with the normal operation of the o2 sensors. Quite specifically. Would such dramatic hardware changes affect the Mastertune's ability to gather consistent usable data in each cell?

Some background on my efforts: I am V-Tuning and finding my results that are not like what is shown in the manual as an example of an over-the-road tune run. Not at all like the picture. It looks like a satellite photo of Italy and is mostly yellow with the centers of the upper left and lower right portion white or light pink.

Before it is asked, yes it is very nearly a closed course, no I do not snap the wick, yes I hold throttle and speed long enough to get 5 or 6 samples, etc. etc. etc.
I go everywhere from 750 rpm to over 5000, from just off parked to over 120. I don't know f the latter is smart with all the protections turned off in the ECM, but that's the protocol.

Steve, please understand that this is not a simple flurry of vitriol aimed your way. I'm just trying to see if I'm wasting my time V-Tuning in this configuration, and if so then what the next step would be..

Thanks, and much respect.
Phil

[Steve Cole]

I could not answer with out seeing the Vtune Datamaster file. You need to get the cells green there first, and if you do not then your data to create the new calibration is not there to work with. The low back pressure can be an issue as free oxygen enters into the pipe between pulses at low speed and the sensors do not care where the oxygen came from just that it is there. Typically on a build like you have described those issues would only happen at < 2000 RPM, from there up things should be fine. Have you checked to make sure there are no leaks inthe exhaust?

[Occam]

I have not yet checked for leaks at the heads, I'll do that over the weekend.
Thanks for the insight and the responses Steve , I'll double check the VE tables - although I thought they went from red to white, not green.

[Steve Cole]

When gathering data with DataMaster the cells will switch from Grey to Green when enough data is collected. Some have misunderstood and thought any color was good enough when collecting data. Since Vtune used the collected data to make the correction we added yellow cells there for the areas that do not have enough data. So in Vtune you get red to white with Yellow on top of it now, all in trying to get people to understand what it is doing.