| Author | Message | |||
     Swordsman |
Whew! Okay, this took awhile to put together, and I don't even know if it'll do any good. I've been wanting to do the whole ECMSpy tuning thing, but there seems to be much debate over how to handle the front cylinder map. Some say add 3 across the board of the rear map and save it as front, and some say it's totally impossible without a front sensor. Knowing practically nothing about it, I thought perhaps by calculating the differences between the stock front/rear maps, one could use that information to correctly adjust the front map. What I have here is a definitive front vs. rear cylinder map comparison from my 2006 Ss. These are stock maps pulled directly from my bike, and the differences between them. What I'm thinking is that after having Megalog analyze and correct the rear cylinder data, one could apply the formulas in this spreadsheet and come up with a more accurate front map, since it's based on whatever the factory engineers worked out. Like I said, I honestly don't have a clue what I'm doing, so there could be a million reasons this idea won't work. However, I thought I'd post the information here, and people could take a look and let me know what they think about it. I'm including the original pics of my maps so anyone can double-check my calculations.  
~SM PS: Sorry for the crappy pics, but the dimension/file size limitations on BadWeb are harsh!  (Message edited by Swordsman on July 05, 2008) | |||
| Ferocity02 |
Without a sensor in the front cylinder, there is no accurate way to get the fuel table for the front using the data from the rear cylinder, and that's it. Although I like this idea a /i{little} better than just adding 3 or whatever. ECMspy and MegaLogViewer are powerful tools, but without individual wideband O2 sensors, they can be very dangerous when trying to tune. | |||
| Zpyro |
why would you remove a bunch of fuel at WOT around 2900? shouldnt you remove it at closed throttle, to help get rid of the decel popping? | |||
| M1combat |
He isn't saying you should remove fuel. He's posting the difference between a stock front and rear map for a 2006 SS. He's making the point that you could theoretically retune the rear cyl then make these modifications to it in order to get a baseline front cyl. | |||
| Mesozoic |
The way I would approach this would be to enter the stock front and rear map into Excel and then compute the percentage differential for each cell. With the only sensor being in the rear pipe, you tune for that and then apply the computed percentage diffs to your updated rear map to develop your front map. Make sense? The front map is just a leaner version of the rear map... it is derived from the rear map. | |||
| M1combat |
I think the percentage theory would be better as well. It's still not a "tune" of the front cylinder though. | |||
| Bombardier |
The front map should be the same as the rear and then the ecm will add the difference. The front should always get more fuel than the rear as it runs cooler and therefore the intake charge air will be denser and need to carry more fuel to achieve the same a/f ratio as the rear cylinder. | |||
| Mr2shim |
I think it's a pretty good theory. I might have to try this vs the ecmspy how-to way. Bombardier, I'm curious to know how do you know this? The front map should be the same as the rear and then the ecm will add the difference. | |||
| Ferocity02 |
Bombardier, I would like to know how you know that also. If you're going off what the "tuning guide" says, I'd be VERY cautious. That thing has a LOT of poor/false information. | |||
| Mesozoic |
Ok, so I inputted the front and rear maps from my stock '08 tune into Excel and computed the percentages the front map cells are to the rear. What each cell indicates is that the front fuel value is X percentage of the rear. Eg., WOT @ 4500 RPM: front fuel value is 104.09% of the rear fuel value. In this case, they've added fuel to the front. Conversely, TPS of 175 @ 4500 RPM is only 94.04%. They've taken fuel out from the front in this case. I would imagine that using these percentages as a guideline would be the safest way to tune the front map.  | |||
| Mr2shim |
^^^ Thanks for that helpful bit of info. I'm going to spend my night @ work adjusting the current front cyl map I run to those values. See what I end up with. (Message edited by mr2shim on July 06, 2008) | |||
| Swordsman |
Bah! One-upped!  ( ) Seriously though, you're right, that makes more sense to do it by percentage. Now if only I could get Megalog to cooperate... Analyzing my datalog gives me some error about a Y-axis value...? ~SM (Message edited by Swordsman on July 06, 2008) | |||
| Swordsman |
Ah, here it is.  Dunno if my Y-axis should be set to "TP" or "8-bit TPS", or something else entirely! ~SM | |||
| M1combat |
"The front map should be the same as the rear and then the ecm will add the difference. " I don't believe that's the case. The stock maps aren't the same front/rear. | |||
| M1combat |
Mesozoic - Would you mind taking the time to get a stock ECM map from each ECM type and creating .XLS docs for each one? It would let us know if they are very close and if they aren't would let us know how far off they are  . Should be good data to compare them like that. | |||
| Typeone |
Swordsman - Change your Y-Axis to 8-bit TPS Mesozoic - Nice werk! Any way we can get that Excel file? I'm awful in Excel, that would be a super-handy sheet to use after datalogging the rear cyl. | |||
| Mesozoic |
M1Combat - I'd love to enter all those values, but I doubt I'll find the time. If you're not too fast at typing or something and you want a hand with your specific binary, I'll punch it in for you, though. I'll post up the Excel file here... just keep in mind that the '08 has more datapoints than the older binaries, ie. the X-axis for RPMs seems have more RPM values than the previous models.
| |||
| Bombardier |
Buell Tuning Guide - Steve Turnbull from the ECMSpy website. | |||
| Bombardier |
As for the cooler therefore needs more fuel I have read this on one of the American motorcycle sites www.rbracing-rsr.com They believe that as the front cylinder is most likely to lean out the o2 sensor should be there and not the rear. I am of the opinion that the sensor is located in the rear header so as not to disturb the look of the bike as to be honest there is not much you can do to make an o2 sensor look good. Given that aircraft(aircooled) engines would overheat and run too rich at altitude due to thinner(less dense air) the fact that the front cylinder is cooler and therefore need more fuel than the front it would seem more prudent to be concerned about correct fuelling for the front cylinder and average it for the rear rather than the current way. My opinion for what it is worth. | |||
| Typeone |
Mesozoic - Thanks for posting the Excel, appreciate it! | |||
| Mr2shim |
Given that aircraft(aircooled) engines would overheat and run too rich at altitude due to thinner(less dense air) the fact that the front cylinder is cooler and therefore need more fuel than the front it would seem more prudent to be concerned about correct fuelling for the front cylinder and average it for the rear rather than the current way. That doesn't make any sense. The rear cyl runs hotter than the front cyl. Thus needing more fuel to keep it cool. The stock map obviously proves this to be true. I don't think BMC are that hell bent on looks to slap the o2 in the rear. That doesn't make any sense either. "The front map should be the same as the rear and then the ecm will add the difference." Not to bash you man, but that statement alone would make me not listen to one thing you have to say. The stock maps are obviously different. Even if you look at it for a half a second you'd notice. If it's not adding any difference when it's stock, what makes you think It'd add differences once you toy around with it. Mesozoic: Thanks a million for posting that Excel! | |||
| Mesozoic |
I don't think Bombardier is completely out to lunch. However, I'm not going to argue with the design work that BMC has done for the bike. It's true that a cooler cylinder will need more fuel to run stoichiometric because the air is denser (more oxygen molecules), but at the same time it's common practice to richen up a hot cylinder as well to ensure it doesn't ping and runs cooler as well. Where does that leave us? Looking at the stock maps, it appears that BMC thinks that sometimes the front cylinder needs more "fuel cooling" and sometimes it's the rear. | |||
| Id073897 |
The rear cyl runs hotter than the front cyl. Thus needing more fuel to keep it cool. Urban legend. Stop believing, start thinking. More fuel gives more torque and more power at constant RPM. Twice the amount of power delivered at the crankshaft will be wasted in form of heat. Thus the cylinder will heat up instead of cool down. You can't cool down an engine by just adding "some" fuel. Too achieve this, you would have to add fuel until you will get black smoke and reach the limits of ignitability. This will most probably work at WOT only. From Fuell Fall 2007: "The left side air scoop was shaped to direct air to the rear cylinder and is very effective at doing that. During our high-speed, hotambient testing, the front and rear spark-plug base temperatures are virtually identical, whereas on the old tube-twin bikes there was a 100 Degree Fahrenheit difference (rear running hotter)." Regarding XB models, the rear cylinder isn't running hotter than the front one, according to the manufacturerer, and therefore doesn't need any additional cooling. On the other hand, the front one isn't running any cooler and doesn't need any enrichment because of that. Very probably the front cylinder had once been mapped using a O2 sensor, so the map will just reflect it's needs. Regards, Gunter | |||
| Lamo |
I have to agree with Mr2shim . The air entering the front cylinder is not cooler than that entering the rear its the same air, the front cylinder runs cooler because its directly in the airflow the rear runs hotter because its being cooled by the hot air flowing off the front cylinder its just how vee engines are unless you use an rss in which case you might be able to run the front and rear maps the with the same configuration imho. | |||
| Lamo |
Just to add to the above I don't think the maps are different between front and rear to cool the rear cylinder , it's because they run at different temps the fueling requirements are different. | |||
| Mesozoic |
The bottom line is that they're different. The question is, how to adjust the front map after tuning the rear? And Gunter, when is thing going to be possible on '08 models using ECMSpy? | |||
| Ferocity02 |
You cannot tune the front cylinder using data from the rear cylinder!!! That is the bottom line. If you want to tune your bike right, install some wideband O2's on both head pipes and go to a dyno. You guys are making gross assumptions to tune the front cylinder. (Message edited by ferocity02 on July 07, 2008) | |||
| Mr2shim |
You cannot tune the front cylinder using data from the rear cylinder!!! That is the bottom line. If you want to tune your bike right, install some wideband O2's on both head pipes and go to a dyno. You guys are making gross assumptions to tune the front cylinder. Want to tell us how to rig up a o2 sensor on the front cyl as well? I'd like to hear this bit of info. You keep saying it but you aren't saying how to do it. You are offering a solution but you aren't offering a solution really. Have you done this before? I've been running my ecmspy tuned bike for some months now. It is fine to the best of my knowledge. Hell, I think it runs better. You are right. The BEST way to tune the bike would be to use wide band o2's on the front & rear cyl but you have to realize everyone doesn't have that option. If you are so against EcmSpy and others fiddling with it, you can just as easily ignore all of these threads because quite frankly. You aren't going to change much by saying.. "oh yea slap some wideband o2's on that bitch" Yea, thanks... How? P.S For all you and the rest of us know, buell did exactly what has been shown in this thread. Please show me otherwise. (Message edited by mr2shim on July 07, 2008) | |||
| New12r |
DID ANY OF YOU READ THIS??? From Fuell Fall 2007: "The left side air scoop was shaped to direct air to the rear cylinder and is very effective at doing that. During our high-speed, hotambient testing, the front and rear spark-plug base temperatures are virtually identical, whereas on the old tube-twin bikes there was a 100 Degree Fahrenheit difference (rear running hotter)." | |||
| Ferocity02 |
Mr2shim... I never said I was against ECMspy. It is an awesome tool that's powerful and very easy to use. However, many people get the impression that they can accurately and safely tune their bikes using just ECMspy, MLV, VEA, and the single NB O2 sensor. The simple fact is that you can't. Sure you can make small tweaks here and there to cure a miss or popping, but without actual numbers you're just doing black magic and you can be harming the motor and not even know it. If people are serious about tuning their motors then welding in a wideband sensor to each cylinder would be the best option. You don't have the leave it in the head pipe so it doesn't look that bad. Just tune one cylinder at a time with a laptop, ECMspy, and some datalogging on a dyno or on the street. The LC-1 from Innovate is only $199, a hell of a lot cheaper than a new motor. Just my two cents, take it as you wish. |
