Decel pop and Powervision
#21
08-19-2014, 07:03 AM
I'm in pretty good shape now. I recently had to send my PV unit into Fuel Moto because it locked up. They were very helpful and returned it good as new promptly.
When I got it back, I installed Win PV on my pc and logged on to the Dynovision website to download some tunes into the unit. Since they didn't have a tune for Kromewerks on the list, I downloaded to the unit 3 tunes with V&H, Rinehart, and Bub 7's shown as the slip on mufflers. I then went for a ride to try each tune.
The tune for the Rineharts was the best. Nearly all decel pop gone and bike running good. Tomorrow I will start autotuning. Thanks for all the input. I'm starting to learn how to use this thing.
When I got it back, I installed Win PV on my pc and logged on to the Dynovision website to download some tunes into the unit. Since they didn't have a tune for Kromewerks on the list, I downloaded to the unit 3 tunes with V&H, Rinehart, and Bub 7's shown as the slip on mufflers. I then went for a ride to try each tune.
The tune for the Rineharts was the best. Nearly all decel pop gone and bike running good. Tomorrow I will start autotuning. Thanks for all the input. I'm starting to learn how to use this thing.
#22
08-19-2014, 09:08 AM
Seasoned HDF Member
That is the auto tune Pro which includes wideband O2 sensors. You would want that if you add mods and are tuning from scratch
All PVs have auto tune Basic built in. It tunes using the stock narrowband O2 sensors. It is good if you get a canned map for your particular bike/mods from a good source (like FuelMoto & DynoJet). It allows you to dial in that tune for your specific bike.
Both have their place. I have had great luck with the auto tune Basic, when starting with a good canned map...
All PVs have auto tune Basic built in. It tunes using the stock narrowband O2 sensors. It is good if you get a canned map for your particular bike/mods from a good source (like FuelMoto & DynoJet). It allows you to dial in that tune for your specific bike.
Both have their place. I have had great luck with the auto tune Basic, when starting with a good canned map...
#23
08-19-2014, 10:14 AM
NOT A MODERATOR
#24
08-19-2014, 10:32 AM
After that, then there are certainly other things to look at, including reversion (which looking at your pipes, is quite possibly the cause!), timing etc.
The decel enleanment only affects what happens the instant you close the throttle, so if you get popping continuing for a second or more afterwards, then this won't help you.
The fact of the matter is that the exhaust contains unburnt fuel which, together with the right amount of oxygen in the exhaust, ignites due to the hot exhaust.
Some people "solve" this by ADDING fuel in the low-load, mid-rpm section of the AFR map, thinking that it cools the exhaust. Of course it doesn't -- they are just saturating the exhaust mixture with fuel and upsetting the balance. But in my mind, that's a waste of good fuel.
Others have success with REDUCING fuel in the same area; reasoning that if there is excess fuel, removing it will stop it burning. Certainly if you have reversion and autotune is giving you artificially-high VEs in this area, that's a reasonable solution (without having AGR) as it counteracts the effect without upsetting the AFV (which would happen if you manually put the VE back to a more reasonable value). This would probably work well in your case.
But if you don't have reversion (eg. longer pipes, reasonable amount of baffling), then the problem is that the engine just isn't getting enough time to burn the fuel mixture before it gets expelled, and the fuel is just being thrown out the back of the engine. I guess the same happens when you reduce the AFR, but you just get less (rather than none) fuel coming out the back. If this is the case, then my favourite fix is to advance timing to allow more time for the mixture to burn in the cylinder. Indeed, it has been argued that HD purposefully set the timing retarded to ENSURE that some fuel gets burned in the pipes to keep the cat temperature high and reduce emissions. Obviously if you have no cat, then it's just wasted fuel.
But you are right in waying that autotune doesn't solve all your problems, especially if your setup is more exotic. But it's far from worthless and (IMO) the very first thing you should do before playing elsewhere.
#25
08-19-2014, 10:47 AM
NOT A MODERATOR
DYnojet told me auto-tune basic will not work for the pipe I have. I did take it and have it dyno-tuned and that helped, but I still get pretty good decel pop. This is inherent with short pipes with little back-pressure. I do run a baffle, but there is not much to it. BTW, this pipe is a 2 into 1 with one long run (front cylinder) and a short run (rear cylinder) that dumps into the long run abruptly.
I need to upgrade to the wide-band 02s, but even then I don't think you can entirely eliminate pop with this style of exhaust. I don't mind some decel-pop anyway.
I need to upgrade to the wide-band 02s, but even then I don't think you can entirely eliminate pop with this style of exhaust. I don't mind some decel-pop anyway.
As I said in my post; you should start with autotuning to get the VEs how the O2 sensors determine they should be, and check for leaks. I didn't say that would solve the problem, but it's easy to do, and is certainly the first thing to do before messing with anything else.
After that, then there are certainly other things to look at, including reversion (which looking at your pipes, is quite possibly the cause!), timing etc.
The decel enleanment only affects what happens the instant you close the throttle, so if you get popping continuing for a second or more afterwards, then this won't help you.
The fact of the matter is that the exhaust contains unburnt fuel which, together with the right amount of oxygen in the exhaust, ignites due to the hot exhaust.
Some people "solve" this by ADDING fuel in the low-load, mid-rpm section of the AFR map, thinking that it cools the exhaust. Of course it doesn't -- they are just saturating the exhaust mixture with fuel and upsetting the balance. But in my mind, that's a waste of good fuel.
Others have success with REDUCING fuel in the same area; reasoning that if there is excess fuel, removing it will stop it burning. Certainly if you have reversion and autotune is giving you artificially-high VEs in this area, that's a reasonable solution (without having AGR) as it counteracts the effect without upsetting the AFV (which would happen if you manually put the VE back to a more reasonable value). This would probably work well in your case.
But if you don't have reversion (eg. longer pipes, reasonable amount of baffling), then the problem is that the engine just isn't getting enough time to burn the fuel mixture before it gets expelled, and the fuel is just being thrown out the back of the engine. I guess the same happens when you reduce the AFR, but you just get less (rather than none) fuel coming out the back. If this is the case, then my favourite fix is to advance timing to allow more time for the mixture to burn in the cylinder. Indeed, it has been argued that HD purposefully set the timing retarded to ENSURE that some fuel gets burned in the pipes to keep the cat temperature high and reduce emissions. Obviously if you have no cat, then it's just wasted fuel.
But you are right in waying that autotune doesn't solve all your problems, especially if your setup is more exotic. But it's far from worthless and (IMO) the very first thing you should do before playing elsewhere.
After that, then there are certainly other things to look at, including reversion (which looking at your pipes, is quite possibly the cause!), timing etc.
The decel enleanment only affects what happens the instant you close the throttle, so if you get popping continuing for a second or more afterwards, then this won't help you.
The fact of the matter is that the exhaust contains unburnt fuel which, together with the right amount of oxygen in the exhaust, ignites due to the hot exhaust.
Some people "solve" this by ADDING fuel in the low-load, mid-rpm section of the AFR map, thinking that it cools the exhaust. Of course it doesn't -- they are just saturating the exhaust mixture with fuel and upsetting the balance. But in my mind, that's a waste of good fuel.
Others have success with REDUCING fuel in the same area; reasoning that if there is excess fuel, removing it will stop it burning. Certainly if you have reversion and autotune is giving you artificially-high VEs in this area, that's a reasonable solution (without having AGR) as it counteracts the effect without upsetting the AFV (which would happen if you manually put the VE back to a more reasonable value). This would probably work well in your case.
But if you don't have reversion (eg. longer pipes, reasonable amount of baffling), then the problem is that the engine just isn't getting enough time to burn the fuel mixture before it gets expelled, and the fuel is just being thrown out the back of the engine. I guess the same happens when you reduce the AFR, but you just get less (rather than none) fuel coming out the back. If this is the case, then my favourite fix is to advance timing to allow more time for the mixture to burn in the cylinder. Indeed, it has been argued that HD purposefully set the timing retarded to ENSURE that some fuel gets burned in the pipes to keep the cat temperature high and reduce emissions. Obviously if you have no cat, then it's just wasted fuel.
But you are right in waying that autotune doesn't solve all your problems, especially if your setup is more exotic. But it's far from worthless and (IMO) the very first thing you should do before playing elsewhere.
#26
08-19-2014, 10:59 AM
Even having it dyno-tuned, if you have any part of the map that is affected by the poor O2 data still in closed-loop, it will use the false data to influence the tune across the board and undo some of the benefit of the dyno tune over time.
I do run a baffle, but there is not much to it. BTW, this pipe is a 2 into 1 with one long run (front cylinder) and a short run (rear cylinder) that dumps into the long run abruptly.
I need to upgrade to the wide-band 02s, but even then I don't think you can entirely eliminate pop with this style of exhaust. I don't mind some decel-pop anyway.
I need to upgrade to the wide-band 02s, but even then I don't think you can entirely eliminate pop with this style of exhaust. I don't mind some decel-pop anyway.
Otherwise, with a poor environment for O2 sensors, having more expensive wide-band ones just gives you more expensive poor data IMO. In the meantime, I'd probably force the tune into open-loop wherever you are seeing popping, leaving only those areas where the VE values "make sense" remain in closed-loop. This would at least allow the ECM some self-regulation for temperature, altitude, fuel mix etc. whilst preventing it trying to use the poor O2 data when there is little exhaust flow. I'm guessing this is what your dyno guy has done.
Adjusting timing to solve this doesn't affect performance at all, and since it is generally believed that a little decel popping causes no harm, I'm guessing there isn't any real reason for your dyno guy to spend his time (and your money) on chasing it further than the open-loop hack. But since there is no load on the engine at these times, there is little danger in advancing timing a bit to see if it helps.
But if you like it, and it isn't causing any problems (with the law, neighbours etc.), then why bother spending the time other than for interest's sake? :-)
#28
08-19-2014, 02:43 PM
Seasoned HDF Member
#29
08-19-2014, 03:34 PM
NOT A MODERATOR
I gotta run me right out an git me some of dat....
I love the internet.
#30
08-19-2014, 06:32 PM
