DYNOJET: Posing a at pro vs mytune question
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Seasoned HDF Member
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From: Florida
Posing a at pro vs mytune question
I recently got a new exhaust which lead me to retuning my bike.
2006 dyna with 95 inch
Street port heads decked to 80cc 1.9 and 1.65 valves
Andrews 37h cams
Thunderheader
Stock injectors at 25degree and stock intake
So I autotune my old map, which is open loop to about 2k and then closed loop, with the at pro kit for my powervision writhing 3 percent rate of change. Less than one percent in lower rpms. I changed my afr table to run closed loop in the lower rpms as well afterward and began to run a data log. In open loop my lowers rpms and idle felt fine
When I changed it to closed loop it would barely idle and my integrators were 115 at idle which tells me it's super lean. I ran a log and used mytune to modify the ve map. It got better and is ok now
My question is why does autotune make the ve's so lean at idle and low rpms that it won't runs like crap in closed loop there. Everywhere else outside of 2k rpms runs excellent and is as close as street tuning can get it. I verified that I don't have any exhaust leaks, leaks at the o2 sensors, and I used the torch gas technique to check for intake leaks with negative results. What gives?
2006 dyna with 95 inch
Street port heads decked to 80cc 1.9 and 1.65 valves
Andrews 37h cams
Thunderheader
Stock injectors at 25degree and stock intake
So I autotune my old map, which is open loop to about 2k and then closed loop, with the at pro kit for my powervision writhing 3 percent rate of change. Less than one percent in lower rpms. I changed my afr table to run closed loop in the lower rpms as well afterward and began to run a data log. In open loop my lowers rpms and idle felt fine
When I changed it to closed loop it would barely idle and my integrators were 115 at idle which tells me it's super lean. I ran a log and used mytune to modify the ve map. It got better and is ok now
My question is why does autotune make the ve's so lean at idle and low rpms that it won't runs like crap in closed loop there. Everywhere else outside of 2k rpms runs excellent and is as close as street tuning can get it. I verified that I don't have any exhaust leaks, leaks at the o2 sensors, and I used the torch gas technique to check for intake leaks with negative results. What gives?
Road Warrior
Joined: Jun 2015
Posts: 1,325
Likes: 140
From: Edinburgh UK
possibly needs DJ to adjust the IVO or MAP tooth position setting (or whatever it's called) ...that made a HUGE difference to my tuning.
I also adjusted the CDE tables to reduce that dip significantly.
EDIT: btw, I find Mytune and the automating of the VE tables in PV Basic significantly different and I haven't decided which is right yet ...the auto mapping in PV I think?? The PV wants to set a few cells to 127, which follows the rest of the VE tables, and you can see those numbers in the New VE column of a log file ...but Mytune drops them to 115 or so ??!!? Mytune doesn't scale the CI does it? I don't see anything
I also adjusted the CDE tables to reduce that dip significantly.
EDIT: btw, I find Mytune and the automating of the VE tables in PV Basic significantly different and I haven't decided which is right yet ...the auto mapping in PV I think?? The PV wants to set a few cells to 127, which follows the rest of the VE tables, and you can see those numbers in the New VE column of a log file ...but Mytune drops them to 115 or so ??!!? Mytune doesn't scale the CI does it? I don't see anything
Last edited by Gordon61; Jul 13, 2016 at 12:04 PM.
Road Warrior
Joined: Jun 2015
Posts: 1,325
Likes: 140
From: Edinburgh UK
Anyways, that sounds about the same as mine ...I have the 57, same as yours with a bit less lift. The right IVO setting got my 40something down to 35, and adjusting CDE got it down to 30-32 (mine is a 103 to your 95 tho)
Road Warrior
Joined: Jun 2015
Posts: 1,325
Likes: 140
From: Edinburgh UK
One of the pro's would have to answer that one but they would need to see the config and logs to see what is going on.
I'm guessing you are putting in more fuel in open loop - I take it you mean an AFR of 13 or so around the idle mark?? I adjusted the CDE table on the front which put more fuel in especially around idle.
There is some discussion in here about sensor accuracy and positioning of the sensors in the pipes and simply the design of the pipes and amount of overlap on the cams all go towards this not being quite as simple as we are led to believe it is.
I'm guessing you are putting in more fuel in open loop - I take it you mean an AFR of 13 or so around the idle mark?? I adjusted the CDE table on the front which put more fuel in especially around idle.
There is some discussion in here about sensor accuracy and positioning of the sensors in the pipes and simply the design of the pipes and amount of overlap on the cams all go towards this not being quite as simple as we are led to believe it is.
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Seasoned HDF Member
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From: Florida
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Road Warrior
Joined: Jun 2015
Posts: 1,325
Likes: 140
From: Edinburgh UK
I "think" I can see what is going on but I'd really like to see some more discussion come out in some of the threads. Steve might get to it in his EFI tuning discussion
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Road Warrior
Joined: Jun 2015
Posts: 1,325
Likes: 140
From: Edinburgh UK
ouch!
Mytune may be good for Spark tuning as others have mentioned, but I have my doubts about the way it seems to be calculating VE
It looks as if it is simply averaging hits in a rather a large block of revs by a large block of throttle percentages.
If your data collected is skewed to one side of that rather large block = you get the wrong answer ...which can be rather significant if you have anything other than a very smooth VE table. Leaves you wondering how good the other "autotune" algorithm are??
I think this highlights just how important collecting the right data is, and comes back to the best you are going to get is on a dyno in a controlled environment, whereas street tuning, unless you really know what you are doing, may be rather hit n miss
Mytune may be good for Spark tuning as others have mentioned, but I have my doubts about the way it seems to be calculating VE
It looks as if it is simply averaging hits in a rather a large block of revs by a large block of throttle percentages.
If your data collected is skewed to one side of that rather large block = you get the wrong answer ...which can be rather significant if you have anything other than a very smooth VE table. Leaves you wondering how good the other "autotune" algorithm are??
I think this highlights just how important collecting the right data is, and comes back to the best you are going to get is on a dyno in a controlled environment, whereas street tuning, unless you really know what you are doing, may be rather hit n miss
Road Warrior
Joined: Jun 2015
Posts: 1,325
Likes: 140
From: Edinburgh UK
...this also has me wondering about the PV itself.
I started with a Vance and Hines FP3 and switched to the Power Vision. One of the first things I noticed was how much quicker the PV was at populating the hit cells compared to the FP3 ...I wonder if the FP3 was only collecting tighter hits??
I started with a Vance and Hines FP3 and switched to the Power Vision. One of the first things I noticed was how much quicker the PV was at populating the hit cells compared to the FP3 ...I wonder if the FP3 was only collecting tighter hits??