Power Vision Information Thread
Intermediate
Joined: Mar 2014
Posts: 30
Likes: 0
From: WA
Sure, your thoughts in general are correct and I log / tune by those standards. all other areas of my timing are set up in that way best I can towards mbt based on logs. but I'm only discussing the specific cruise area of timing table (low map 30-60kpa, 2500rpm and up), which is normally set upwards of 41-45 degrees. MBT logic goes out the window here in favor of increasing MPG and lowering emissions. There is little chance of detonation with combination of a stock lean afr tune in that area, low map and greatly advanced timing.
Since I am running much richer at cruise area, what's the ramification of setting timing to say 28, 30 or 33 vs 41/45. - that is the question.
Since I am running much richer at cruise area, what's the ramification of setting timing to say 28, 30 or 33 vs 41/45. - that is the question.
The fuel and air already in the cylinder has a set amount of energy it can deliver. The ignition timing will determine how much of that energy will be delivered as motion. If the timing is adjusted to ensure maximum energy is transferred to motion (MBT), you've achieved the maximum efficiency for that engine with that fuel air mixture. That in turn will give you maximum MPG for that engine with that air fuel mixture. It will not provide minimum exhaust emissions.
Reducing timing from optimum will decrease MPG and emissions, as you slow the combustion process to allow more complete burning to occur, but at the cost of lower effective pressure in the cylinder.
Road Master
Joined: Feb 2014
Posts: 804
Likes: 237
From: TN
Dog from personal experience, if you you go to far, you will feel it. With my 12, running a tts, I had some pinging. I played with the timing in the cruise area, 4-5 deg was the wiggle room for that bike. 6 deg was useable, but the performance changed. 8 or more was the pits, bike was sluggish. Doesn't hurt to experiment, but if you change the timing to much, you need to redo the ve tables. I've seen the changes in the ve's with big timing changes. Others may disagree, just my experience.
Outstanding HDF Member
Joined: Jun 2014
Posts: 3,185
Likes: 189
From: 90210
Dog from personal experience, if you you go to far, you will feel it. With my 12, running a tts, I had some pinging. I played with the timing in the cruise area, 4-5 deg was the wiggle room for that bike. 6 deg was useable, but the performance changed. 8 or more was the pits, bike was sluggish. Doesn't hurt to experiment, but if you change the timing to much, you need to redo the ve tables. I've seen the changes in the ve's with big timing changes. Others may disagree, just my experience.
Riding-wise, I only noticed two things- 1, riding ET's were lower and 2, light roll on power was better. this was compared to a previous tune where the only single difference was leaving timing up at the 40,41,42,43 range. same 13.8 afrs. I did a few more runs with timing backed down to 38 range, then 35 range, and now at 33. nothing bad detected.
I'm assuming - probably wrongly - that the overly high timing in this area is solely for economy and EPA reasons and working in conjunction with closed loop leaner AFRs. I can't see where, mechanically speaking, the motor would actually require timing that high in that area- hence the original question. Decel timing yeh I totally get why putting it up at 35-38-40-45 helps and there is a lot of info on decel timing- but *zero* on cruise area timing.
Last edited by LA_Dog; Mar 17, 2016 at 05:54 PM.
Outstanding HDF Member
Joined: Jun 2014
Posts: 3,185
Likes: 189
From: 90210
For DE/AE- Those do not log on my bike- never have. If I add those signals the logged data columns are always blank.
Did you see my IDC's at mid rpm and high map? I don't think I'm going to be able to complete my fuel tuning without larger injectors. I have the 50mm TB and 4.9 injectors on my bench- need some time to put it in.
Outstanding HDF Member
Joined: Jun 2014
Posts: 3,185
Likes: 189
From: 90210
here's a shot of my F/R spark tables and the lambda table so it's easier to see vs opening the tune file. as you can see I've worked the cruise area timing down incrementally over several tunes- nothing negative noticed, just some lower ET's and bit peppier light roll on in cruise area. but how far down is too far? I say 28 is the limit but that is only based on Big-Twin engine timing in general.
I know my lambda table is rich and I'm working my way leaner on it now that I have the timing dialed in how I like it. We have crap e10 gas here.
I know my lambda table is rich and I'm working my way leaner on it now that I have the timing dialed in how I like it. We have crap e10 gas here.
Tourer
Joined: Apr 2012
Posts: 482
Likes: 30
From: Michigan/Florida
To optimize timing, we want to find MBT, for each cell in the map. To do that we have to measure torque, or some indication of torque.
Road Master
Joined: Mar 2007
Posts: 1,177
Likes: 23
From what I was seeing, your injectors are plenty large enough. The closest they got to maxing out was 80% of allowable DC and you we fat when it happened.
You were at 4647 RPM at 97 KPA at the time at 71.5 DC and 12 AFR
Andy
You were at 4647 RPM at 97 KPA at the time at 71.5 DC and 12 AFR
Andy
Last edited by whittlebeast; Mar 17, 2016 at 09:07 PM.
Road Master
Joined: Feb 2014
Posts: 804
Likes: 237
From: TN
Thanks for the input Wmitz- so which way you talking on adjustment, down or up in cruise area timing? Most stock maps have AFR set to 14.1 in the cruise area and matching advanced timing of 41,42 up to 45 degrees. I have mine presently set at 30-33 and AFRs are 13.8. if you look at my tune file you'll see the layout.
Riding-wise, I only noticed two things- 1, riding ET's were lower and 2, light roll on power was better. this was compared to a previous tune where the only single difference was leaving timing up at the 40,41,42,43 range. same 13.8 afrs. I did a few more runs with timing backed down to 38 range, then 35 range, and now at 33. nothing bad detected.
I'm assuming - probably wrongly - that the overly high timing in this area is solely for economy and EPA reasons and working in conjunction with closed loop leaner AFRs. I can't see where, mechanically speaking, the motor would actually require timing that high in that area- hence the original question. Decel timing yeh I totally get why putting it up at 35-38-40-45 helps and there is a lot of info on decel timing- but *zero* on cruise area timing.
Riding-wise, I only noticed two things- 1, riding ET's were lower and 2, light roll on power was better. this was compared to a previous tune where the only single difference was leaving timing up at the 40,41,42,43 range. same 13.8 afrs. I did a few more runs with timing backed down to 38 range, then 35 range, and now at 33. nothing bad detected.
I'm assuming - probably wrongly - that the overly high timing in this area is solely for economy and EPA reasons and working in conjunction with closed loop leaner AFRs. I can't see where, mechanically speaking, the motor would actually require timing that high in that area- hence the original question. Decel timing yeh I totally get why putting it up at 35-38-40-45 helps and there is a lot of info on decel timing- but *zero* on cruise area timing.
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Joe Kucinski
Outstanding HDF Member
Joined: Jun 2014
Posts: 3,185
Likes: 189
From: 90210
Dog, this was reducing timing from the can map from tts. From what I've read higher compression motors require less timing. With all the engine combos out there I believe that most tune are computer generated, unless you happen to have the exact combo that has been tested. How much did you take out compared to the original map that was sent to you. The only negative thing I've read is that running too retarded will put excessive heat into the exhaust valve causing premature wear/failure on the valve or seat.
Outstanding HDF Member
Joined: Jun 2014
Posts: 3,185
Likes: 189
From: 90210
Interesting- I'm looking at Injector Time F/R in the logs and seeing regular 19+ ms. there are only 20ms in an injector duty cycle.