Author Topic: DynoJet: Advance #'s  (Read 807 times)

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Offline Darreldanger

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Advance #'s
« on: September 25, 2017, 03:30:14 PM »
Hi guys,  much has been said about air fuel ratio's but how much advance are you running at WO throttle?  Mine is maxing out @ 31 degrees @ 6000 RPM.  My comp is 10.1-1.  Am I leaving anything on the table?
« Last Edit: September 25, 2017, 07:41:13 PM by Darreldanger »

Offline ultraswede

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Re: Advance #'s
« Reply #1 on: September 25, 2017, 10:41:13 PM »
Whats your build?

The components has huge impact on the optimum ignition timing.

Offline Darreldanger

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Re: Advance #'s
« Reply #2 on: September 26, 2017, 10:09:48 AM »
Andrews 57h fuel moto level b head with 10.1-1 comp 2-1-2 S&S headpipe with 4.5 muffs

Offline KE5RBD

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Re: Advance #'s
« Reply #3 on: September 26, 2017, 10:46:06 PM »
I have found that from 2000 to 3500 I run 26 to 27 in the 95 and 100 column.  From 3500 up I drop to 24 with stock compression and as low as 18 with 11 to 1.  Too much timing above 3500 will actually slow you down.  The stock timing map is too much there.  It is easy enough to try.  No need at WOT to run more than can use.  It can activate the spark knock and cause to back off timing too much.  Also the area from 70 Kpa to 95 Kpa and 2000 to 3500 needs to be lower than stock.  I run around 23 in the 70 to 80 area then bump it up to maybe 26 80 up.  Also don't try to run too lean in the 2000 to 3500 area 25% throttle position up or 70 to 100 Kpa as it will cause it to be flat and will also activate the spark knock system when twisting on the throttle from cruise.  Autotune will likely leave you 10% too lean in that area. The VE's will likely work best on yours in the acceleration area to WOT from cruise low 105 in 25% TP and 115+ in WOT area.  Or same for 60 up Map Kpa.  Go all the way down to 1250 rpms in that range to 6000.  It will take the flat spot from 2000 to 3000 rpms out. Works for me anyway.  More timing than needed is not a good thing.
2014 FLHTK, PV2, Andrews 55, Game Changer sprocket, Rush Wrath Stepped  2 in 1

Offline Gordon61

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Re: Advance #'s
« Reply #4 on: September 27, 2017, 05:15:46 AM »
I'm not sure that is helping ...any chance of a picture to explain?

It's just that most of the spark table we look at seem to flow smoothly from lowest advance in the top right to the highest in the bottom left ...yet you seem to be suggesting blocks of the same number, and making the advance higher in higher kpa columns rather than lower, as in typical tables.

...for example you suggest 23 in the 70-80kpa / 2000-3500rpm area, yet the stock/stage maps I was looking at range from something like 14 to 32 across that area?  You then suggest that the 80 to 100kpa columns be 26 or 27 which is higher rather than lower?

I was also wondering about 95/100kpa or WOT where you suggest that above 3500rpm be lower than 2000-3500?

Offline KE5RBD

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Re: Advance #'s
« Reply #5 on: September 27, 2017, 10:32:27 AM »
I'm not sure that is helping ...any chance of a picture to explain?

It's just that most of the spark table we look at seem to flow smoothly from lowest advance in the top right to the highest in the bottom left ...yet you seem to be suggesting blocks of the same number, and making the advance higher in higher kpa columns rather than lower, as in typical tables.

...for example you suggest 23 in the 70-80kpa / 2000-3500rpm area, yet the stock/stage maps I was looking at range from something like 14 to 32 across that area?  You then suggest that the 80 to 100kpa columns be 26 or 27 which is higher rather than lower?

I was also wondering about 95/100kpa or WOT where you suggest that above 3500rpm be lower than 2000-3500?
You are correct on the top right being lowest which is low speed WOT which can't stand much timing without clattering when taking off.  the bottom left is strictly decel area which is pretty insignificant.  Top left is idle and low speed cruise area and bottom right is WOT high speed stuff.  The cruise area is 35 Kpa to 60Kpa depending on engine mods.  The time there mostly effects the MPG and at lower rpms if too much will cause little roughness. 
The amount of timing you can run and still make max power is more dependent on the engine load, efficiency of head/ intake/ exhaust, and RPM.  The ideal timing is when piston nears TDC on compression to fire the cylinder to where the cylinder combustion reaches maximum pressure as the piston reaches TDC or just after not before.  Before can cause the ping and takes away from crank rotational force, or saying another way it takes away power by causing the piston to try and go the opposite direction.  Too slow of timing causes the combustion process to not be spent by the time piston reaches bottom of cylinder and the combustion expansion goes out the exhaust valve instead of pushing down on piston.
That 70 to 80 area from 2500 to 3500 where you say I recommend a block of numbers is one tricky area with the drop in cams.  The cams seem to get really efficient there and with less than WOT is somehow disturbing the flow.  That is one of the hardest spots to get just right.  I use data logs and Megalog viewer and have spent many long hours working on the area to get best performance without spark knock.  You can do this however you want.  Just telling you that it works for me and many bikes around here and all around the country.  There are lots of articles on internet that can explain all this much better than I. 
2014 FLHTK, PV2, Andrews 55, Game Changer sprocket, Rush Wrath Stepped  2 in 1

Offline Darreldanger

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Re: Advance #'s
« Reply #6 on: September 27, 2017, 11:50:09 AM »
here it is.  I'm gonna add 2 degrees at 4000 and up in the 95 and 100 MAP columns.

Offline KE5RBD

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Re: Advance #'s
« Reply #7 on: September 27, 2017, 12:24:43 PM »
Run a log and look at the spark knock.  Also see how bike accelerates at 85 up in 6th is pretty good test.  Put a second map with 24 degrees in the 4000 up 95 and 100 with around 115 VE in same columns and see if can tell difference.  You can always go back if doesn't work.
2014 FLHTK, PV2, Andrews 55, Game Changer sprocket, Rush Wrath Stepped  2 in 1

Offline Gordon61

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Re: Advance #'s
« Reply #8 on: September 27, 2017, 03:00:09 PM »
here it is.

Sorry I meant one from KE5RBD to show us what he meant ...if I understood correctly I think what he said would look something like the following pic, but I wasn't sure if I was picking it up right


Offline KE5RBD

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Re: Advance #'s
« Reply #9 on: September 27, 2017, 04:12:20 PM »
That one should work just fine.  Maybe couple high in the 2000 at 50 Kpa.  If 6th gear feels little rough at 2000 then may want to back off couple degrees there.  Map should work fine for most drop in cams.  Will also work for stock cams too. Attached is the one I am running.  It is maxed out in the 60 up and I use closed throttle spark table for idle so I don't run that much at idle.  16 degrees at Idle.  The other is from a ANdrews 57 bike.  Notice how the timing is much lower in the higher load areas.  The 57's tend to like that better.  Mine has Andrews 55 which is over cam situation, but got later plans.  Both have 2 in 1 exhaust. 
2014 FLHTK, PV2, Andrews 55, Game Changer sprocket, Rush Wrath Stepped  2 in 1

Offline Gordon61

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Re: Advance #'s
« Reply #10 on: September 27, 2017, 04:33:05 PM »
Thanks for clarifying and the examples, very interesting to see what you were thinking

Mine won't go much above 12 or so at 2K/WOT, and that is with scaled CI and the VE still up around 115~120.

As you say tho, best to keep the knock count on and tune it accordingly

Offline KE5RBD

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Re: Advance #'s
« Reply #11 on: September 27, 2017, 05:00:45 PM »
What ever works for you.  I never scale and seldom cap. Only reason I would cap is to find the culprit cells.  On drop in cams and stage 1 thru 3 I don't find a need to cap.  If you will look at the cell/cells that are at 127.5 you will see they are in non critical areas usually.  A lot of times it is around 4000 rpms middle of VE table or in decel area which is not necessary.  If you find maxed out cells in area above 2000 and to the right of cruise area then something is wrong.  Not even going to list all possibilities.  If injectors are matched to build, and cams are timed right you shouldn't need it.  Of course no vacuum leaks, bad leak downs, low fuel pressure, just to name few. I don't think it should even be an option to scale.  Don't mask the problem fix it. That is my opinion and everyone has one.
2014 FLHTK, PV2, Andrews 55, Game Changer sprocket, Rush Wrath Stepped  2 in 1

Offline Gordon61

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Re: Advance #'s
« Reply #12 on: September 28, 2017, 01:07:22 AM »
Good info  :up:

Offline Harley Pilot

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Re: Advance #'s
« Reply #13 on: January 17, 2018, 06:22:53 PM »
That one should work just fine.  Maybe couple high in the 2000 at 50 Kpa.  If 6th gear feels little rough at 2000 then may want to back off couple degrees there.  Map should work fine for most drop in cams.  Will also work for stock cams too. Attached is the one I am running.  It is maxed out in the 60 up and I use closed throttle spark table for idle so I don't run that much at idle.  16 degrees at Idle.  The other is from a ANdrews 57 bike.  Notice how the timing is much lower in the higher load areas.  The 57's tend to like that better.  Mine has Andrews 55 which is over cam situation, but got later plans.  Both have 2 in 1 exhaust.

Would you Have any recommendations for front and rear timing for 106" with 551's?

Offline Sunny Jim

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Re: Advance #'s
« Reply #14 on: January 18, 2018, 10:54:16 PM »
So does this discussion apply to M8s as well?

Offline wolf_59

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Re: Advance #'s
« Reply #15 on: January 19, 2018, 06:03:42 AM »
That one should work just fine.  Maybe couple high in the 2000 at 50 Kpa.  If 6th gear feels little rough at 2000 then may want to back off couple degrees there.  Map should work fine for most drop in cams.  Will also work for stock cams too. Attached is the one I am running.  It is maxed out in the 60 up and I use closed throttle spark table for idle so I don't run that much at idle.  16 degrees at Idle.  The other is from a ANdrews 57 bike.  Notice how the timing is much lower in the higher load areas.  The 57's tend to like that better.  Mine has Andrews 55 which is over cam situation, but got later plans.  Both have 2 in 1 exhaust.

Would you Have any recommendations for front and rear timing for 106" with 551's?
here is a tts timing map for 551 cams, you'll have to work it to fit your build but it is a starting point


Offline Harley Pilot

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Re: Advance #'s
« Reply #16 on: January 19, 2018, 03:57:56 PM »
Quote
here is a tts timing map for 551 cams, you'll have to work it to fit your build but it is a starting point

Thank you, KE5RBD has already got me headed in the right direction!!👍🏻