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Fuel map suggestion for a slant six
https://www.slantsix.org/forum/viewtopic.php?t=47274		 Page 2 of 2
Author:  Dart270 [ Wed Dec 21, 2011 6:55 pm ]
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You haven't ridden in it yet! It has some "character" still...

Love your sign off quote, Sam!

Lou
Author:  Sam Powell [ Wed Dec 21, 2011 7:23 pm ]
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I'm looking forward to it. What is your req-fuel number? I would like to do the math on your chart compared to mine to see where mine varies from yours.

That sign off quote is actually true as well as being kind of funny. I'm glad it resonates with you.

Sam
Author:  Sam Powell [ Thu Dec 22, 2011 7:23 pm ]
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Lou, I looked at the ratios of your low RPM and high rpm numbers and the row for 53 KPA is the only one that shows much of a rise going to the right. The ratio is 1.22:1 which is precisely what my 30 KPA row is. This reflects a fair amount of auto tune driving. My 60 KPA row has a ratio of 1.34:1. which is considerably higher than your ratio of 1.108.1 for the 66 row.

Our selected KPA scaling numbers are so different it is hard to compare on that scale. However going from 33 to 130 on your map produced a ratio of 2.95 at 2200 RPM. My map going from 30 to 120 yields a ratio of 1.6 at 2133 RPM. Your fueling actually gets richer in the boost range when compared to the high vacuum regions. Either my high vacuum regions are actually too rich, or I took too much fuel out in the boost regions at 2000 RPM.

AT 3400 rpm your table yields a ratio of 3:1. Mine is roughly 2:1 if I take more fuel out of the 30 KPA cell@3520. These are just observations. I have no basis for drawing any conclusions yet.

I think it is interesting that your upper most row has nearly the same numbers all the way across. How did you arrive at your numbers? I assume you were watching your AF gauge, or data logging and tuning off of that. Would you tell me once again please what ratios you were striving for as you go up the KPA scale. Thanks.

I will study your table more for insight into how to go about getting a better tune on mine. You were always like magic sitting over there in the passenger's seat tapping away on the laptop keys. I really respect your seat-of-the-pants dyno work. Unfortunately, all those trips were made with faulty fuel pressure, and cannot be relied on to show us anything useful.



Sam
Author:  Dart270 [ Fri Dec 23, 2011 5:04 pm ]
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Did top row tuning using WB O2 AFR gauge and shooting for 11.0-11.5:1 at full boost. Shot for around 13:1 at 100 kPa and was quite close across the board as well. For me, plenty of street tuning miles under different conditions is my preferred way to tune. AFR is quite stable through a full pull once I get to full boost.

Lou
Author:  Sam Powell [ Sat Dec 24, 2011 4:44 am ]
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How do you tune and drive at the same time.? Do you datalog?Sam
Author:  Dart270 [ Sat Dec 24, 2011 1:01 pm ]
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Usually I don't datalog anymore. If I'm being good (usually), I pull over after some driving and tweak the map. Was great driving to MN-NE and back with Neal in June since we could drive and have the other one tune in real time.

Lou
Author:  lgu32 [ Thu Dec 29, 2011 12:19 pm ]
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Quote:
Here is Lou's fuel table. You can see that the numbers do not advance as quickly moving to the right as mine do. I think when you compare his boost number to his idle number, it may actually be higher than mine compared to my idle number. However,to be objective and scientific, we would need to know what his and my Req-fuel number is in order to compare the two charts, and what AF ratio his idles at. I was able to idle at a much leaner ratio with MSII. Probably a more indicative comparison would be to compare 2000 RPM at 30 KPA to 2000RPM at 130 KPA on both charts.
I wish mine ran like his does. Maybe one day.
Image

This kind of table is my favourite one. Flat rows, no need to compensate fuel flow to rpm. As shown examples are from turbo engines, could you give an example which is from naturally aspirated /6 engine?.

Before taking the head off for manifold change I did play with a vacuum meter shortly. Seems that with MP268 cam there is almost no need to have table continuing to 20kPa. With this cam it idles and run somewhere in between 50 to 100kPa and just with braking with engine there exist shortly higher vacuum readings.



Jari
Author:  Sam Powell [ Thu Dec 29, 2011 1:44 pm ]
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You can probably get higher vacuum readings with more timing advance.

Sam
Author:  lgu32 [ Fri Dec 30, 2011 7:37 am ]
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I cant put more. There is now 12-15 advance at idle, 28-30 degrees at high rpm. Plus vacuum advance (quite minimal, just few degrees).

Thanks for help.
Author:  Sam Powell [ Fri Dec 30, 2011 9:49 am ]
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I can see you are right.

Sam
Author:  Sam Powell [ Sat Dec 31, 2011 6:27 am ]
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So Lou, Can you say a little more about your tuning process? How do you keep track of what is going on under full throttle runs? Things happen so fast, and change so quickly, I cannot keep track of events, drive, and remember what to change when I stop. How do you do that? Is there any light you can shed on this for us?

Sam
Author:  Dart270 [ Sat Dec 31, 2011 6:42 am ]
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I don't know of any tricks. I quickly glance down several times at the AF meter (and sometimes tach) as I accelerate. You can usually hear and estimate revs. I try to find a wide, straight road with little or no traffic.

This will get harder to do as traction becomes more of a problem. I am due to buy some new sticky but streetable tires for this thing, which will help.

I need to do a gauge location redesign like you have done...

Lou
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