'88 5-speed dyno log
06-18-2013, 03:14 PM
#166
06-18-2013, 03:16 PM
#167
When you see solutions in your head, for complex problems you are working on, while you are doing something else (drilling parts, showering) - thats a sign that you are either:
1) Crazy
2) Genius.
1) Crazy
2) Genius.
06-18-2013, 03:17 PM
#168
Boost exponentially requires more fuel because of the ramp up in air. Maybe not exponential, but it is not linear.
Id say you would need 42s or 72s. But that is aftermarket ECU territory.
Bet you didn't have any knocks though.
06-18-2013, 04:25 PM
#169
Drifting
Either way.. A sign of Great things to come
06-18-2013, 05:56 PM
#170
Nordschleife Master
I think that you probably don't need a full dimensional map for WOT. I think that all you need is two rows, one for low load and one for high load. Then, I think you can just let the usual LH interpolation algorithm work it's magic. The fuel demand is probably linear enough in the MAF load, so it'll interpolate well enough based on changes in temperature and altitude.
Just a hunch that this might be a way to save on space, if that ever becomes a constraint. Especially if you're also doing this with EZK, I vaguely recall that having less space.
Just a hunch that this might be a way to save on space, if that ever becomes a constraint. Especially if you're also doing this with EZK, I vaguely recall that having less space.
Anyhu, during the hours of drilling PKT brackets, I 'saw' what an ideal WOT table should look like. One that would automatically compensate for weather and gearing, weight, etc.
WOT programming can essentially be done in a 'flat', RPM only table, because there is no throttle restriction. Trouble is, weather, gearing, weight change the MAF to RPM relationship, pulling the AFR up or down.
At full throttle, airflow and ignition are essentially fixed by RPM according to the cams and intake. Weather etc. change the percentage up or down over the whole range, but the curve, RPM to RPM, stays pretty much the same.
EG. colder air makes MAF volts higher at the same RPM, so the map should compensate by returning a reduced value at that RPM.
I already had made a completely new (16-bit) base MAF table for WOT, so all I had to do was make a progressive slope from low MAF to high MAF.
The WOT table is overlaid over this base table as normal. To make adjustments, all I have to do is edit a single value in the WOT table.
Note that it is read diagonally, from upper right to lower left, as MAF and RPM values go up. The upper left and lower right areas are never read.
I am still tuning the individual RPMs, but fueling is now very stable (like my S3s), even in the 5600-6000 range. I guessed on the slope, but even as-is, the AFR change from gear to gear is minimal.
WOT programming can essentially be done in a 'flat', RPM only table, because there is no throttle restriction. Trouble is, weather, gearing, weight change the MAF to RPM relationship, pulling the AFR up or down.
At full throttle, airflow and ignition are essentially fixed by RPM according to the cams and intake. Weather etc. change the percentage up or down over the whole range, but the curve, RPM to RPM, stays pretty much the same.
EG. colder air makes MAF volts higher at the same RPM, so the map should compensate by returning a reduced value at that RPM.
I already had made a completely new (16-bit) base MAF table for WOT, so all I had to do was make a progressive slope from low MAF to high MAF.
The WOT table is overlaid over this base table as normal. To make adjustments, all I have to do is edit a single value in the WOT table.
Note that it is read diagonally, from upper right to lower left, as MAF and RPM values go up. The upper left and lower right areas are never read.
I am still tuning the individual RPMs, but fueling is now very stable (like my S3s), even in the 5600-6000 range. I guessed on the slope, but even as-is, the AFR change from gear to gear is minimal.
06-18-2013, 07:13 PM
#171
Inventor
Rennlist Member
Rennlist Member
Thread Starter
Even more extravagant, there is also the (8-bit) addition table (non-cat here), which is added, also.
I have it set to all zeros (128), but it could be used for some other compensation.
One nice thing about scaled tables in LH2.3 is they are self contained.
The table format says which variable to use (EG. RPM), the number of scaled rows, the scale, then data.
The WOT table currently has 17 columns, but I could add as many as needed for even greater precision.
The returned WOT value would be added to the interpolated value from the 16 columns in the base + addition tables.
There are already two extra (92 non-cat and 89 cat) EZ tables to use for WOT. The EZ uses 8-bit tables.
There is no overlay of WOT in EZ like the LH, so the entire map will have to be entered by hand.
06-20-2013, 03:54 PM
#172
So if there was one thing to change on these motors, Ken, that you feel would break though, whether its the computer, the cams, the intake, etc - what do you think it is, using your growing knowledge of these 32V engines, and how the S4 sits against the S3.
06-20-2013, 04:36 PM
#173
Race Director
In my experience the next easiest would be cams.....Colin's or reground 85-6 using Elgin is the next best...thats another 40whp easy....
I do know that my puny 1981 4.5L makes 265whp-289 torque..or around S4 power.....
06-20-2013, 05:16 PM
#174
06-20-2013, 05:16 PM
#175
I have a white 88 with 78k I want to sell but I want to drive it a bit with a Ken ship first.
06-20-2013, 06:46 PM
#176
Drifting
06-20-2013, 07:24 PM
#177
06-20-2013, 08:55 PM
#178
Nordschleife Master
06-27-2013, 03:16 PM
#179
Inventor
Rennlist Member
Rennlist Member
Thread Starter
64 column WOT map? Too much? Heck no! 
(64 is the max the code can handle.)
Unfortunately, RPM is read in a bell curve, like a temp sensor, so some areas are more detailed than others (25 ~ 200 rpm divisions).
Still, the injector duty is now super smooth up to 5900, where it levels off. (Compare with the spiky mess in previous logs, above.)
From 6000 up the fueling is dropping quickly so it's difficult to control/more random. It would be nice if the rpm divisions were 25, there!
I may try using a different variable for rpm over 5900. This var is from a set of vars used to calculate the main rpm var.
I may try adjusting the 6000 up region using the (non-cat) adjustment map, or even the MAF ideal (slope) map for more detail.
IIRC, ±1 on the WOT map fuels about 3-4 times what ±1 on the adjustment map.
The MAF reading for the first torque peak's height is highly dependent on weather.
It's close to 70F here, so it's not very high. The first peak is made by the flappy (closed).
(64 is the max the code can handle.)
Unfortunately, RPM is read in a bell curve, like a temp sensor, so some areas are more detailed than others (25 ~ 200 rpm divisions).
Still, the injector duty is now super smooth up to 5900, where it levels off. (Compare with the spiky mess in previous logs, above.)
From 6000 up the fueling is dropping quickly so it's difficult to control/more random. It would be nice if the rpm divisions were 25, there!
I may try using a different variable for rpm over 5900. This var is from a set of vars used to calculate the main rpm var.
I may try adjusting the 6000 up region using the (non-cat) adjustment map, or even the MAF ideal (slope) map for more detail.
IIRC, ±1 on the WOT map fuels about 3-4 times what ±1 on the adjustment map.
The MAF reading for the first torque peak's height is highly dependent on weather.
It's close to 70F here, so it's not very high. The first peak is made by the flappy (closed).
06-27-2013, 07:03 PM
#180
Under the Lift
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