i think stall wall is when you put a big converter in your car and it refuses to shift at WOT. not entirely sure, my only automatic 4l60e car was stock and untuned.
i think stall wall is when you put a big converter in your car and it refuses to shift at WOT. not entirely sure, my only automatic 4l60e car was stock and untuned.
if i said make me a set of shift tables that'd be not great but just passable for a midsize cam with a medium and large stall, could you rough them out? how about just more aggressive for a stock-ish car, a bit more line pressure and higher shift points?
now on beta 12.
im thinking this one is ready for public use
i've tested it on windows xp and it seems really good.
it uses way less ram than previous versions.
i added a 'programming stability test' to the flash routine section that repeatedly uploads routines and retrieves data for 15 iterations to ensure programming is stable (so you can see if flashing is a good idea or not).
the only thing that's missing is additional data from the e-side, but im not sure i even care about the e-side data right now? it's just a treat that it works at all.
and the only fault i can find is that cpu usage during playback with the graphing window open is fairly high due to constant graph refreshing. it works well, though.
manged to cut cpu usage in half for cursor refresh. might be good enough. it's 5% on my quad core, just concerned it'll be heavy on a netbook or whatever.
Well, the transmission operation is rather complex. Gear ratio and tire size changes also change the input shaft torque in each gear which then affects the converter slip. So, even just changing the shift curves 21% because the rear gear changed from 3.08 to 3.73 is not likely to produce the desired results.Originally Posted by steveo
This is how I made my shift curves. I went for a drive with each gear manually selected and recorded the speed at 10%, 20%, 30%, 40% throttle. Then, I created a shift curve that follows these just below those values blending it to the WOT shift speed. I logged WOT to determine the top speed reached in each gear. You have to set the downshift mph points in the kickdown mode table to the same upper values as the main shift table. Otherwise, funny things happen as the throttle transitions back and forth past the kickdown mode scalar.
So, I suppose you could calculate the approximate WOT mph for each shift by using gear ratios and allowing some rpm drop for the stall. Then, make curves that start at a minimum speed for each gear (maybe 1/4 for 1st, 1/3 for 2nd etc) and curves up into this maximum mph. Make the curve whatever shape you think would work best. I don't know how well this would work but it'd be a good start.
I have not experimented with line pressure enough to say just do this to make it better. But, you could pull-up the low and middle parts of the main line pressure table and still be safe. Messing with the force motor current isn't a very good idea. But then, if you make a tune for an unknown transmission build then who knows how well the force motor current table matches with the transmission. I mostly just find lots of comments about too much line pressure blowing the pump or low pressure burning out clutches from people who have blindly messed with line pressure changes (via tuning or shift kits or shims or turning the screw in the force motor or ???) when trying to find useful info about this. Which basically tells me you actually need to put a pressure gauge on your transmission to do it right. So, once again a way to manually set the line pressure to do testing would be beneficial. I would basically linearly vary the line pressure from 0 to 96 and ensure the actual pressure also linearly increases from the minimum to maximum. Then, if I didn't like the minimum or maximum I would adjust the force motor table and test again.
I find this very interesting. I wonder if I haven't been experiencing these funny things.
1994 LT1/4L60E Formula
this entire line of tuning conversation makes me really glad i have a stick. the human mind is a perfectly good transmission controller.
seems there's a lot of opportunity for a bad transmission tune to cause long term damage too.
Yes, and on top of that the 4l60e is notoriously difficult to build. I'll be investing in a new trans soon and after the cost of this rebuild plus the previous rebuild I could have had a t56 in my car and been happier, until I grenaded the ten bolt.
1994 LT1/4L60E Formula
4.5 stable: http://fbodytech.com/eehack-2/download-eehack/
It's not just the same points, but the curve as well. Otherwise, what basically happens is that when the normal downshift is lower between the 2 tables then you can get this downshift-upshift thing happening if you move the throttle into and out of kickdown. Also, you get to the speed where you have to be at WOT to downshift when it should happen at a lower throttle. Here is an example where the normal 2->1 shift point is 10mph while the kickdown mode is 28mph. So, one you are over 10mph you have to go WOT to get a kickdown.
Attachment 10378
Now, if you modified the normal curve so it came up to 28mph as well then you could get part throttle kickdown between 10mph and 28mph. For example, at 17mph 50% TPS might cause a kickdown. To me, it just makes more sense to build a kickdown curve so that it will kickdown into a lower gear once I give it enough throttle to be accelerating in the lower gear, rather than requiring WOT for a kickdown.
some people reported issues with log playback
apparently if you go back and forth a bit it was possible for stale data to be displayed.
this was due to some edge cases in logic i was struggling with earlier, related to the fact that i maintain a single linear log for all datastream messages, making truly time-linear display more expensive.
released 4.5.1 to address these issues
Ok this is not the kind of issue I've been having. Mine sometimes doesn't want to shift into 3rd gear until way high up in rpm, and sometimes not at all. When it does this I put it in neutral and let the rpms come down then I shift it back into gear and it shifts. Always has shifted firm and no slipping at wot. I had some bad shutter above part throttle recently and after that 3rd and 4th slip above around 50% throttle, but hold fine otherwise. Time to hook up a pressure gauge.
I agree, seems logical.
1994 LT1/4L60E Formula
now packaging an installer-free eehack for 64 bit linux:
http://fbodytech.com/now-packaging-linux64-build/
Stall wall is actually the computer seeing the stall at launch as the transmission slipping because of the setting of the vss diagnostic rpm, the trans then goes into "limp mode" and you get second gear starts until the car is restarted. From what I've read doing research, changing the vss enable min diagnostic rpm to something above your stall speed is supposed to cure this. I did read something from a highly respected high dollar lt1 tuner where he straight up stated that there's more to it and there's something else you have to change that isn't available in tuning software and he had a special hack to fix it. I got the feeling that he was saying this because he charged a lot of money to do tunes...
Last edited by fbody_Brian; 03-24-2016 at 04:19 PM.
1994 LT1/4L60E Formula
ahh i never even noticed what the diagnostic rpm was really for. that's a good tip.Stall wall is actually the computer seeing the stall at launch as the transmission slipping because of the setting of the vss diagnostic rpm
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