A4 3500 stall converter info....
<small>[ March 28, 2002, 06:12 PM: Message edited by: DUKE ]</small>
I'm working on my 3.73/SY3500 now. I was unhappy with the linear shift speed models that I had been happily using with the 3.15s. I restarted from square one today with the stock shift speed and TCC tables corrected for the 3.73 and was much happier.
The stock shift speed curves are more sigmoidal in shape and I think are better suited to the higher stall than the linear curves. I'm thinking I'll lower the shift speeds a little more at intermediate TPS. Also tighten up the shift durations and line pressure to get a little better shift definition. It's still too slushy at medium-low TPS for pleasant cruising around.
I have 373's and a SY3500.
This is what one tuner did for me:
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">code:</font><hr /><pre style="font-size:x-small; font-family: monospace;"> 0 6 12 18 25 31 37 43 50 56 62 68 75 81 87 93 100
1 to 2 Shift 11 11 13 15 18 21 25 28 32 36 38 40 40 40 40 40 40
2 to 3 Shift 20 20 23 28 33 39 47 53 59 64 70 75 79 82 84 85 89
3 to 4 Shift 28 28 33 40 50 58 65 100 255 255 255 255 255 255 255 255 255
2 to 1 Shift 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 36
3 to 2 Shift 18 18 18 19 21 24 27 29 33 36 40 43 46 52 58 66 83
4 to 3 Shift 25 25 27 29 33 37 43 49 55 64 76 95 108 116 123 132 148</pre><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I liked the following table better, because I make it shift quicker under lower throttle percentages and adjusted the downshifts to match that. It also makes it downshift a little quicker for peppier response instead of lugging the engine in certain situations... but that is driver's preference... you may hate it.
Also, I made 3-4 gear shift lower at higher percentages because I want the car to shift into 4th at WOT at a certain speed. I have not tested this out yet and may have that aspect of it all wrong. But, the lower speed shifts and the WOT shifts from 1st to 2nd to 3rd gear work great for my gearing (3.73) and tire height (26")... for me. Here is the table, but you should REALLY adjust your table from where you are and dial it in:
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">code:</font><hr /><pre style="font-size:x-small; font-family: monospace;"> 0 6 12 18 25 31 37 43 50 56 62 68 75 81 87 93 100
1 to 2 Shift 6 9 12 15 18 21 25 28 32 37 39 41 41 41 41 41 41
2 to 3 Shift 20 20 23 28 33 40 48 54 60 65 71 76 80 83 85 86 90
3 to 4 Shift 28 28 33 41 51 59 66 101 109 113 116 119 122 125 128 131 134
2 to 1 Shift 5 8 10 10 10 10 10 10 10 10 10 10 10 10 10 10 37
3 to 2 Shift 18 18 18 19 21 24 27 29 33 37 41 44 47 53 59 67 84
4 to 3 Shift 25 25 27 29 33 38 44 91 98 102 105 109 112 115 118 121 124</pre><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">
Thanks for the info. That is a great help. I am working with John at Team ZR-1 and he has the engine tunning on track but is not familiar with the specs for an A4...we need somewhere to begin. Thanks again.
You are lockin the TC in lower gears? Will that allow the rpm to reach peak before lockin? Would be interested in your impressions of which set up you think is stronger.
I haven't done WOT TC Lockup adjustments yet. My rearend is about dead (moaning and groaning) and I'm waiting for my 12-bolt. Soon after that I hope to have a stroker. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
My stragegy will be to find where I can have the converter lock up at WOT in 3rd without lugging the engine too much... hoping to pick up some more RWHP on the top end of the quarter. I don't want to lose the advantage of the stall when I need the motor to work hard, but I also want to find when locking the converter will make the car pull harder.
I'm just not in a position to adjust and test this feature yet. <img border="0" title="" alt="[Sad]" src="gr_sad.gif" />
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I think it would be crazy to lock up the converter in 1st gear. I wouldn't bother with 2nd gear either, and apparently GM thinks so, too, since they raise the lock-up points to MPH infinity (255 MPH).
I'd only bother playing around with 3rd gear for racing purposes and 4th gear for cruise convenience. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
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<strong>I'd only bother playing around with 3rd gear for racing purposes and 4th gear for cruise convenience. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I think I'd agree with this. I was playing around with this yesterday and managed exactly the situation you described, lockup in third then shift to fourth. Not really what I was after at all.
DUKE, at this point, I think I'd be willing to say that the converter has a significant influence on the shape of these curves (plots of the tables) and gears have a significant influence on the position of the curves, numerically lower ratios having curves shifted up and numerically higher ratios having curves shifted down. So far I am pretty pleased with the stock curves corrected for just the gears. I don't care for the stock curves with the stock converter but they seem to work quite well with only minor tweaks for the SY3500.
I don't think it's a good idea to think of the shift speed and TCC tables independently. I had to make some plots showing both on the same graph in order to get a clearer picture of the relationships.
Pro tuned shift speeds, 3.15 gear
Pro tuned TCC, 3.15 gear
stock shift speeds, scaled for 3.73 gear
stock TCC, scaled for 3.73
You can see that in general this pro tune uses very linear curves and requires only small increases in TPS to downshift. The stock upshift curves have that flattened and stretched out 'S' shape while the downshift curves are generally concave up. This requires more change in TPS for intermediate TPS to initiate downshift. It's the placement and steepness of the curve in the intermediate TPS that you can play with most effectively to get the throttle response to your liking (within limits.) Make sense?
<small>[ April 01, 2002, 10:15 AM: Message edited by: ToplessTexan ]</small>
On the 4-3 downshift table at 43% TPS, you changed the speed from 49 to 91. Does that make it:
1) At 43% TPS and speeds below 91 mph the car will downshift to 3rd
or
2) At 43% TPS and speeds above 91 mph the car will downshift to 3rd.
I'm asuming its the first choice but wanted to double check.
<strong>Black:
On the 4-3 downshift table at 43% TPS, you changed the speed from 49 to 91. Does that make it:
1) At 43% TPS and speeds below 91 mph the car will downshift to 3rd
or
2) At 43% TPS and speeds above 91 mph the car will downshift to 3rd.
I'm asuming its the first choice but wanted to double check.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Pick option 1. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
My take on it is that it shifts from 3-4 at a Speed vs %TP and you want a 4-3 speed that is somewhere less than that on the deceleration back down. How much less is depending how long you want it to cruise in the new gear before it downshifts back to the previous gear.
So far my car hasn't flipped over on me. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> Anyone else want to interpret?
I look at it like an upward curving line crossing a straight reference line. But the reference line is shifted lower when you cross it. If the reference line did not change, as soon as you reached a certain %TP you would be within a hair of it downshifting if your speed decreased. If the refence line is way down, like the previous table, you cruise in that higher gear longer.
Someone school me if I'm totally whack on the concept. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
I discovered that most of the time I'm in the 12 - 18% range with occasional runs into the mid 20% range. When I give it 33% or more, I expect the car to start moving briskly. With that in mind, I quicken the 4-3 and 3-2 downshifts, primarily at 37% and above.
I also decided that with a loose converter, 3rd & 4th gear really make the car feel dead at low speed. I raised the 2-3 and 3-4 upshifts in the 6% - 18% range to keep the car from bogging and forcing the converter to work so much.
I'm glad I saw this thread. It gave me the push to go out and do it and the car feels better now. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />



