Sunset01

I continue to battle getting my shift points consistent. See sig for mods. I have to either jack the rpm several hundred rpm high or the mph as much as 10mph high (2-3) to get it to shift where I want.... problem is even then, I get inconsistency. The 2-3 will be in a range of 6100-6550, though usually toward that upper end. But then every once in a while you'll get a 6100 shift. (all WOT of course). When it short-shifts 2-3 it does it at around 77mph if it is really short and a desired/good shift is more like 82mph. I'm commanding over 90mph and 6600 rpm at least. The quality of the shift is good and the same whatever the location.

One other questions- when you are logging rpm/gear to determine where it actually shifted-- do you consider the absolute highest rpm reading the shift point? Or is a little drift up through the shift considered normal?

mikey

iTrader: (6)

Log the current gear, mph and rpm. When the PCM commands the shift you will see the gear change. Sometime after that you will see the rpm drop. Thats when it actually happened. Look at the difference and modfiy accordingly. 4L60E's are horribly inconsistent in stock form. I had Rossler build a few of them and they are very consistent.

Sunset01

Thanks, I appreciate it. I have many logs that way & I will go back and study, but I believe the commanded point, as indicated by the gear reported in the scanner, is inconsistent, as I'm describing.. i.e, I don't think the issue is variability in the time the trans takes to shift from when commanded. But I'll study it again. Thanks.

jimmyblue

iTrader: (11)

Line pressure is key to shift cycle time and the force
motor tables vary it with tranny temp (as well as load).
So if your trans is having large temp swings that could
be a player. Short adaptation times should also be put,
otherwise it can take its sweet time deciding and more
variability is "allowed".

Sunset01

Looking at my logs, the variability IS with the time that the PCM is commanding the shift. The actual shift by the trans takes about the same time, whatever the rpm the PCM decided to shift that time.

Jimmyblue, what do you mean by adapation times? I am fairly comfortable with my trans builder as far as setting up the liine pressure, etc. I also thought there was a temp issue, as I first started moving my shifts up for the cam in cold weather just coming off winter. I've logged trans temp and it's pretty steady. THanks all.

I'm ready to plug in another PCM just for kicks. Or trying to think how else I can test. At first, I had mph low & was trying to shift by rpm. At that time, I believe the shifts were more consistent, but low (2-300 rpm low). Then I tried moving the rpm to shift several hundred rpm high- I belive this began some of the inconsistency. Then I moved mph way higher too.... and that's where I am.

deezel

I think jimmyblue is talking about the desired shift time being set low.

Sunset01

I thought it might be that. Not sure if it really has anything to do with my problem, but I'd like to understand it better. i.e., if once the PCM commands a shift, it's up to the transmission, what does the computer change to try to make it shift faster? Also, with a trans that is already performance built, I dont' know what lower settings will do to a trans that already has higher line presssure, etc. Maybe go from another direction what is a good non-trans killing shift time to actually get, regardless of the edit setting...ie., I want to evaluate the shifts I'm getting with my stock trans pressure/shift time/etc tables.

MNR-0

My stock converter will generate as much as 150RPM 1-2 shift variation from run to run depending on the launch. So I jacked the RPM shift back down to 6200 and now whift on MPH. Seems to be more consistent.

Sunset01

I'm going to try going back that way too- going to put the rpms back down and maybe set the mph way down to see where it shifts, though if I go down too far, you get to where the converter is the least efficient and I'm not sure what the computer is going to do with all that extra slip. I'll aim for 58-5900 rpm equivalent and just see what happens. I always assumed the check engine light would come on or a code would be thrown if the trans 'slip' came into play with the computer- anybody know?

Sunset01

On the part throttle shift tables- I have always set them to tail up to the same WOT shift mph by 100%.... and have moved to where they are at my full WOT mph by 70-80% throttle. This should work alright, no?

Sunset01

Ok, set the rpm shifts to 5500. Set the 1-2 and 2-3 mph to 37 and 73 respectively, which would be somewhere around 57-5800 rpm. It shift at 5100rpm this way, about 32mph from my 1 1-2 shift and 63mph for a couple 2-3 shfits. This 86.5% and 86.3% of the commanded shift speed. And I am going on the time the gear changes in the scanner. The actual time to complete the shift seems reasonable. Ugh.
Any help or suggestions much appreciated.

Frame Time RPM Gear MPH
927 174.25 3583.8 2 25.5
928 174.43 3659.3 2 27.3
929 174.67 3740.5 2 30.4
930 174.79 3811.8 2 32.9
931 175.03 3900.5 2 34.8
932 175.21 3994 2 37.3
933 175.39 4077.5 2 39.8
934 175.51 4158.8 2 41.6
935 175.69 4235.3 2 43.5
936 175.93 4327.5 2 46
937 176.11 4400 2 47.8
938 176.23 4464.3 2 49.7
939 176.41 4535.5 2 51.6
940 176.65 4613.8 2 53.4
941 176.84 4693.8 2 55.3
942 177.02 4771.5 2 57.2
943 177.26 4889.8 2 59.7
944 177.38 4992.3 2 61.5
945 177.62 5108 3 63.4
946 177.74 5076.8 3 63.4
947 177.98 4302.5 3 65.9
948 178.1 4202 3 67.1
949 178.28 4212.8 3 67.7
950 178.46 4249 3 69
951 178.7 4275.8 3 71.5
952 178.82 4308.8 3 72.1


1205 224.42 789.8 3 17.4
1206 224.66 762.5 3 16.8
1207 224.84 1489.8 3 16.8
1208 225.02 2679 2 18
1209 225.26 3321.3 1 20.5
1210 225.38 3530.3 1 22.4
1211 225.63 3680 1 24.2
1212 225.75 4012 1 24.9
1213 225.99 4688 1 29.8
1214 226.17 5054.5 2 32.9
1215 226.29 4609.5 2 49.7
1216 226.47 4505.5 2 48.5
1217 226.71 3855.8 2 39.1
1218 226.83 4125.8 2 40.4
1219 227.07 4223.3 2 42.9
1220 227.19 4310 2 44.7
1221 227.43 4391 2 47.2
1222 227.55 4464.3 2 49.1
1223 227.79 4538.3 2 51.6
1224 227.97 4605.3 2 53.4
1225 228.15 4688 2 55.3
1226 228.27 4786.8 2 57.2
1227 228.45 4853.5 2 58.4
1228 228.69 4959.3 2 60.9
1229 228.87 5085.5 3 62.8
1230 229.05 5032.5 3 64
1231 229.17 4335 3 65.2
1232 229.41 4197.3 3 66.5
1233 229.59 4216.3 3 68.4

MNR-0

How are you loggin this? HPTuners? If so, what PID are you using for the commanded gear?

My car will command a gear change in all gears at the 5800RPM watermark regardless where I set the shift at (RPM and/or MPH). Ignore that. Have a look at your RPM vs time plot and check the RPM at which the gear change ACTUALLY occurs, ie., when the revs peak then drop like a lightning bolt. That is where the transmission is ACTUALLY changing.

Allow some shift lag at the track of 150-250RPM or so, but you should be shifting within that margin.

Also, dont bother setting your RPM and MPH to be consistent. Shift on one or the other. I set my RPM at 6200RPM and shift MPH at 44MPH 1-2 and 81MPH 2-3 which corresponds to 6400RPM and 6250RPM respectively.

Sunset01

MNR,

I tune with ls1edit and scan with Ease. Maybe I should try Carputing's beta scanner. I use the 'Current Gear' pid. With my lower shift test, as you can see, I am leaving the rpms down at 5500rpm, while the mph I specify is supposed to be the equivalent of 57-5800.

What do you mean you car will command a gear change at 5800? How come your actual shifts then aren't right around 6000 ?

Thanks.

Sunset01

Well, looks like I solved the problem. I started fresh with a stock '01 Formula 3.23 gear car file, scaled my 3.42 gears and made ALL my edits. I had a problem where TCC lockup occured in 4th gear 10mph earlier than commanded- all fixed, locks up EXACTLY where commanded. 2-3 shift initiated at 79mph/6180rpm while set to 81mph/6200.... a little early, but very close. One more shift (unlogged) seemed exactly the same. SO, what is THE word on which I should bump and let govern the shift-rpm or mph ?

MNR-0

Because the commanded gear doesnt actually engage at WOT until both the WOT RPM and MPH are exceeded, regardless of when the shift "prepares". The VCM will shift off MPH for everything else apart from WOT.

I cant explain it, but I get a gear change commanded at 5800RPM then the shift actually occurs at the WOT RPM and MPH I specify. I think it may be a safety buffer built into the VCM that allows preparation time for the tranny to negage the required line pressure at high RPM.