Since converter is unlocked WOT, lower mph shift points ?
04-05-2004, 02:53 PM
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Since converter is unlocked WOT, lower mph shift points ? As the subject says, since most of us run unlocked, wouldn't the shift points need to be set a few hundred rpm equivalent (or more?) lower than what a pure tire diameter/trans gear/rear gear calculator would say? Of course, I see the opposite if anything, with my short shift issue possibly still lingering...
04-06-2004, 10:31 PM
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"since most of us run unlocked"
EDIT show my yank st3500 in locked at shifts why and what is the differance or best? running 3.23's, all bolt on' over,under and in between ( stock heads)shift set 1-2 @ 6600
( 38 mph) and 2-3 @6500 (78 mph) ( if 2-3 set @ 6600 hit rev limit set at @ 6800
EDIT show my yank st3500 in locked at shifts why and what is the differance or best? running 3.23's, all bolt on' over,under and in between ( stock heads)shift set 1-2 @ 6600
( 38 mph) and 2-3 @6500 (78 mph) ( if 2-3 set @ 6600 hit rev limit set at @ 6800
Last edited by SS SLP2; 04-06-2004 at 10:44 PM.
04-07-2004, 12:31 AM
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I'm starting to wonder about this lock on shifts...
I did more testing, found some open road and the 3-4 shift
happens where it is commanded at least ~6400rpm.
I noticed mph was about 8mph below where I expect
due to converter unlocked I guess.. But here's
the weirdness-- when (default) pcm is supposed
lock on shifts, when does is start this process? A few
hundred rpm before shift, instantly on shift? How quick
can the converter lock/unlock ? If it locks, the mph
and rpm should go to the pure gear calculator type #s-
easy to see when cruising at light throttle, simple, the
rpms just drop 100-200rpm. Maybe the same thing happens
at WOT.. what if early in anticpating shift, maybe it never
lets revs get quite to where it really wanted to shift.
I'll try running with unlocked during shifts, but currently
have no idea whether this is a good/bad idea otherwise-- but
if it might be the only solution to get my motor to run from 6000-6500
at the top of 1st and 2nd gear, got to be done.
Sorry for the rambling post...
I did more testing, found some open road and the 3-4 shift
happens where it is commanded at least ~6400rpm.
I noticed mph was about 8mph below where I expect
due to converter unlocked I guess.. But here's
the weirdness-- when (default) pcm is supposed
lock on shifts, when does is start this process? A few
hundred rpm before shift, instantly on shift? How quick
can the converter lock/unlock ? If it locks, the mph
and rpm should go to the pure gear calculator type #s-
easy to see when cruising at light throttle, simple, the
rpms just drop 100-200rpm. Maybe the same thing happens
at WOT.. what if early in anticpating shift, maybe it never
lets revs get quite to where it really wanted to shift.
I'll try running with unlocked during shifts, but currently
have no idea whether this is a good/bad idea otherwise-- but
if it might be the only solution to get my motor to run from 6000-6500
at the top of 1st and 2nd gear, got to be done.
Sorry for the rambling post...
04-07-2004, 08:40 AM
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You have to "lead" it a little, the shift starts when you
get past the second of the two thresholds (both MPH
and RPM) and needs to get done before Rev Limiter.
On a stock converter you are so tight that you might as
well use the calculator I reckon. Even a 3000 stall, by
6100, is pretty coupled up. Maybe subtract a few miles
off calculated, and then add one by one until you bump
up against trouble.
I don't see converter-locked-during-shift checked in my
HPTuners view of things, in my stock archive image.
My TCC can't hold (just apply some drag) against WOT
anyway....
get past the second of the two thresholds (both MPH
and RPM) and needs to get done before Rev Limiter.
On a stock converter you are so tight that you might as
well use the calculator I reckon. Even a 3000 stall, by
6100, is pretty coupled up. Maybe subtract a few miles
off calculated, and then add one by one until you bump
up against trouble.
I don't see converter-locked-during-shift checked in my
HPTuners view of things, in my stock archive image.
My TCC can't hold (just apply some drag) against WOT
anyway....
04-07-2004, 01:06 PM
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i thought the TCC's were PWM so lockup was not on/off but more like 0-100%. I could be wrong. It would make sense to lockup in a slope from 0-100% if its pressure based or something as it would be less violent on the clutches.
Am i wrong here? Is TCC lockup on/off only? or can it be modulated at all?
Am i wrong here? Is TCC lockup on/off only? or can it be modulated at all?
04-07-2004, 01:19 PM
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There is a PWM, in my tables it's at 97-98% across the
board (close enough to "on") though I believe the apply
is "feathered". There is a TCC Offset param I don't
understand though, and I believe the TCC PWM is a sub-
regulation off main line pressure which fades in and out
with "load".
board (close enough to "on") though I believe the apply
is "feathered". There is a TCC Offset param I don't
understand though, and I believe the TCC PWM is a sub-
regulation off main line pressure which fades in and out
with "load".
04-07-2004, 02:06 PM
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In my '01'-02 edit, you have the apply/release by tps and there is an explicit box 'lock TCC on shift'.
I searched and found a comment that someone believed that the PCM may force an early shift if line pressure is getting out of hand. The valve body work in my built trans is supposed to be mild, so I wouldn't have expected that issue to flare up for me. It seems the short shift for me is worse at a light load, i.e. slightly downhill and/or the first blast that I do. An old school acquaintance of mine suggested that a performance trans needs to be warm enough to operate properly and that some deliberately thin the fluid- maybe something to my experience there, not sure.
I'm going to go back out and log only rpm, gear and line pressue, in order to get more granularity of the rpms and to see where line pressure is on shifts.
I'll report back.
I searched and found a comment that someone believed that the PCM may force an early shift if line pressure is getting out of hand. The valve body work in my built trans is supposed to be mild, so I wouldn't have expected that issue to flare up for me. It seems the short shift for me is worse at a light load, i.e. slightly downhill and/or the first blast that I do. An old school acquaintance of mine suggested that a performance trans needs to be warm enough to operate properly and that some deliberately thin the fluid- maybe something to my experience there, not sure.
I'm going to go back out and log only rpm, gear and line pressue, in order to get more granularity of the rpms and to see where line pressure is on shifts.
I'll report back.
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04-07-2004, 03:33 PM
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Log trans temp too... I see a table that varies base line pressure
(?) with trans operating temp. Though I don't think this "should"
vary the shift decision, it might have some back door effect.
Might as well log as many of the tranny related PIDs as you have
the bandwidth for....
(?) with trans operating temp. Though I don't think this "should"
vary the shift decision, it might have some back door effect.
Might as well log as many of the tranny related PIDs as you have
the bandwidth for....
Originally Posted by Sunset01
In my '01'-02 edit, you have the apply/release by tps and there is an explicit box 'lock TCC on shift'.
I searched and found a comment that someone believed that the PCM may force an early shift if line pressure is getting out of hand. The valve body work in my built trans is supposed to be mild, so I wouldn't have expected that issue to flare up for me. It seems the short shift for me is worse at a light load, i.e. slightly downhill and/or the first blast that I do. An old school acquaintance of mine suggested that a performance trans needs to be warm enough to operate properly and that some deliberately thin the fluid- maybe something to my experience there, not sure.
I'm going to go back out and log only rpm, gear and line pressue, in order to get more granularity of the rpms and to see where line pressure is on shifts.
I'll report back.
I searched and found a comment that someone believed that the PCM may force an early shift if line pressure is getting out of hand. The valve body work in my built trans is supposed to be mild, so I wouldn't have expected that issue to flare up for me. It seems the short shift for me is worse at a light load, i.e. slightly downhill and/or the first blast that I do. An old school acquaintance of mine suggested that a performance trans needs to be warm enough to operate properly and that some deliberately thin the fluid- maybe something to my experience there, not sure.
I'm going to go back out and log only rpm, gear and line pressue, in order to get more granularity of the rpms and to see where line pressure is on shifts.
I'll report back.
04-07-2004, 03:42 PM
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I've having trouble finding a PID for line pressure- for one to exist there would have to be a pressure sensor of some sort in our trans...
Ok, I will log temp, trying to keep the pids to bare minimum to get accurate rpm scans.... Thanks...
Ok, I will log temp, trying to keep the pids to bare minimum to get accurate rpm scans.... Thanks...
04-07-2004, 10:21 PM
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I'm going to post a new thread with my logging results- if the PID is to be trusted, the converter wasn't locking even when the default 'lock TCC on shift' box is checked. Unchecking it with edit didn't help my short shift problem at all, which makes sense if it wasn't locking in the first place.
I also discovered two other minor issues- 4th gear locks up at around 33mph. hangs in there until it disengages at about 27mph- wow. This is why I was getting shaking of the backlash in my rear at low speeds in 4th. The ls1edit tables stock & modified have engage somewhere in the 40s . The stock 3rd gear tables are VERy close to where 4th is happening. The other oddity was getting some surging, but the log revealed it was because the trans was hanging in 3rd gear as I came to a stop in the parking lot instead of downshifitng to 2nd/1st !!
I also discovered two other minor issues- 4th gear locks up at around 33mph. hangs in there until it disengages at about 27mph- wow. This is why I was getting shaking of the backlash in my rear at low speeds in 4th. The ls1edit tables stock & modified have engage somewhere in the 40s . The stock 3rd gear tables are VERy close to where 4th is happening. The other oddity was getting some surging, but the log revealed it was because the trans was hanging in 3rd gear as I came to a stop in the parking lot instead of downshifitng to 2nd/1st !!
