Safest base shift pressure????
Thread Starter
TECH Resident
Joined: Aug 2003
Posts: 960
Likes: 1
From: Central, FL
Safest base shift pressure???? I need to know what the safest base shift pressure is to run? I have mine set at 90, then 93, then 96 for the last 1/4. that is the only way I could get the nice firm shifts at part throttle with my loose stall. the force motor current is stock. I want firm shifts at part, and WOT.
is this safe?
maybe I should adjust the force motor current? any tables out there with firm part throttles, and hard wot's?
is this safe?
maybe I should adjust the force motor current? any tables out there with firm part throttles, and hard wot's?
I recommend that you log the trans input and output
shaft RPM, and look at the ratio in Excel across the
shifts. A proper shift will snap to the next proper ratio
(these will be the gear ratios of the box, dead-on)
in 2 frames or so, whatever your shift adaptation time
is set to. All slip should be across the converter. If
this is the case then you don't need more pressure,
the shift itself is fine and softness is just an artifact
of the looser converter.
However if you are shifting into some torque multiplication
and overrunning the clutches' holding ability then you do
want more pressure.
The messing I've done with the force motor table has been
oriented to the low end, trying to work with a wimp TCC
and low commanded PWM pressure. The big end, you
probably have the pressure you need. But the logs will
tell you, with the right data and display.
If you are snapping to smartly, then more pressure will
not improve anything, just raise stresses. You may
already be seeing this by the "lack of results" (because
the results are already fine, just being masked by the
natural slip elsewhere in the driveline).
shaft RPM, and look at the ratio in Excel across the
shifts. A proper shift will snap to the next proper ratio
(these will be the gear ratios of the box, dead-on)
in 2 frames or so, whatever your shift adaptation time
is set to. All slip should be across the converter. If
this is the case then you don't need more pressure,
the shift itself is fine and softness is just an artifact
of the looser converter.
However if you are shifting into some torque multiplication
and overrunning the clutches' holding ability then you do
want more pressure.
The messing I've done with the force motor table has been
oriented to the low end, trying to work with a wimp TCC
and low commanded PWM pressure. The big end, you
probably have the pressure you need. But the logs will
tell you, with the right data and display.
If you are snapping to smartly, then more pressure will
not improve anything, just raise stresses. You may
already be seeing this by the "lack of results" (because
the results are already fine, just being masked by the
natural slip elsewhere in the driveline).
hey, jimmy, i was logging my trns yesterday after i noticed some slipping and i was wondering if you would like to check it out?
an email would be great...
im not to familiar with line pressure but i have noticed a few things that catch my eye when logging....
i noticed that the force motor duty cycle is at 100%, is this normal? The only time is chages it goes to 0% but only a fractiong at a time and at braking right befre a complete stop..it happens only rarely. Line pressure at idle is at 4%-6%, then goes up to 20-35%. The temps are at 150-217/220ish and never goes back down..... pcs current is somewhere at .40-.50ish (not sure, will double check....but rarely have i seen it go up to 1.x)
sometimes it stops logging and gets stuck.....the line pressure, pc soleniod cycle is at 0, while the line pressure is stuck on previous setting (e.g. 35%) and the force motor stays on 100%...
is this normal ya'll?
sorry for hijacking your thread but i thought that this fit right in with this thread and didnt need another thread....
an email would be great...
im not to familiar with line pressure but i have noticed a few things that catch my eye when logging....
i noticed that the force motor duty cycle is at 100%, is this normal? The only time is chages it goes to 0% but only a fractiong at a time and at braking right befre a complete stop..it happens only rarely. Line pressure at idle is at 4%-6%, then goes up to 20-35%. The temps are at 150-217/220ish and never goes back down..... pcs current is somewhere at .40-.50ish (not sure, will double check....but rarely have i seen it go up to 1.x)
sometimes it stops logging and gets stuck.....the line pressure, pc soleniod cycle is at 0, while the line pressure is stuck on previous setting (e.g. 35%) and the force motor stays on 100%...
is this normal ya'll?
sorry for hijacking your thread but i thought that this fit right in with this thread and didnt need another thread....
update, had the trans checled today I installed two 18k coolers inline and my trans so far hasnt gone above 184*, from the usual 226* that i saw today!!!!!!.......
my shop guy said that the trans is fine but i know there is something wrong. I explained that the car is getting dyno tuned on friday and he reassured me that it wil hold..if not its under warranty and im not apying for the rebuild...
I have question though........i keep noticing that sometimes the values in hp tuner keep getting "Fixd" and at the same point. The pcs actual current is at 0.0, and the pcs duty cycle is at 0.0%, will the line pressure is fixed at 35% and the trans is shift mode "6"...
where do, or better yet, how do i check to make sure the connections to the pcs are ok and not the root of my problems....... because it seems as if the tans is recieving a constant level of line pressure at all rpm ranges, which is not a good thing...
anyone, thanks.
my shop guy said that the trans is fine but i know there is something wrong. I explained that the car is getting dyno tuned on friday and he reassured me that it wil hold..if not its under warranty and im not apying for the rebuild...
I have question though........i keep noticing that sometimes the values in hp tuner keep getting "Fixd" and at the same point. The pcs actual current is at 0.0, and the pcs duty cycle is at 0.0%, will the line pressure is fixed at 35% and the trans is shift mode "6"...
where do, or better yet, how do i check to make sure the connections to the pcs are ok and not the root of my problems....... because it seems as if the tans is recieving a constant level of line pressure at all rpm ranges, which is not a good thing...
anyone, thanks.
