Boosting line pressure
LS1Tech Sponsor
Joined: Aug 2007
Posts: 380
Likes: 0
boosting line pressure to much brakes things....shift kits make a tranny shift faster and firmer if installed correctly...
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Free Cooler, Free shipping always, 2 year warranty Trans/Coverter combos, No Core or Core charge, $150 LS1 core buy back, All trans Dyno Tested to Be sure it works when you get it.Customer videos, Tech Thread, Open 7 Days a Week! Call or http://opi.yahoo.com/online?u=performabuilt&m=g&t=2
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I have been running around for maybe 5 years now
with a higher than stock pressure profile, in the
lower and mid torque regions and "all in" much earlier.
This by tailoring the force motor table. No evident
downside, a lot firmer shifts and better holding on
the torque converter clutch when locked.
You don't end up any higher pressure at the big end,
zero current is still zero current is still full mechanical
line pressure.
Now, jacking with the mechanical could put you over
the top and blow something out, but simply adjusting
the taper of it doesn't do anything, that doesn't get
done at WOT anyway. Maybe some more pump losses.
Most of the slip complaints I have seen, and experienced,
have to do with the low end where it's really the PCM's
fault, trying to blow off all pressure for fuel economy's
sake. That behavior is easy enough to tweak right.
Shift kits can alter the phasing of events in ways that
simple programming can't; the shift action can be made
quicker, etc. without added pressure and so on. They
are complementary and some aspects can be improved
by either one. I got enough out of programming (spending
much time in experimenting) that I never bothered to do
the shift kit that I have (somewhere). People who have
driven the car, think I have one.
Only if I were seeing slip in the main frictions at the big
end, would I mess with the hardware. Maybe someone
who's real good at setting up, would go the other way
but if you can fix it from the driver's seat, adjustments
are way easier and more fine-tweakable.
with a higher than stock pressure profile, in the
lower and mid torque regions and "all in" much earlier.
This by tailoring the force motor table. No evident
downside, a lot firmer shifts and better holding on
the torque converter clutch when locked.
You don't end up any higher pressure at the big end,
zero current is still zero current is still full mechanical
line pressure.
Now, jacking with the mechanical could put you over
the top and blow something out, but simply adjusting
the taper of it doesn't do anything, that doesn't get
done at WOT anyway. Maybe some more pump losses.
Most of the slip complaints I have seen, and experienced,
have to do with the low end where it's really the PCM's
fault, trying to blow off all pressure for fuel economy's
sake. That behavior is easy enough to tweak right.
Shift kits can alter the phasing of events in ways that
simple programming can't; the shift action can be made
quicker, etc. without added pressure and so on. They
are complementary and some aspects can be improved
by either one. I got enough out of programming (spending
much time in experimenting) that I never bothered to do
the shift kit that I have (somewhere). People who have
driven the car, think I have one.
Only if I were seeing slip in the main frictions at the big
end, would I mess with the hardware. Maybe someone
who's real good at setting up, would go the other way
but if you can fix it from the driver's seat, adjustments
are way easier and more fine-tweakable.
Wow what a good explaintion that is. Yeah his cars feels like someone just snatches the clutch out on a manual everytime the car shifts. It come close to breaking your neck if you are not expecting it.
So in a nut shell the boosting line pressure to a certian point is about the same as buying a shift kit, or comes to a certian degree of a shift kit. But seeing as the shift kit costs money it maybe a better route to just adjust the line pressures?
So in a nut shell the boosting line pressure to a certian point is about the same as buying a shift kit, or comes to a certian degree of a shift kit. But seeing as the shift kit costs money it maybe a better route to just adjust the line pressures?
I have been running around for maybe 5 years now
with a higher than stock pressure profile, in the
lower and mid torque regions and "all in" much earlier.
This by tailoring the force motor table. No evident
downside, a lot firmer shifts and better holding on
the torque converter clutch when locked.
You don't end up any higher pressure at the big end,
zero current is still zero current is still full mechanical
line pressure.
Now, jacking with the mechanical could put you over
the top and blow something out, but simply adjusting
the taper of it doesn't do anything, that doesn't get
done at WOT anyway. Maybe some more pump losses.
Most of the slip complaints I have seen, and experienced,
have to do with the low end where it's really the PCM's
fault, trying to blow off all pressure for fuel economy's
sake. That behavior is easy enough to tweak right.
Shift kits can alter the phasing of events in ways that
simple programming can't; the shift action can be made
quicker, etc. without added pressure and so on. They
are complementary and some aspects can be improved
by either one. I got enough out of programming (spending
much time in experimenting) that I never bothered to do
the shift kit that I have (somewhere). People who have
driven the car, think I have one.
Only if I were seeing slip in the main frictions at the big
end, would I mess with the hardware. Maybe someone
who's real good at setting up, would go the other way
but if you can fix it from the driver's seat, adjustments
are way easier and more fine-tweakable.
with a higher than stock pressure profile, in the
lower and mid torque regions and "all in" much earlier.
This by tailoring the force motor table. No evident
downside, a lot firmer shifts and better holding on
the torque converter clutch when locked.
You don't end up any higher pressure at the big end,
zero current is still zero current is still full mechanical
line pressure.
Now, jacking with the mechanical could put you over
the top and blow something out, but simply adjusting
the taper of it doesn't do anything, that doesn't get
done at WOT anyway. Maybe some more pump losses.
Most of the slip complaints I have seen, and experienced,
have to do with the low end where it's really the PCM's
fault, trying to blow off all pressure for fuel economy's
sake. That behavior is easy enough to tweak right.
Shift kits can alter the phasing of events in ways that
simple programming can't; the shift action can be made
quicker, etc. without added pressure and so on. They
are complementary and some aspects can be improved
by either one. I got enough out of programming (spending
much time in experimenting) that I never bothered to do
the shift kit that I have (somewhere). People who have
driven the car, think I have one.
Only if I were seeing slip in the main frictions at the big
end, would I mess with the hardware. Maybe someone
who's real good at setting up, would go the other way
but if you can fix it from the driver's seat, adjustments
are way easier and more fine-tweakable.
I know when Frost was tuning my car last week, my transmission was shifting softer than stock. We bumped the profiles and now she is nice and firm. Sometimes I can chirp 2nd gear with about 50% throttle, but when I am at WOT no chirping, just nice firm shifts. There should be a difference in your neck being snapped verse you feeling a nice bump when the car is shifting.
I have my own way of doing it.
I have a shift kit, the only thing I did to the programmed line pressure was raise the upshift pressure modifiers.
I've had a gauge and HP Tuners on the car at the same time.
Raising the pressure modifiers increases the pressure only right before the shift, during, and for a very short time after.
I've fixed shift timing issues like this as well.
But mainly this allows pressure to be raised when needed most and it lets it run normal all other times.
I've also been into my trans and done other mods so nothings slipping, and the tcc holds at stock pressure.
I have a shift kit, the only thing I did to the programmed line pressure was raise the upshift pressure modifiers.
I've had a gauge and HP Tuners on the car at the same time.
Raising the pressure modifiers increases the pressure only right before the shift, during, and for a very short time after.
I've fixed shift timing issues like this as well.
But mainly this allows pressure to be raised when needed most and it lets it run normal all other times.
I've also been into my trans and done other mods so nothings slipping, and the tcc holds at stock pressure.
