Transmission tune questions
04-24-2017, 08:34 AM
#1
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Transmission tune questions
Hi guys!
Got 3:42 gears installed had 3:15 in the vette
Wondering if I buy a Programmer if I can tune the trans..
Let the computers knows it is 3:42. Change shift point??
Car shift good but once in a while stall converter will not lock up. And it throw a p1870 code if I remember right. While driving I cleared the code and converter locked right away
Thanks
Got 3:42 gears installed had 3:15 in the vette
Wondering if I buy a Programmer if I can tune the trans..
Let the computers knows it is 3:42. Change shift point??
Car shift good but once in a while stall converter will not lock up. And it throw a p1870 code if I remember right. While driving I cleared the code and converter locked right away
Thanks
04-27-2017, 12:57 AM
#2
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St. Jude Donor '13-'14-'15
You do NOT have to make a speedo corrction on a C5 when changing gears---Howeve you do have yo make a "shift point correction" for both P/T shifting and WOT shifting
A handheld tuner cannot do this--You need to go to a tuner with HP or EFILIVE to corrct these issues properly
As far as the TCC lock up goes--A stall converter requires special tuning as a stall creates "false misfires" which can randomly lock/unlock your converter---A competent tuner knows how to eliminate these false misfires----ALSO It is also a good idea to delete the 3rd gear lock up entirely and then raise the 4th gear lock up not to happen until about 50-53 MPH and the Unlock table to be 13 MPH less thru out the entire table
And finally The lock up is "pulse width modulated" meaning thetrans pressure comes in very slowly to lock the converter This is bad on a stall converter as it creates excessive heat----Tuners can set the PWM tablea to ramp in the lock up very quickly to reduce slippage and heat---best is to set the entire Minimum PWM table to 98% and the maximum PWM table to 99%-----
A handheld tuner cannot do this--You need to go to a tuner with HP or EFILIVE to corrct these issues properly
As far as the TCC lock up goes--A stall converter requires special tuning as a stall creates "false misfires" which can randomly lock/unlock your converter---A competent tuner knows how to eliminate these false misfires----ALSO It is also a good idea to delete the 3rd gear lock up entirely and then raise the 4th gear lock up not to happen until about 50-53 MPH and the Unlock table to be 13 MPH less thru out the entire table
And finally The lock up is "pulse width modulated" meaning thetrans pressure comes in very slowly to lock the converter This is bad on a stall converter as it creates excessive heat----Tuners can set the PWM tablea to ramp in the lock up very quickly to reduce slippage and heat---best is to set the entire Minimum PWM table to 98% and the maximum PWM table to 99%-----
04-30-2017, 11:31 PM
#4
You do NOT have to make a speedo corrction on a C5 when changing gears---Howeve you do have yo make a "shift point correction" for both P/T shifting and WOT shifting
A handheld tuner cannot do this--You need to go to a tuner with HP or EFILIVE to corrct these issues properly
As far as the TCC lock up goes--A stall converter requires special tuning as a stall creates "false misfires" which can randomly lock/unlock your converter---A competent tuner knows how to eliminate these false misfires----ALSO It is also a good idea to delete the 3rd gear lock up entirely and then raise the 4th gear lock up not to happen until about 50-53 MPH and the Unlock table to be 13 MPH less thru out the entire table
And finally The lock up is "pulse width modulated" meaning thetrans pressure comes in very slowly to lock the converter This is bad on a stall converter as it creates excessive heat----Tuners can set the PWM tablea to ramp in the lock up very quickly to reduce slippage and heat---best is to set the entire Minimum PWM table to 98% and the maximum PWM table to 99%-----
A handheld tuner cannot do this--You need to go to a tuner with HP or EFILIVE to corrct these issues properly
As far as the TCC lock up goes--A stall converter requires special tuning as a stall creates "false misfires" which can randomly lock/unlock your converter---A competent tuner knows how to eliminate these false misfires----ALSO It is also a good idea to delete the 3rd gear lock up entirely and then raise the 4th gear lock up not to happen until about 50-53 MPH and the Unlock table to be 13 MPH less thru out the entire table
And finally The lock up is "pulse width modulated" meaning thetrans pressure comes in very slowly to lock the converter This is bad on a stall converter as it creates excessive heat----Tuners can set the PWM tablea to ramp in the lock up very quickly to reduce slippage and heat---best is to set the entire Minimum PWM table to 98% and the maximum PWM table to 99%-----
I agree about deleting the lockup in 3rd, as well as increasing the PWM percentage.
I've gone the other way with my lockup speeds. Don't know why you'd want to wait until 50 mph, particularly with the 3.42 gears. I've got the 3.15 gears and lock up around 40 mph at low throttle.
05-01-2017, 08:36 PM
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St. Jude Donor '13-'14-'15
At 40 MPH at lock up the engine tends to lug too much and is prone to detonation
Also if you data log your fuel usage the car will actually use LESS fuel at say 1800 RPMs when un locked rather than if it's locked at 1600 RPM's again because the engine is lugging and when an engine lugs the ECM dumps more fuel and subtracts timing to compensate for the extra low RPM load----all bad when coming to fuel mileage and max HP/TQ
Also if you data log your fuel usage the car will actually use LESS fuel at say 1800 RPMs when un locked rather than if it's locked at 1600 RPM's again because the engine is lugging and when an engine lugs the ECM dumps more fuel and subtracts timing to compensate for the extra low RPM load----all bad when coming to fuel mileage and max HP/TQ
Last edited by tblu92; 05-12-2017 at 05:52 PM.
05-01-2017, 09:43 PM
#6
At 40 MPH at lock up the engine tends to lug too much and is prone to detonation
Also if you data log your fuel usage the car will actually use LESS fuel at say 1800 RPMs when locked rather than if it's locked at 1600 RPM's again because the engine is lugging and when an engine lugs the ECM dumps more fuel and subtracts timing to compensate for the extra low RPM load----all bad when coming to fuel mileage and max HP/TQ
Also if you data log your fuel usage the car will actually use LESS fuel at say 1800 RPMs when locked rather than if it's locked at 1600 RPM's again because the engine is lugging and when an engine lugs the ECM dumps more fuel and subtracts timing to compensate for the extra low RPM load----all bad when coming to fuel mileage and max HP/TQ
Second, the point isn't whether the car is using more fuel at 1600 locked versus 1800 locked, it's whether it uses more at 1600 locked versus 2000 or so unlocked. I'm not so sure you'd see 1600 locked using more fuel in that case. But just as important, probably more important, is slipping in the torque converter generating heat in the transmission when running a high stall converter. These cars have very limited cooling capability at low speeds. At 40 mph the radiator fans aren't running in stock tune as they cut out at 35. I've bumped mine up to 40.
05-12-2017, 05:56 PM
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St. Jude Donor '13-'14-'15
First, I am not experiencing lugging at 40 mph. Maybe my cam does better at low rpm than what you normally see.
Second, the point isn't whether the car is using more fuel at 1600 locked versus 1800 locked, it's whether it uses more at 1600 locked versus 2000 or so unlocked. I'm not so sure you'd see 1600 locked using more fuel in that case. But just as important, probably more important, is slipping in the torque converter generating heat in the transmission when running a high stall converter. These cars have very limited cooling capability at low speeds. At 40 mph the radiator fans aren't running in stock tune as they cut out at 35. I've bumped mine up to 40.
Second, the point isn't whether the car is using more fuel at 1600 locked versus 1800 locked, it's whether it uses more at 1600 locked versus 2000 or so unlocked. I'm not so sure you'd see 1600 locked using more fuel in that case. But just as important, probably more important, is slipping in the torque converter generating heat in the transmission when running a high stall converter. These cars have very limited cooling capability at low speeds. At 40 mph the radiator fans aren't running in stock tune as they cut out at 35. I've bumped mine up to 40.
When data logging------ The engine will actually use LESS fuel in 4th gear at 1800 RPM's UNLOCKED--- then it will LOCKED at 1600 RPM's
while maintaining the same speed---