Predator - A4 shift points - Help
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Joined: Apr 2004
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From: St. Louis MO
Predator - A4 shift points - Help
Installed the Predator "Performance Tune" on my '04 coupe (2.73 A4) yesterday took it over to dyno shop for a couple of pulls and everything was fine.
I went into the modifications menu to see what the adjustments were and noticed that the standard performance tune set my axle ratio to a 3.42. Unfortunately, I have a 2.73 so I made only that change, saved it and modified the tune.
This morning, I took the car out for a test drive and when I put the pedal down (shifter in "D" or "3"), the RPM's would run up in 1st and bounce off the rev limiter without shifting to 2nd. I assume that I need to either lower the 1st-2nd shift speed or raise the RPM limiter. I would rather do the first since the RPMs are breaking 6K and I don't know where the Predator performance tune set the limiter.
I am desparate for help and would really appreciate some assistance with this matter. Thank you in advance for your input.
I went into the modifications menu to see what the adjustments were and noticed that the standard performance tune set my axle ratio to a 3.42. Unfortunately, I have a 2.73 so I made only that change, saved it and modified the tune.
This morning, I took the car out for a test drive and when I put the pedal down (shifter in "D" or "3"), the RPM's would run up in 1st and bounce off the rev limiter without shifting to 2nd. I assume that I need to either lower the 1st-2nd shift speed or raise the RPM limiter. I would rather do the first since the RPMs are breaking 6K and I don't know where the Predator performance tune set the limiter.
I am desparate for help and would really appreciate some assistance with this matter. Thank you in advance for your input.
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Joined: Apr 2001
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From: S.W. Ohio. . . . . . NRA Life Member
I took the car out for a test drive and when I put the pedal down (shifter in "D" or "3"), the RPM's would run up in 1st and bounce off the rev limiter without shifting to 2nd.
In other words when did the problem actually take place... after the Performance Tune upload - or after the change to the 2.73 parameter?
If you didn't go WOT after the dyno tune (but before the change to 2.73) then you might not know which specific step caused the problem.
You can change the Predator back to the 3.42 setting and try it again.
The Predator default setting for rear axle ratio is "3.42". And I've never heard of that causing problems for those with 3.15 or 2.73 ratios... leaving it at the defaulted ratio (even though it is not technically correct).
.
Last edited by Mike Mercury; Feb 16, 2005 at 01:20 PM.
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Mike - Thanks for the prompt response.
Everything was working fine before I changed the axle ratio from 3.42 to 2.73. The dyno runs were made with the performance tune in place and I had made several WOT runs without one instance of the shifting problem. I have not tested to see if the same problem exists for the 2-3 shift, although I will check it out on the way home tonight on the interestate.
It may be as simple as me reducing the "Upshift RPM" with the RPM shift point function. The car seems to be shifting fine at part-throttle shifts, so it it has to be that the "Upshift RPM" is set higher than the "RPM Limit". My Predator manual says:
"NOTE: The shift point functions work in conjunction with each other, based on load. Use the RPM shift point function for WOT (wide open throttle) shifts, and MPH shift point function for part throttle shifts. The vehicle WILL shift at whichever point it reaches first! This is dictated by load on the vehicle, RPM vs. MPH."
Maybe I need to change both settings. I need to see how the performance tune changed the factory settings. I'm at work now, so I will have to wait until I get home to check it out. I'm afraid that if I keep the 3.42 settings, my spedo will be way off.
Everything was working fine before I changed the axle ratio from 3.42 to 2.73. The dyno runs were made with the performance tune in place and I had made several WOT runs without one instance of the shifting problem. I have not tested to see if the same problem exists for the 2-3 shift, although I will check it out on the way home tonight on the interestate.
It may be as simple as me reducing the "Upshift RPM" with the RPM shift point function. The car seems to be shifting fine at part-throttle shifts, so it it has to be that the "Upshift RPM" is set higher than the "RPM Limit". My Predator manual says:
"NOTE: The shift point functions work in conjunction with each other, based on load. Use the RPM shift point function for WOT (wide open throttle) shifts, and MPH shift point function for part throttle shifts. The vehicle WILL shift at whichever point it reaches first! This is dictated by load on the vehicle, RPM vs. MPH."
Maybe I need to change both settings. I need to see how the performance tune changed the factory settings. I'm at work now, so I will have to wait until I get home to check it out. I'm afraid that if I keep the 3.42 settings, my spedo will be way off.
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From: St. Louis MO
Mike - I just got off the phone with Diablosport Tech Support and they said it was a software glitch that was fixed and that I needed to send in my unit for a software update. Hopefully that fixes the problem.
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From: S.W. Ohio. . . . . . NRA Life Member
I'm afraid that if I keep the 3.42 settings, my spedo will be way off.
Team Owner
Joined: Apr 2001
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From: S.W. Ohio. . . . . . NRA Life Member
if you ever want to change your WOT shift points, here is how I selected mine.
Place your A4 shifter in position "1". Take the car to redline and note the MPH on the speedo. Then set your Predator 1-2 shift MPH to 2mph below what you noted earlier.
Then do the same 'cept with the shifter in "2" and take the car to redline - noting the MPH. Then prog your Predator 2-3 shift to 2 mph below that reading.
If you're brave enough... do this in "3" as well
Set all shift point RPM's to 6000.
You may still need to tweak from there, but this will get you to a good starting point.
Your Predator has a few more program fields than my older version.
Place your A4 shifter in position "1". Take the car to redline and note the MPH on the speedo. Then set your Predator 1-2 shift MPH to 2mph below what you noted earlier.
Then do the same 'cept with the shifter in "2" and take the car to redline - noting the MPH. Then prog your Predator 2-3 shift to 2 mph below that reading.
If you're brave enough... do this in "3" as well
Set all shift point RPM's to 6000.
You may still need to tweak from there, but this will get you to a good starting point.
Your Predator has a few more program fields than my older version.
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From: St. Louis MO
Originally Posted by Mike Mercury
please... pleASE... PLEASE edit that out. You do know by now that there is no speedo error induced on the C5 with rear axle ratio changes.
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What version is you predator? I would like to know which one has the software glitch in it. Has this been fixed in the 04 model?
Thanks,
AZC5
Thanks,
AZC5
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From: St. Louis MO
My predator was for 2004 GM vehicles. It was one of the early production models and was running software ver 1.11. The Diablosport website says that the current version is 2.04. I was not told when the glitch was fixed, just that the current version of the software would fix the problem I was having. When you first power-up your programmer, it says what software version you are running at the top of the screen.
