S-sport shifting issue on high HP
Dec 30, 2011, 09:05 AM
#1
S-sport shifting issue on high HP
Hi guys,
I'm wondering if anyone else out there has run into this issue or has found a solution. At WOT in S-sport mode my SST refuses to shift. The revs just hang and it will slowly push itself into gear. In some instances rev's will actually go up.
In Sport mode this will not happen. Car shifts fine at whatever load I throw at it.
My theory behind it is, ignition advance. In Sport the ECU retards ignition advance to whatever timing I have set in the lower bound timing table. In S-Sport the ECU does not retard ignition advance at all. It keeps whatever timing I have set in the high octane map. In sport mode the closer I bring the lower bound table to match the high octane table the shifting issues will begin to start. Has anyone found someway to control fueling and ignition advance during shift in S-Sport mode? I would be grateful for any suggestions, help or work around's anyone has found. This is driving me nuts.
I'm wondering if anyone else out there has run into this issue or has found a solution. At WOT in S-sport mode my SST refuses to shift. The revs just hang and it will slowly push itself into gear. In some instances rev's will actually go up.
In Sport mode this will not happen. Car shifts fine at whatever load I throw at it.
My theory behind it is, ignition advance. In Sport the ECU retards ignition advance to whatever timing I have set in the lower bound timing table. In S-Sport the ECU does not retard ignition advance at all. It keeps whatever timing I have set in the high octane map. In sport mode the closer I bring the lower bound table to match the high octane table the shifting issues will begin to start. Has anyone found someway to control fueling and ignition advance during shift in S-Sport mode? I would be grateful for any suggestions, help or work around's anyone has found. This is driving me nuts.
Jan 1, 2012, 02:37 PM
#4
Evolving Member
What sort of HP are we talking here?
and does it happen at any particular rpm? or just whenever the car is at WOT?
do you have logs of you trying to shift? Load / Timing / Boost / RPM etc
Have you manipulated any SST related tables at all?
I have heard of this sort of thing happening on powered up MRs, when it just won't upshift and revs stay the same for quite a while - like suspended animation for the SST
Never seen it in person though.
and does it happen at any particular rpm? or just whenever the car is at WOT?
do you have logs of you trying to shift? Load / Timing / Boost / RPM etc
Have you manipulated any SST related tables at all?
I have heard of this sort of thing happening on powered up MRs, when it just won't upshift and revs stay the same for quite a while - like suspended animation for the SST
Never seen it in person though.
Jan 1, 2012, 02:59 PM
#5
375 WTQ 412 WHP tuned on a dyno dynamics. Loads of 300 + . I do have logs I will have to sift through my log folder to find them or go get new ones. What you are describing is exactly what is happening. Suspended Animation for the SST. Loads under 280 it shifts a little slow but shifts. Only at WOT around Peak TQ and Peak power is the problem is the worst. I have manipulated any SST table that would have an effect on this issue that I have access to. TQ limits, TQ exceedance. I have access to many other SST tables that I have basically just been changing to see the effect on the car.
In Sport mode the car shifts great at the same loads. If I increase ignition in the lower bound table to be similar to the high octane map sport mode will begin to have shifting issues. I have been able to get sport mode to shift in .4 10th's of a second at any load, any RPM with the lower bound timing table. There has to be some table either in the ECU or TCU that controls what timing table the ECU references during shifts in different SST modes.
In Sport mode the car shifts great at the same loads. If I increase ignition in the lower bound table to be similar to the high octane map sport mode will begin to have shifting issues. I have been able to get sport mode to shift in .4 10th's of a second at any load, any RPM with the lower bound timing table. There has to be some table either in the ECU or TCU that controls what timing table the ECU references during shifts in different SST modes.
Jan 1, 2012, 03:31 PM
#6
Evolving Member
Ok that's pretty similar to what I'm seeing, Load wise. ~290-310 throughout a pull. And pretty similar power on a DD dyno.
I know this will make it drive like rubbish, but IF you put every SST table back to stock, will it shift ok? I only ask, as i had some very modifed tables, and when i went back to stock and slowly increased things again, i found a happy medium where i wasn't getting slip, and the shifting was still pleasant enough to live with day to day. I realise this isn't your issue though.
Sport mode doesn't get the same line pressure as SuperSport though, so obviously you need to get this sorted!
I know this will make it drive like rubbish, but IF you put every SST table back to stock, will it shift ok? I only ask, as i had some very modifed tables, and when i went back to stock and slowly increased things again, i found a happy medium where i wasn't getting slip, and the shifting was still pleasant enough to live with day to day. I realise this isn't your issue though.
Sport mode doesn't get the same line pressure as SuperSport though, so obviously you need to get this sorted!
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