Strange Experience at the Track
05-17-2008, 12:06 PM
#1
Strange Experience at the Track I replaced my TCI 3000 a couple of months ago with a Yank SS3600, hoping to 60' a little better. It's been working normally on the street since the install.
Last night was the first time I took it to the track. I lowered my tire pressure from my usual 22lbs. to about 18, thinking this converter might hit harder. After the burnout, I tried my usual technique of stomping it from idle. The car came out of the hole incredibly slowly (2.2 60'), but I wasn't spinning. Once it got going, it hit the rev limiter at the top of second repeatedly and would not shift to third. It stayed in second all the way back on the return road. I thought "Oh no, 3-4 clutch pack is toast."
I shut it down and then drove it around a bit and it shifted normally. I let the car cool, upped my tire pressure to the usual 22, and took it for another pass. Same launch technique. It acted completely normally (1.79 60'). Third pass was the same.
Drove home, checked my ATF, all good. What could have happened??
Last night was the first time I took it to the track. I lowered my tire pressure from my usual 22lbs. to about 18, thinking this converter might hit harder. After the burnout, I tried my usual technique of stomping it from idle. The car came out of the hole incredibly slowly (2.2 60'), but I wasn't spinning. Once it got going, it hit the rev limiter at the top of second repeatedly and would not shift to third. It stayed in second all the way back on the return road. I thought "Oh no, 3-4 clutch pack is toast."
I shut it down and then drove it around a bit and it shifted normally. I let the car cool, upped my tire pressure to the usual 22, and took it for another pass. Same launch technique. It acted completely normally (1.79 60'). Third pass was the same.
Drove home, checked my ATF, all good. What could have happened??
05-17-2008, 01:13 PM
#2
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So even when it acted right you lost .08 off of your previous 1.71 60' with the TCI 3000 stall? How did the weather compare? How was the rest of the runs when compared to your old times?
05-17-2008, 03:17 PM
#3
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I have never gotten decent stall until I 'loosen' the convertor with a few hard launches and hard shifts at the track street just doesn't provide enough grip in my experience.
I bet the convertor has more to give and will after a few more hard launches. Also try bowing it up and different RPM launch, you did change setup so try to find the new sweet spot hopefully it is there for u
I bet the convertor has more to give and will after a few more hard launches. Also try bowing it up and different RPM launch, you did change setup so try to find the new sweet spot hopefully it is there for u
05-17-2008, 09:49 PM
#5
It is a little slower coming up, so I think stalling it up will help. I did that a little on my third run, but I have to practice with it and find the best launch technique for it.
But what concerns me was hitting the rev limiter and failure to shift into third. I drove it around on the street today and it continues to behave normally. For whatever reason, my first pass with it was a disaster. I think I'll check my MAF tomorrow and make sure it isn't dirty or anything.
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05-19-2008, 07:45 PM
#8
I know you said you didn't spin, but the behavior you got is similar to what happens when you spin.
FWIW, shift points that worked with ET Streets at the track did not work well on the street with nittos at 26 lbs. My street shift points were 6% - 8% higher than what worked at the track.
FWIW, shift points that worked with ET Streets at the track did not work well on the street with nittos at 26 lbs. My street shift points were 6% - 8% higher than what worked at the track.
05-19-2008, 08:01 PM
#9
I know you said you didn't spin, but the behavior you got is similar to what happens when you spin. FWIW, shift points that worked with ET Streets at the track did not work well on the street with nittos at 26 lbs. My street shift points were 6% - 8% higher than what worked at the track.
Your experience with tires resonates with one of my theories ... that somehow the looser converter with the behavior of the tires at lower pressure threw off the VSS reading and confused the computer. Sounds far-fetched, I know. But after I upped the pressure the next two runs were completely normal.
Or I could have had a shift solenoid malfunction. But it's been normal since.
05-19-2008, 09:27 PM
#12
I think you're on to something. But why? Maybe the long burnout (the tires hadn't been run since last fall) with low tire pressure heated up the tranny. This conveter may generate more heat than my old TCI 3000.
I remember now that my car went into limp mode a couple of times after I first got it, driving on hot summer nights with the A/C (and thus fans) off. It hasn't happened since I lowered my fan temps and got a tranny cooler. But it freaked my out the first couple of times it happened. I thought my tranny was toast - just like I did the other night.
Sorry for the long post - thinking out loud - but I think you've solved my mystery. Limp mode - that explains all my symptoms. Thanks!
05-19-2008, 10:36 PM
#13
I know a bigger converter can cause limp mode, but I don't the science behind it. I know mine will go into limp mode sometimes when I slow down but don't stop completely and the trans is in 3rd gear. When I go to accelerate again, it acts like it doesn't want to drop into 2nd, and when it finally does it sometimes triggers limp mode. Probably need some more tuning.
Anyways, glad I could help. Hope you get it worked out.
Anyways, glad I could help. Hope you get it worked out.
05-19-2008, 11:32 PM
#14
Correction: I double checked my V1 "black box" and found that I was mistaken - I did indeed log that run. That pass showed a P0502 -VSS circuit low voltage DTC. The log showed also that the car started in second - as you suspected - and never left second.
Evidently the converter/tires resulted in a confused VSS signal that triggered limp mode. I guess I could have spared y'all all this drama had I looked more carefully at my record of logs.
Evidently the converter/tires resulted in a confused VSS signal that triggered limp mode. I guess I could have spared y'all all this drama had I looked more carefully at my record of logs.
05-20-2008, 09:20 PM
#15
Correction: I double checked my V1 "black box" and found that I was mistaken - I did indeed log that run. That pass showed a P0502 -VSS circuit low voltage DTC. The log showed also that the car started in second - as you suspected - and never left second.
Evidently the converter/tires resulted in a confused VSS signal that triggered limp mode. I guess I could have spared y'all all this drama had I looked more carefully at my record of logs.
Evidently the converter/tires resulted in a confused VSS signal that triggered limp mode. I guess I could have spared y'all all this drama had I looked more carefully at my record of logs.
05-20-2008, 11:04 PM
#16
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Great Info & Sure glad it's nothing major too!
...By accident, I left my Formula in 3rd instead of D at the track once, and it did the same thing. I also once tried to shift it manually, it didn't like that either and stayed in the lower gear even when I shifted. It shifted only when I backed off the gas. Sure unlike the old school Turbo 400's I'm use to.
(I have a TCI 3200 w/3.73's in my Formula and 1.67-1.70 60 fts. have been my best while flashing the converter. Any more up on the converter and it'll blow away the 26" tall 255/55 X 16" BFG's) When I can find some 17" Chrome WS6 2000-2001 wheels i'll jump up to a 28" tall tire for more footprint and hopefully be able to use more stall.
Good Luck with your sitch & Go Faster...
...By accident, I left my Formula in 3rd instead of D at the track once, and it did the same thing. I also once tried to shift it manually, it didn't like that either and stayed in the lower gear even when I shifted. It shifted only when I backed off the gas. Sure unlike the old school Turbo 400's I'm use to.
(I have a TCI 3200 w/3.73's in my Formula and 1.67-1.70 60 fts. have been my best while flashing the converter. Any more up on the converter and it'll blow away the 26" tall 255/55 X 16" BFG's) When I can find some 17" Chrome WS6 2000-2001 wheels i'll jump up to a 28" tall tire for more footprint and hopefully be able to use more stall.
Good Luck with your sitch & Go Faster...
