4L60E slow after 60 MPH in H/C car
#1
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4L60E slow after 60 MPH in H/C car
My son bought a 02 Z28 last month and it already had a P&P heads, rebuilt transmission, trans cooler, 3k stall and shift kit installed, basically full bolts-on and suspension.
He never got on the car hard because it had a pretty harsh engine sound at the time but the trans shifted well and hard with the kit. Last week he did a cam swap (VRX5), top end refresh, and we had the car dynoed and tuned and its idling well, except its absolutely dead after 60mph.
In [D] the car will down shift at 55mph and pull slightly, but nothing like what one would think. He's putting 416hp to the ground. After 60mph the car barely even accelerates in [D], but runs hard in D (3rd).
Any ideas?
Thanks in advance!
He never got on the car hard because it had a pretty harsh engine sound at the time but the trans shifted well and hard with the kit. Last week he did a cam swap (VRX5), top end refresh, and we had the car dynoed and tuned and its idling well, except its absolutely dead after 60mph.
In [D] the car will down shift at 55mph and pull slightly, but nothing like what one would think. He's putting 416hp to the ground. After 60mph the car barely even accelerates in [D], but runs hard in D (3rd).
Any ideas?
Thanks in advance!
#6
I am no expert, so I could be way off here but.... from what I hear these automatics have a deadzone area in that mph range you are talking about. If I punch the throttle at 50-60 in my a4 trans am, i don't get near the quick acceleration that I get if I lay the pedal down at a slow roll or stop.
I believe with a tune (I am ordering a frost tune eventually) he can turn off torque management in the automatics that will give you more pull in that range. Also, I've read that different gears will reduce that deadzone. It sounds to me like you may be possibly experiencing the same thing I do in my automatic.
I believe with a tune (I am ordering a frost tune eventually) he can turn off torque management in the automatics that will give you more pull in that range. Also, I've read that different gears will reduce that deadzone. It sounds to me like you may be possibly experiencing the same thing I do in my automatic.
#7
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If Im not mistaking: Toruqe management only happens for a split second while the trans is changing gears. Its designed to keep the clutches from slipping until all the hydraulic pressure is engaged on the apply pistons. what hes talking about kinda reminds me of a slipping trans, I know its got a conveter thats designed to slip but thats only till it reaches full stall speed. What brand is the stall?
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#13
I know it's probably annoying, but my style of learning new things is to ask questions in the form of a statement. So, when I say "I've read it could be this", I am really asking "Could it be this?" "Could this problem be related to something I read earlier?" because I want to know for myself.
I'm hoping someone with more knowledge will chime in and correct me because if I'd never mentioned the torque management or deadzone spot in the auto trans, then I would be still questioning it in my mind.
I do this frequently with more experienced engineers at my job, and have benefited greatly from it. Like I said i'm not an automotive tech, just happen to love to drive and would like to learn more.
Good luck to the OP, i will follow this thread because I want to know what the fix ends up being!
I'm hoping someone with more knowledge will chime in and correct me because if I'd never mentioned the torque management or deadzone spot in the auto trans, then I would be still questioning it in my mind.
I do this frequently with more experienced engineers at my job, and have benefited greatly from it. Like I said i'm not an automotive tech, just happen to love to drive and would like to learn more.
Good luck to the OP, i will follow this thread because I want to know what the fix ends up being!
#15