yfz350

iTrader: (1)

Let me start out by saying all I do with my car, 2002 Camaro SS A4, is drive it approximately 10 miles to the dragstrip to bracket race and then back home. I have tried to tune my car to make it run more consistent times and have been pretty successful, however, can't seem to get it to shift consistently. If someone could take a look at my tune and give me suggestions, it would be greatly appreciated as I am still very new to this. Thanks in advance!

kbracing96

iTrader: (25)

Do you have a log of the inconstant shifting? What have you done to the tranny? Shift kit? Servos? Could be that the tranny is slipping and not capable of making the shift happen when it is commanded.

yfz350

iTrader: (1)

Do not have any logs at this time. I will try to get some next time I go to the track.
Completely stock transmission with 87,000 miles.

redsscamaroboy

iTrader: (7)

What is inconsistent? Shift mph?shift rpm?both? shift taking too long/slipping ?
dreaded 2-3 rev limiter?

Looking for some more info.

David

yfz350

iTrader: (1)

Not sure about mph. I know the RPM varies. It seems to shift normally when hot. If I let it sit in between rounds and cool down around 45 minutes it seems to shift a couple of hundred rpms higher. I did have trouble with 1-2 rev limiter, but changed my shift point down to avoid this. I'm running 1/8 mile so I don't get to 3rd.

jimmyblue

iTrader: (11)

Force motor table has a very strong slope with
temperature. This is the last stage of translating
commanded pressure to delivered pressure via the
current in the PCS.

Check whether you are getting to zero (or 90mA
in stock tune) PCS current when you are at WOT.
Since the tables run off delivered torque you may
or may not hit max pressure. Things that modify
the delivered torque computed value then will
significantly alter line pressure.

Running at "all in" shift pressure may still leave you
with variation in shift speed, with viscosity / true
pressure at the "business end" varying w/ temp.
But you can eliminate or counter the table-based
pressure variation if you can correlate the behavior
to trans fluid temp, delivered torque, etc.

Me, I'm not for bracket racing; just mat it and get
what I get. My force motor current is on the floor
by 300 lb-ft just so I know the trans isn't going
hungry.

Also note in some models there is an insane "blowoff"
current value in the 100% column. If you ever get
over the index value for the second-last one (like if
you raised max-line clip limit which is stock set to
the exact value) you might be interpolating slightly
into "give me less when I wanted more" territory.
I'd set that 100% column to the same as 96% (or
whatever) column just for sanity & safety.

yfz350

iTrader: (1)

thanks! I'll check it out and see what it does. I'm going to try to go to the track tonight if it doesn't rain and get a few data logs to post up.

yfz350

iTrader: (1)

I went to the track to try to get a few logs this weekend but everything was acting normal. Will try again next time.

Russ K

iTrader: (1)

yfz350,

Try this trans tune, I firmed up the shifts, set up the part throttle & WOT shift speeds. Also set up the TCC min & max duty cycle tables, and the lock up points. You had your tune set up to disable the trans upshift torque reduction. That is not a good plan, I set your tune to have 50% of stock upshift torque reduction. The trans will live a lot longer this way.

Looking over your tune, you have too much spark timing. What is your WOT AFR?

Russ Kemp

yfz350

iTrader: (1)

I uploaded the tune you modified but was unable to get any data logging due to my laptop battery dieing on me :\ Everything seems to be normal at the moment though *shrug* I'm still going to try to get a good data log for you guys to take a peak at for me if you don't mind doing so though.

Hantzum

iTrader: (13)

I had the same problem when I was running my 4L60E. I was commanding shift points at 5850 at 1>2 then 5900 2>3. Every time I went from 2 > 3 I banged the limiter, had to let off then it would shift. The thing is I was commanding at such a high shift point because by the time the car actually shifted it was almost 7000 grand. Almost a 900 RPM difference between what was commanded and what actually happened.

The way I fixed it was either dramatically lowering the shift points, but then you lose your power band and run shitty times or leave our car in drive.
Do you burnout then stage, but as our staging leave your car in drive, don't manually shift, almost can guarantee this will fix it. The 4L60E's are bad about this. When you manually shift them they seem to not like it very much thus banging the rev limiter, but for some wierd reason this seemed to work every time with me until I blew the transmission. When that happens to you just upgrade to a TH350 or power glide, then you won't have to worry about shift points anymore, everything is manuel shift from then on out.
Hope that helps.