UnleashedBeast

iTrader: (2)

I began programming a friends 1998 TA with HPTuners. He has scorched every gear in two transmissions so far with his prior tuning and I noticed something frightning while looking at his shift times/speeds.

The mail order tuner had his shift speed/timing set to .100 in every cell. He didn't increase the factory pressure cap from 90, but I was shocked to see every cell at .100

Is this the reason why he has killed two A4s in his car? He does run a TR224 112 LSA cam, 3200 stall, LT headers, sprays 100 shot of nitrous and runs it at the track almost every weekend.

HumpinSS

iTrader: (1)

I would think the 100 shot on the stock 4l60 is your biggest problem

UnleashedBeast

iTrader: (2)

I see guys running a 100 shot on the stock 4L60E all the time with little to no trouble at all. Surely the shift speed programmed to fast was the problem.

Anyone else have some insight on this matter?

JimMueller

iTrader: (9)

I never ran nitrous, but I think I had that problem in my '95 TA. I bought a built 4L60E from Art Carr with all the valve upgrades. I continued to use the firmest shift settings in Hypertech. I went through three 3-4 clutch packs in six months. I couldn't find a shop which would install the vacuum modulator, so I traded into my current car. But OMG did that car shift hard. Even part throttle shifts could generate whiplash

2xLS1

iTrader: (25)

Why would eliminating any delay in the shift be a problem? Slow clutch pack engagement = slipping = heat. That is what kills tranny fluid and trannies. GM put the delay in there to satisfy the masses buying these cars. Not the hard core racer. I set them all to 0. A better question would be is your friend spraying through the shift?

jimmyblue

iTrader: (11)

I drove around with them zeroed for quite a while.
But commanding less cycle time than the trans is
capable of meeting, simply means the adaptation
will force it to use maximum line pressure whether
it needs it or not.

You could probably get similar and more clear
results just by the pressures and pressure
modifier tables. At least those don't go wandering
around seeking goals and stuff.

Supposedly in some parts of the trans, action has
to wait for things to bleed down and maxed line
can make that -slower-. Maybe if you are trying to
hurry up the next step and the previous hasn't let
go, something bad goes on. Not that I've seen any
such, myself. But I have mellowed it back out and
only put the short adaptation times on it at higher
loads. There's no real value I can see in shifting
hard at part throttle. Other than "feel", which may
or may not relate to anything in the way of reliability
or performance.

Anyway, seen some folks report cleaner shifting with
these settings (really the working line, adapted-to)
relaxed (slower). If he feels anything like a "bind" in
the middle of shifts this is something worth exploring.
Not like 0.15 is really noticeably different from 0.1,
but maybe the trans spends a lot better percentage
of time not being flogged....

UnleashedBeast

iTrader: (2)

I was just curious as to why it was happening and I assumed it was the reduced shift times from programming. He has destroyed 2 built trannys so far with he old tuning.

wait4me

iTrader: (10)

the Shift speed on that table is just telling the trans to try to hit that time during a shift. The shorter the better, but the firmer the shift will be.

If you 0 out that table, then you are just shutting off the adaptive trans learning system. It dont mean you are commanding a 0 second shift..

People with shiftkits are supposed to remove the adaptive shift system. So zeroing out that table is correct.

If not removed with a shiftkit, then the computer sees that the trans is shifting too fast and it will pull pressure " via the adaptive shift system " and try to slow the shifts back down.

That is why guys with a shift kit or modded tranny see the transmission shift really good for a couple miles when they first plug on thier battery. then the trans slowly starts backing down....

jimmyblue

iTrader: (11)

Interesting. So you would zero the table, watch
the shift event speed (as best you're able on a
1/10 or 1/20 sec tick) and just mess the shift
pressure & modifiers until you see a proper cycle
time?

I didn't know that zero turned it (adaptation) off.

kbracing96

iTrader: (25)

That's interesting, only mine does the opposite. I have a shift kit and vette servo, but mine shifts softer on the part throttle 1-2 when it is reset and then get harder the more I drive it until it is too firm for my liking. I'm going to try setting the times to 0 and adjust the part throttle shift with shift pressure to where I like them and leave the high torque shift where they are.

Another_User

That shift setting could cause damage, but frmo what I understand your transmission will never shift faster than about .2. No computer tuning can make your transmission shift faster than it is physically possible to shift. A lot of factory tunes use .2 in their settings, so I don't think that alone would cause a lot of damage. If you combine it with zeroing out your torque reduction during shift tables you might as well throw your transmission in the trash. I noticed on a lot of factory tunes for V6ers with the "performance" button for the transmission they would reduce one setting and raise the other, so your transmission would shift faster but the PCM would pull more timing/torque during the shift or vice-versa. I pulled mine on my Malibu down from .350 to .2 because you could feel the transmission lagging during the 1-2 shift and you cuold tell the difference. It already pulls plenty of timing during the shift itself, but I left that part alone.

Ed Wright

iTrader: (1)

Many factory calibrations have the 3-4 shift times already set to zero.