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-   -   Uprev Transmission Tuning 7AT (http://www.the370z.com/tuning/50754-uprev-transmission-tuning-7at.html)

370Zfeeler 03-04-2012 06:07 PM

Uprev Transmission Tuning 7AT
 
From what i've searched there are two options included on the Osiris tuning, that would enhance the driveability of the 7AT:

1-Throttle mapping: Being able to eliminate the throttle lag, and provide a better "Feel" to throttle reponse This is a Great Thread on the Topic

2-Tranny Torque Map: Provides the ability to adjust line pressure and shifting speeds, as You add more power to your car the ECU stock torque estimates are way off, by adjusting this parameters You can make the transmission shift smoother and faster and complement your mods.

On this second feature I tried searching for more information but very little came up, any of you guys have played with this option and bumped up values according to different power levels?

370Z JT 03-05-2012 01:02 AM

I had my tuner adjust the line pressure just for fun on my NA Z. The shifts were slightly faster, but don't expect too much difference.

Jordo! 03-05-2012 03:43 AM

Quote:

Originally Posted by 370Zfeeler (Post 1581205)
From what i've searched there are two options included on the Osiris tuning, that would enhance the driveability of the 7AT:

1-Throttle mapping: Being able to eliminate the throttle lag, and provide a better "Feel" to throttle reponse This is a Great Thread on the Topic

2-Tranny Torque Map: Provides the ability to adjust line pressure and shifting speeds, as You add more power to your car the ECU stock torque estimates are way off, by adjusting this parameters You can make the transmission shift smoother and faster and complement your mods.

On this second feature I tried searching for more information but very little came up, any of you guys have played with this option and bumped up values according to different power levels?

You can increase them quite a bit. The shift firmness and speed is also load dependent, so you can have it set to give lightning fast hard shifts even at part throttle if you want.

wstar 03-05-2012 04:37 AM

On the second bit, obviously opinions will vary, but I don't think there's a lot of room to mess with it on an NA car without making things awful for daily driving. You push the numbers just a little bit too high and you get really hard engagements with an ugly drivetrain shock to them. I've seen very shock-y engagements in some areas of the map when raising the stock numbers as little as ~5-10%.

In any case I'm not really convinced the harder shifts are usefully faster on the road (as opposed to trying to shave milliseconds at the drag strip). After all, clutch engagement isn't anywhere near the primary delay factor, most of the delay is in the electronics and other bits in-between your paddle shifters and the actual clutch engagement.

Mostly I think the useful purpose of this map to just to ensure you're not getting slippage (which will cause premature failure) if you've significantly bumped the power (i.e. TT/SC setups). With all that extra power, it takes more line pressure to keep it from slipping like crazy. If it's not slipping now (and it shouldn't be on NA, but you can check via Cipher), there's not a lot of point toying with it.

Jordo! 03-05-2012 04:50 AM

^^^ Driving in regular auto the shifts don't feel particularly different. When gunning it, just slight modulation of throttle input can vary the shift firmness. 3-4 is sometimes a little harsh but definitely not enough to upset the chassis and it's definitely banging into gear faster than stock.

wstar 03-05-2012 04:53 AM

Well, I never drive in "regular auto", so it could be different there. In the M-mode it's a lot more finicky about what you're doing with the throttle when you click for a shift. It generally does it reasonably smoothly if you hold a consistent throttle position all through the process, but lifting or pushing it much during the shift (or just before/after with all the lag in play) leads to uglier shifts.

DougChoe715 03-05-2012 12:51 PM

Quote:

Originally Posted by wstar (Post 1581876)
Well, I never drive in "regular auto", so it could be different there. In the M-mode it's a lot more finicky about what you're doing with the throttle when you click for a shift. It generally does it reasonably smoothly if you hold a consistent throttle position all through the process, but lifting or pushing it much during the shift (or just before/after with all the lag in play) leads to uglier shifts.

That what I thought too. I find it difficult to do smooth gear change when pushing or lifting the throttle.

wstar 03-05-2012 01:49 PM

It's mostly the various forms of lag that cause that. My guestimation (based on behavior I've observed over the past 3 years) is that for the M-mode shifts, the TCM takes a snapshot of your current revs/speed/accel-pedal and decides on a shift-timing and rev-matching strategy to match it, but doesn't update this data as it goes through the process. So if you change the pedal input after it takes its snapshot and it will throw off the results a bit.

If you're trying to force a softer or harder shift, and you nudge the pedal at just the right time in the process, you can have the intended effect flawlessly, but figuring out the timing is somewhat counter-intuitive (again, because of all the inbuilt tiny delays in various systems between button-click and various actions taking place).

I *have* played with D-mode driving from time to time actually, and in general D-mode does seem to cope with arbitrary mid-shift throttle changes better than M-mode does. On the track I have zero issues with this whole M-mode + throttle position stuff anyways though, because if I'm downshifting I'm completely off the accel and into the brakes, and if I'm upshifting I'm generally at a constant throttle position (either nailed to the floor straight line, or some in-between value that's holding a perfect traction balance during a sweeper).

370Zfeeler 03-05-2012 03:56 PM

Quote:

Originally Posted by 370Z JT (Post 1581801)
I had my tuner adjust the line pressure just for fun on my NA Z. The shifts were slightly faster, but don't expect too much difference.

Do you have the numbers He put in your setup? and how different is the shifting feel compared to stock?

-Wstar:
Seems You've played around with it, from the different tweaks You've tried, do You think that in general for a full boltons NA application there's no real gains compared to stock??

wstar 03-05-2012 04:36 PM

I don't drag race (well, I've been to the local strip a couple times for fun, but it's just not something I care much about). It could easily be the case that if you're drag-racing a bolt-on NA 7AT 370Z, upping the line pressure can shave some milliseconds off your times. It certainly does have the intended effect of upping the line pressure, and you can feel the difference in the seat-of-the-pants shock on shifting.

All of that said, I don't think it's worth messing with (again, on an NA car) for regular street driving, or Auto-X, or Road Course racing / HPDE stuff. If anything, it just makes it more likely that you get a jerky engagement and upset the car's balance, which can really screw you if you're on the bleeding edge of traction. With the stock map, the engagements are smooth enough that if you're on the throttle accelerating out through a curve at say 80-90% traction limits, you can upshift while still in the curve (tracking out) and not suffer a spinout. With the jerkier engagements I wouldn't risk it.

Z eliminator 03-05-2012 06:29 PM

I should have my fully built GTM stage (evertyhing) in about 6 weeks.
i will be taking it down the 1/4 mile and will data log it compared to the stock 7 AT.
12.19's here we come, all motor.


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