auto trans shift points - Tuning Forum

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auto trans shift points
Saturday, August 05, 2006 12:15 PM
ok so im going to buy hpt soon. already know a few things im going to do. but my main question is about the auto trans shift points.

the trans automatically shifts a good amount before the red line but can i move that shift point closer to redline and still shift right so it doesn't hit the limiter. like is there a buffer i need between the shift point and the rev limiter? if there is then what is it? or can i set the shift point right to redline and still work perfectly?



If I'm weird and everyone else is weird, does that make me normal?
-me

Versus Motorsports really @!#$ sucks
and so does DHL...but more

Re: auto trans shift points
Saturday, August 05, 2006 3:49 PM
To answer your question, yes but it really depends on how much power you are making or actually how fast your motor revs up. You can set both the shift point and rev limiter higher as well as shift speeds. If you have a high hp motor that revs up faster than the trans can shift you will hit the rev limiter if the shift point and rev limiter are too close to one another.

For example, on my car the shift point is currently set to 7,000rpm and the rev limiter is set to 7,200rpm. In first gear my motor revs up so fast at wide open throttle the trans simply can not shift fast enough to avoid hitting the rev limiter at it's current settings. A solution to this would be to set the rev limit higher until it is the trans has enough time to shift bewteen gears without hitting the limiter. There are many other settings in the software for the trans as well but i am not very familiar with them. If there is something i missed, i'm sure Protomec will post the rest of the details.


- 93 mph in the 1/8 mile
Member of J-Body Of Michigan.

Re: auto trans shift points
Saturday, August 05, 2006 8:27 PM
There is a desired shift time table.





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Re: auto trans shift points
Saturday, August 05, 2006 10:19 PM
Shifted wrote:There is a desired shift time table.


That really didn't help much at all for avoiding hitting the rev limiter, at least in my case. It did however make the partial throttle shifts feel much better.


- 93 mph in the 1/8 mile
Member of J-Body Of Michigan.

Re: auto trans shift points
Saturday, August 05, 2006 11:11 PM
Might have to play with the force motor current table along with the WOT shift speed table to get it to kick at the right time.





4cyltuner.com - Information Source For 4 Cylinder Tuners
Buy stuff from CarCustoms Ebay! Won't be disappointed!

Re: auto trans shift points
Sunday, August 06, 2006 11:27 AM
there is no reason to ever play with FMC.



What makes the original poster really thing his car is shift so far ahead of the rev limiter?

Post a log.


sig not found
Re: auto trans shift points
Sunday, August 06, 2006 2:23 PM
protomec wrote:there is no reason to ever play with FMC.



What makes the original poster really thing his car is shift so far ahead of the rev limiter?

Post a log.


and why is that? the FMC is a good way to get more firm/qucker shifts.


_______________________
** Flat Broke Racing Inc.**
Re: auto trans shift points
Sunday, August 06, 2006 3:29 PM
its a way, just not a particularly good way

FMC is just a look up table for the pcm to know how to get the trans to do what other settings in the calibration call for.

There really isn't any reason to change it unless you make physical changes to the hydraulic system inside the trans causing the the table to now be inaccurate.

If you change the table to change how it shifts, you are only faking how it shifts... pretty much the same way an Autotrans interceptor or B&M unit does it.

The reason this is less than optimal is because the other parts of the calibration still expect this to be accurate.
Example (# are for example only and not necessarily accurate): the PCM makes a shift command at what it expects to be 30 psi. At 30psi the pcm expects the piston and accumulater to fill when it opens solenoid 2 in .08 seconds. So it holds Solenoid 1 on for the 1st .05 seconds because it knows it will take .02secs for it to dump its fluid. Your changes to FMC now have it running 60psi when it commands 30psi and this causes solenoid 2 to fill in .04 seconds. Causing 2 circuits to be partially engaged at one time.

The best way to make similar changes is to alter the shift pressure and shift time tables. This will get you the proper results while keeping the PCM accurately in control of all functions.


sig not found
Re: auto trans shift points
Saturday, August 12, 2006 9:36 AM
eh i figured it out guys...thanks

got it shifting at like 6650 now. took alot of trial and error and help form eric. hit the limiter several times lol. but got it working nicly now



If I'm weird and everyone else is weird, does that make me normal?
-me

Versus Motorsports really @!#$ sucks
and so does DHL...but more
Re: auto trans shift points
Saturday, August 12, 2006 4:17 PM
How does it feel? Did the power drop off any at higher rpms?
Re: auto trans shift points
Saturday, August 12, 2006 11:28 PM
yeah it was kinda fun

now to learn more on tweaking the more difficult settings








Re: auto trans shift points
Friday, April 11, 2008 12:20 AM
AZSpitFire97 (Todd) wrote:eh i figured it out guys...thanks

got it shifting at like 6650 now. took alot of trial and error and help form eric. hit the limiter several times lol. but got it working nicly now


i know this post is old, but do you still have that file? it is a little tricky. lol



Listen F***ers. FASTERTHANAHONDA is a joke because I WORK FOR HONDA. I'll talk @!#$ about Fords to, that doesn't mean I can beat a 12 second mustang.
Re: auto trans shift points
Tuesday, April 15, 2008 3:59 AM
I would be interested also.



PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
Re: auto trans shift points
Friday, April 25, 2008 9:47 PM
sorry about not seeing this earlier...jarett told me about this thread

honestly no car is the same with the shift points. the points were different between my vert and coupe.

it is alot of trial and error till it doesn't hit the limiter



If I'm weird and everyone else is weird, does that make me normal?
-me

Versus Motorsports really @!#$ sucks
and so does DHL...but more
Re: auto trans shift points
Tuesday, April 29, 2008 6:35 AM
mine slaps the limiter... can i simply raise the rev limiter until it shifts correctly at WOT?



Rollin' on question marks since 07.
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