Jeep Garage  - Jeep Forum

Jeep Garage - Jeep Forum (http://www.jeepgarage.org/forums.php)
-   Suspension/Driveline/Brakes (http://www.jeepgarage.org/f172/)
-   -   SRT8 W5A580 Trans Question (http://www.jeepgarage.org/f172/srt8-w5a580-trans-question-24783.html)

Jeeps 06-22-2011 01:48 PM

SRT8 W5A580 Trans Question
 
Anyone know if the programming has been updated for this trans in SRT8 that allows for RPM matched downshifts since it has paddle shifters on the steering wheel? That would be sweet!

Scottina06 06-22-2011 03:04 PM

Re: SRT8 W5A580 Trans Question
 
good question

soontobesrt 06-28-2011 01:34 PM

Re: SRT8 W5A580 Trans Question
 
Very good question! I know that the older A580s did not have the feature as downshifts weren't seamless and actually allowed for engine breaking. The downshift rev matching I believe HAS BEEN introduced on the new transmission tuning but dont quote me.

Don't remember where I read it, probably Milous info or WK2 jeeps maybe but one of the modes sport/track had this feature I think as they control the trans/suspension/engine tuning and it allowed for rev matching for ideal use of the paddles :) Hope Im recollecting correctly, maybe someone knows for sure?

P-Dawger 06-30-2011 02:35 PM

Re: SRT8 W5A580 Trans Question
 
Wouldn't it have to be ? Otherwise wouldn't it just be moving the old shifting from the console up to the paddles? So that is not much of an imporvment in my mind.

True paddle shifting matches revs...

mjw930 06-30-2011 03:00 PM

Re: SRT8 W5A580 Trans Question
 
Quote:

Originally Posted by P-Dawger (Post 440051)
Wouldn't it have to be ? Otherwise wouldn't it just be moving the old shifting from the console up to the paddles? So that is not much of an imporvment in my mind.

True paddle shifting matches revs...

Well, the AMG folks might beg to differ, none of theirs do it and they use the same trans. Personally, I'm of the belief anything short of a dual clutch or sequential auto-manual isn't "paddle shift" but merely an extension of the slap stick shifting on a slushbox that goes by a number of different names.

P-Dawger 06-30-2011 03:30 PM

Re: SRT8 W5A580 Trans Question
 
Quote:

Originally Posted by mjw930 (Post 440064)
Well, the AMG folks might beg to differ, none of theirs do it and they use the same trans. Personally, I'm of the belief anything short of a dual clutch or sequential auto-manual isn't "paddle shift" but merely an extension of the slap stick shifting on a slushbox that goes by a number of different names.

OK well then that is probably the answer...unfortunately.

So they did just move the slap stick to the paddles. I remember the first iteration of the 06 tranny for my Jeep would just bang the rev limiter instead of shifting to the next gear...I remember the first time that happened I was like wft? Software change ensued.

So I'm with you for a true paddle sequential system...but like you said, doubt we got that. (I would have expected more from AMG personally)

About the only thing the slappy stick was good for was slapping down to 1st gear with the Mopar/Corsa exhaust while going through the parking garage in the morning and seeing how many car alarms you could set off. I guess I can do that with my thumbs now :confused: Thanks Chrysler for the upgrade :rolleyes:....

There was a true correlation in the number of alarms set - vs. how well the day went.

soontobesrt 07-05-2011 12:47 AM

Re: SRT8 W5A580 Trans Question
 
Quote:

Originally Posted by P-Dawger (Post 440075)
OK well then that is probably the answer...unfortunately.

So they did just move the slap stick to the paddles. I remember the first iteration of the 06 tranny for my Jeep would just bang the rev limiter instead of shifting to the next gear...I remember the first time that happened I was like wft? Software change ensued.

So I'm with you for a true paddle sequential system...but like you said, doubt we got that. (I would have expected more from AMG personally)

About the only thing the slappy stick was good for was slapping down to 1st gear with the Mopar/Corsa exhaust while going through the parking garage in the morning and seeing how many car alarms you could set off. I guess I can do that with my thumbs now :confused: Thanks Chrysler for the upgrade :rolleyes:....

There was a true correlation in the number of alarms set - vs. how well the day went.

LMAO thats funny, Id hate it I was in the garage since i have a 2-way viper system but would do it at the same time to anyone anytime the opportunity became available haha

Anyway, I just cant see the feature having been introduced only in that it would require a TON more R&D as well as general labor costs upping the total production cost which they wouldnt do. I say this because to rev match on an automatic, paddles or not, the trans software would have to signal to the trans to drop into neutral or at least disengage the TC and then would have to blip the throttle and go into the next gear seamlessly for you, all of which is done manually of course in a MT and naturally occurs and comes with the territory in any MT car. So for an automatic do this without any manual driver input would not only be a first in any auto as far as my knowledge goes (not too far haha) but would also require lot more $ in general. So yeah I'm pretty sure that this is just an extension of our autostick on the steering wheel.

Personally I dont mind, I like the advantage of being able to shift with both hands on wheel for better track racing or hard street racing (in Mexico obviously) All in all its a nice add on, sure its not the bees knees but will certainly make driving more fun. As long as the shift schedule and clutch pressure variable and maybe a few other little tuning specs were bettered for the 6.4 I'll be happy :D

mjw930 07-05-2011 12:15 PM

Re: SRT8 W5A580 Trans Question
 
^^^^

The WV DSG, Porsche PDK both rev match on downshift via fly by wire and I'm sure others like the BMW and Ferrari systems do as well. My wife's SE5 Can-Am Spyder rev matches or "blips" the throttle on downshifts via a hard cabled servo setup.

soontobesrt 07-05-2011 08:36 PM

Re: SRT8 W5A580 Trans Question
 
Quote:

Originally Posted by mjw930 (Post 442463)
^^^^

The WV DSG, Porsche PDK both rev match on downshift via fly by wire and I'm sure others like the BMW and Ferrari systems do as well. My wife's SE5 Can-Am Spyder rev matches or "blips" the throttle on downshifts via a hard cabled servo setup.

hmmm, have any information on these systems? Im googling as I type as I may edit this once I stumble upon it. Seems to make sense based on what you are saying. Im guessing the TCM communicates with the TPS system and automatically blips the throttle the appropriate calculated amount based on the rev change.

The only thing Im still wondering about is the physical transmission action. For a true rev match like in a MT,the trans has to be effectively disengaged, throttle blipped, then reengaged in the lower gear. So guessing for a rev match the computer obviously does it all when the paddle shift down is signaled. Guess its not too much to design into the system, I just dont know exaclty how they do it and what it takes. Seems simple enough, I just figured its not something youd normally see in a Jeep nut then again WHO THE HECK thought they'd ever see FLAPPY PADDLES in a JEEP :eek: Im not against it :)


EDIT: Interesting reads on some newer cars and other forums talking about similar stuff. Apparently the 370Z claims it has this but I too wonder exactly how it does it?

http://www.bimmerfest.com/forums/arc.../t-510059.html
http://www.the370z.com/nissan-370z-g...rev-match.html

mjw930 07-06-2011 03:33 PM

Re: SRT8 W5A580 Trans Question
 
On our GTI with the DSG the electronic throttle increases the revs when the trans shifts to a lower gear but because it's a dual clutch there is no neutral or a time when the clutch is disengaged since it engages the second clutch AS it's disengaging the first. I've noticed that if you paddle shift down and aren't slowing down it will rev match to the lower gear but if you don't also push down the throttle it will engine brake as it comes back to your commanded throttle position. When the throttle position is zero and you downshift it rev matches then removes the throttle so engine braking is more abrupt but not as abrupt as dropping the clutch on a manual without adding throttle. From what I've read it's a much about reducing shock loads to the trans as it is about performance.

On a slushbox with a torque converter there's so much going on based on hydraulic pressures that aren't controlled by the ECU that it would make it next to impossible to program the e-throttle to correctly compensate. I imagine it could be done but I suspect there's so little payback that it's not worth the effort.

soontobesrt 07-08-2011 08:37 PM

Re: SRT8 W5A580 Trans Question
 
Quote:

Originally Posted by mjw930 (Post 443111)
On our GTI with the DSG the electronic throttle increases the revs when the trans shifts to a lower gear but because it's a dual clutch there is no neutral or a time when the clutch is disengaged since it engages the second clutch AS it's disengaging the first. I've noticed that if you paddle shift down and aren't slowing down it will rev match to the lower gear but if you don't also push down the throttle it will engine brake as it comes back to your commanded throttle position. When the throttle position is zero and you downshift it rev matches then removes the throttle so engine braking is more abrupt but not as abrupt as dropping the clutch on a manual without adding throttle. From what I've read it's a much about reducing shock loads to the trans as it is about performance.

On a slushbox with a torque converter there's so much going on based on hydraulic pressures that aren't controlled by the ECU that it would make it next to impossible to program the e-throttle to correctly compensate. I imagine it could be done but I suspect there's so little payback that it's not worth the effort.

Exactly, yea Im with you. So from this the chances that "revmatching" has been built intot his trans programing is slim to none and i think well . . . you know how it goes :lol:

Would have been sweet and may have significantly aided in tranny life but at the same time as has mentioned time and time again, this 580 NAG is a proven performer and handle tons of power, more than anything any SRT8 has thrown at it yet :) Im happy with it and think its a god fit for the new Jeep. Id personally hate an 8 speed (not suggesting anything of course) as Id feel like im in an 18 wheeler with all the gear changes and such close ratios ughhh would suck around town, although it would probably pull like a mofo at any and every speed :D I think a nice 6 speed ZF would be the bees knees though a 5 speed with OD for some nice highway mileage :)

mjw930 07-09-2011 08:32 AM

Re: SRT8 W5A580 Trans Question
 
If you want to talk trick, a dual clutch executed the way Porsche did with the 500hp turbo would be beyond sweet.

http://www.topspeed.com/cars/car-new...e-ar90261.html


All times are GMT -5. The time now is 01:44 AM.

Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Copyright 2012 - JeepGarage.Org
The Jeep Grand Cherokee Owners Community