02-16-2019, 09:52 AM | #1 |
Drives: 2017 2SS A8, 2018 Macan GTS Join Date: Sep 2017
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R&T Performance Car of the Year a ZR1...with an A8!
So Road and Track magazine's 2019 performance car of the year is a Corvette ZR1, and that's up against several exotics plus. That being said, I can't help wonder why GM engineers chose to place the A8 in the ZR1 as opposed to the new A10?
The biggest complaint of the judges was in fact the A8. "the awful eight- speed automatic of our test ZR1. The eight speed is faster over a lap than the standard [and excellent] seven-speed manual, but so frustratingly dim-witted and slow to respond that it has no place in a fast car." Personally I find the A8 fast to respond and very intuitive. However my point of comparison is not a Mclaren, a Ferrari or a Porsche. But in spite of this major disapproval the car is still the winner of the group. Although I had the vibration, the two flushes then a torque convertor swap out, I can honestly say I love the A8 on my 2SS and I've always had manuals over the years. Yes it can be temperamental at times when its cold but that goes away at temp. For those of you that have tuned the A8 trans, how would you describe the difference in feeling, shifting and in daily smooth driving. After reading all these threads on the A8's over the forum it would seem they are very tuned down, like the ECM down-tunes the engine and creates throttle lag. Any thoughts? |
02-16-2019, 10:40 AM | #2 |
Drives: 2024 2SS Join Date: Dec 2013
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The takeaway for me is , the awful eight speed automatic is still better and faster than the best seven speed manual.
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02-16-2019, 10:44 AM | #3 |
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02-16-2019, 10:44 AM | #4 |
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02-16-2019, 10:50 AM | #5 |
Drives: 2017 SS 1LE Join Date: Mar 2016
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It’s very simple, there is no trans-axle version of the A-10. Rumor has it that it’s to big for trans-axle.
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02-17-2019, 02:36 PM | #6 |
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The A8 just needs a powertrain engineer/programmer to program it that knows what they are doing. It seems like to me they must have some 75 year old programmer doing the programming who is only interested in making it shift like you are carrying a pallet of eggs that cant be broken.
GM needs to take the cue from Audi ZF 8spd programmer. The Audi's Drive mode is worlds better than the Gm sport mode, Sport mode and Manual mode are worlds ahead of GM's programming.
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02-17-2019, 03:28 PM | #7 | |
Drives: 17 SS 1LE Join Date: Dec 2015
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02-17-2019, 04:20 PM | #8 |
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02-17-2019, 05:20 PM | #9 |
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The fact that any new GM vehicle still comes with the 8 speed makes no sense. Even the new trucks still have it but that’s GM for you.
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02-17-2019, 08:17 PM | #10 |
Drives: 2016 Camaro 1LT Join Date: Jan 2016
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if lap speeds are your measure of success and two cars are all but the same except the transmission and you still say the transmission in the faster lap car is worse, that just looks like you're being stubborn or have an agenda separate from your measurement.
Either the lap times are a poor measure and should be replaced or you need to replace your judges. |
02-17-2019, 11:13 PM | #11 |
Drives: 2016 2 SS Vert Join Date: Dec 2018
Location: Stratford Ont Canada
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My guess is being the trannies are mounted in the rear it doesn't make sense to build a 10 speed for 1 year with small production #s
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02-18-2019, 01:31 AM | #12 | |
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02-18-2019, 07:05 AM | #13 |
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For the 1000th time... the trans is not the issue. The transmission itself is strong and reliable. The tune along with AFM causes shudder issues. On cars without AFM or those with a tune and it disabled there is no problems.
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02-18-2019, 08:17 AM | #14 |
Drives: 17 2SS, 8L90, Cam, Heads, E85 Join Date: Dec 2016
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With what I've seen from HP tuners, as far as I know is the only ones who have consumer tuning support for the 8L90, we don't have access to the parameters we need. From my experimentations the parameters we do have access to don't have any effect or are overshadowed by other ones we don't have access to.
Sure we can change shift speeds and when the TCC locks up, but to me that's just a small part of it, when the shift points seen very good to me considering fuel economy. I think there are hydraulic limitations that need to be corrected, especially in terms of drivability, I just can't believe the programming would sabtoge the transmission like that, low speed/low throttle hard shifts and clunks, etc. It would be one thing if we could monitor the correct PIDs to see exactly what the controls are doing with the pressure ect. To see for example why at 30-40mph on a 8-2, 7-2, downshift why there is a 2 second delay, is it hydraulic? Mechanical? Or is it just the TCM being over protective? I don't think we have the support we need to really tune this transmission, and I'm not sure what everyone else is doing to "tune" the 8L90 to make it so much better? Yes there is the shutter, that mine had and has been gone for 30k since the flush, but to me that's still a very small part of it. I think you have to look at the whole driveline as well, driveshaft, pinion backlash, etc. Like how the car sounds like crap, like it's broken,shifting from drive to neutral to reverse and why it chooses to garage shift sometimes and other times slam into gear making people riding with you think it's broke. |
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