DCT update
Thread Starter
Racer
Joined: Sep 2018
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DCT update
https://www.roadandtrack.com/new-cars/future-cars/a29758062/c8-corvette-dual-clutch-dct-tremec-technical-specs-analysis/
As suggested by some, tweaks are underway.
As suggested by some, tweaks are underway.
Last edited by midengine; Nov 11, 2019 at 05:01 PM.
Popular Reply
Nov 11, 2019, 06:47 PM
Le Mans Master
Joined: Oct 2005
Posts: 7,088
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From: Metro Detroit Michigan
From the article:
"Too often we found ourselves running into the rev limiter, or having downshifts denied after a paddle pull."
Well duh, that's an operator problem. What is the car supposed to do if the driver is dumb enough to ask for operation outside the engine's rev range, Road and Track?
"Too often we found ourselves running into the rev limiter, or having downshifts denied after a paddle pull."
Well duh, that's an operator problem. What is the car supposed to do if the driver is dumb enough to ask for operation outside the engine's rev range, Road and Track?
Le Mans Master
Joined: Dec 1999
Posts: 6,516
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From: One Hour From Boston!
Le Mans Master
Joined: Oct 2005
Posts: 7,088
Likes: 1,829
From: Metro Detroit Michigan
From the article:
"Too often we found ourselves running into the rev limiter, or having downshifts denied after a paddle pull."
Well duh, that's an operator problem. What is the car supposed to do if the driver is dumb enough to ask for operation outside the engine's rev range, Road and Track?
"Too often we found ourselves running into the rev limiter, or having downshifts denied after a paddle pull."
Well duh, that's an operator problem. What is the car supposed to do if the driver is dumb enough to ask for operation outside the engine's rev range, Road and Track?
Instructor
Joined: Jul 2019
Posts: 161
Likes: 84
From the article:
"Too often we found ourselves running into the rev limiter, or having downshifts denied after a paddle pull."
Well duh, that's an operator problem. What is the car supposed to do if the driver is dumb enough to ask for operation outside the engine's rev range, Road and Track?
"Too often we found ourselves running into the rev limiter, or having downshifts denied after a paddle pull."
Well duh, that's an operator problem. What is the car supposed to do if the driver is dumb enough to ask for operation outside the engine's rev range, Road and Track?
Drifting
Joined: Aug 2019
Posts: 1,859
Likes: 1,264
From: Houston
With the C8 you can shift down to the lowest available gear by holding the paddle, and it will continue to do so as the speed goes down. I wonder why they didn't do this to overcome the issue with it not queueing gears.
Melting Slicks
Joined: Feb 2016
Posts: 2,984
Likes: 380
From: Edmond Oklahoma
From the article:
"Too often we found ourselves running into the rev limiter, or having downshifts denied after a paddle pull."
Well duh, that's an operator problem. What is the car supposed to do if the driver is dumb enough to ask for operation outside the engine's rev range, Road and Track?
"Too often we found ourselves running into the rev limiter, or having downshifts denied after a paddle pull."
Well duh, that's an operator problem. What is the car supposed to do if the driver is dumb enough to ask for operation outside the engine's rev range, Road and Track?
Don't forget, this is the first go for GM and the supplier for DCT. And Chevy's last auto in the C7 has been a bust too.
Last edited by LowRyter; Nov 11, 2019 at 07:26 PM.
Melting Slicks
Joined: Feb 2016
Posts: 2,984
Likes: 380
From: Edmond Oklahoma
So you think they didn't read the directions or hear the briefing before they wrote this?
Last edited by LowRyter; Nov 11, 2019 at 07:30 PM.
Burning Brakes
Joined: Dec 2017
Posts: 1,068
Likes: 858
No, not really the first go-round since Tremec bought Hoerbiger Drivetrain Mechatronics, which has been doing DCTs for many years!
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Le Mans Master
Joined: Oct 2005
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From: Metro Detroit Michigan
Last edited by Warp Factor; Nov 11, 2019 at 07:50 PM.
Melting Slicks
Joined: Feb 2016
Posts: 2,984
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From: Edmond Oklahoma
But you still didn't consider the substance of the complaint.
I don't think so. As Jason said above, if one wants to cue downshifts as they come into range, you simply keep the downshift paddle pulled. That way, you don't have stored downshifts occurring when you don't expect them, or at inopportune times, or when you no longer want them. R&T just didn't know how to work the car.
Really?
Last edited by Steve Garrett; Nov 11, 2019 at 10:35 PM. Reason: Merged Posts-please use the Multi-Quote button to make your response look like this.
Le Mans Master
Joined: Oct 2005
Posts: 7,088
Likes: 1,829
From: Metro Detroit Michigan
Melting Slicks
Joined: Feb 2016
Posts: 2,984
Likes: 380
From: Edmond Oklahoma
So you're implying that you've driven one? Or know better than someone that has and is writing about it?
Race Director
Joined: Feb 2011
Posts: 14,742
Likes: 5,605
From: AZ
The writers prefer an actual automatic shift at the rev limiter in manual mode and prefer to have the downshift saved. Having owned and driven an E46 M3 that did both of those things (like the C8) I much prefer that to upshifting when I don't want it to (If I do, next lap I will) or saving the downshift until just after I start turn-in and have the rear spin out because I was already cornering at the limit of the tires.
These are the same guys that prefer a manual tranny. Do they expect the manual tranny to upshift at the rev limiter by itself? Do they expect to do a downshift that will over rev the engine? not if they have to pay for the damage .
These are the same guys that prefer a manual tranny. Do they expect the manual tranny to upshift at the rev limiter by itself? Do they expect to do a downshift that will over rev the engine? not if they have to pay for the damage .
Pro
Joined: Oct 2019
Posts: 526
Likes: 525
I don't think so. As Jason said above, if one wants to cue downshifts as they come into range, you simply keep the downshift paddle pulled. That way, you don't have stored downshifts occurring when you don't expect them, or at inopportune times, or when you no longer want them. The geniuses at R&T just didn't know how to work the car.
Le Mans Master
Joined: Oct 2005
Posts: 7,088
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From: Metro Detroit Michigan
"At a powertrain engineering seminar held by Chevy last week, we asked Glen Hoeflinn, controls program manager for the DCT, what will change from the car we drove.....
The C8 has two manual modes. If you pull a paddle while in Drive, you get a temporary manual mode, which automatically times out, or can be exited sooner by holding the upshift paddle. In this mode, the car will automatically upshift at redline. If you press the M button in the center console, you get full manual mode. There's no time out, and the car won't upshift at redline.
There are two other neat tricks available for drivers to exploit. First, if you hold the downshift paddle, the DCT will serve up the lowest possible gear. Do that while braking, and the transmission will keep downshifting as engine speed allows. And second, pulling both paddles at the same time is equivalent to pushing in the clutch pedal on a manual car, which allows you to rev the C8's new V-8 as much as you want."
https://www.roadandtrack.com/new-car...pecs-analysis/
Last edited by Warp Factor; Nov 11, 2019 at 09:57 PM.
Pro
Joined: Oct 2019
Posts: 526
Likes: 525
It sounds like they complained when they published, and only later got an explanation from a GM power train engineer, according to the article.
https://www.roadandtrack.com/new-car...pecs-analysis/
https://www.roadandtrack.com/new-car...pecs-analysis/
Le Mans Master
Joined: Oct 2005
Posts: 7,088
Likes: 1,829
From: Metro Detroit Michigan
Cammisa said they discussed it with the Chevy guys when they were out there testing. I’m guessing the new article which was written after Chevys tech day last week was to provide some confirmation of what many of us have said which is to expect updated and improved programming over time.
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Race Director
Joined: Aug 2019
Posts: 12,351
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From: Central Illinois
A bust too, as in inclusive. So now with all your in depth knowledge, the Tremec DCT it is officially a bust? Why don't you go get in your FWD econobox and tell the world that good gas mileage and a cheap price is what the definition of performance is. 
Last edited by Phil1098; Nov 11, 2019 at 11:17 PM.
Melting Slicks
Joined: Sep 2013
Posts: 2,235
Likes: 1,160
From: montreal quebec
Hopefully the transmission makes me choose the gear that I want ,and hold that gear for as long as I would like....it’s all that I ask for...if not... my car will be on drive all the time and my paddles wouldn’t even be touched,and I’ll officially become a waxer.
Drifting
Joined: Aug 2019
Posts: 1,859
Likes: 1,264
From: Houston
Then why did R&T complain about downshifts being denied (apparently not knowing about holding the paddle), and hitting the rev limiter in manual mode? These aren't anything new. GM has used the this paddle strategy on prior transmissions (the A8) for a number of years. Maybe R&T didn't know how to work those transmissions either.
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Yea I'm gonna have to wait until I drive the car myself.