C8 range device?
Thread Starter
Melting Slicks
Joined: Aug 2009
Posts: 3,042
Likes: 2,144
From: Schaller Iowa
C8 range device?
Hey guys and gals, my car should be here in August and as a new C8 owner I'm sure I'll have lots of questions. I did a search but didn't see anything regarding a C8 using a "range device" that eliminates the AFM system. With the new drivetrain is it necessary, or have there been any reported issues? Both of my current C7's have one but I don't know if it's needed on the new platform.
Race Director
Joined: Mar 2007
Posts: 11,271
Likes: 8,410
No "range" device available as far as I know. I run my C8 in Z-mode, with powertrain setting to track. It not supposed to go into V4 mode with that setting, and I have never see it do so. I sometimes run in Tour mode so that the car will shift into 7 and 8 gears. In Tour mode it will use V4. It is nearly seamless and does not concern me. I can detect the transition but it is very subtle. Many report not hearing it at all. People debate whether or not it may lead to engine issues. All I can say is I am not concerned about it.
Race Director
Joined: Jan 2014
Posts: 10,709
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From: Fulshear, TX
Le Mans Master
Joined: Feb 2006
Posts: 5,979
Likes: 4,142
From: Kansas City, MO
There's a gateway module between the diagnostic port and the ECM. It's like a network firewall. The entire point of the gateway is to prevent devices like Range from passing bogus or otherwise unwanted data to the ECM.
So as I said, cracking the ECM has nothing to do with it. The ECM could be wide open and it wouldn't matter because you have to get around the gateway first.
So as I said, cracking the ECM has nothing to do with it. The ECM could be wide open and it wouldn't matter because you have to get around the gateway first.
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Melting Slicks
Joined: Nov 2012
Posts: 3,161
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From: SUFFIELD CONNECTICUT
Safety Car
Joined: Jul 2019
Posts: 4,079
Likes: 2,413
From: Florida
This way I reduce clutch wear during my break in miles and if you want to adjust the suspension on the fly you just twist the **** to wet ptm mode and youll get softer suspension. Bur you retain all other settings like trans and engine remain in track mode.
Never seen 4 cyl mode yet.
Melting Slicks
Joined: Nov 2012
Posts: 3,161
Likes: 686
From: SUFFIELD CONNECTICUT
I drive in z mode at all times with steering soft, angine and transmission in track, and suspension is ptm sport.
This way I reduce clutch wear during my break in miles and if you want to adjust the suspension on the fly you just twist the **** to wet ptm mode and youll get softer suspension. Bur you retain all other settings like trans and engine remain in track mode.
Never seen 4 cyl mode yet.
This way I reduce clutch wear during my break in miles and if you want to adjust the suspension on the fly you just twist the **** to wet ptm mode and youll get softer suspension. Bur you retain all other settings like trans and engine remain in track mode.
Never seen 4 cyl mode yet.
E-Ray, 3LZ, ZER, LIFT
Joined: Sep 2007
Posts: 34,861
Likes: 12,295
From: NE South Carolina
Yep I drive often in Z mode! It's a different car. Will not go into V4 or the last 2 overdrives! It won't shift to 6th until about 72 MPH! Try it. See #8. I only drive in one of two Modes, Z Mode (powertrain set to track Ride with my MRC set to Sport) and MY Mode, I have set to Sport. That will go into all 8 gears and V4. Unlike my two M7 C7s the switch to V4 s totally transparent. A non issue!I made a summary of the DCT feathers that mostly includes statements from GM’s DCT Controls Manager, a C8 forum post by Tadge and comments about "boosted shift" made by a GM engineer Ed Piatek. Pretty impressive.
- The C8 DCT transmission has different automatic shift strategies for the various drive modes, which adapt in real time. The more aggressive, the more spirited you drive, the more aggressive the car's responds, -start to relax, the car starts to relax.
- The DCT uses latitudinal and longitudinal accelerometers, and looks at information like throttle position and steering angle to gauge how the car is being driven, and react accordingly. In Track mode set to automatic, the car will downshift aggressively when the driver is braking hard into a corner, and hold upshifts until corner exit.
- 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.
- 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.
- 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.
- The paddles are directly wired to the transmission control module (TCM) for quicker response times. This doesn't mean the paddles will give you a downshift that over-revs the engine—the TCM prevents that.
- With the C8's Performance Launch mode, the car uses the inertia of the engine coming down between revs to propel the car forward. Frankl, GM has not provided many details on this feature. This is more info by GM’s Engineer Ed Piatek: “We found that during very aggressive launches we can drive torque through both shafts/clutches simultaneously which improves the 0 to 60 times.” Road and Track interpretation of that statement was: "With the C8's Performance Launch mode, the car will actually use the inertia of the engine coming down between revs to propel the car forward. Chevy calls these "Boosted Shifts," and they're only used with a Performance Launch."
- You can avoid V4 mode using the “M” manual button or temporally for 5 seconds after pulling the last shift paddle. The new "Z" mode comes from the factory set up as an extra sporty mode including shift schedules pulled from the "Track" mode, so that will be V8 only. You can customize "Z" mode any way you want, so if you elect another shift pattern, V4 mode will return.
- I follow what a poster recommended as it’s like a different car! I drive in Z MODE with Power set to Track. If you have MRC you can set ride to Touring and get a softer ride. Can set Steering, eBoost and NPP where you would like. It upshifts and downshifts at higher rpm. Seldom shifts past 5th gear (have to be at ~72 mph before it will shift to 6th.) Never goes into V4. Can still pull paddles if and when desired.