C7 General Discussion General C7 Corvette Discussion not covered in Tech
Sponsored by:
Sponsored by:

Two Questions

Thread Tools
 
Search this Thread
 
Old Nov 12, 2012 | 08:38 AM
  #1  
Rubber Ducky's Avatar
Rubber Ducky
Thread Starter
Racer
Supporting Lifetime
10 Year Member
 
Joined: Apr 2006
Posts: 304
Likes: 0
From: Cocoa Beach FL
Default Two Questions

1. Any informed guess on the load/operating conditions under which the 4-to-8 cylinder switchover would occur and vice versa?

2. Any guess on CAGS yes or no?
Reply
Old Nov 12, 2012 | 08:49 AM
  #2  
BlueOx's Avatar
BlueOx
Race Director
 
Joined: Feb 2012
Posts: 10,776
Likes: 11
Default

Originally Posted by Rubber Ducky
1. Any informed guess on the load/operating conditions under which the 4-to-8 cylinder switchover would occur and vice versa?

2. Any guess on CAGS yes or no?
I haven't seen any info on either of those yet. My guess would be there won't be a CAGS given different engines/trannies...but who knows?
Reply
Old Nov 12, 2012 | 10:22 AM
  #3  
Jinx's Avatar
Jinx
Le Mans Master
20 Year Member
 
Joined: Feb 2000
Posts: 8,099
Likes: 398
From: Oakland, CA
Default

I wonder if they'll still want CAGS to maintain near parity between the manual and the automatic. They don't want to advertise significantly different numbers between the two.

I bet we still have CAGS.
Reply
Old Nov 12, 2012 | 10:30 AM
  #4  
Rubber Ducky's Avatar
Rubber Ducky
Thread Starter
Racer
Supporting Lifetime
10 Year Member
 
Joined: Apr 2006
Posts: 304
Likes: 0
From: Cocoa Beach FL
Default

Originally Posted by Jinx
I wonder if they'll still want CAGS to maintain near parity between the manual and the automatic. They don't want to advertise significantly different numbers between the two.

I bet we still have CAGS.
My guess would be no unless it's needed to hit EPA/CAFE numbers. That's its origin in the C6 (before I even sat in my '11 GS, had the dealer install a skip-shift eliminator and do a street alignment).

Not trying to answer my own question - just guessing e nada mas.
Reply
Old Nov 12, 2012 | 10:35 AM
  #5  
Larry/car's Avatar
Larry/car
Race Director
10 Year Member
 
Joined: May 2008
Posts: 10,742
Likes: 629
From: Manheim Pennsylvania
Default

Your only allowed one question. I bet there will be a CAGS system of some sort. As for cylinder activation, the cylinders come on line as power is required, idle would be 4 cyl., when the throttle is advanced the remaining cylinders should immediately fire, cylinder drop off will happen as engine power reaches power level required, I think (my guess) all cylinders will not be on line at cruise power, they will come and go as power demand dictates (activation will be immediate as required). Simple example; remember the hit/miss engines of the past, the rpm remains constant, when power is required the cylinder immediately fires to hold required rpm. This is accomplished mechanically, just think how fast a computer system will manage power. I wonder what is programed into the engine if a computer failure would happen, all cylinders on line?
Reply
Old Nov 12, 2012 | 01:48 PM
  #6  
McGirk94LT1's Avatar
McGirk94LT1
Drifting
10 Year Member
 
Joined: Feb 2008
Posts: 1,682
Likes: 3
From: Coatesville PA
Default

I can guarantee it'll have CAGS. It's pretty simple. With direct injection it might hit the same mpg highway. But why stop there, that's no improvement and doesn't help protect the corvette from the EPA police. The displacement on demand helps improve the highway mpg, however, without cags the city will stay the same if not be slightly lower. So with cags and displacement on demand, both highway and city mpg should be greater then currently.
Reply
Old Nov 12, 2012 | 02:52 PM
  #7  
Jinx's Avatar
Jinx
Le Mans Master
20 Year Member
 
Joined: Feb 2000
Posts: 8,099
Likes: 398
From: Oakland, CA
Default

Originally Posted by McGirk94LT1
The displacement on demand helps improve the highway mpg, however, without cags the city will stay the same if not be slightly lower.
I do not think this is correct. I believe AFM can help city mileage as well -- combustion in half the chambers should be more efficient at such light loads.

Where did you pick this idea up, that it's only good for highway economy? Am I missing something?

.Jinx
Reply
Old Nov 12, 2012 | 03:51 PM
  #8  
Bill Dearborn's Avatar
Bill Dearborn
Tech Contributor
25 Year Member
Liked
Top Answer: 1
Top Answer: 3
 
Joined: Oct 1999
Posts: 41,037
Likes: 9,801
From: Charlotte, NC (formerly Endicott, NY)
Default

Originally Posted by Jinx
I do not think this is correct. I believe AFM can help city mileage as well -- combustion in half the chambers should be more efficient at such light loads.

Where did you pick this idea up, that it's only good for highway economy? Am I missing something?

.Jinx
My daughter's Tahoe varies between 4 and 8 cylinder modes during city driving. Light load and it will switch to 4 cylinder op very quickly.

Bill
Reply
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

 Michael S. Palmer
story-1

Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

 Joe Kucinski
story-2

150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

 Joe Kucinski
story-3

8 Coolest Corvette Pace Cars (and Replicas) of All Time

 Verdad Gallardo
story-4

Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

 Joe Kucinski
story-5

Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

 Verdad Gallardo
story-6

Top 10 Corvettes Coming to Mecum Indy 2026!

 Brett Foote
story-7

Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

 Michael S. Palmer
story-8

10 Revolutionary 'Corvette Firsts' Most People Don't Know

 Joe Kucinski
story-9

5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

 Michael S. Palmer
Old Nov 12, 2012 | 04:31 PM
  #9  
McGirk94LT1's Avatar
McGirk94LT1
Drifting
10 Year Member
 
Joined: Feb 2008
Posts: 1,682
Likes: 3
From: Coatesville PA
Default

Ah. I swore I had seen, at least for the camaro, that there was a certain speed range it would activate in, as well as engine load. I swore someone posted the limitations of afm for the camaro in one of the 100 other "4-6-8 er... afm will spell doom for the corvette." Always made sense to me that it kicked in for highway use since that's where minimal hp is needed.

As for city driving, it might help real world for the vette, but no way it's activating THAT much around town for a camaro or especially a suburban size suv. Yeah a 2 mile long stretch doing 40 sure helps, but accelerating to and from a stop light every half mile there's no way it's effective.
Reply
Old Nov 12, 2012 | 04:55 PM
  #10  
McGirk94LT1's Avatar
McGirk94LT1
Drifting
10 Year Member
 
Joined: Feb 2008
Posts: 1,682
Likes: 3
From: Coatesville PA
Default

Well, seems to be solely based on throttle percentage. So it can engage at any speed, so long as the gear its in puts it under the threshold of throttle percentage. So it will kick off at ahigh enough speed because the throttle will simply be open enough to retain that speed, but it won't not kick on simply because you're going to slow. However a quick search found that for the g8 gt, it was only active at 7% throttle or less. Obviously they can tune each car to kick in at at higher or lower percentage, but it doesn't sound like it does much good real-world city driving if the torquey g8 demands v8 power at only 8% throttle.

Now, could it help the official ratings, I'm sure, but I don't know the exact testing procedure.
Reply

Get notified of new replies

To Two Questions





All times are GMT -4. The time now is 01:42 PM.

story-0
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

Slideshow: How to Protect A Convertible Top: 10 DOs & DON'Ts

By Michael S. Palmer | 2026-04-03 00:00:00


VIEW MORE
story-1
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

Slideshow: The 10 most explosive Corvettes ever built based on power-to-weight ratio.

By Joe Kucinski | 2026-05-20 07:23:03


VIEW MORE
story-2
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

Slideshow: From C1 to C8 we compare every Corvette generation by the numbers.

By Joe Kucinski | 2026-05-12 16:54:12


VIEW MORE
story-3
8 Coolest Corvette Pace Cars (and Replicas) of All Time

Slideshow: Some Corvette pace cars became collectible legends, while others perfectly captured the look and attitude of their era.

By Verdad Gallardo | 2026-05-11 09:50:51


VIEW MORE
story-4
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

Slideshow: Ranking the top 10 Corvette engines by torque output.

By Joe Kucinski | 2026-05-05 11:58:09


VIEW MORE
story-5
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

Slideshow: A Corvette pace car nearly matching IndyCar speeds sounds exaggerated, until you look at the numbers.

By Verdad Gallardo | 2026-05-04 20:03:36


VIEW MORE
story-6
Top 10 Corvettes Coming to Mecum Indy 2026!

Among a rather large group of them.

By Brett Foote | 2026-05-04 13:56:44


VIEW MORE
story-7
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

Slideshow: the top 10 things Corvette owners want in the C9 Corvette

By Michael S. Palmer | 2026-04-30 12:41:15


VIEW MORE
story-8
10 Revolutionary 'Corvette Firsts' Most People Don't Know

Slideshow: 10 Important Corvette 'firsts' that every fan should know.

By Joe Kucinski | 2026-04-29 17:02:16


VIEW MORE
story-9
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

Slideshow: Should you buy a 2020-2026 Corvette or wait for 2027?

By Michael S. Palmer | 2026-04-22 10:08:58


VIEW MORE