[Z06] Do you shift to neutral at stoplights?
Melting Slicks
Joined: Aug 2010
Posts: 2,855
Likes: 78
From: Sammamish WA
WA Events Coordinator
I had my 2002 Z06 w/6K miles in for some warranty work (column lock recall (recall doesn't fix it! Get a LMC5), right door not unlocking, bad washer fluid censor, etc) and complained about how it sometimes will not go into 1st gear when I get the green light at a stop light and I have to start from 2nd.
It is the case where it goes halfway into first but not fully in and will pop back out if you let the clutch out. I got a technician to try it while I was there and he reproduced it a few times, and called GM tech support center (or whatever it is called) about this, but the end result is to drive it some more for now which I am not happy with.
-kg
It is the case where it goes halfway into first but not fully in and will pop back out if you let the clutch out. I got a technician to try it while I was there and he reproduced it a few times, and called GM tech support center (or whatever it is called) about this, but the end result is to drive it some more for now which I am not happy with.
-kg
Safety Car
Joined: Nov 2002
Posts: 4,394
Likes: 6
From: Melbourne FL
I'd really like to see Evil Twin reply to this thread and possibly answer the question from an engineering / engine development point of view. But, my gut tells me that even under 0% accelerator position / tps sensor position and transmission in gear, there is still a small amount of fuel going through the injectors under a deceleration condition. I think one would be able to log injector duty cycle with EFI live or HP tuners and figure this out. Maybe I'll hook mine up tomorrow and test the theory. 
I would bet injector duty cycle is not 0 under decel.
I would bet injector duty cycle is not 0 under decel.
Safety Car
Joined: Sep 2007
Posts: 4,168
Likes: 21
From: Sunniest city on Earth
I have not personally logged this to check it, but it is certainly using less fuel than coasting or sitting in neutral, which was his point
Heel & Toe
Joined: Feb 2014
Posts: 19
Likes: 1
Coasting in gear with the throttle closed doesn't necessarily put it in DFCO. You won't save gas by coasting in gear to a red light, unless you downshift and decelerate enough that the engine revs up enough to even enter DFCO mode, and nobody drives like that as it would be annoying as hell, not to mention all the unnecessary wear and tear.
I know DFCO completely shuts off the injector from doing hundreds of tunes for my turbo camaro over the course of a few years, including countless hours of datalogging. Granted it wasn't on a C5z, but I'm certain its the exact same.
If you want to hypermile your corvette, accelerate slowly and start coasting to a stop very early and never touch the brakes. Braking (including engine braking) returns no gains from gas that has already been converted to potential energy of motion. Coasting allows you to use that potential and travel much much further, and an idling engine consumes very little gas.
Le Mans Master
Joined: Sep 2009
Posts: 6,937
Likes: 348
From: My interests are mobile
I'd really like to see Evil Twin reply to this thread and possibly answer the question from an engineering / engine development point of view. But, my gut tells me that even under 0% accelerator position / tps sensor position and transmission in gear, there is still a small amount of fuel going through the injectors under a deceleration condition. I think one would be able to log injector duty cycle with EFI live or HP tuners and figure this out. Maybe I'll hook mine up tomorrow and test the theory. I would bet injector duty cycle is not 0 under decel.
I would bet injector duty cycle is not 0 under decel.Make your bet that fuel is being injected under 0 throttle in gear decel so we can all take something from you. Systems I've tuned didn't re-initiate the injectors below 1100rpm. Injecting fuel during this period would do absolutely nothing for the motor whatsover. It'd merely dump unburned fuel down the exhaust and raise emissions...hence why eliminated long ago.
Last edited by RC000E; Apr 6, 2014 at 09:16 PM.
Safety Car
Joined: Feb 2013
Posts: 4,346
Likes: 755
From: Greensboro Nc
I think I misunderstood the initial point of the post. I read it as "when sitting at the stoplight do you leave it in first with the clutch in, or leave it in neutral until the light changes then put it in first"
I downshift and decel in gear because I like the noise and popping and control. If my rev matched downshifts caused premature drivetrain wear, I would be very surprised.
I downshift and decel in gear because I like the noise and popping and control. If my rev matched downshifts caused premature drivetrain wear, I would be very surprised.
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Le Mans Master
Joined: Sep 2009
Posts: 6,937
Likes: 348
From: My interests are mobile
I think about 3/4 of the people in this thread need to go to a driving school...that's what I think.
I heel/toe down if I feel frisky and wanna disturb the locals, I heel/toe but skip a gear or two if I feel less frisky, or I just coast down quite far in gear then push pedal to neutral just before I stop if a cop is around.
There is no "rule" as some have insinuated, nor do I put it in neutral at 65 mph and coast down...that's absurd...that's amateur hour with a manual tranny technique. You can brake down to like 20mph in 5th without the motor starting to chug hard. Typically I come down, probably do a rev/match or an actual heel/toe from 5th to 3rd...then bring that down to damn near stopped...then sit in neutral.
I actually have two "heel/toes"...on heavy braking I will apply full heel toe technique, but in random street driving, I push the brake on decel and blip with the side of my foot....kind of like a toe/toe...lol.
Is this thread over yet....?
I heel/toe down if I feel frisky and wanna disturb the locals, I heel/toe but skip a gear or two if I feel less frisky, or I just coast down quite far in gear then push pedal to neutral just before I stop if a cop is around.
There is no "rule" as some have insinuated, nor do I put it in neutral at 65 mph and coast down...that's absurd...that's amateur hour with a manual tranny technique. You can brake down to like 20mph in 5th without the motor starting to chug hard. Typically I come down, probably do a rev/match or an actual heel/toe from 5th to 3rd...then bring that down to damn near stopped...then sit in neutral.
I actually have two "heel/toes"...on heavy braking I will apply full heel toe technique, but in random street driving, I push the brake on decel and blip with the side of my foot....kind of like a toe/toe...lol.
Is this thread over yet....?
Drifting
Joined: Nov 2011
Posts: 1,279
Likes: 18
From: Oklahoma
Agreed with above. If you learn to rev match on downshifts at the track, you can do it on the street too. Common sense tells me this alone should prolong the life of your drivetrain. I've been rev matching (heel/toe) for several years when I am taking a corner, but not coming to a complete stop.
