Off idle throttle response
Thread Starter
Heel & Toe
Joined: Jul 2014
Posts: 15
Likes: 0
From: Findlay Ohio
Off idle throttle response
I have 500 miles on my 14 convert. manual transmission. Took museum delivery in March. Trailered the car home. Noticed a throttle response condition: during idle a quick jab to the throttle results in a loud vacuum noise and very little engine rpm response. If the revs are brought up a little prior to the throttle jab the condition is eliminated. This is an annoyance when driving in stop and go traffic and you are stopped on a minor slope and you stay on the brake to stop drift back then when you try to release the clutch and jab the throttle you get no response.
Any ideas?
Any ideas?
Thread Starter
Heel & Toe
Joined: Jul 2014
Posts: 15
Likes: 0
From: Findlay Ohio
Yep it works that way on a hill but if you are on a small slope that doesn't engage the hill assist it is a real problem. As you know when driving a manual shift car you always jab the throttle to get things going and this car acts just like a "back in the day" engine with a carb and a bad accel pump.
Burning Brakes
Joined: May 2014
Posts: 776
Likes: 372
From: Yukon Oklahoma
Yep it works that way on a hill but if you are on a small slope that doesn't engage the hill assist it is a real problem. As you know when driving a manual shift car you always jab the throttle to get things going and this car acts just like a "back in the day" engine with a carb and a bad accel pump.
Race Director
Joined: Jul 2007
Posts: 10,961
Likes: 2,643
From: Texas Hill Country
I know exactly what you mean. I mentioned this same thing in a post a month or so ago and had no others responded noticing this. I'm comparing to my days long ago with my 1966 Chevelle SS 396-360HP (Holly Carb.) that had a Muncie 4-Speed, and a limited-slip with 4.10 gear. It was an instant response. Glad I'm not the only one that noticed this difference with the C7.
put the two cars side by side and let yourself become confused at how poor the human memory really is. your chevelle was a turd.
Drifting
Joined: Sep 2013
Posts: 1,505
Likes: 13
While gearing can certainly have an effect I believe the comments are based on the e-throttle programming and the numb tip-in they have programmed into all GM e-throttles. Track mode improves it but tuners like Diablo allow you to adjust the throttle response values to get it where it feels much more like a cable.
I know it's an apples to oranges comparison but the difference between my 2014 Silverado and 2014 Ram are night and day. The Ram literally jumps when the throttle is moved, in the Silverado throttle position was basically a suggestion, both have 3.9x gears. (sold the Silverado because I hated the way it drove).
I know it's an apples to oranges comparison but the difference between my 2014 Silverado and 2014 Ram are night and day. The Ram literally jumps when the throttle is moved, in the Silverado throttle position was basically a suggestion, both have 3.9x gears. (sold the Silverado because I hated the way it drove).
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Burning Brakes
Joined: May 2014
Posts: 776
Likes: 372
From: Yukon Oklahoma
a 4.10 rear is going to roll out a lot better than a 3.42.......not to mention probably a 1.5 inch shorter tire on your old car, it's like having a 4.56.
put the two cars side by side and let yourself become confused at how poor the human memory really is. your chevelle was a turd.
put the two cars side by side and let yourself become confused at how poor the human memory really is. your chevelle was a turd.
While gearing can certainly have an effect I believe the comments are based on the e-throttle programming and the numb tip-in they have programmed into all GM e-throttles. Track mode improves it but tuners like Diablo allow you to adjust the throttle response values to get it where it feels much more like a cable.
.
.
I agree that this difference we're experiencing is likely due to the computer controlled systems of today over-thinking a variety of conditions and causing this noticeable delay, something we didn't have back in simpler times and is just something we now have to adjust for and get use to.
As for my Chevelle being a "turd,"
it was a competitive performer in it's day, obviously not in today's world. I'm old (65), that's obvious too, but my memory is still good enough to be able to compare and realize my C7 would seriously out perform my old Chevelle...
Team Owner
Joined: Jul 2006
Posts: 97,155
Likes: 1,471
From: Calgary, AB. There's a reason why white was the only color offered on every year Corvette. Proud Canadian German Jamaican!
St. Jude Donor '09, '12-'13-'14-'15-'16-'17
track mode = quicker throttle response, problem solved. 
Race Director
Joined: Jul 2007
Posts: 10,961
Likes: 2,643
From: Texas Hill Country
I only mentioned the rear-end gear ratio as part of the description of the car I had, not that it was relative to the topic. Sorry about that.
I agree that this difference we're experiencing is likely due to the computer controlled systems of today over-thinking a variety of conditions and causing this noticeable delay, something we didn't have back in simpler times and is just something we now have to adjust for and get use to.
As for my Chevelle being a "turd," it was a competitive performer in it's day, obviously not in today's world. I'm old (65), that's obvious too, but my memory is still good enough to be able to compare and realize my C7 would seriously out perform my old Chevelle...
I agree that this difference we're experiencing is likely due to the computer controlled systems of today over-thinking a variety of conditions and causing this noticeable delay, something we didn't have back in simpler times and is just something we now have to adjust for and get use to.
As for my Chevelle being a "turd,"
it was a competitive performer in it's day, obviously not in today's world. I'm old (65), that's obvious too, but my memory is still good enough to be able to compare and realize my C7 would seriously out perform my old Chevelle...
Racer
Joined: Feb 2014
Posts: 285
Likes: 1
From: Virginia
Yep it works that way on a hill but if you are on a small slope that doesn't engage the hill assist it is a real problem. As you know when driving a manual shift car you always jab the throttle to get things going and this car acts just like a "back in the day" engine with a carb and a bad accel pump.
Drifting
Joined: Sep 2010
Posts: 1,581
Likes: 50
From: Prosper TX
No it does not. Only on relatively steep grades. From what I've seen here in Colorado, if I were to guess, anything over a 4-5% grade it holds for me. Less than that and no hill assist. My driveway is 13 degrees, so I sure love having it!
Race Director
Joined: May 2008
Posts: 10,742
Likes: 629
From: Manheim Pennsylvania
I have not noticed the hesitation you are experiencing, probably technique. As for hill hold assist, I have not discovered a good way to verify when the hold is applied. Twice now, I have stalled the engine thinking hill hold was active when it wasn't. I think the system needs updating, computer should adjust brake application according to the incline. The car should remain stationary without any drift, no guessing.
Racer
Joined: Feb 2014
Posts: 285
Likes: 1
From: Virginia
interesting. I'm pretty sure it engaged on every stop in my BMW
Thread Starter
Heel & Toe
Joined: Jul 2014
Posts: 15
Likes: 0
From: Findlay Ohio
My C5 LS1 has instant throttle response and as far as a stick car goes I enjoy driving it more than my C7. Rear end gearing has nothing to do with the response since you get it in neutral all you have to do is quick jab the throttle and you don't have to jab it far a small quick jab off idle and you get a huge vacuum suction noise and very little engine rev. This is a real problem with stop and go driving in town!
Race Director
Joined: Jul 2007
Posts: 10,961
Likes: 2,643
From: Texas Hill Country
My C5 LS1 has instant throttle response and as far as a stick car goes I enjoy driving it more than my C7. Rear end gearing has nothing to do with the response since you get it in neutral all you have to do is quick jab the throttle and you don't have to jab it far a small quick jab off idle and you get a huge vacuum suction noise and very little engine rev. This is a real problem with stop and go driving in town!
rear end gearing has everything to do with response because when you move from 0 to any other speed, the car is in gear, not in neutral. not to mention that if you let the clutch out before giving it gas your car will stall out. therefore sitting at idle and jabbing the pedal is not indicative of real world starts where you are on the gas slightly before working the clutch.
your hypothesis is severely flawed.
Thread Starter
Heel & Toe
Joined: Jul 2014
Posts: 15
Likes: 0
From: Findlay Ohio
I will not argue that rear end gearing will influence engine throttle response from a zero mph start but it is not wholly responsible for lack of engine response. As you know the fuel air mixture needs to be richened when you quickly open the inlet throttle from an idle condition. It is obvious that lack of engine response from off idle to a rapid throttle opening is mainly due to too lean a fuel air mixture. This condition I am reporting on occurs every time you require a quick throttle response from an idle condition whether you are starting in 1st gear or just reeving the engine in neutral. I only reported this anomaly on this forum to determine if I had a unique condition or if is the nature of the beast. So far I have had one response who agrees with me that the off idle response is not very good. I will be visiting my dealer in a week or so and let the service people evaluate it. All I know is that I have been driving performance cars for more than 50 years, including carb inducted, fuel injected with mechanical throttle linkage, and electronic throttle fuel injected as well as manual and automatic transmissions and this is the only car I have experienced that behaves this way.
Pro
Joined: May 2009
Posts: 608
Likes: 39
From: NW Ohio
