C7 Z06 vs Base C7 engine smoothness
05-08-2016, 08:47 AM
#1
Pro
Thread Starter
C7 Z06 vs Base C7 engine smoothness
I posted yesterday about my new 2016 Z06 and asked the question if the idle is almost as smooth as the base C7. Mine is an A8 and the idle seems a little lumpy and before I bring it back to the dealer I would like to get some feedback and opinions whether this is the way it should be. Thanks in advance for any answers.
05-08-2016, 11:12 AM
#2
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My Z06 seems a bit rougher as well....I did notice fuel trims are about 20% off at idle, which I thought was weird....
05-08-2016, 01:05 PM
#4
Melting Slicks
Thought someone mentioned the Z06 has an aggressive cam which makes the idle lumpy.
05-08-2016, 01:36 PM
#5
Le Mans Master
The Z06 is a little lumpy, but not bad. It's smoother than my wife's 2015 DI Escalade, which the dealer can't get any smoother!
One thing to keep in mind - the OBD2 system monitors the acceleration/deceleration of the crankshaft throughout its rotation so it KNOWS if there was a misfire of any kind, and it will set the Check Engine light for a misfire.
My point? Even if it's a little lumpy at idle, those are NOT misfires if the light's not on, so it's running "right" and I doubt there's anything the dealer can do... it's "supposed" to be that way I imagine unless and until the light is on.
All that said you could have something specific about your car that is causing transmission of a vibration or something, but it's not missing.
I'm kind of beating on this point because it's an important psychological distinction for me - if the car was missing, I want it fixed. If it's just a lumpy idle because of the cam and intake charge reversion, all of that, I'm fine.
One thing to keep in mind - the OBD2 system monitors the acceleration/deceleration of the crankshaft throughout its rotation so it KNOWS if there was a misfire of any kind, and it will set the Check Engine light for a misfire.
My point? Even if it's a little lumpy at idle, those are NOT misfires if the light's not on, so it's running "right" and I doubt there's anything the dealer can do... it's "supposed" to be that way I imagine unless and until the light is on.
All that said you could have something specific about your car that is causing transmission of a vibration or something, but it's not missing.
I'm kind of beating on this point because it's an important psychological distinction for me - if the car was missing, I want it fixed. If it's just a lumpy idle because of the cam and intake charge reversion, all of that, I'm fine.
05-08-2016, 01:48 PM
#6
Le Mans Master
It's the nature of the LT4. My Idle is a little rough. At first I was a little concerned, but after reading several related threads/posts, it reassured me of its commonality.
Either it has smooth out a little, or I simply don't notice it anymore...
Either it has smooth out a little, or I simply don't notice it anymore...
05-08-2016, 04:14 PM
#7
I remember I could balance a nickel standing up on my LT5 engine.
05-08-2016, 04:53 PM
#9
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The Idle Torque tables are set up a little differently from an LT1...I don't mean different, of course they are different, I mean the thought process behind it seems different. Something I intend to look into a bit.
05-08-2016, 05:14 PM
#10
Le Mans Master
Curious what you mean by that. What happened in 1985?
Engines with bigger cams still will lope a little. Superchargers and VVT have taken the place of big cams for the most part, but I think they still run what they can get away with from a NVH and emissions perspective. No?
Engines with bigger cams still will lope a little. Superchargers and VVT have taken the place of big cams for the most part, but I think they still run what they can get away with from a NVH and emissions perspective. No?
05-08-2016, 09:11 PM
#11
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Curious what you mean by that. What happened in 1985?
Engines with bigger cams still will lope a little. Superchargers and VVT have taken the place of big cams for the most part, but I think they still run what they can get away with from a NVH and emissions perspective. No?
Engines with bigger cams still will lope a little. Superchargers and VVT have taken the place of big cams for the most part, but I think they still run what they can get away with from a NVH and emissions perspective. No?
LT1 200/207 @ 116.5
LT4 has more duration but less lift.
Does anyone have the duration specs (or better yet valve events) of the LT4 cam?
05-08-2016, 09:30 PM
#12
Found it!!
189/223 on a 120lsa
.492 intake
.551 exhaust
Last edited by T/A KID; 05-08-2016 at 09:34 PM.
05-08-2016, 10:21 PM
#14
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nice work, TA! obviously smaller on the intake side and a wider lobe separation, both would contribute to a better idle so any idle roughness is coming from the longer exhaust duration and the tune.
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slingssr (05-09-2016)
05-09-2016, 07:39 PM
#17
Burning Brakes
It is some what humorous that it seems that most of the new Z06 owners were not owners of the big block power of the old days. Back when the 427/435 days, you be lucky it the car would idle below 1000RPM's and the idle was so lumpy, the whole car shook. I as well have a new Z, and it amazes me it idles as smooth as it does with 650Hp & 650 lbs of torque, in fact of a lot of us old guys like the little bump to remind us the power the new Z has.
05-10-2016, 12:10 AM
#18
The Z06 is a little lumpy, but not bad. It's smoother than my wife's 2015 DI Escalade, which the dealer can't get any smoother!
One thing to keep in mind - the OBD2 system monitors the acceleration/deceleration of the crankshaft throughout its rotation so it KNOWS if there was a misfire of any kind, and it will set the Check Engine light for a misfire.
My point? Even if it's a little lumpy at idle, those are NOT misfires if the light's not on, so it's running "right" and I doubt there's anything the dealer can do... it's "supposed" to be that way I imagine unless and until the light is on.
All that said you could have something specific about your car that is causing transmission of a vibration or something, but it's not missing.
I'm kind of beating on this point because it's an important psychological distinction for me - if the car was missing, I want it fixed. If it's just a lumpy idle because of the cam and intake charge reversion, all of that, I'm fine.
One thing to keep in mind - the OBD2 system monitors the acceleration/deceleration of the crankshaft throughout its rotation so it KNOWS if there was a misfire of any kind, and it will set the Check Engine light for a misfire.
My point? Even if it's a little lumpy at idle, those are NOT misfires if the light's not on, so it's running "right" and I doubt there's anything the dealer can do... it's "supposed" to be that way I imagine unless and until the light is on.
All that said you could have something specific about your car that is causing transmission of a vibration or something, but it's not missing.
I'm kind of beating on this point because it's an important psychological distinction for me - if the car was missing, I want it fixed. If it's just a lumpy idle because of the cam and intake charge reversion, all of that, I'm fine.