Knocking?

molamann · 03-17-2009, 11:36 AM

Maybe I'm just overreacting but I've had my car for about 2 months now but there's sort of "knocking" after driving the Z. I know cars tend to "knock" when you put it in the wrong octane gas but I've only put 91 in it so far, not to mention I don't know even know how the bad octane "knock" is supposed to sound like...

Is this one of the signature of the Z? My previous car was a Z28 and it was virtually quiet when I finish driving the car unless I drive it really hard.

RCZ · 03-17-2009, 12:12 PM

Are you cereal?

Do you mean when you turn it off??

Knocking is premature ignition in your cylinders...it sounds as if there were glass marbles bouncing around inside your engine. What you are experiencing is not knocking...

Knocking with lower octane fuel happens because lower octanage = more prone to combustion. That means that if your motor is running "hot" (lean) there's a greater chance that the air/fuel mixture will ignite before the spark fires (from heat in the cyl). Pre-ignition aka detonation aka knocking is when that happens.

If you are talking about the crackling sounds after you turn the car off...thats just metals contracting as they cool...

shumby · 03-17-2009, 12:44 PM

I wounder if you are experiencing the VVEL knocking that the G37S has run into. Need a better discription of the sound and when you hear it.

semtex · 03-17-2009, 01:07 PM

Have you perchance done your first oil change yet? If yes, what type of oil did you fill it with?

nogoodname · 03-17-2009, 01:14 PM

Take a vid because it could be the vvel actuator. I had it and it was loud knocking noises

03-17-2009, 11:36 AM	#1 (permalink)
molamann A True Z Fanatic Join Date: Jan 2009 Location: Los Angeles Posts: 1,666 Drives: 370Z with NAVVVVV Rep Power: 284	Knocking? Maybe I'm just overreacting but I've had my car for about 2 months now but there's sort of "knocking" after driving the Z. I know cars tend to "knock" when you put it in the wrong octane gas but I've only put 91 in it so far, not to mention I don't know even know how the bad octane "knock" is supposed to sound like... Is this one of the signature of the Z? My previous car was a Z28 and it was virtually quiet when I finish driving the car unless I drive it really hard.

03-17-2009, 12:44 PM	#3 (permalink)
shumby Captin Canuck Join Date: Dec 2008 Location: with your mom Age: 44 Posts: 6,288 Drives: your sister Rep Power: 237	I wounder if you are experiencing the VVEL knocking that the G37S has run into. Need a better discription of the sound and when you hear it. __________________ Originally Posted by SAM@GTM Engine detonation is not normal and it should never never happen, and whoever told that need to do something else for living . Sam

03-17-2009, 01:07 PM	#4 (permalink)
semtex A True Z Fanatic Join Date: Jan 2009 Location: Behind enemy lines Age: 54 Posts: 5,995 Drives: People to drink Rep Power: 32	Have you perchance done your first oil change yet? If yes, what type of oil did you fill it with? __________________ "There are no small accidents on this circuit." -- Ayrton Senna 316.8whp & 248 ft/lbs (Dyno Dynamics) \| 319whp & 256 ft/lbs (DynoJet) (04/23/10) Stillen G3 CAI, CBE, Pulley / F.I. LTH / GTSpec Ladder Brace / Setrab Oil Cooler / UpRev-tuned by Forged Perf.

03-17-2009, 12:12 PM	#2 (permalink)
RCZ A True Z Fanatic Join Date: Nov 2008 Location: Miami Posts: 6,403 Drives: '09 370Z Rep Power: 1119	Are you cereal? Do you mean when you turn it off?? Knocking is premature ignition in your cylinders...it sounds as if there were glass marbles bouncing around inside your engine. What you are experiencing is not knocking... Knocking with lower octane fuel happens because lower octanage = more prone to combustion. That means that if your motor is running "hot" (lean) there's a greater chance that the air/fuel mixture will ignite before the spark fires (from heat in the cyl). Pre-ignition aka detonation aka knocking is when that happens. If you are talking about the crackling sounds after you turn the car off...thats just metals contracting as they cool...

03-17-2009, 01:14 PM	#5 (permalink)
nogoodname Lifetime Premium Join Date: Nov 2008 Location: Montreal Posts: 22,357 Drives: E46 M3 Rep Power: 1765	Take a vid because it could be the vvel actuator. I had it and it was loud knocking noises