Exhaust Tone During Cold Start

nis350 · 04-30-2015, 12:23 AM

I noticed that the exhaust tone (oem) is louder during the first 10 seconds during the cold starts and it toned down as the rpm drop a bit. However, I couldn't duplicate the same exhaust tone when I rev the engine up after it warned up.

BGTV8 · 04-30-2015, 01:02 AM

This is the cat-converters warming up - once they flash-off, it alters the exhaust note. HFC are worse because they take longer to flash-off (is the difference between 400, 200 and 100 cell cats)

kalkat102 · 04-30-2015, 11:29 AM

i wish my car sounded like that all the time. It's beautiful. Anyone know a way to do that?

FPenvy · 04-30-2015, 11:33 AM

Quote:

Originally Posted by kalkat102

i wish my car sounded like that all the time. It's beautiful. Anyone know a way to do that?

yes buy an aftermarket exhaust lol

i don't think it's really the cats warming up aside from just the warm up process. i don't have cats but my engine idles high for those 10 seconds or whatever at 1200 rpm then it idles at 1k to warm up fully then its normal idle is 600 i believe.

Davey · 04-30-2015, 11:35 AM

Quote:

Originally Posted by kalkat102

i wish my car sounded like that all the time.

Me too.

POS VETT · 04-30-2015, 03:44 PM

I suppose a "tuner" could put the cams on a larger overlap to create a "lope" during idle. Ford did this for the TrackKey calibration on'12 &'13 BOSS 302.

FPenvy · 04-30-2015, 03:49 PM

Quote:

Originally Posted by POS VETT

I suppose a "tuner" could put the cams on a larger overlap to create a "lope" during idle. Ford did this for the TrackKey calibration on'12 &'13 BOSS 302.

pretty sure the VVEL would not like that and override it on its own.

DavidZ370 · 04-30-2015, 04:14 PM

Quote:

Originally Posted by POS VETT

I suppose a "tuner" could put the cams on a larger overlap to create a "lope" during idle. Ford did this for the TrackKey calibration on'12 &'13 BOSS 302.

Or you can buy a damn exhaust smh

FPenvy · 04-30-2015, 04:15 PM

Quote:

Originally Posted by DavidZ370

Or you can buy a damn exhaust smh

see my above post lol beat you to it

DavidZ370 · 04-30-2015, 04:29 PM

Quote:

Originally Posted by FPenvy

see my above post lol beat you to it

Exhaust whore you are

Nick M · 04-30-2015, 04:32 PM

Quote:

Originally Posted by POS VETT

I suppose a "tuner" could put the cams on a larger overlap to create a "lope" during idle. Ford did this for the TrackKey calibration on'12 &'13 BOSS 302.

As said above, VVEL wouldn't allow it.

FPenvy · 04-30-2015, 04:39 PM

Quote:

Originally Posted by DavidZ370

Exhaust whore you are

yes i most certainly am......speaking of that.

OP, go check out Fast Intentions if you want to take care of that exhaust sound issue. Tony and the guys will get you squared away with the perfect exhaust to match your needs 100%.

tell them i sent you

POS VETT · 04-30-2015, 06:21 PM

Do the cam phasers operate independently? Are they operated by the ECM/PCM/ECU?

nis350 · 04-30-2015, 10:02 PM

It is apparent that the oem exhaust can produce nice sound, but just not quite sure how/why during the first 5 to 10 seconds on a cold start up.

However, I do know that it sounds pretty nice at high rpm.

Quote:

Originally Posted by kalkat102

i wish my car sounded like that all the time. It's beautiful. Anyone know a way to do that?

ta-kid · 04-30-2015, 10:47 PM

I would argue that it has anything to do with the cats that the tone changes approximately 10 seconds after a cold start up.The rpm does not change either much if any in the first minute or longer for me, but the tone does go from a harsh raspy note to a softer note within that 10 seconds,like there is an exhaust valve in the system somewhere closing.I wonder if the ECU is changing the variable valve timing once the cold start has been sucessively established?

04-30-2015, 12:23 AM	#1 (permalink)
nis350 A True Z Fanatic Join Date: Oct 2014 Location: socal Posts: 1,108 Drives: 370z Rep Power: 13435	Exhaust Tone During Cold Start I noticed that the exhaust tone (oem) is louder during the first 10 seconds during the cold starts and it toned down as the rpm drop a bit. However, I couldn't duplicate the same exhaust tone when I rev the engine up after it warned up.

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04-30-2015, 01:02 AM	#2 (permalink)
BGTV8 A True Z Fanatic Join Date: Dec 2009 Location: 03350 Australia Posts: 1,514 Drives: 09 Nissan 370Z M6 Rep Power: 39973	This is the cat-converters warming up - once they flash-off, it alters the exhaust note. HFC are worse because they take longer to flash-off (is the difference between 400, 200 and 100 cell cats)

04-30-2015, 11:29 AM	#3 (permalink)
kalkat102 Base Member Join Date: Feb 2015 Location: Fairfield, CA Posts: 101 Drives: 10 Nissan 370z Sport Rep Power: 10	i wish my car sounded like that all the time. It's beautiful. Anyone know a way to do that?

04-30-2015, 03:44 PM	#6 (permalink)
POS VETT Track Member Join Date: Apr 2015 Location: Columbus OH Posts: 612 Drives: Z34\|C4LT4\|C6Z06\|V25 Rep Power: 3366	I suppose a "tuner" could put the cams on a larger overlap to create a "lope" during idle. Ford did this for the TrackKey calibration on'12 &'13 BOSS 302.

04-30-2015, 06:21 PM	#13 (permalink)
POS VETT Track Member Join Date: Apr 2015 Location: Columbus OH Posts: 612 Drives: Z34\|C4LT4\|C6Z06\|V25 Rep Power: 3366	Do the cam phasers operate independently? Are they operated by the ECM/PCM/ECU?

04-30-2015, 10:47 PM	#15 (permalink)
ta-kid Base Member Join Date: Feb 2015 Location: Maple Ridge BC canada Posts: 51 Drives: Kia soul, 370Z vert Rep Power: 10	I would argue that it has anything to do with the cats that the tone changes approximately 10 seconds after a cold start up.The rpm does not change either much if any in the first minute or longer for me, but the tone does go from a harsh raspy note to a softer note within that 10 seconds,like there is an exhaust valve in the system somewhere closing.I wonder if the ECU is changing the variable valve timing once the cold start has been sucessively established?