Rorty exhaust note on cold start for about 15 secs

[doctor austin]

Just wondered if anyone else with a 370 has this, not that its a problem just curious. On a cold start the exhaust note is decidedly rorty for about 15 seconds, then it quietens down to a smooth even fast idle. I have no leaks and the noise comes out of the exit pipes rather than a leak etc. I imagine its the engine management.. as I said no issue and the cars only done 12,000 miles etc and running a standard exhaust sytem....just wondering.

[Will370z]

Same with mine mate and others that i have heard.

[AK350Z]

350s and 370s all start with a fast idle from cold. Totally normal.

[doctor austin]

Its not the fast idle its the rorty note ...just for the first 15 seconds..sounds a bit like the bafles are missing then it quietens down... my 350 didn't do this......but from the earlier comment from will370z it may well be a Idiosyncrasy with the 370 engine management.

[R35LEE]

Same for all 370z's mate, nothing to worry about

[The G Man]

Never had the stock system on for that long but even aftermarkets do this, I love it, sounds like a big mean V10

[Kev T]

My HKS SSM does this as well, nothing to worry about.

[Mark@Abbey m/s]

its all to do with the variable lift/variable cam timing and cold start map. Once the car has been running a short time and warmed up it revert sback to the normal running map.

[Ebized]

its all to do with the variable lift/variable cam timing and cold start map. Once the car has been running a short time and warmed up it revert sback to the normal running map.

And with a valet parking map on retricting the rpm it certainly does sound like there is soemthing very big under the bonnet warming up, eh Mark