Is it better to idle the car or restart the car?

Reply Subscribe

Thread Tools

Search this Thread

Jan 26, 2012 | 07:19 PM

#21

bob

Legacy TMS Member

Joined: May 16, 2004

Posts: 5,206

Likes: 18

From: Bristol, TN

Quote:

Originally Posted by askjeffro

That's correct. Its dirtier at a COLD startup as the CATs are less effective when cold. This is why when you start the car in the morning, the car will rev itself up a bit above a warm idle to warm the cats faster and reduce emissions. This is a non-issue for the OP use case however.

And dont forget the ignition timing is altered as well so that the engine fires with the exhaust valve patially opened to help the cats heat up. This was particulalry evident on my 02 GT which had the high-flow SLP X-pipe and Loudmouths. There was a distinct difference between the car's idle and acceleration depending on if it was cold or warmed-up.

Jan 26, 2012 | 07:39 PM

#22

SCHMOKN

GT Member

Joined: January 13, 2012

Posts: 163

Likes: 0

From: FLORIDA

Neither. Tell your friend to be ready on time

Jan 26, 2012 | 09:01 PM

#23

cdynaco

Post *****

Joined: December 14, 2007

Posts: 19,953

Likes: 4

From: State of Jefferson Mountains USA

Quote:

Originally Posted by bob

And dont forget the ignition timing is altered as well so that the engine fires with the exhaust valve patially opened to help the cats heat up.

Interesting. You'd think that would fail emissions.

Quote:

Originally Posted by SCHMOKN

Neither. Tell your friend to be ready on time

Last edited by cdynaco; Jan 27, 2012 at 03:42 AM.

Jan 31, 2012 | 06:33 PM

#24

karman

Tasca Super Boss 429 Member

Joined: January 4, 2006

Posts: 3,904

Likes: 32

Quote:

Originally Posted by cdynaco

Interesting. You'd think that would fail emissions.

It does fail.
My buddy's shop is 1 mile from my house, downhill.
It comes up "not ready for testing" if I just roll it over there.
They have to warm up before testing.

Jan 31, 2012 | 07:04 PM

#25

Glenn

Legacy TMS Member

Joined: August 7, 2006

Posts: 16,113

Likes: 789

From: In Boredom

I always shut it off while waiting. Drive through at the bank anything where I think I will have to wait more than a minute or so

Jan 31, 2012 | 07:08 PM

#26

Shelby08

Cobra Member

Joined: October 18, 2011

Posts: 1,652

Likes: 0

From: North Carolina (currently deployed)

Quote:

Originally Posted by Glenn

I always shut it off while waiting. Drive through at the bank anything where I think I will have to wait more than a minute or so

I read an article about a year ago that said since cars have come so far it's best to shut them off...it said on average after idling for 1 minute you've burned the same amount of fuel it would take to restart the car...