Bumping up idle speed for summer?

[qship96]

I am considering bumping up the idle speed from 650{in drive} to 800-900rpm to allow for more airflow and cooling while idling.....any downside other than a little extra fuel consumed?

[Infinitiguy19]

When putting the transmission in gear there might be a little more shock to the transmission, Because of the higher idle.

Just keep an eye out for the temperature in the summer and change the coolant as necessary and you will be fine.

[qship96]

I am not worried about engine overheating{all new radiator/waterpump/thermostat/pullies/belts/hoses within the last 35 months and full coolant flush 6 months ago}- I am wondering if the additional airflow created by faster spinning mechanical fan at a slightly higher idle speed will keep underplenum items cooler and also move more air thru condenser making a/c more efficient while stopped in 100 degree weather.

[Trumpkin]

I don't think I have ever heard of someone doing that. Won't your cold idle be affected? I would think you would get a huge thunk going into drive.

[Romeo5k]

I am not worried about engine overheating{all new radiator/waterpump/thermostat/pullies/belts/hoses within the last 35 months and full coolant flush 6 months ago}- I am wondering if the additional airflow created by faster spinning mechanical fan at a slightly higher idle speed will keep underplenum items cooler and also move more air thru condenser making a/c more efficient while stopped in 100 degree weather.

it gets 100 out there??

[qship96]

Sometimes it even gets to 105F. Yesterday and today we saw 93-94F. Way too early for those temps!!!!!

[Infinitiguy19]

I don't think I have ever heard of someone doing that. Won't your cold idle be affected?

Assuming the Fast Idle Cam screws are unmolested (LOL). Then it might just confuse the ECU a little, Especially causes its a bit smarter OBDII ECU. I don't know how true this is "But it may also cause a leaner idle because more air is coming in..." Again the previous statement was a guess.

Try it and see what happens....

[Q45tech]

My [with 30 foot of wire] outdoor peak hold digital thermometer always tells the tale. That the worse situation is the 50>100F underhood rise when you shut the engine off. The underplenum can go from 200F to 300F for 10-15 minutes without hood vents or electric shut down fans.Obviously this exceeds the knock sensor rated temperature.

What is important is the running and shutdown temperature of the heads not the coolant [except for conduction back to transmission].

[qship96]

My [with 30 foot of wire] outdoor peak hold digital thermometer always tells the tale. That the worse situation is the 50>100F underhood rise when you shut the engine off. The underplenum can go from 200F to 300F for 10-15 minutes without hood vents or electric shut down fans.Obviously this exceeds the knock sensor rated temperature.

What is important is the running and shutdown temperature of the heads not the coolant [except for conduction back to transmission].

Sooo, any reason not to bump idle to 750-900 rpm???? I am thinking the extra airflow will make a/c more efficient at idle and also do a little underhood cooling

[Infinitiguy19]

My [with 30 foot of wire] outdoor peak hold digital thermometer always tells the tale. That the worse situation is the 50>100F underhood rise when you shut the engine off. The underplenum can go from 200F to 300F for 10-15 minutes without hood vents or electric shut down fans.

I think he means to install a digital thermometer and measure the temperature under the worse conditions (Stuck in traffic at 100*F).

Compare what idling at 650 RPM's VS 900 RPM's does in terms of temperature.

I don't think it will make a big difference but thats my hypothesis.

Obviously this exceeds the knock sensor rated temperature.

What is important is the running and shutdown temperature of the heads not the coolant [except for conduction back to transmission].

I think this means that you shouldn't worry about idling in 100*F temperatures as much as you should worry shutting off the car after such temperatures.

If thats the case then do what 1 million mile man does (did?) with his Chevy ( ) and let the car idle for at least five minutes then shut the car off when going home. Or you could leave the hood open when you reach your house.

[Q45tech]

For the 5 years I garaged the Q45, I always left the hood up when it was put away each night. Unfortunately for the last 10 the AMG has occupied that space.

The AMG has been out of service for the past 2 months due to an oil leak in front cover [?] waiting on parts from Germany. They told me none in stock until they make another round. Ah Mercedes.