Questions

(We're not talking about necessarily hot hot 100 degree days vs. 50 degree days. I've not had a chance to experience 100 degrees or 50 degrees.)

We've recently had cooler nights and I really notice a difference between the warmer days (mid to high 70s and clear with strong direct sunlight) and the cooler nights (mid 60s). These are nights that as soon as you open the door and have contact with the air it feels cold enough to put on a sweatshirt.

My car feels noticeably quicker on these nights when the car's ambient air thermometer reports mid mid-high 60s. Passengers have commented on this difference as well.

AMG menu oil temp remains the same, not too low, not too high. I understand these cars need to run a bit warm, so oil temp seems divorced from the temp/density of the air it's sucking in.

Have heard the 63s are sensitive to this but this is kind of ridiculous, I haven't experienced a car changing this much. Feels like a chunk of the car's performance is missing on warmer days, just that extra bit that makes you go, "whoa", is m.i.a.

Do you notice ambient air temps making that much of a difference for your car as well? Love to hear everyone chime in.

Mort

This is true for any car that has high compression or FI. With these type of vehicles you can feel the reduction in power and response caused be less dense hotter ambient air. The hot air is not as dense (with oxygen) as cold air. The computer adjusts the fuel mixture based on MAF readings and O2 trims. It reads less dense air and cuts the fuel a bit. This in turn reduces the power and throttle response enough that you can feel it in the SOTP. The closer a car is tuned to the edge the more apparent this phenomenon will be.

gOt BoOsT

youll also loose a few degrees of timing in the hot weather. oil temp will be the same in hot and cold under normal operating conditions

gsrjc

hmm, 90s in DC but haven't really paid attention.

DAGREEKNYC

I had TTM thermal wrap all fuel lines and intakes and also installed the plenum spacers with a 180 thermo my car feels great . And of course colder temps equal better performance .Also the ceramic coating of the Kleemann headers made a world of difference as well

40-50 degrees is prime if you want to track the car .

EUGENE-Taiwan

I would say any car like cooler temp.

PetroC63

Had a couple of high 90 degree humid days in New Jersey
last week and the 63 felt a little slugish.

Merc63

Yep she definitely likes the cooler weather for performance. Makes a big difference.. Id run my best times at the track when the engine would cool down as well as the air temp.

propain

Yup, runs much slower. Also tranny is even more sluggish if thats even possible.... I hate the tranny in this car.. HATE IT. Give me a manual!

Tatorr

+1
Over here in La too.

Brian GT PRO

Yes, what happens is that it is part of the tuning process that is happening here. a tuning map is 3D, meaning that timing and fueling events are based on sensor input, such as air temp, coolant temp, load, rpm etc etc. A cool air temp signal and coolant signal def. kicks up the timing, and the car loves it, however the block/cyl head temp are also lower, and the air is cooler/more dense which creates a situation where the car is not so prone to detonation, and the timing can be more aggressive as well. Heat will always kill power, period..

Questions

I'm just surprised at how much of a difference it is. But as Mort said,

Especially with these tunes half of us have.

Questions

It's actually kind of disappointing, I don't feel like I'm driving a beast during these days. Makes it kind of boring, to be honest. I think I need to drive a regular car then I won't be saying that

Brian GT PRO

time to get a Single X or Double XX

Questions

Oh yeah? What's that gonna do for me on warm days?

Brian GT PRO

it was kind of a joke and shameless plug for my X pipes , they will do nothing for hot temps..but the pipes do offer a more freeflow exhaust, with a boost in HP and TQ, so on those days that the car is a little more sluggish, this added power should at least get you on par.

Questions

Oh. How much power are we talking about?

Brian GT PRO

We have seen gains in the 15-25hp mark in the midrange on the dyno, many members here on MBW are running them, and have testimonials and youtube sound clips.

Sorry for the hijack of the thread..

http://www.youtube.com/watch?v=VWA_ZnEFZXY
http://www.youtube.com/watch?v=jSlmf...eature=related
http://www.youtube.com/watch?v=8_Nrz...eature=related
http://www.youtube.com/watch?v=J5MbKJqvJ98&NR=1
http://www.youtube.com/watch?v=O4L9k991QXw
http://www.youtube.com/watch?v=0C7KTFwv7D8