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Each year when it starts to get hot I notice a drop in snap with my M5. I have the Dinan IATS and I know that helps but I can still tell a diffrence probably because when we near 100 degrees the air becomes less dense. Anyone else notice this? In contrast I also notice the power comes back when the air becomes more dense, on those cold dewy nights.

I also notice that when it is near 100 degrees and the AC is on my oil guage which usually runs just left of the 6 oclock tends to run at 6 oclock or a slight bit to the right if I am on the gas hard. Does this also seem pretty consistent with what others are seeing?

I dont know why I ask becasue I know this is normal but sometimes it helps to gain agreement on these things...

:M5launch:
 

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Yep, is see this in all 3 gas vehicles. I don't have the IATS (yet, installing it next weekend).

Today I was stuck in traffic coming back from Niello BMW at 5pm.. over 105 on the freeway. Temp guage was halfway between the 6 oclock and the dot to the right.

Heat is a killer. Just think what it is doing to automatic trannies...

A


PS Who's M5 was dropped at niello this AM? Carbon fiber air boxes, front strut brace, aftermarket wheels, silver.... anyone here?
 

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It helps when you think of temps in this way. Since as you know hot air is less dense, it acts like air does at a higher altitude. That is called density altitude, and it is altitude corrected for non standard temps and pressures. On a really hot day, the air around you is akin to air at a few thousand feet higher. I deal with this all the time when I fly up in Prescott, as even though the airport is at 5045', a hot day with low pressure can make it act like 7500'. There is a good drop in performance on those days. It's kinda like taking your M5 up to Lake Tahoe and feeling the drop in power.
Oil temp being higher makes sense too, as you need to dissapate the same amount of heat, but since the ambient air is hot too the temp transfer isnt as effective as it would be on a hot day.
:cheers:
 

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Hi Guys!

Sorry but I've got another question too if somebody mensioned the connection of the weather and the beast :) So, how does your M5 behave in the winter?! It's maybe a crucial questin in Münich :haha:
I'm really intrested in your opinions! THX!

Bye!
:byee55amg
 

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I see what you see. It really freaked me out the first time as I had never seen the oil temp guage go past the 6 o'clock position.

Now I see it every day on the freeway sitting in traffic. Also my car is registering the outside temp as 110 - 122 degrees farenheit when I am on the freeway sitting in traffic...

Remember, I am in Phoenix and it is getting to be 112 here in the daytime!

I have noticed a large drop in performance.


SACM5 said:
Each year when it starts to get hot I notice a drop in snap with my M5. I have the Dinan IATS and I know that helps but I can still tell a diffrence probably because when we near 100 degrees the air becomes less dense. Anyone else notice this? In contrast I also notice the power comes back when the air becomes more dense, on those cold dewy nights.

I also notice that when it is near 100 degrees and the AC is on my oil guage which usually runs just left of the 6 oclock tends to run at 6 oclock or a slight bit to the right if I am on the gas hard. Does this also seem pretty consistent with what others are seeing?

I dont know why I ask becasue I know this is normal but sometimes it helps to gain agreement on these things...

:M5launch:
 

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akosm5 said:
So, how does your M5 behave in the winter?!
My M5 behaves very well in winter. I drive it year round, just switch the tires to snow tires when the outside teperatures consistantly get below 45°F. Of course you have less traction with snow tires and on snowy/slushy roads but the car is as well mannered, comfortable and fast in winter driving as it is in the summer.
 

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jhowton said:
My M5 behaves very well in winter. I drive it year round, just switch the tires to snow tires when the outside teperatures consistantly get below 45°F. Of course you have less traction with snow tires and on snowy/slushy roads but the car is as well mannered, comfortable and fast in winter driving as it is in the summer.

Hi!

I've seen a Mercedes last winter which couldn't overcome an aprox 10cm high climber because it was a rear driven car and some BMW did it too excluding the "X" signed ones. Anyway if you switch off the DSC I think nobody can drive the car perfectly like in summer. You can feel the power just can't use it quite enough I think. On the whole I like the BMW :blink:
 

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akosm5 said:
I've seen a Mercedes last winter which couldn't overcome an aprox 10cm high climber because it was a rear driven car and some BMW did it too excluding the "X" signed ones. Anyway if you switch off the DSC I think nobody can drive the car perfectly like in summer. You can feel the power just can't use it quite enough I think. On the whole I like the BMW :blink:
The mercedes must not have had snow tires on it. I live just outside Chicago in a rural area where the roads are not plowed at all. I have had no trouble driving through 8" of fresh snow with either of my cars equipped with snow tires, up hills, down hills it doesn't matter. More than about 8" of snow and I just take my Ford F250 4x4 pickup truck but only because it has so much extra ground clearance.
 

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During the summer you are asking your car to keep you cool and give you performance. I don't drive my car as hard during the 100+ days, but spring, fall and winter, watch out!!:7:
 

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Do the IATS relocation mod. You will notice a great difference in the heat!

:cheers:
 

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XrayMD said:
Do the IATS relocation mod. You will notice a great difference in the heat!

:cheers:
I am in a few days-

it is interesting why this makes such a big difference- your 'out of the hole' acceleration (from a dead stop) is what you notice the most, and this is PRECISELY the situation when a poorly placed intake air sensor will kill you- when you are stopped or moving slowly, the heat under the hood 'soaks' the air around it, and all the components- the temp sensor sees these temps and says 'ahah- hot air!, lets dial back the timing'. But the air being sucked into the intake is not THAT hot- and once you begin to move a bit it gets even better. having the intake air sensor in the air that is going into the intake is a more precise measure of the air the engine will get and the ECU can act accordingly...

right?

:)

A
 

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I was driving in traffic here in NC and the outside temp was close to 100.

Although the oil temp has never gone past the 6 o'clock mark, it always feels a little sluggish on these real hot days.

The humidity was extremely high today as well with dew points in the mid 70's.

A/C worked great - felt a little sorry for the beast's engine though.
 

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The nice thing about summer (depending on where you live) is that the roads are hot and dry so your tires will hook up. While effortless, easy to control oversteer at low speeds is fun in the rain, I can't mash the pedal on even damp roads because the rear tires break loose at the mere hint of instant torque. Original 2000 PS1s with half their tread left.
 

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On the those nice cool nights my beast runs so much stronger than in the hot sun. Cool air is a hot motors best friend, unless your a diesel motor:1:
 

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Don't forget in our great state of California we get the summer fuel that started pumping last month.
 

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tomlavelle said:
The nice thing about summer (depending on where you live) is that the roads are hot and dry so your tires will hook up. While effortless, easy to control oversteer at low speeds is fun in the rain, I can't mash the pedal on even damp roads because the rear tires break loose at the mere hint of instant torque. Original 2000 PS1s with half their tread left.
Get PS2s with good wet & dry grip. You´ll love em´. :)

David
 

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ard said:
I am in a few days-

it is interesting why this makes such a big difference- your 'out of the hole' acceleration (from a dead stop) is what you notice the most, and this is PRECISELY the situation when a poorly placed intake air sensor will kill you- when you are stopped or moving slowly, the heat under the hood 'soaks' the air around it, and all the components- the temp sensor sees these temps and says 'ahah- hot air!, lets dial back the timing'. But the air being sucked into the intake is not THAT hot- and once you begin to move a bit it gets even better. having the intake air sensor in the air that is going into the intake is a more precise measure of the air the engine will get and the ECU can act accordingly...

right?

:)

A
Right! The intake air temperature sensor is part of one of the MAFs, and get heat soked presumably by conduction of heat through its mechanical mount from the hot air trapped under the bonnet.

When more air is sucked in through the intakes and pass the MAFs the temp sensor is cooled again.

With an IATS (intake air temperature sensor) relocation that sensor does not get so heated by conduction and the heatsoking at standstill problem is solved.

If you get an OBD-II tool you can directly monitor the IATS signal and see for yourself how fast it clibms when you stop driving, or how high it is when the car has been driven hard and then parked in the sunshine.

David
 

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I'm in Phoenix. In the summer even MY performance drops a little!!! The M5's AC rocks............and that's what counts right now!
 
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