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WLD-18L
10th December 2006, 03:48 PM
i did a fair bit of driving over the past 2 days in which it was 37. just woundering if your motor is more subjected to wear wile driving in such hot conditions.

Poogene2001
10th December 2006, 05:32 PM
I dunno about the motor being subjected to more wear, but my 1.8 certainly hates the heat. Becomes very sluggish, harder to start and if you kick in the A/C then you can pretty much forget about any sort of performance.
The biggest issue is keeping the vehicles oil and water temperature under control. Clearly 40 degree air hitting the radiator is not as effective at keeping the oil and water temperature low as 15 degree air.
Alot of people on here are all for de-restricting the air intakes to allow more air to pass, hence eliminating some of these problems.

digifish
10th December 2006, 06:19 PM
Note that your engine runs at 80-90C or so naturally so the difference between a 27 and 37 degree day is how far the thermostat opens.

You should notice that your temparature guage is about the same regardless of the outside temp. Within reason of course :) so that means the engine is under about the same level of heat stress. Yes things like the gearbox will be hotter, but it's not a big deal....so long as the oil is doing its job...which it will be.

As noted the warmer (less dense) air doesn not generate as many KW.

That said this is my first summer with a CDTi...we had 40C here the other day and I had air-con on and I honestly was struggling to notice the difference...score another point for diesel turbos :P

digifish

WLD-18L
10th December 2006, 07:01 PM
yep i can deffinatly tell. it was hell slugish when i tried to pass this old ford when 2 lanes closed into one.

temp gage stays the same, about 5 mins after i got home i went out and checked the temp again it had risen abit which is normal as the heat coming off the motor is traped uunder there.

poped the hood and touched all the air intake system, which was extremly hot, which would creat the slugishness i presume, hot air, less dense not as combustable, less power.

compare this to driving in winter, everything thats ment to be cool stays that way,

digifish
10th December 2006, 07:10 PM
temp gage stays the same, about 5 mins after i got home i went out and checked the temp again it had risen abit which is normal as the heat coming off the motor is traped uunder there.

Indeed heat-soak is worse in summer. If you can pop your bonnet when you arrive home on a very hot day it can be kinder to your battery etc that tend not to like roastings...

digigish

stevedee3
10th December 2006, 08:18 PM
My Vectra doesn't seem to be bothered by that sort of temperature... On the other hand, the driver seems bothered by the hot seats, steering wheel and gear knob until the air conditioning does its thing... :)

EL BURITO
10th December 2006, 09:37 PM
My Vectra doesn't seem to be bothered by that sort of temperature... On the other hand, the driver seems bothered by the hot seats, steering wheel and gear knob until the air conditioning does its thing... :)
lol

yer my aceleration gos to **** in the hot 38+

digifish
10th December 2006, 09:53 PM
I just did the calculations...

The difference in density between 10C and 40C (in kg/m3) is about 10%, that's 10% less oxygen to burn. Probably important :)

http://www.ce.utexas.edu/prof/kinnas/319LAB/Book/CH1/PROPS/GIFS/densair.gif

digifish

Poogene2001
10th December 2006, 09:55 PM
ummm, you have way too much time on your hands digifish :p

JasonGilholme
11th December 2006, 12:43 PM
Interesting....but damn man, what do you do on your weekends?!?!?! :P

WLD-18L
11th December 2006, 02:22 PM
makes sense ! nice work digfish

lowey22
11th December 2006, 04:24 PM
Nice graph. maths = fun! :dance:

Blue_Dvl
11th December 2006, 08:10 PM
yeah i noticed a bit of a lacking in off the line acceleration but other than that the old 1.8 banger had no problems with 40*.

low astra
11th December 2006, 08:19 PM
i find mine dosnt like standard unleaded in high temps, always seems more gutless and pings its tits off

bill142
11th December 2006, 09:24 PM
Probably not so bad if your at sea level and the air is thicker. Poor us up in the hills who have to put up with high temps and thinner air then normal.