Rick2014

iTrader: (3)

Does anyones Subaru seem to be affected by this hot weather .My forester seems to run a lot better before it hits hot temperatures in the evening.

neil-h

Yup, fairly sure my fuel consumption is better now it's hot

Rick2014

iTrader: (3)

Rick2014

iTrader: (3)

I only get to drive it to work and home again the missus has it all day.I notice the difference in the morning the car flys and in the evening its a different car like its suffering from heat soak or some thing.I used to have a Volvo s40 1.9 petrol turbo with 240 bhp and that had an oil coil as std fitment bolted to the side of the sump.I wonder why Subaru didn't do this on there earlier cars

Milneragain

It's to do with the density of the air.

Cold air is more dense than hot air, so your car will run better in cold weather than it does in hot weather because more dense air is running through your turbo.

Donnie Brasco 46

iTrader: (2)

Your car is at it's most powerful on a misty morning. As the last post said, the air is denser.

ossett2k2

iTrader: (9)

Love those cold misty mornings

fawor

iTrader: (3)

just travel on Sunday at Germany - 37 degrees with no problems at all(on LPG -hotter fuel)
good i did regas my AC week before

ossett2k2

iTrader: (9)

Hmmmm wonder if the aircon can be converted to blow cold air onto the engine? Mind you doesn't the aircon zap some power? My ic water spray doesn't seem to have much affect even on the warmest of days

Turbotits

iTrader: (2)

You may not think the i/c spray does alot. If you had a charge temp guage you see how hot they get while stationary and what effect the spray has.

Gambit

iTrader: (6)

With top mount intercooler I can see inlet temps of 55degree when sitting in traffic on the psi3 monitor

Shaun

I think you'll find that isn't correct.

Air will be at its most dense when there is the least amount of water in it, being at its coldest.

Moisture will take space, where oxygen could take up instead.

ossett2k2

iTrader: (9)

I never really used it as I thought there would be no difference. I might fill the bottle with some ice cold water and go for a drive on my back roads to see if I can feel a difference

cuprajake

iTrader: (11)

Mines always on auto spray and I give it a blast just after setting off from stationary too

fpan

iTrader: (11)

Same here. it can even reach 68C if you are stuck in traffic for a long time.
The trick is to drive off boost until IAT have dropped down to at least 35C or so.

ossett2k2

iTrader: (9)

Excellent,I will start using I/c spray to cool things down. Also read a good thread on the throttle body water bypass. Has anyone done this and seen a positive result? I'm guessing any kind of temp drops will make some difference

Gambit

iTrader: (6)

It doesnt make that big a diff to be honest, it helps things cool quicker when on the move but dont be thinking temps will plummet just on spraying. Tho I dont have a temp sensor in ic to throttle body coupling

dabiscuit

Petrol is more dense in colder weather

JusNoGood

oooh interesting. When and where did you have the LPG conversion? How many miles have you done since conversion and what have your experiences been?

Carnut

Air density also changes at different altitudes, the lower the better.

Rick2014

iTrader: (3)

well said.Doesnt help stood in traffic on the m60 .My rad fan was on for a while when I got back the other day

Smkxh95

Out of curiosity is It okay to put tap water into ic spray or have to be De ionised or some thing?
Had the car a yr never topped It up as never used it lol well tbh I forgot I had it.
Cheers
Kev

scoobyskool

iTrader: (1)

If its had water sitting in for a year and not been refreshed or used first thing I would do is whip the bottle out and give it a damn good bleach or antibac - http://www.bbc.co.uk/news/10293519

Smkxh95

Good point mate. Happened to a friend of mine. Could I just pop some window wash in there? Just a tiny amount and let it mix up? Would it be okay? Or some sort of cleaner like little bit of fairy?
Thanks

scoobyskool

iTrader: (1)

idk tbh - when I got this wrx the washer bottle was real horrid inside and smelt a bit off when you cleaned the screen - having read about legionnaires before I just took no chances and took it out the car and cleaned it on an outside tap then bunged the pump hole up and left it overnight in a strong bleach solution - final clean next day and many rinses then refit and top up with screenwash and the odd smell is gone and it seems to clean the screen with fewer smears but that could just be down to decent screenwash etc

Smkxh95

ok mate nice one. I just read on here that someone does put screen wash In there's as it keeps it from going green and acts as anti freeze in winter.
I have a read up if screen wash will kill any unwanted guests then pop some In and let it swirl about about a bit lol
What's the worst that can happen???
Lol also apparently the EVO shares the screen wash bottle with the ic spray.
Thanks
Kev

LuckyWelshchap

Ah - but denser air means the car has to overcome greater aerodynamic resistance, so any extra power is negated by the need to push through denser air.

LuckyWelshchap

Er.... density is mass per volume.
Any given volume of air with water in it is heavier that the same volume without water, since water is of a far higher mass than air.

That means that 'wetter' air is harder to push through than 'drier', so more power is needed to produce the same performance.

Which is harder to drive through - air or the ocean?

Theoretically the ideal situation would be to have some form of heat exchanger concentrating and projecting the excessive heat from under the bonnet as a beam onto air in front of the car, causing it (the air) to reduce significantly in density and hence lower the aerodynamic resistance that the car has to overcome.

Either that or simply stick Fergie as a mascot on your bonnet and ask him about Beckham.

Carnut

F1 cars run a bit slower at higher altitude, thinner air, and with there high down force they would have more to gain.

But in case that isn't enough, if you go to the extreme of everest where the air is very thin and by your logic easier to move through, you will find anything that requires oxygen is at a massive disadvantage.

LuckyWelshchap

The down force is created by 'aerodymanic manipulation' increasing the speed and intensity of air molecules that hit the wing and converting that kinetic energy into downforce.
If the air is less dense then there is a lesser intensity (unless the car's speed can be increased significantly) and hence less downforce. If an F1 race at 20,000 ft was in a straight line that wouldn't matter of course but since it wouldn't be, then the cars will have to be slower through bends, resulting in lower lap speeds.

Also, the air intakes are a fixed volume and hence only a fixed (maximum) volume of air can be sucked in over any period of time.
Less dense air means less oxygen molecules, hence oxygen starvation, lower combustion and a marked degradation in engine efficiency.

PS do I sound like I know what I'm on about?