slybunda Posted July 1, 2015 Report Share Posted July 1, 2015 Dunno if its just me but today its fairly warm in Coventry 32c and driving the car it feels like its lost torque throughout the entire rev range. Anyone else effected? Or is my car nackered? Lol Link to comment Share on other sites More sharing options...
Knighty Posted July 1, 2015 Report Share Posted July 1, 2015 Only when the air con is on! Jesus that thing sucks the power. Link to comment Share on other sites More sharing options...
slybunda Posted July 1, 2015 Author Report Share Posted July 1, 2015 Ah yeabi had the aircon on all the time. That probably explains it Link to comment Share on other sites More sharing options...
Knighty Posted July 1, 2015 Report Share Posted July 1, 2015 Yes sir, that be your issue. Tell you what, it might suck some power, but today it's been bloody refreshing! Link to comment Share on other sites More sharing options...
toiletduck Posted July 1, 2015 Report Share Posted July 1, 2015 How much power does the aircon take? tbh mines on nearly all the time! Link to comment Share on other sites More sharing options...
Knighty Posted July 1, 2015 Report Share Posted July 1, 2015 How much power does the aircon take? tbh mines on nearly all the time! You can certainly feel it mate. Turned mine on travelling on a road at 30 and you could instantly hear the engine change note. Pickup under acceleration can be much slower too! I only turn it on when I have to. Link to comment Share on other sites More sharing options...
geraintthomas Posted July 1, 2015 Report Share Posted July 1, 2015 Not to mention a big impact on mpg Link to comment Share on other sites More sharing options...
Black Knight Posted July 1, 2015 Report Share Posted July 1, 2015 Also keep in mind that in these sort of exceptionally hot conditions the air coming into your engine is far hotter than normal.....and hot air intake equals power loss 1 Link to comment Share on other sites More sharing options...
Akuma77 Posted July 1, 2015 Report Share Posted July 1, 2015 snap today i had the aircon on coming home , it certainly works nicely and i you can hear the changes on the rev range Link to comment Share on other sites More sharing options...
RUToyota Posted July 2, 2015 Report Share Posted July 2, 2015 I'll happily take a temporary loss of power..AND a decrease in mpg,... to stay nice and cool.!!!! Neil Link to comment Share on other sites More sharing options...
Dorris Posted July 2, 2015 Report Share Posted July 2, 2015 (edited) AC will put more load on your engine but is minimal compared to what the heat is doing to your induction, in fact you will get more negative drag effect over 50mph with your window down then using the AC. Higher temperatures effects the power an engine will produce as the fuel injection system is putting much less fuel in to the engine in relation to the less dense hot air then it would do on a cold winters morning and this is much more noticeable with the smaller engines or older engines that may not be as efficient. Dorris Edited July 2, 2015 by Dorris Link to comment Share on other sites More sharing options...
KeoGT Posted July 2, 2015 Report Share Posted July 2, 2015 Put it this way, if it's 30c outside then with a stock air box, your intake temperature will be around 35c. People with SRI's will be getting intake air temps in the 40s Link to comment Share on other sites More sharing options...
Monkey Boy 1 Posted July 2, 2015 Report Share Posted July 2, 2015 From memory I think Air con takes around 5hp - 8hp from an engine when running. On a 100hp car that is quite a hit, on a 200hp engine then it is a small effect. 300hp it would hardly be noticeable. If you are travelling around at 2000 - 3000 RPM, then your engine is probably only producing about 1/3 the max HP. so a 5 - 8 hp drop would be quite noticeable. Fuel economy would probably be hit a little, but no where near as much as driving, say at 50pmh with the windows down. Air temp & altitude also can greatly effect the power of an engine. The latter we don't need to worry about too much in the UK, but the former will cause issues, hence many 'switched on' modifiers strive to get decent cold air feeds for their engines intake rather than just fitting a 'trick looking' cone filter but still pulling in air from a rather hot engine bay. Basically, our hot summers which would effect engine performance last about a couple of days, so not something to really worry about. 1 Link to comment Share on other sites More sharing options...
madcusslerfan Posted July 2, 2015 Report Share Posted July 2, 2015 I noticed a difference today compared to yesterday, acceleration was much better today with the colder air going into the airbox. I didn't have the a/c on yesterday and I still noticed a drop in performance due to the heat! Link to comment Share on other sites More sharing options...
slybunda Posted July 2, 2015 Author Report Share Posted July 2, 2015 hmm so hot air in means less fuel put in too = better fuel economy? Link to comment Share on other sites More sharing options...
J03 Posted July 2, 2015 Report Share Posted July 2, 2015 God bless the front mount intercooler 1 Link to comment Share on other sites More sharing options...
Monkey Boy 1 Posted July 2, 2015 Report Share Posted July 2, 2015 hmm so hot air in means less fuel put in too = better fuel economy? Basically Yes, but at a loss of power. I found this which may explain a bit better You might have noticed, driving through the summer months, that you're filling up the car a little less often than you would over winter. It's not your mind playing tricks on you, but a fairly common occurrence for all drivers. Cars simply get better gas mileage during warm weather than they do when it's cold. There are several reasons for that, and we've picked the most relevant ones below. Warm air There's a scientific explanation for why you use less fuel in warmer weather, and it's to do with air temperature. As you may know, your engine uses air, as well as gas, in order to generate energy. In fact, it uses huge amounts of the stuff, though only the oxygen is used in combustion. These oxygen molecules combine with carbon in the fuel during combustion, to form--you guessed it, carbon dioxide. Anyway, one property of air, like many substances, is that it expands when it warms. This makes it less dense--molecules of the various gases are spread further apart. This means that every gulp of air your car is taking during combustion has less oxygen in it at warmer temperatures, and if there's less oxygen, the engine compensates by using less fuel. This is bad from a power perspective, but good for economy. The engine is combusting less fuel due to the warm air, improving fuel economy. During winter, the reverse is true--denser air encourages the engine to chuck in more fuel, boosting performance and harming economy. Link to comment Share on other sites More sharing options...
geraintthomas Posted July 2, 2015 Report Share Posted July 2, 2015 (edited) hmm so hot air in means less fuel put in too = better fuel economy? Don't think it works like that?EDIT: Posted late, just read the above - that's sure surprised me! Edited July 2, 2015 by geraintthomas Link to comment Share on other sites More sharing options...
Monkey Boy 1 Posted July 2, 2015 Report Share Posted July 2, 2015 It surprised me too, but sort of makes sense. Race car engines prefer cooler air to get the power up but they are not worried about fuel economy (unless it's F1 and they have to 'fuel manage') Link to comment Share on other sites More sharing options...
KeoGT Posted July 3, 2015 Report Share Posted July 3, 2015 Also don't forget that the warmer the air (less dense) then it's easier to travel through at higher speeds meaning less work for the engine. That's why when car manufactures like Bugatti are going for the highest speed possible they do it in the hottest place possible Link to comment Share on other sites More sharing options...
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