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twilightprotege
26-06-2004, 02:19 PM
hey

well a mate and i were having a talk today about racing on a track and how (obviously) we turn the air cond off when we want the most power, but i had an idea.

you know how the air cond air compressor kicks in when it reckons the gases are too warm and allows the gases to circulate, well what if a system could be drawn up so that the compressor only kicks in when the brakes are applied???

i wouldnt think this would be too hard, but me thinks would be great for track work. you could have the windows up (better aerodynamics) and the air cond going. then when you brake into the corner it not only cools down the gas a little, it also helps with engine braking....

so what do you think? is it possible??? what are your thoughts?

lamby1986
27-06-2004, 07:24 PM
how long do you expect to be on the brakes? cuz if the air con is only active for breif seconds at a time, i dont no if it would make great difference to the internal temp of the car. is it that hot up in brisbane you cant stand the heat?

and as they say, if you can't stand the heat, get out of the kitchen. or the cockpit. or the drivers seat. Just give it to me! :twisted:

Cosmo Dude
27-06-2004, 07:33 PM
You could break the A/C only when the go peddle is fully depressed, this would allow it more time to operate on the track as well as travelling too and from he grid form the paddock and sitting on the grid.

twilightprotege
27-06-2004, 08:46 PM
that's a good idea cosmo - the a/c electric clutch disabled at WOT....hmmmmm. but that might have it kick in between changes of gears???

lamby - what i was meaning is the air cond going all the time while racing. so you'll have atleast outside temp air coming in, but the air cond compressor kicking in when braking to allow the gas to move through the system and cool it down a little

lamby1986
28-06-2004, 09:20 PM
i see your point more clearly now, but im still not sure if the difference will be noticable, but i haven't done a study of thermodynamics yet [starts next semester] so i no nothing. as for engine braking, that 4 ish less hp is not imo going to make a noticable difference either, although if you were going to do it, i think cosmo is really on to something.

Nate
29-06-2004, 12:53 AM
i see your point more clearly now, but im still not sure if the difference will be noticable, but i haven't done a study of thermodynamics yet [starts next semester] so i no nothing. as for engine braking, that 4 ish less hp is not imo going to make a noticable difference either, although if you were going to do it, i think cosmo is really on to something.

true but on the track every tenth of a second counts ... and comso is on something ... just nobody knows what!!

twilightprotege
29-06-2004, 06:23 AM
like what nate said - every tenth of a second counts! every little hp helps, every little decrease in your coefficient of drag helps....and what helps the most? a comfortable driver.

andrewgrazier
29-06-2004, 02:18 PM
id have to say i dont think it would be worth the effort or time.
umm and i thoguht the air conditioner was alywas on, but the other fan kicks in when the engine gets too hot

twilightprotege
29-06-2004, 03:57 PM
not quite. you can have the air cond on all the time, but the gases in the system will only be circulated when the electric clutch on the air compressor kicks in. this happens at the same time when the fan kicks in. you'll notice that when idling, the revs will go slightly up (air compressor on) and then drop again (air compressor off). also, if you ever take the belt off the air compressor, you'll see that the pulley on it turns ever so easily

ccall48
31-08-2004, 05:31 PM
bugger all that... why dont you just get a 12 volt compresser and run your air off your battery so no power is consumed by your engine...? (12v compressors are expensive tho) then you could race with air on - some american car co. (GM i think) are experimenting with this atm and could possibly have already released a car with a system, also toyota has a system to i believe.

short little bursts you would get from rigging something up so the clutch was engaged (on the compressor) only when brakes applied would not work in my opinion... not enough time given for the gas to evaporate and condense... (giving you the cooling effect) lamby would be right. and engaging the clutch when accelerator is disengaged would cause more problems then its worth... with the a/c coming on when you dont want it too.

just flick the switch for a/c to off, win the race and turn it back on... it might be easier and cheaper?

twilightprotege
31-08-2004, 06:34 PM
yeah i decided to do nothing about it, just thought it was an interesting idea.

anyway, a 12v compressor would take more power to run then the battery could produce, so the alternator would be used. that would then defeat the purpose of it all

Nate
31-08-2004, 06:36 PM
just thought it was an interesting idea.


hence the thread name

Cosmo Dude
31-08-2004, 07:20 PM
Many cars have an A/C demand circuit in the ECU, the ECU will automaticly turn the A/C off when full power is required. You could hook in a tempory lamp to tell you when/if this happens.
You may be fighting a battle that is already won.




The A/C demand also uses the idle-up so that the motor doesn't stall.

ezin
09-09-2004, 03:57 PM
I know that all the new subarus cut the compressor out under full throttle conditions (dont know about ours, will look into in sumer). U could easily hook up a kill switch to the ac and accelerator pedal, Im not really a fan of this because when u back of the comp cuts in and that could be at 6k rpm which the clutch and belt arent a fan of.

Yeah if i lived where its hot i probably would do it but i never use the ac except for about 10 days of the year, and then i just hit the swith to off when draging and flick it back on when the engine rev's have dropped.

chipa
09-09-2004, 05:11 PM
You could use Cosmo's idea but also integrate a 555 timer electronic circuit to make sure it doesn't turn on immediately. say wait for 2 seconds. That way gear changes would be skipped as you'd be back to WOT and the timer would reset...

The max a timer circuit like that cost is around $20. That's for a basic jaycar kit with the few extras that you need. (I made a similar circuit to auto cancel a friend's motorbike turn signal if left on for too long).

Cosmo Dude
09-09-2004, 05:52 PM
Further to my post of August thirty first, has anyone hooked a temporary lamp into the compressor circuit?
Placed in series it should turn on with the compressor without changing the circuit characteristics more than an ohm or two.