AC horsepower loss

[Geodudes550]

Okay this is going to sound extremely silly but bear with me. I had a thought while stuck in traffic on the 405 on a hot day. I’ve always wondered how ridiculous it would be to mount a small window unit AC to the front of a turbo car to really bring down intake temps.

I mean, a window mount weighs maybe 60-75 lbs and I bet there are smaller ones. Sure they’re power intensive but since it’s not belt driven from the car, you’re not stressing the engine any more than adding the weight of the thing.

I had an ecoboost for a bit and I quickly noticed that on hot days you could definitely feel the power loss. I know you can upgrade the intercooler and such but what would happen if you upgrade the intercooler and use your bumper mounted AC in tandem so your initial intake temp is 15-20 degrees cooler than the outside temps (and dehumidified) before it even hits the intercooler. Wouldn’t this promote higher air density which turbos crave?

Sure it’s silly but ever since I saw an old caddy with an oem looking aircon in the window the idea intrigued me. Why not tap into you AC and route some of that sweet Freon love into your airbox?

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[robvas]

Okay this is going to sound extremely silly but bear with me. I had a thought while stuck in traffic on the 405 on a hot day. I’ve always wondered how ridiculous it would be to mount a small window unit AC to the front of a turbo car to really bring down intake temps.

I mean, a window mount weighs maybe 60-75 lbs and I bet there are smaller ones. Sure they’re power intensive but since it’s not belt driven from the car, you’re not stressing the engine any more than adding the weight of the thing.

I had an ecoboost for a bit and I quickly noticed that on hot days you could definitely feel the power loss. I know you can upgrade the intercooler and such but what would happen if you upgrade the intercooler and use your bumper mounted AC in tandem so your initial intake temp is 15-20 degrees cooler than the outside temps (and dehumidified) before it even hits the intercooler. Wouldn’t this promote higher air density which turbos crave?

Sure it’s silly but ever since I saw an old caddy with an oem looking aircon in the window the idea intrigued me. Why not tap into you AC and route some of that sweet Freon love into your airbox?

April fools!

 

[Garfy]

Really ? No idea it turned off the charging as well at WOT.

I suppose the way to find out is to turn on your voltmeter display and go WOT and see if it drops somewhat...

 

[K4fxd]

I suppose the way to find out is to turn on your voltmeter display and go WOT and see if it drops somewhat...

Use a real volt meter not the dash idiot light err gauge.

 

[K4fxd]

Just looked at tune parameters and it turns off the radiator fans too.

 

[engineermike]

It might turn off charging but it doesn’t lower system voltage. One of my tools in my toolkit is to turn up system voltage during high fuel demand so the fuel pump will output more.

 

[K4fxd]

I might be wrong on the alternator but I'm sure I saw it somewhere.

 

[Garfy]

It might turn off charging but it doesn’t lower system voltage. One of my tools in my toolkit is to turn up system voltage during high fuel demand so the fuel pump will output more.

Actually, if the alternator is turned off the system voltage will drop as there's nothing to boost the battery/system voltage if the alternator isn't outputting current. Unless of course, there's a battery voltage booster going to the fuel pump; like we have for ham radio where MFJ makes a booster that will increase the voltage to 14.5V until the battery input voltage to the booster drops to 11.0V at which point it sounds an audible alarm before ceasing boost operation. I'm pretty sure Ford has not incorporated that into the system so once the alternator field current drops to zero, system voltage will begin to drop almost immediately.

 

[engineermike]

@Garfy i don’t think they turn off the alternator at wot. They may turn off the battery charging but not the alternator. The stock pcm has the functionality to increase system voltage as a function of fuel flow. This is a feature few tuners take advantage of (they prefer to sell parts), but I boost it to 15.2 volts and fuel pump flow greatly increases.

 

[ORRadtech]

I don't think that hp loss because of using the ac can be given a set number. On a cool, dry day the ac compressor won't be working as often or as hard. A hot, humid day will make it work much harder.
From what I've read, depending on conditions, you can expect somewhere between a half hp loss to around 10/12 hp loss.
I'm sure that the system condition will matter as well
A system low on refrigerant or with blocked coils will work harder to.

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