helghast7

iTrader: (6)

you would feal the difference if you removed the system like a fat chick would feal the difference after lypo, the extra weight is loading down the power, however it is neccessary for cooling the drivizer humanizer part of the car.

i wish i had A/C

Valkyrie

I had no A/C, then installed it. Not that much difference in speed.

SirCygnus

iTrader: (1)

its a ton. you can feel it. put the ac on going down the highway. then put it on cruise controle. youll feel that **** instantly.

NZConvertible

If you remember they did two different tests at two different speeds and got two opposite results. At the lower speed having the windows down was more efficient than having the A/C on, but at the higher speed having the A/C on was more efficient than having the windows down. This is because the A/C's average load is more or less constant regardless of speed, but the aerodynamic drag from open windows increases with speed. Every vehicle will have a particular speed above which using the A/C is more fuel efficient than lowering the windows, depending on the vehicle's aerodynamics and A/C capacity. In the Mythbusters tests that speed was in between their two test speeds.

Did you really need to quote the entire post above yours just to say that?

Nope, that's not how AFM-based EFI systems work. The extra air is metered and fuel is added accordingly. Any AFR change would be tiny and simply a result of being at a slightly different load/rpm point on the fuel map.

There's definitely a small performance loss whenever the A/C compressor is engaged, there's no way to avoid that. Other than increasing the idle speed, the ECU does nothing to make the engine perform any differently with the A/C on, the extra load being compensated for by your right foot. Maybe you’re just over-compensating.

Idle speed cannot have any effect on throttle response, because by definition throttle response is how the engine response while driving, and you don't drive at 750-1000rpm.

I don't even think the BAC valve operates once engine speeds is over 1500-2000rpm.

My5ABaby

iTrader: (7)

I can see it robbing a minimal amount of power. If you want to go as fast as possible I guess just roll your windows up, turn off the A/C, and stick a toothpick in yourself and wait for it to come out without any residue. Then you'll be ready to eat.

Valkyrie

I didn't really see any reason not to.

Yes, but I think there would be more air for whatever level of throttle the ECU is seeing, so I think it's possible that the BAC could give you extra air, although it will be partially compensated for by the AFM. Of course that depends on whether the AFM "overrides" the TPS, and whether the BAC actually does anything above idle.

'87 turbo II

iTrader: (1)

new AC question. I turned on the A/C and white thin smokey stuff came out of th events. It was cool(as in low temperature) but what made it smokey?

rx7racerca

iTrader: (1)

High humidity perhaps? As in mist/condensation? If it didn't smell like smoke or burnt wiring or plastic, that'd be my guess (and if it did, that's bad news).

NZConvertible

Nobody wants or needs to read the whole post again.
Your reply had nothing to do with most of the post you quoted.
It clutters up the thread with useless, wasted space.
It's inconsiderate to other readers.
It makes you look like a 15yo forum noob.

Need more?

The BAC valve is simple throttle bypass, hence the name. It works no differently to you opening the throttle a little bit with your right foot. It doesn't add "extra air", but the increased airflow it allows is metered so that the right amount of fuel is added.

The TPS has nothing to do with this.

It's not smoke, it's just water vapour that occurs briefly in certain high-humidity conditions. When the A/C is running, moisture in the air condenses into liquid on the cold evaporator and drains off. When the system is first turned on, it takes a short while for the evaporator to come down to temp, so at first the moisture in the air only partly condenses into an airborne vapour. Once the evaporator temp drops low enough, the moisture is fully condensed into liquid and the vapour disappears. I know it can give you a fright the first time you see it, but it's harmless and perfectly normal.