For some reason my truck seems to run better when it’s raining outside.
Seems smoother and the turbo whistle appears to be louder. Seems to run awesome!

Why does this happen?

It is not like water is getting past the air filter, and if humidity is the cause than why doesn’t it seem to run better when very foggy outside.

Has this ever been brought up?

My old 71 Chevy truck acted the same way so guessing this is a normal occurrence.

thanks for any input.

TD

 

Probly has to do with cooler denser air when it rains.

 

What ofcmarc said. This has been brought up on other forums. Some VERY scientific kinda guys posted, poo-pooing this and blah-blah-blah and all the specific gravity, mass density, adiabatic this and thermodynamic that saying it was all imaginary etc. Problem was about 80%-90% of the people posting said they'd noticed the same thing, myself included!

Water injection is water injection regardless of how it's accomplished.

 

anyone driving a old John Deere knows you shift up one gear as air is intercooled by the man upstairs after the sun goes down

 

To quote Johnny Rivers:


"....rain went to blowing up under my hood

.....'knew that was a doing my motor good...Maybelline...why can't ya be

true...etc., etc.



I bet yall didn't know I could sang, did you??

 

I have done alot of off roading in a landrover discovery, and where we go and play, there is alot of water, some 4' doop, we all run raised air intakes, with all the steam generated, being snorted in out intakes, we all expirenced the same thing, OUR engines run better, Water in small amts reomves carbon, and steam is 2000X the size it is when water, so high humidity/rain, is good!
Peter.

 

My '93 w/318 runs like a bag in the rain. i guess cool dense air is doing nothing for me there

 

Sounds like water in the ignition or something.

 

As water travels over the intercooler and evaporates the efficiency of your intercooler is increased by at least 200 percent and combined with air density giving h.p. you've got a cheap increase. When the sidewinder project ran on the flats they used ice on the intercooler to increase density. The same thing goes for gas motors. Ive seen several occasions where guys will purposely angle the intercoolers on turbo charged gas rigs back so that they can stack ice on it before they run. Subaru WRX guys unhook their windsheild washer lines and aim em at the intercooler to give em extra horsepower. Works too........

 

You pretty much proved it I'd say.

 

We have a winner!

 

Just because your tires spin easier when it's raining doesnt mean your truck has more power.

 

The water in the air slows the burn also which helps when your timing is advanced.

 

Also, if I'm not mistaken, atmospheric air with high humidity is going to have a greater specific gravity or more inertial mass in the gas column going through turbo. Seems that would mean that the force put on the gas is going to result in more inertia, therefore jamming the gas into the cylinder a little harder? Once the gas column is spun into greater motion it will tend to continue in that motion until a change occurs, therefore it may help with a slight scavenging effect at the intake. Added to this are the effects of water injection to some degree with benefits there, too.

RE: "My '93 w/318 runs like a bag in the rain. i guess cool dense air is doing nothing for me there." Might be time to check the oxygen sensor and MAP sensor values, and check the electrical connectors at harnesses, relays and solenoids. While you're at it it's good to double check grounds which can react to moisture also. The computer checks the sensor values against a reference signal voltage and makes adjustments. Doesn't take much to mess up either the signal voltage or the control voltage to throw things off.

 

My take on it is that ~

Considering our engines run because we heat air with fuel and that heated air expands, pushing the pistons, etc.
Be it Diesel or Otto ignition, it's all the same.

However, Water in general has a much higher expansion of volume compared to air if I'm not mistaken. Such is made evident with the water/methanol injection systems. Even when running pure water, one sees a marked jump in boost as a result of the increased combustion pressures (See blown head gasket).

With that, as the outdoor air increases in relative humidity, the potential for an overall larger expanded volume is there provided the heat for expansion is given.

This ignores all the other effects such as inhibiting detonation, slowing flame front, etc.

It literally boils down to more push on the piston.