Why does it run better in the rain?

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Model T Ford Forum: Forum 2012: Why does it run better in the rain?
Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Young in Mays Landing, NJ on Wednesday, July 11, 2012 - 08:53 pm:

My speed and power seem to increase when l run in the rain. What's the reason for this? We were tooling along at 40 mph and it began to shower. All of a sudden, she jumped up to 45, 47, 48 and l backed down. Denser oxygen?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Wednesday, July 11, 2012 - 08:57 pm:

Cooler air associated with the rain shower?


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Leming on Wednesday, July 11, 2012 - 09:14 pm:

Yes, it is the humidity that affects the intake. Dense air will always make them run better. There used to be an accessory Bottle that held water and a bit of alcohol. It was a bubbler type device that worked off vacuuum and pulled moist air into the intake.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Warwick Landy on Wednesday, July 11, 2012 - 09:57 pm:

Dave-
i have always enjoyed late afternoon or even night time driving as my cars always seem to run best at those times. Early version of 'cold air induction'???. Interested if other can confirm better running in colder temperatures?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ricks - Surf City on Wednesday, July 11, 2012 - 11:22 pm:

It doesn't seem right, but humid air is less dense than dry air. The power increase is strictly due to cooler air being denser. Denser air is about equivalent to increasing compression ratio.


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Dare - Just a little South West . on Wednesday, July 11, 2012 - 11:29 pm:

Oooops it aint gona work if l leave my pre heater on ( stove pipe ) is it...
Warwick are you back already from your O/S trip ??
David.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Danial - Veneta OR US Earth Solar System on Wednesday, July 11, 2012 - 11:41 pm:

Yep. This is why my hot rods always sounded throatier and ran better in the morning when the air was cool. Higher compression by just a bit.

Ever see them put big ice packs on an engine under the hood just before a drag race?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Fred Dimock, Newfields NH, USA on Thursday, July 12, 2012 - 01:54 am:

Oldsmobile had water injection on one of their high performance vehicles in the 50's. It cooled the combustion chamber and allowed more gas/air to enter - like a cheap turbo charger.

We used the water trick when drag racing by drilling a very small hole in the intake so water from the radiator would get into the intake. We even went as far as packing bags of ice on the manifold and putting ice water into the radiator before a race to lower the density of the gas/air so we could get more into the combustion chamber.
I guess it worked because we held the NHRA modified production record for a short time.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Page on Thursday, July 12, 2012 - 02:18 am:

Here is some words of wisdom from the original master of Model T .( Murray Fahnestock ) . From " The Model T Fordowner " The best of Murray Fahnestock available at most of the vendors. I have had this book for years, A lot of very interesting information in it.

Regards, john


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Page on Thursday, July 12, 2012 - 02:42 am:

I was looking through some of my old Ford Owner and Dealer magazines and found that article as well. All the articles in " The Model T Ford Owner " book are reprints of articles from those old 1920's magazines. Regards, John



Top of pagePrevious messageNext messageBottom of page Link to this message  By Will,, Trenton,,,New Jersey on Thursday, July 12, 2012 - 05:52 am:

Not to rob from another thread but I guess this give credit to removing the hot air pipe to improve power? I have always been told to never take off the hot air pipe but with all the comments on this I guess I will take mine off and give it a try


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Thursday, July 12, 2012 - 06:47 am:

Oldsmobile had water injection on its turbocharged 1962 Specials. Note the word turbocharged in the preceding sentence Fred.


Water vapor in air reduces the available amount of oxygen in naturally aspirated (non supercharged) engines. This reduces power 100% of the time, if the engine is in proper tune.

Despite all the old wives tales and your perceptions to the contrary, this is an irrefutable scientific fact.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Thursday, July 12, 2012 - 10:45 am:

I would guess that because of the rain, you failed to notice a slight downgrade. I have had people say their cars run better in rain, but only thing I have noticed over the years is that if you have a car which has a spark knock (ping) it will usually ping less in rain. The reason water injectors were used in the past was so the owners could use lower octane "regular" gas. Our newer cars have a "ping detector" which will automatically adjust the timing and fuel mixture to eliminate the ping. With our modern gas, it is almost impossible to make a Model T ping unless you have very heavy carbon buildup and the engine is running hot.
There, I've said it. Now critics can analyze what I said and tear it apart!
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ricks - Surf City on Thursday, July 12, 2012 - 11:10 am:

from en.wikipedia.org
----
Density altitude is the altitude in the International Standard Atmosphere at which the air density would be equal to the actual air density at the place of observation, or, in other words, the height when measured in terms of the density of the air rather than the distance from the ground. "Density Altitude" is the pressure altitude adjusted for non-standard temperature.

Both an increase in temperature and, to a much lesser degree, humidity will cause an increase in density altitude. Thus, in hot and humid conditions, the density altitude at a particular location may be significantly higher than the true altitude...

The power output of the engine — power output depends on oxygen intake, so the engine output is reduced as the equivalent "dry air" density decreases and produces even less power as moisture displaces oxygen in more humid conditions.
------

There may another factor: a rich mixture fires easier than a lean mixture.

Speculation: an overly lean mixture might ignite easier if the spark is aided by moisture.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Young in Mays Landing, NJ on Thursday, July 12, 2012 - 12:29 pm:

Norman, the power increase held up for about 40 minutes as we ran about 30 miles or so over the flat roads of South Jersey in a downpour, as we were off on a 400 mile, 4 day, trip to Maryland last week in 100 degree temperatures. This "pep" occured one other time on that trip. The skies had turned black and the temp dropped a bit, but the rain never reached us by more than a few miles.

More interesting, is that l even had my hot air pipe installed. After reading the dyno test thread, that thing is coming off tonight. The car was weighted down with 5 day's luggage and my wife's new pink lphone!
1


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Thursday, July 12, 2012 - 02:59 pm:

Maybe you had a 30 MPH tail wind? A rainy day reduces power.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Thursday, July 12, 2012 - 03:37 pm:

I think I have it figured out! It is the radio signals pushing on that phone. How does it run when the phone is turned off?
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jeff Hood on Friday, July 13, 2012 - 11:47 am:

This thread is very similar to the discussion on the dyno test thread but with seemingly different opinions. Cool dense air does increase power through better mixture with more oxygen. That is why race cars and now even modern cars draw the intake air from outside the engine compartment through hood scoops or cold air intakes in front of the radiator.

By the way, what happened to the dyno test thread? It seems to have disappeared!


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