Dyno run

Of course, there's no such thing as a free lunch - damp air also brings the risk of carb or inlet icing. When that happens, power can drop off to zero!!

Greg
 
I think the power the water injection / power thing has something to do with the water droplets vaporising in the cylinders, and therefore lowering the charge temperature and making it more efficient.

Basically, working in the same way that an intercooler does on a turbo or supercharged setup to lower the charge temperature.
 
Water injection...

scurrell said:
A few years back a mate of mine was marketing some gizmo I can't remember the name of now. It consisted of a small water reservoir in the engine compartment with a hose to each inlet. Water vapour was drawn into each cylinder with the fuel, supposedly giving a more efficient burn.

He fitted one to my old Renault 25 2.2, and it certainly made a difference - more power, and increased m.p.g.

Used by the RAF in WW11 on the Lancaster and others. Purpose is to get more oxygen into the engine and boost power, necessary when the plane was on its weight limit for bomb load and the pilot needed to fly higher than a normally aspirated engine would allow.

Used on cars by people that did not realise that injecting water into the engine...combustion chamber via the inlet tract....would scour the carbon deposits off of the piston crown and make the engine use oil.

Fairly obviously the water injection (dribble in some designs) also had a cooling effect upon the combustion chamber and reduced the possibilities of overheating during maximum acceleration.

Windscreen waher motor, length of copper tubing wrapped around exhaust manifold and inlet jet into top of carb, throttle body and hey presto, instant extra oxygen (cotained in the water) and a nicely steam cleaned interior, shiny pistons and massive oil consumption. :)
 
Always told.......myth!

Ben said:
quote:
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Originally posted by GEOFFREY DEACON
If temps and pressures make a difference to dyno results??, What are the perfect conditions for the best dyno results,?..
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"Cold, damp air, with high atmospheric pressure should give best bmep."



My knowledge won't stand up to much here..however, as a pilot of a lightly powered biplane, I would dispute the 'damp' bit.

Damp implies stacks of water vapour displacing both Oxygen and fuel..which would have an adverse affect.

High air pressure (density) is great though. Not sure about 'cool'.

I was always told that the 'engine has more power when it's damp' belief was a myth.

Any comments?

Ben


Come on, how can damp displ....a...ce oxygen?

Damp air is made up of water droplets suspended in the air, the main reason why nearly every vehicle on the road will run better in the late evening. As this damp air is more dense due to the droplets of oxygen containg water, it goes without saying that the engine will benefit from this greater oxygen boost.

When we can, we will wait until the last minute to go out and qualify, produce the best track time before a race if there is the possibilty of rain approaching the track we are attending. Obviously you need to be careful and not get caught out by the rain actually falling whilst out on the track, so timing is important in more ways than one.

The neat oxygen that you/we sometimes need to breathe in hospital or when flying higher than 30,000 feet(?) is extracted from.....wait fot it.......wait....WATER.

There is a difference though and I for one would not like to fly through a rain cloud, there the difference is gallons of water and not just fine mist droplets. :rolleyes:
 
Every day's a damp air day...

...if you invest in an ERL Aquamist injection system.

Main benefit in turbo's and supercharged systems though...mainly.

"The main function of these systems is to suppress detonation caused by high temperature and pressure developed within the combustion chamber when the effective compression ratio has been taken beyond the auto-ignition point by either a turbo or a supercharger. Water, with its high latent heat content, is extremely effective for controlling not only the onset of detonation but also the production of oxides of nitrogen in the modern leanburn engines."

Lot's of them fitted to Saab turbos .
 

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The company who used to do water injection kits for SAABs was called Guy Sweeton, I think they were based near Blackpool.
 


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