No "Hot water bypass" for this car.

I believe paper filters are better than foam anyway.
That is the cool thing about sharing experiences hey!

 

Hi Drifty...,

I am confused on this one. Can you explain how "Vapor Lock" forms in a thottle body of a fuel injection car, where there is no fuel running in a tubular line ?

Maybe this is a terminology thing, but I thought "Vapor Lock" was when gasoline or air bubbles got into fuel lines between the fuel pump (usually engine mounted fuel pumps) and the gas tank. Then when a suction pulse occured, the bubble just stretched a little and recovered, resulting in no gasoline transport from the gas tank to the fuel pump. This usually happened on 100 degree days, not cool days, and where the fuel line passed close to the exhaust system, or after an exhaust system heat sheild had fallen away from rust.

As most cars in the last ten years have had in-tank gasoline pumps "Vapor Lock" has been a non-issue.

Or maybe this is a different problem unique to newer cars?

The Prius does not have preheated intake air. Hobbit has done some mods to see if it could improve cold-weather fuel economy with inconclusive results. If you think about, with proper computation, the number of oxygen molecules could be calculated from air temperture and air flow. Which is what the MAF does.

The original reason for preheat air was that carbuerators were sensative to temperature, and cars would be quite stinky until both the carbuerator and intake manifolds were warm.

In a fuel inejected car the fuel is injected right at the valve, its plenty warm there most of the time. Even more so in a Miller Valve Train car such as the Prius. During the compression cycle some intake air in the piston is pushed back out of the piston. So, the warmed air from a regulated throttle body temperature would just be overkill in the Prius. As the intake manifold is getting heated from the reverse flow air during the Atkinson cycle/ Miller Valve train action. The warm air is advantageous to atomizing fuel. Atomisation is very temperature sensistive. To get the finest droplets, the air has to be at the right temperature.

There is also no EGR in the Prius, either. So things stay cleaner.

As for the Cone-Shaped K+N filter, maybe you can replumb the intake air-horn, and just splice the filter on the very input end. Then, just leave the filter in the housing out. There might be enough room over to the pasneger side of the engine for it. Mabye K+N will make a fitting that will just plug right onto the air box ?

 

I believe the problem which can sometimes be encountered in fuel injected cars is icing of the idle bypass passage due to expansion of the air as it passes the idle speed regulation air valve. The Prius engine rarely runs at idle or small throttle opening so I doubt there would be a problem with icing.

 

And since there's no bypass in the Prius throttle body, the only
possible icing concern would be in the throat itself right around
the narrow gaps at the butterfly. That's where the coolant loop
runs, to keep the throat slightly warmer so the ice doesn't form.
.
That loop also will not add any significant heat to the air passing
by it, so there's really no reason to bypass it at all. Heck, the
heat simply conducted from the block to the intake runners will add
more heat to the incoming air than the tiny area at the warmed
throat could ever hope to.
.
While there is a slight constriction at the throttle plate area, the
throat of that thing isn't really a venturi -- no real need for it
to be, it's just a place to control airflow.
.
_H*

 

<div class='quotetop'>QUOTE(patsparks @ Nov 3 2007, 09:46 AM) [snapback]534279[/snapback]</div>

Icing can be a problem with non-injected engines too. That's why airplanes have carb heat.

Tom

 

Because they are looking for maximum air density not atomisation. It is correct that warmer air will allow the fuel to vaporise more completely it wasn't said that this lead to more power but it may lead to better fuel combustion even though the air in the cylinder is less dense. The less dense air will have slightly less fuel in it so it will make slightly less heat but as the fuel is better vaporised it will burn more completely releasing more power per unit of fuel but less power on each stroke.

Hot Rod Harry is seeking maximum power from a given engine capacity, most Prius owners are seeking maximum power from each drop of fuel.
Volumetric efficiency versus fuel efficiency.

 

Head is a little bigger now.
Thanks, not sure extra power will make it to the ground, the power to the wheels is limited by the electric motor/generators. I think MG1 determines the torque of the engine to the wheels. The electric throttle will limit revs.
Good luck with it. I hope you find what your looking for.

 

The other reason I got out of the trade.