Cold air Intake? - Not a Joke or Noob question

Doesn't matter when its warm-hot out? LOL check your science there buddy

heat has a drastic affect with fuel and it turning into a vapor if you get it hot enough that is

 

I just got a 2002 Prius as a 3rd car, or back-up car when gas hits $4 again. The first thing I thought was: "How can I make it more fuel efficient?". So I websearched and got here. Interested in learning/seeing any tested results to make the car even more fuel efficient.

 

perhaps the "throttle response" is improved by cutting restrictions before the throttle plate.
since most drivers don't wot often, it seems at normal accelerator pedal positions that the car is a bit quicker. wot single digit hp increases wouldn't be noticable even if there were any. my CAI kit was louder than just pulling the resonator, i vaguely remember that i did drive for a couple days without the res. before i got the cone filter installed. i try not to be fooled by engine noise cause it sure sounded faster when we flipped the lid on dad's v8 air cleaner, but prob'ly didn't do anything but piss off dad.

 

to your foot that "restricted throttle plate setting" feels like its making more power sooner, ie. better throttle response. but the atkinson cycle isn't really capable of using much add'l airflow even if it didn't have the teeny exhaust pipe. (anybody notice the ex pipe is very restrictive?)
from what i understand on a normal engine, colder air being denser, will need more fuel. and both my carbureted engines love cool weather. but does this matter to the atkinson?

 

And the A/F sensor just keeps on adding the wrong amount of fuel instead of taking into account the "more air". Maybe though it is taking in warmer air. I suppose on either stock or the CAI cone you could put in a restrictor cardboard and see if it changes much.

 

Green bars on the battery meter is not a good thing. Ideally the SOC should stay in the blue range. In your case green means the ICE is running more than needed.

Tom

 

Dense air means more oxygen per unit volume, regardless of the engine type, so Atkinson doesn't come into it. The real issue becomes the fuel injection system and whether it can keep up with the additional air mass.

Tom

 

It would be interesting to see if the Fuel Injector part number was the same as the Otto cycle engine using the same engine block, as it makes 4/3 the HP.

Toyota ZR engine - Wikipedia, the free encyclopedia
Toyota NZ engine - Wikipedia, the free encyclopedia

 

i doubt the efi is so close to maxed out that it would not be able to handle a slight increase in air volume. atkinson cycle is a factor since it shoves a fair amount of the intake charge back out into the manifold. how much is that intake charge warmed in the process? what then happens to intake manifold vacuum levels?

 

it would make economic sense to use common parts if possible...

 

nope. maf is there to read volume; upstream o2 sensor tells ecu if mixture is correct. ecu will compensate if "more air" is actually being used by the engine.

 

Atkinson engines run at similar compression levels to Otto cycle engines. Quasi Atkinson engines, like that on the Prius, achieve this by pushing some of the charge back into the intake. This is done deliberately to lower compression levels, so warming is not an issue. If you cool that charge or otherwise increase its density, you start increasing the compression above limits. If it was good to run at higher compression levels, the engineers could have simply reduced the amount of charge returned to the intake.

Regardless, the shoving of air back into the intake doesn't alter our discussion. It just means that an Atkinson cycle engine needs a longer stroke to achieve the same mass air flow.

Tom

 

yeah, i know how it works. similar compression levels to racing engines. the prius runs 13.5/1. if it was otto cycle you'd need to run avgas or cam2.
a supercharger can increase density beyond safe limits; there is no chance a CAI is gonna raise the effective compression ratio on any engine enough to cause problems.
manufacturers tune most engines conservatively, and they also look at considerations like most consumers are not interested in hearing the motor rev up. on our cars specifically, performance was about the last thing toyota was thinking about. as long as it can get mostly out of its own way, that was good enough for them. i think the engineers were trying to get the ice to behave as if it had less displacement. and they did want it to be too quiet, i think to go along with the boring paint.
i would love to see what would happen if someone could convert one to otto, or put a yaris motor in it. i guess the hard part would be programming the ecm.

 

These guys did (low on the page)
Modifying the Prius

 

13:1 is the expansion ratio. The compression ratio is 9.5:1, which is fairly ordinary. People often quote the 13:1 figure as the compression ratio, but this is really misleading. Sometimes they add the modifier "geometric" to get geometric compression ratio, which is just another way of saying what it would be without the delayed intake valve closure. I still think it's a misleading term, but it is commonly used, so I supposed I need to get over it.

The engine on my boat has a 22:1 compression ratio. Now *that's* a compression ratio.

Tom

 

toyota gives a mechanical compression ration of- maybe it was 13:1- its been a long time since i read it. i guess your boat has a diesel? different animal. fishing or water skiing?
i had read about the bonneville prius before; i had forgotten about the engine swap though. i wish they'd have done some street testing w/ the echo motor and a dyno run. still it means it can be done. it would be awesome to see a prius dust off some supposedly faster cars.

 

A Prius can be driven on a (tight) road course faster than some sports cars. Depends on the driver.

 

yeah, but i mean in a straight line. wouldn't it be nice to pass the punk in the turbo'd honda or the jerk in the bmw that wants to cut you off?