Remove charcoal pad in air cleaner box?

Neither is a good idea.
The engine will NOT benefit from greater air flow (less restriction) and the charcoal filter is there to catch fumes and I don't think the incoming air actually passes through it.

Both subjects have been discussed here is some detail before.
Have you actually tried a search ?
Sometime it works and sometimes not.

 

i think it's there to filter gas fumes for emissions.

 

"Seems to help." Most snake-oil is based on perceptions, not reality.

 

On a related subject, there's a video by an electrical engineer who gives a detailed explanation of the scams being pulled on people who pay up to $500 for low-quality cables that cost much less than a dollar to produce. Some of the commenters were very upset and angry at the insinuation that they were being duped in this way. Apparently some people are incapable of judging quality, except by the price. No wonder millions are made out the backs of vans, selling this junk to idiots.

P.S. I know it might belong in FHOP, but it also belongs here.

 

OH, now your Prius is a living, breathing organism.

An engine only benefits from more air IF the fuel controls put in more fuel to go along with it.
Otherwise it just leans out.

Having a free flow air filter creates more noise........and perception is at least half of reality.

But if it makes you happy that's all that counts.......right ??

 

We've explored this subject already in other threads. The OEM filter doesn't restrict airflow any differently from expensive after-market add-ons, at least not according to any scientific evidence. Testimonials by-the-way, have nothing to do with scientific data.

If you want to win races, buy a race car. Spending hundreds of dollars just for a few imaginary percentage points in performance is just silly.

 

I took out that charcoal pad thats in the upper air box, but i kept OEM filter though, no gains however, but intake noise increased slightly more throaty noise . Its OP's choice ppl don't be flamming him for using something that you may think its "snake oil" im not a fan of K&N products but it makes OP happy then so be it.

 

"A fool and his money are soon parted." -Old English proverb.

 

When I was young I put a K&N in my 2002 Camry and "thought" I felt more power. Then I did an oil analysis and I knew the engine was eating dirt. Then I went back to paper.

The old K&N is somewhere in my tool chest where it can do no harm to engines.

As for the charcoal, it might be part of the emission control equipment. Tampering with it might be against federal law.

 

OP (Original Poster).

Only way to OBJECTIVELY verify Horse Power output is to put the car on a dyno, then run two tests. One test with a new, K&N air filter. The second test with a new OEM air filter. The air filter would obviously be the only variable that changes on the car. Until you do this, your claims have no validity.

Read the following link in its entirety (its not long). Its an objective test performed on nine air filters, one being a K&N.
http://www.nicoclub.com/archives/kn-vs-oem-filter.html

"However, if a filter is using “better airflow” as their marketing tool, remember this….Does it flow better? At very high airflow volumes, probably. BUT, our engines CAN’T flow that much air unless super-modified, so what is the point? The stock filter will flow MORE THAN ENOUGH AIR to give you ALL THE HORSEPOWER the engine has to give. And this remains true until the filter is dirty enough to be recognizeable. At that point performance will decline somewhat. Replace the filter and get on with it."​

Filter Efficiency (How well does the filter captures debris.)


Accumulative Gain (Total amount of dirt that passed through the filter.)



These two graphs speak volumes. If you logically think about K&N's premise: increase Horse Power by increasing air flow. The less restrictive the air filter, the greater the air flow. Unfortunately, more debris will be passing through the air filter (as shown above), into the intake manifold, then into the cylinders. Even if no cars are ever damaged running K&N air filters, is the cost of the filter, filter oil, filter cleaner, and required maintenance of these filters require, worth K&N's claim of 1-4 Horse Power increase?

Most of us are probably changing the air filter prematurely. An interesting report by the EPA on clogged air filters and the impact on MPG, concluded:

"Closed-loop control in modern fuel injected vehicle applications is sophisticated enough to keep a clogged air filter from affecting the vehicle fuel economy."LINK to the EPA study (2-2009).​

The factory engine is a balanced system (a compromise of performance, reliability, and efficiency). Air filter all the way to the exhaust, don't forget the programming. Add a K&N filter, the system is unbalanced. To maximize the potential, additional air flow increase K&N can offer, one would have to change out many other parts; exhaust system for sure, as the stock exhaust is very restrictive compared to a "performance/racing" exhaust systems.

Formula 1, Nascar, and Rally cars, are probably using K&N or something comparable. But those aren't normal everyday engines. Those bad boys are built from the ground up around performance, and cost a pretty penny. Penny is an understatement. I was off by many factors, when I searched "cost of formula 1 engine." 2014 F1 engine: average price $7.7MILLION (I'm assuming USD, as no currency unit is stated). LINK

You are driving a Prius. Not a sexy car, nor a fast car. But sexy MPG.