High Performance Air Filter

Measure your air filter and see if the dimensions compare to the Gen II or another Toyota. You could be the first with a K&N on your Gen III.

 

I would like to purchase one eventually. I haven't checked yet, but normally you change out the air cleaner filter at 30k or 2 years. Amsoil has IMO a better air cleaner filter than K&N. Instead of cleaning, drying, and re-oiling the filter, you just use a vacuum to clean it. Much easier and re-usable like the K&N. Amsoil makes quality products.

 

The difference in HP between a new standard filter vs. a K&N is rarely measurable let alone noticable with the "seat of pants" meter. Most people suffer from the placebo effect when it comes to minor "performance" parts. I've spent a lot of time on a dyno and the numbers don't lie. 5HP is very rarely noticable and that is about all you ever get from a filter swap unless your original filter was filthy and highly restrictive, in which case, any new filter would have provided a boost in performance. Even on high performance cars like the 98-2002 Camaro LS1 (280-310rwhp stock) you would only see about a 5-13rwhp difference with a swap to a K&N AND intake system. The K&N alone was worth very little.

From a money savings standpoint the K&N makes sense, especially if you are buying full price Toyota filters but from a performance standpoint with regards to the Prius I would wager $100 you cannot feel a HP difference between a quality filter and a K&N.

 

Be aware there is some controversy re the effectiveness of K&N and other cloth filters. Some have tested them and found they pass fine dust, particularly in industrial applications. I've used them in the past (but so far not in Pearl) and didn't notice anything getting past but my tests wouldn't be hard to pass (paved road driving most of the time).

While a little more restrictive, a paper filter does work very well. They just put more filter area in to keep the restriction under control.

As already posted, Prius engine rarely runs at full RPM, usually cruising along below 2K RPM (by design). This requires very low volumes of air. Note also that the max. RPM the engine will see is also not high (5000 for the GII) so air volume requirements may not be that great.

 

Agreed.

 

I am going to buy a K&N for my Prius not because of the increase in power or mpg (because we all know it will be negligible) but because it can be reused.

On my turbo Eclipse however, the K&N did help a lot but that is because I run twice the amount of air that a naturally aspirate engine does.

Can someone confirm the size of the Gen III?

 

Same here. However, I find I keep falling off the rollers. How do you manage to stay upright when you're running on those things? I bet one of those loggers who roll logs in the water would produce good numbers. At least they could stay on the roller. If you use a 4WD dyno, do you use your feet on one roller and your hands on the other? lI'd fall flat on my big belly if I tried that! Do performance shoes increase the dyno numbers? Which shoe do you find to provide the best traction on the rollers? Do you just attach the safety chains to your belt, or do you have a harness? Do you monitor RPM (Running-shoe-hits Per Minute) and speed to calculate HP (Human Power)? Do you calculate speed in feet per second? I only have 2 feet - more feet might be an advantage. Hmmm, now I'm hungry for a foot-long hot dog. I think I'll run off to lunch.

 

I've never seen a measurable HP difference on a naturally aspirated car with a K&N filter, but on high boost applications, it definitely makes a difference. My supercharged mustang has a whipple filter (same as K&N) and it makes a huge difference. A paper filter probably couldn't stand up to that much boost.

Regardless of HP, I will be getting a K&N when it becomes available for the prius. You can't argue with a 1 million mile warranty!

 

That is because you are going about it all wrong bru. You need to be strapped down to the dyno properly then you don't have to worry about falling. You just have to worry about reving to quickly!

I'm properly pinned down. This is how you do it.

 

I was avoing FI vehicles since they are completely different beasts. I do agree with you. I've seen a 40rwhp gain just from increasing the size of a K&N cone filter on a turbocharged Tran Am. Granted this was an over 700rwhp application. The thread on that can be found on LS1Tech.com. Your arch rivals.

 

Not me, bro. I love the F-bodies!

 

Good man. Anything with high HP and is easy to mod is cool in my book.

 

Ah, that's my problem. I've never been "properly pinned down" in my life!

Back to topic - last time I ran a car on a dyno it was my Cobalt SS auto. The auto SS is naturally aspirated. I was running the GM Performance Parts intake, and a functional hood scoop. We ran first with the stock air cleaner, next with just the GMPP intake, then the GMPP intake with the scoop open. The intake made a difference, but the scoop and intake made a serious improvement for a naturally aspirated car. I posted the install on cobaltss.com, as well as the dyno results and dyno sheets.

So, from that we concluded that a cone type intake can produce meaningful improvements as long as it has access to enough cool air. Stock air boxes, even with a K&N filter are probably intake limited by their design, inlet pipe size and inlet location to the point where a better filter would have little effect.

When I turbocharged the car, I modified the GMPP intake to use it and the scoop to feed the turbo. It was a great set-up, but we never managed to get the tuning right - the OBD II computer on the Cobalt was too smart to outsmart with our add-on computer. I ended up going back to natural aspiration and trading the car for a pick-up.

 

Well as you can see in the picture it took 6 of em to do it properly. *Sigh*

 

Yeah, I'm always reminded of the last line in the the mad scientist sketch in Woody Alan's "Everything You Wanted To Know About Sex": "But what worries me is, they usually travel in pairs."

 

Agreed mate. Two against One just isn't fair.

 

Very true - Amsoil air filters have always greatly outperformed the K&N filters in every area. The reason the K&N is so popular is because people see a decrease in flow restriction, but that decrease comes at the high price of poor filtration quality. Amsoil is one of the greatest performance secrets in the automotive world and all of their products are of the absolute highest quality in both performance and quality. I personally own two of the 2010 Priuses and will be converting them both to Amsoil 0W-20 synthetic and the Amsoil air (and hopefully oil) filter as soon as they become available. Also plan to use the Amsoil Performance Improver fuel additive once every 3-4k miles for even further milage increases resulting from a pristine fuel delivery system. Once you use the Amsoil products you will sold on them for life like I am. Give them a try, you won't regret it.