Aftermarket Air Filters

[1stToyota]

Originally Posted by Kaotic Lazagna

Hey Brian, does .5 more displacement really do a big difference? I mean, my GTI only had 9 more hp than my Yaris.

YarisHilton, I'm sorry, I kinda got lost in your post (doesn't help that I'm rushing here, I'm also studying for a test).

In simple terms, when engines were dumb, as with carburetors, they could be fooled by a HP filter, but new cars with OBD-II watching the airflow isn't going to let itself be fooled for long; it'll adjust to anything new that it's seeing, unless tuning is altered.

[Kaotic Lazagna]

Originally Posted by 1stToyota

In simple terms, when engines were dumb, as with carburetors, they could be fooled by a HP filter, but new cars with OBD-II watching the airflow isn't going to let itself be fooled for long; it'll adjust to anything new that it's seeing, unless tuning is altered.

My GTI was OBD-2, but it was also a '97, so less technology in it

[GeneW]

Originally Posted by 1stToyota

In simple terms, when engines were dumb, as with carburetors, they could be fooled by a HP filter, but new cars with OBD-II watching the airflow isn't going to let itself be fooled for long; it'll adjust to anything new that it's seeing, unless tuning is altered.

....not exactly. ECUs are not infinitely adaptable.

When you restrict air flow the computer will adjust mixture, valve and spark timing and other factors, but only up to a point. Once you constrain the airflow sufficiently the ECU will start to bounce close to soft and hard limits, and will eventually throw a trouble code light

Gene.

[1stToyota]

Originally Posted by GeneW

....not exactly. ECUs are not infinitely adaptable.

When you restrict air flow the computer will adjust mixture, valve and spark timing and other factors, but only up to a point. Once you constrain the airflow sufficiently the ECU will start to bounce close to soft and hard limits, and will eventually throw a trouble code light

Gene.

What I was getting at was that taking out a stock air filter and dropping in a hi-flow filter won't do what the box claims, but people will think it's really made a big difference in hp and fuel economy. I try not thinking about it now, but not too long ago a tool salesman that used to come around told me how he installed a K&N drop-in in his late model automatic Dodge truck, and instantly he noticed that it now gets sideways and lights up the rear tires at 55mph.

[Yaris Hilton]

Right. The reason all sorts of things get sold, accessories for cars, bikes, guns, sound systems, health and "wellness" items, etc. is that they create an expectation that they'll give a benefit, so the user perceives they've gained one and are happy with it.

[1stToyota]

Originally Posted by Yaris Hilton

Right. The reason all sorts of things get sold, accessories for cars, bikes, guns, sound systems, health and "wellness" items, etc. is that they create an expectation that they'll give a benefit, so the user perceives they've gained one and are happy with it.

There's an old saying: Possession is 9/10ths of the law; there needs to be a new one...Perception is 9/10ths of the flaw!

[GeneW]

Originally Posted by 1stToyota

What I was getting at was that taking out a stock air filter and dropping in a hi-flow filter won't do what the box claims, but people will think it's really made a big difference in hp and fuel economy. I try not thinking about it now, but not too long ago a tool salesman that used to come around told me how he installed a K&N drop-in in his late model automatic Dodge truck, and instantly he noticed that it now gets sideways and lights up the rear tires at 55mph.

If you can't measure performance gains it's a pretty tough sell.

Gene

[1stToyota]

Originally Posted by GeneW

If you can't measure performance gains it's a pretty tough sell.

Gene

I think they sell plenty of them, and customers simply change habits (aka: driver's mod) easily enough to see what they're expecting...lead foot, wow that feels better now. Slow it down some, yeah, it improved the mpg just like the box said it would.

[Yaris Hilton]

Exactly.