Ali SC3

iTrader: (10)

the stock ecu will aim for the correct air fuel ratio only in closed loop, meaning under a certain throttle % and under a certain rpm if there is more total air that it sees it would add more fuel. this is generally cruise or slow acceleration where you wouldn't notice much of the BFI anyways.
This does not relate exactly to a change in mpg.

If you are getting more colder air through the same size intake/throttle body, it will require less throttle amount to achieve the same total air as if you were letting in hot air, and in closed loop the ecu will adjust the fuel to arrive at the ideal air fuel ratio 14.7 whichever case it may be. at the same air fuel, you get about the same efficiency, but with hot air you are not getting as much air in the cylinder (cause its less dense) so you need more of it. the problem on a non turbo engine, is that there is only a certain volume of air you can pass through the intake since there is no boost, so the only things you can do to get more air in at the top end is to increase the whole intake size all the way through the motor (intake, heads, valves, etc..) or you can get more air in by increasing the density of the air (making it cold or using cold air).

now the mod is really not going to be noticed that much in the above closed loop scenario (except for throttle response cause you can get more cold air in faster than more hot air) , but it really shines when the ecu is in open loop as the ecu ignores the o2 sensors more or less. it injects a very rich static amount usually around 10-12 afr mixture which is like turbo mixtures almost. so any extra air you can get in there is going to help you make more power by leaning out that mixture to a certain amount. (you can't add too much with an intake but maybe a turbo then yeah you could lean it out too far and thats why turbo people use other management). So your intake will add a little extra air and on a cold day you will notice it has a whole new attitude, and in open loop it will actually get better mpg's than it did before, which is not a big thing cause you are often not WOT all the time and even with a slight increase the mpg is still going to be terrible at WOT.

The resonators in the intake pipe can be removed, they are actually called "surge tanks" and were put by toyota to help smooth rapid throttle changes by having a sort of extra "reservoir" of air along the intake path for sudden throttle changes. it also helps quite down the noise. you can remove it really it does not make much of a difference in practice and alot of times those things crack from heat/age.

ems

iTrader: (1)

the aluminum sounds! great I did some throttling on it and sounds like notorious big mid verse! performance we will see..

Duck05

So, the "card board thingies" I assume are the "templates" you created to use as a "pattern" to cut out the final plastic or aluminum parts for the end assembly?

At one point I had thought to replace the existing air filter box with an after market intake and filter but have since agreed that sucking in warm/hot air from under the hood made little sense.

This mod can't hurt and getting more cold air from the front of the moving car has to have some positive effects..... I will hopefully wait to see how Chris applies this to his car and maybe have him help me do mine (hint hint.... ).

962jzsc415

Hey Duck05, im doing this mod this weekend. Let you know how it goes. Turbo kit coming in for XMAS ....might be awhile before im actually running it though. 1 step closer.... LOL!

t2d2

iTrader: (8)

I've never understood why people will go to the trouble to: a) install an aftermarket intake, or b) mod up a traditional BFI and seal off all the surrounding areas, but not combine the two by sealing off a cone filter with a simple heat shield for engine bay heat. Build it around the intake tube (picture the filter being a dog's head sticking out of a cone for biting issues) and wedge it into the corner with some door edge guard on top and it will do a perfectly good job.

Duck05

Take some before, during, and after photos..... Will look forward to seeing your handy work (and your new wheels in person...).

Ali SC3

iTrader: (10)

I read this and all i can picture is a dogs head sticking out of a cone.

There is nothing wrong with the stock filter, its big and does a good job especially with a more free flowing drop in filter you can get for our box or the supra box. what is bad is that only the lower 1/4 of the front of the box has a snorkel on it from the factory, so what you are doing with the BFI is snorkeling the whole box to the same area, and this area gets fresh air from the front bumper area which is alot of outside air when you are moving along.

You could also just cut a hole in the passenger side fender and run a pipe down in there and stick the cone in the passenger bumper side.
Sort of like this picture except I would tuck the cone up much higher.
from this thread
http://www.supraforums.com/forum/sho...old-Air-Intake

Rickbean

Yea that's the word I was looking for. Thanks I was at work when I posted that and couldn't think of what they were called even though I've just about every BFI thread on the net lol. Anyway I have finished my bfi for the most part I will post pics tommrow or Sunday.

t2d2

iTrader: (8)

I'll take a pic to help clarify that mental image.

See, that's where I disagree with, well, pretty much everyone on the topic. The BFI doesn't add any volume. If anything, it lessens the volume of air able to reach the filter because of how narrow the passageway is from the modified opening in the grill. Opening up the front of the air box is pointless if you haven't increased the volume of air flowing through the tubing leading into or out of it.

The actual benefit of the BFI, in my opinion, is pressurized air at speed. The stock snorkel just pulls indirect (low pressure, presumably) air in below the headlight. But, there are better ways to do it... And that's where this comes into play:

That's basically what I did by modifying the snorkel to scoop air up from that location, but with less likelihood of the filter getting soaked.

Edit: Maybe I'm using the term "volume" wrong. Would "surface area" better describe the two-dimensional concept? "Volume" is more a CFM measurement, which gets complicated by high pressure vs low pressure.

t2d2

iTrader: (8)

Here you go...



It's real easy to use a cone filter and isolate it from the bulk of the engine bay heat that way. You can still pull air in via the same source(s) as the BFI or stock snorkel. Whether it's any better than the fairly large surface area of the stock filter is debatable, but it looks cooler and generally sounds better.

t2d2

iTrader: (8)

I had reason to build a heat shield for a SC cone filter intake this week, so here's another example:

https://www.clublexus.com/forums/bui...ml#post9658625

Golden95SC

iTrader: (21)

Unfortunately on a stock or NA car a bfi intake or any intake of that matter will have very little to no affect. Sometimes in decreased HP due to higher intake temps from exposed systems

Sure they can be aesthetically pleasing and have a unique sound, but definitely not a real gainer on these cars.