This is debatable, air induction kits

[aandy]

guys make my day. i will like to know, advantages and disadvantages of air induction kits. convince me to buy one or, not to buy. if BUY wins what is the best brand ?

[Frustrated Pilot]

BUY APEXI

IT IS THE BEST.. good price too...

blitz steel ones may not filter as well.. each time i take one off to clean.. i find such a oily dusty mess inside the metal air in thing (of which i cannot remember the name)

NEVER BUY HKS.. youre better off buying a bath sponge and stuffing it in as far as your AFM.. if you have one.

apexi is great!!!! sounds sweet too.. THE ONE TO BUY.. I can do a recording if you like???

KnN...??? well i associate them with novas/chavs..... so i personally steer clear

[ducatichick]

BUY APEXI

IT IS THE BEST.. good price too...

apexi is great!!!! sounds sweet too.. THE ONE TO BUY.. I can do a recording if you like???

SPOT ON-thats whats on mine and she purrrrrrrrrrrs lovely

[Dave Goodhand]

I've got a K&N Induction kit on my tubby.

The filter is huge, probably at least 50% bigger than the Apexi my mate had on his NA 2.

I find its great, has allowed the engine to be more revvy through every gear, whereas the car used to hit small flat spots before (usually in 3rd and 4th around 4000rpm) Now it pulls great all the way to the redline.

[Peter Gidden]

Size is irrelevant. Flow rates and filtering ability is all that matters.

Both Apexi and K&N are top makes, but i go for (and have) the Apexi since it retains the expansion chambers which assist in maximising low end torque.

Take a look here for a back to back test:

http://www.mkiv.com/techarticles/filters_test/2/

[Frustrated Pilot]

well thats it then.. APEXI WINS

no need for any more voting

[Dave Goodhand]

To be honest I don't think size is totally irrelevant.

Thinking about it logically. If you can filter enough air through a greater surface area, then a greater volume of filtered air will be getting into the engine. Which is imperitive on a turbocharged car (hence dragsters in the USA and JAP don't use filters.. they just let the turbo pull air in from where it can.

Hence surface area will be a better measure.. which I'd imagine you'd call flow rates (as this would determine how quickly the air can pass through the filter and how much (ie bigger surface area, more air!)

Try putting a straw sized filter on your airbox and tell me that it doesn't make any difference.

I can see on a NA car you don't want too much air as you'll lean the mixture thoroughly.. but seeing as most of these cars are pretty much downtuned from the factory it shouldn't be an issue until you've upped the horsepower more.

Plus keeping the resonator box will lower the exhaust noise (for track days and the such)

[ryan]

Size is irrelevant. Flow rates and filtering ability is all that matters.

Both Apexi and K&N are top makes, but i go for (and have) the Apexi since it retains the expansion chambers which assist in maximising low end torque.

Take a look here for a back to back test:

http://www.mkiv.com/techarticles/filters_test/2/

Hi Peter.
What do you mean by expansion chambers? The plastic boxes you remove when fitting aftermarket induction? I thought the apexi kit involved getting rid of the 2 box std setup?

[phild]

OK OK, I know I'm going to get flamed for this but to my mind, the induction kit for my NA didn't realy do much apart from liberate a few quid from my pocket. Think of it logically, Toyota spent millions trying to extract maximum HP from the engines, do you think that they might have forgotten to think about the air fuel mixture? Nope, if you allow too much air into the system then you (as has been said already) lean the mixture, which in turn reduced the "oomph" especially at low revs or when pulling away. When you have the peddle way down and are giving it some at the limit, then I guess that the higher allowable volume of air might give you a little more top end but how much time do you spend there comapred to normal driving?
You can use the idea that they are going to save fuel...but again, at what cost to performance, something has to give as there's no such thing as a free lunch.
Some people buy them for the noise factor, they do make a varied amount of noise dependant on how you are driving but if you have a loud exhaust then you can't really make out much. (the K&N makes an unusual sucking noise at low revs which makes the unsuspecting passenger wonder whats going on behind them).
I don't have a Tubby but I suspect that an induction kit on one of these will make a lot more difference than on a NA.
Also, the stock air filter is probably better at filtering dirt particales than an after market add on...how long do you intend on owning your 2?
P.S. I'm back to stock now.

[jonb-]

Phil, i hope you don't get flamed for a good post. All valid points, but might i add toyota obviously have to design with noise levels in mind so cone filters are out. Stick one of those in, map the engine properly and i'm sure you could get a few more bhp as standard.

That said, most people stick them in for noise. I've the standard airbox on mine, but the feed pipe is missing and it's not bolted down properly so i'm going to stick a cone on. Probably work out cheaper than Mr T replacement parts and hopefully save me a few quid in petrol

[alexwainwright]

What are people's opinions on air temperature and induction kits? I can't help think the standard airbox is taking in cooler air than any induction kit which just sucks in hot air from the engine bay, being quite close to the turbo. (Also applies to NA cars, just not as high temps). I've got the means to do some temp testing, so will hopefully have something to report in the near future (Part of my job is assessing engine installations in prototype vehicles, albeit diesel engines, but the same principles apply).

I understand the flow rates are probably higher, but at what cost?

Alex "Cat among the pigeons" Wainwright

[RICHIE S]

induction kits can take more air in than stock filters but they too need a supply of cold air otherwise they can be less efficient than stock.
size of filter does matter when you want to run serious HP,look at some of the K&N filters made for the big power boostlogic and sound performance kits for the supra,some of the filters are 5" in length!

[Frustrated Pilot]

i love the regular quarterly induction kit / exhaust argument.

My car is the best.

[lower]

people like induction kits because the manufacturers tell you they give you more power and they tend to be noisier so make people think they are going a bit faster.

the thing you have to consider is that if you get more flow through a same sized filter you are getting poorer filtration. the only way to get more air with the same level of filtration is by using a filter with a bigger surface area. the surface area of the standard paper filter is huge and it filters very well until the point where it starts to get choked. you are unlikely to get the same level of filtration through an aftermarket filter.

secondly, toyota did spend a lot of money locating the air intake where they did to get the coolest air into the engine, and also tuned the intake lengths and chambers to get maximium power from the engine. the resonator and chambers are not just there to reduce noise, but also because resonance can be used to increase the power of the engine.

by strapping a random aftermarket filter and intake onto an NA car, you are destroying all of the work toyota has done.

this is less of an issue on turbo engines because of the forced induction. IIRC the standard induction system only starts to become a restriction on turbo cars once the engine is producing in excess of 300 bhp. up until that point you get no signifcant gains.

[KiwiMR2]

What does this "kit" actually consist of?? I see it mentioned a LOT...mainly in the UK forums, are you just talking about A pod filter??

What are people's opinions on air temperature and induction kits? I can't help think the standard airbox is taking in cooler air than any induction kit which just sucks in hot air from the engine bay, being quite close to the turbo. (Also applies to NA cars, just not as high temps). I've got the means to do some temp testing, so will hopefully have something to report in the near future (Part of my job is assessing engine installations in prototype vehicles, albeit diesel engines, but the same principles apply).

induction kits can take more air in than stock filters but they too need a supply of cold air otherwise they can be less efficient than stock.

secondly, toyota did spend a lot of money locating the air intake where they did to get the coolest air into the engine

All points I agree with, a pod that isn't shielded from the engine bay may suck in more air but that air will be hot....even worse when crawling along or stopped. I notice some people shove it all the way down to the vent and make it peep out the side, ok more cooler air...but more dust & crap so unless your cleaning it every 2nd day your again doing the intake system no favours.

and also tuned the intake lengths and chambers to get maximium power from the engine. the resonator and chambers are not just there to reduce noise, but also because resonance can be used to increase the power of the engine.

I read a good article in an Australian fast four mag like 3 years ago where the dyno tested a car with a mixture of different resonators, even used a coke bottle in one test & nothing at all. All on the same car etc. the left the OEM setup all bar the resonator and the OEM one came out with the best performance.

IMO an aftermarket panel in the OEM box is better for a MR2 than a pod in the engine bay...unless you go to the effore of boxing it off.

Cheers
KiwiMR2

[Baker]

having fitted a k&n i have found the std recirc valve much louder, and also spool up time quicker.
No improvement in accel or anything though.

[phild]

A "K&N induction kit" is basically a wire cone covering a pleated paper filter, a pre-determined length of rubber pipe, one end of which connects to the cone via a jubilee clip, the other to the engine air intake mouth, again by a jubilee clip. At the cone end (depending upon which model MR2 you have) you attach the air flow sensor which just pushes into a hole in the cone.
The Pipe also has a hole through which you press the engine rocker cover breather pipe which recirculates the fumes.
The K&N also has a length of expandable aluminum pipe which supposedly directs cool air from the intake ducts towards the cone...but can't see it doing much really, especially at idle or slow speed.

[BLOODUK]

Wonder what i can sell my Blitz induction kit for hmmm

[waelwulfas]

.
I read a good article in an Australian fast four mag like 3 years ago where the dyno tested a car with a mixture of different resonators, even used a coke bottle in one test & nothing at all. All on the same car etc. the left the OEM setup all bar the resonator and the OEM one came out with the best performance.

IMO an aftermarket panel in the OEM box is better for a MR2 than a pod in the engine bay...unless you go to the effore of boxing it off.

Cheers
KiwiMR2

I've tried both routes with N/A albeit the FE (same principle) the full OEM setup with a K&N panel filter is measurably quicker off the mark.

[BenF]

guys make my day. i will like to know, advantages and disadvantages of air induction kits. convince me to buy one or, not to buy. if BUY wins what is the best brand ?

Basically it boils down to this:

On an NA, it will cost you a few BHP as the filter will be drawing in warm air from the engine - ditto the Mk2 Turbo.

BUT - they sound fantastic.

So, buy one if you enjoy the induction noise, but don't expect any more power.

I've got one on my Mk1 NA Trackday car just because I think the sound it makes when coming on cam above 4,000 rpms is fantastic.