Direct replacement Ramair or Pipercross filter for '89 SC AW11

[Fab4MR2]

Any news on the ITG Fab4?

Well, only a slight bit. I managed to get the car running, in order to do a couple of needed errands, but I still have the starting issue, and it looks like the starter solenoid has gone bad. I'm waiting for a new starter and won't be able to do any definitive testing until then. Hopefully within a day or two.

However, I did run the errands with the ITG, about 40-60 minutes of off & on driving, and it seemed to work rather well. The initial estimate would be that it was roughly at least the equivalent of the stock filter, which has proven best so far. That would be good news considering how badly almost all of the others have done.

It's idle level appeared to be the equal of the stock, or slightly better, but the weather is extremely cold here right now, and my car takes a very long for the idle to settle down completely. I suspect the people who rebuilt my engine employed a colder thermostat, as I remember them asking me several times if my car had a tendency to run hot, although I always told them that it never did. Who can you trust?!

With the ITG, so far, it pulled away from idle quite well. Seemingly, at least as good as with the stock. It also seemed to rev quite freely and the engine made no more noise at top end than with the stock unit. The poorer filters definitely make the engine sound more constrained and noisy up there.
The overall intake sound seemed almost cleaner than the stock unit, but perhaps I was imagining this as I was rather excited with its decent performance to that point, considering how little air surface the unit has.

Lastly, and this is a point I forgot to make previously, in regards to how air filters can affect the performance of the engine, etc., the car appeared to brake at least as evenly and consistently as with the stock filter. Yes, filters make a significant difference in this regard because they can significantly affect the vacuum level and therefore the performance of the vacuum brake assist. I first noticed this many years ago when initially going back to a stock filter, after having had a K&N on it for some time, and not having been happy with the engine’s top end performance (after the engine rebuild). The difference was so noticeable, that I immediately put the K&N back on in order to confirm it. Of course this was also while I was trying to eliminate the last of the small air leaks I had, so I repeated the tests later on, after doing so. The results were always the same. And just to let you know, I use Porterfield R4S pads, with SS brake lines, so the braking is fairly good, with either filter, but there was a very noticeable difference that I had not expected. It is quite apparent whenever I change back and forth between different filters.

Hopefully, I'll have something more definitive to say within a few days, as I am anxious to back up my initial impressions.

[cartledge_uk]

Thank you for your in-depth analysis so far, good reading, and interesting findings

[Firestick]

Thanks for that look forward to your findings.

[Fab4MR2]

Thanks for the replies.

I got the new starter this afternoon (hope that is the solution), and now have to work up the courage to go out in that freezing gargage. It's cold out there!
I just realized somebody needs to develop a "it's cold as h*ll out there" emoticon, at least for when people's heaters break down.

[greglebon]

WOW..what a thread....!

I suppose it is easy to get a little too deep on the subject of air filters..?

If you wanna go REAL deep..(deeper than Axel Foley went undercover in the '80's..! ):

http://www.knfilters.com/efficiency_tes ... cedure.htm
http://www.knfilters.com/efficiency_testing.htm

This topic crops up a lot, but a few things are needed to bring it into perspective:

1) The restriction of the airflow is a fairly minor point: even a basic K+N 57i is good for 250HP.

2) As to filtration, surely particles below a certain size are going to have zero effect on engine wear...?
Also, consider what happens to said particles when they enter the chamber...... They get incinerated, big time, instantly....!

So, unless theres a lot of them, its gonna make 0% difference?

It stands to reason that as the OEM filter has far smaller "holes", then its surface area needs to be x times more for the same airflow as a K+N with x times bigger holes.
That said, though, the K+N's filtration will not be x times worse than the OEM, as the "stickiness" of the oil coating will attract particles that would get through if the K+N was "dry" so to speak..?

I would suggest that the K+N will filter any potentially harmful particles: the design of it must be based around this principle....?
The OEM (and others which "offer superior filtration") are probably over-engineered for the purpose, and do restrict airflow a little more than necessary, and, as a result will need to have a larger surface area to restore airflow ability?

I must say, though, that a mesh filter with bigger holes, but run "dry" is probably not too good an idea....?

Those S/S mesh filters which look cool in the engine bay are probably not the best.....?

As mentioned, K+N are tried and tested: probably the best all-round solution....?

I did run a car for 3 years with, IIRC, 2 pairs of nylon tights stretched over a frame as a filter, with no problems (4 layers, basically)...

Of course, if I had entered the Paris-Dakar I would have fitted something better......!

[Fab4MR2]

Thanks for your input, but I think you might have missed the main point of this thread. The main issue for me, and I think many of the others, is basically airflow restriction caused by the various designs of aftermarket vs oem filters.

Additionally:

1) Airflow restriction is hardly a minor point, at least not in how we are discussing it, especially as many air filters, in particular the drop in types, which we are mainly discussing, are often made in inferior designs and definitely restrict engine airflow and therefore horsepower and vacuum levels. You say a basic K&N 57i is good for 250 hp, but what does that really mean? You can put any large size filter on a car and make claims like that, but a) is it practical, b) must it be installed as part of an induction kit, c) must it also be installed in the engine compartment, or d) would it be installed in the trunk, but take up extra valuable space. These are the reasons why we have been discussing direct fit filters and why some of us prefer them to the induction type and for good reason.

and

2) Sure particles below a certain size probably won't do essential immediate harm to an engine in general, but you're going to have to provide some hard empirical evidence if you want to ascertain which filters do or do not pass overly large particles. And yes, for the most part they get incinerated, but then what happens to them, they very likely end up as extra deposits on all kinds of engine parts, causing hot spots and additional wear. Hardly what you should be looking for. I realize that any filter, which seems to pass at least as much air as the oem filter, but has a significantly smaller air surface, is likely to pass a lot more dirt than the oem one does. However, because of this I probably wouldn't chose to use it full time, but would definitely consider it for track or similar use.

The size of the particles being passed by various filters and the proven methods for trapping said particles, it is a bit beyond the scope of this discussion unless someone has the scientific equipment to back it up. We already realize that some manufacturers may be foregoing the ultimate in air filtering in order to increase air flow, but more importantly, we also know that some manufacturers are also foregoing adequate air flow design in order to make a buck off their previous reputations. K&N could have, for instance, actually made a better than stock drop in filter by use of a better/proper filter design, but instead chose the cheaper route and actually seem to have decreased air flow. They should have opened up the closed end of the filter and designed the sidewalls with parallel sides, doubling the air filter surface, as other manufacturers have done for some induction kit filters. That would have solved the issue right there and we wouldn't be having this discussion.

For those waiting for further ITG results, it may be at least a few days yet. I got the car back up and running (turned out it was the starter relay and not the starter), but God just dumped a rather unusual amount of snow on the ground up here, which rarely ever happens. We got about a foot of really nice powder over night and I'm not going to even try driving in that stuff as either really good snow tires, which I don’t have, or snow chains, which would really impede the tests, would be required. As continued extremely cold temps, for our area, are forecast for the next several days, I am not sure when I'll be able to finish this up. But as soon as things do warm up a bit I'll be back out there.

[Firestick]

Cheers Fab

Enjoy the powder

[viperrr]

Very detailed stuff!

Fab4MR2, would you be able to post some pictures of the modifications you've made to the air piping in the rear boot?

It'd be interesting to visualise what you've done here.

[LimeyMk1]

Surely a good way to compare air resistance through a filter is to look at the back pressure produced at a set 'draw'?

For eg I calibrate single speed aerosol sampling machines as part of my job (it's a nice break from toxicology) and we do this by measuring the amount of air pumped through at various backpressures (40, 45 and 50 inches of water) to assess the health of the motors. The back pressures are set up by obscuring the inlet of the pump.

If you were to set up an old vacuum cleaner to some second hand MR2 inlet trunking with a vacuum gauge between the vacuum and the filter it would give a very good comparison between the filters in question.

I have noticed with the K&N panel filter on my Celica that on turning off the ignition you still get an induction hiss. Theoretically this could be due to ther still being a lower pressure on the engine side equalising, however it may be exactly the same with the paper filter but the nature of the material being used does not induce the same noise.

Just my thoughts on the matter, keep up the investigations.

[Fab4MR2]

Very detailed stuff!

Fab4MR2, would you be able to post some pictures of the modifications you've made to the air piping in the rear boot?

It'd be interesting to visualise what you've done here.

I'd be happy to post some pics, but this forum doesn't seem to allow for it. If you have any simple suggestions for posting them elsewhere, so that I can provide a link to them, let me know.

Limeymk1: I actually thought about the vacuum cleaner test myself, but don't know of an adequate manner in which to accurately test either the air draw, or the various loads upon the vacuum motor. Being able to measure the amperage drawn by the vacuum would probably give a rough enough estimate, but how could that be done by any simple means?

Firestick: I'd enjoy the powder a lot more if I could get to a ski resort. They usually only get wet clumpy stuff here, but this stuff is just great fluff! I'm about two miles from the nearest plowed roads and a lowered MKI is little more than a snow plow when it gets this deep.

[LimeyMk1]

Limeymk1: I actually thought about the vacuum cleaner test myself, but don't know of an adequate manner in which to accurately test either the air draw, or the various loads upon the vacuum motor. Being able to measure the amperage drawn by the vacuum would probably give a rough enough estimate, but how could that be done by any simple means?

I'd guess that you'd need to crack open the vacuums casing and wire an ammeter into the motor power supply. However I don't think it's strictly necessary to get an idea of how the filter performs. I reckon it would be more accurate than testing on the car, as the variables involved in the percieved performance of a car are impossible to control or take into account.

[Fab4MR2]

I'd guess that you'd need to crack open the vacuums casing and wire an ammeter into the motor power supply. However I don't think it's strictly necessary to get an idea of how the filter performs. I reckon it would be more accurate than testing on the car, as the variables involved in the percieved performance of a car are impossible to control or take into account.

I'm not sure I would feel comfortable giving any assessments on filter performance, using the vacuum, unless I could measure it in some form that was relatively accurate. Along that line, I do wish manufacturers would stick to using vacuum type tests for their filters, as sucking air through them may be quite different from blowing air out of them, depending upon the filter’s structure. I know that K&N has used the blowing air out of them trick, at the big SEMA show, along with small wind velocity scales, in order to wow customers.

As for testing on the car, so far I haven't had too many filters that did not give significantly different results. As long as they're tested on the same car, under the same conditions, and for a long enough period, the results should be fairly reliable. I generally want to use each filter for at least about 1-2 hours of driving in order to get an accurate assessment of their performance. Remember also that you have to give the ecu some time to adjust to the difference in air flow before you can really tell what's going on.
I, as much as anyone, had always hoped the K&N would perform better, but I have switched it in and out many times and have unfortunately always found that the oem filter always performed significantly better. And it was never by amounts that you had to guess at. It's relatively obvious, from looking at the oem filter, that Toyota used a different material than on most of their other filters and a rather unique design as well, in order to increase the filter surface area, so I guess maybe it shouldn't come as that big of a surprise.

Speaking of surprises, a snow plow just went by my house for the first time in 4 years, that I am aware of. Yeah!!

[LimeyMk1]

I'd go with a voltmeter and ammeter on the motor feed to ensure constant running of the motor and to record any variations and a vacuum gauge on the pipe work to record restriction of the airfilter.

You could fit an anemometer to the inlet to measure airspeed into the system but that's belt and braces stuff.

[Fab4MR2]

I'd go with a voltmeter and ammeter on the motor feed to ensure constant running of the motor and to record any variations and a vacuum gauge on the pipe work to record restriction of the airfilter.

You could fit an anemometer to the inlet to measure airspeed into the system but that's belt and braces stuff.

Good thoughts! That gives me a decent idea of possibly how to put together a proper (semi-proper anyway) method for testing these things somewhere down the road, when I can put together that sort of system. I'll do some checking on items to use for that, but don't anyone get your hopes up for that sort of setup and testing to happen anytime soon , as I've got a massive SC project I'm working on and it's taking up the majority of my free time and definitely most of my money. The starter issue, on my '87 NA, was a bit of an annoyance (cost and time wise) as that was the very first unusual problem I have had with it in the 10+ years I have had it. Well, live and learn. I'll know exactly what the problem is next time, which of course will probably never come up again.

[Tiny]

just had a thought on this.........probably wrong but i thought i would share.

could you not take a tapping off the MAF sensor wiring and at a given throttle input/RPM measure the difference in the MAF signal for each filter and then the one that flows the best would be the one that has the largest MAF reading.

[Fab4MR2]

just had a thought on this.........probably wrong but i thought i would share.

could you not take a tapping off the MAF sensor wiring and at a given throttle input/RPM measure the difference in the MAF signal for each filter and then the one that flows the best would be the one that has the largest MAF reading.

While it sounds good in theory, I'm not so sure it would work in practice. I believe you would need to run the engine under identical full load runs to guarantee proper consistent readings and also to know at what position the swing plate inside the MAF is at. But under those conditions the swing plate, which I believe is what alters the signal from the MAF, may swing all the way open regardless of if the air mass moving through it is at its maximum or not. Full throttle loads may simply be enough to swing the plate all the way open, and therefore the readings would be identical. At least that's how I interpret things might happen. Let me know if you think it might be otherwise, or if there is something about the MAF I am interpreting incorrectly.

[LimeyMk1]

Good thoughts! That gives me a decent idea of possibly how to put together a proper (semi-proper anyway) method for testing these things somewhere down the road, when I can put together that sort of system. I'll do some checking on items to use for that, but don't anyone get your hopes up for that sort of setup and testing to happen anytime soon , as I've got a massive SC project I'm working on and it's taking up the majority of my free time and definitely most of my money. The starter issue, on my '87 NA, was a bit of an annoyance (cost and time wise) as that was the very first unusual problem I have had with it in the 10+ years I have had it. Well, live and learn. I'll know exactly what the problem is next time, which of course will probably never come up again.

I'd put something together but I have a load of other things going on at the moment too (V6 conversion & house restoration) and no air filters.

[greglebon]

Having read all this v. interesting post, I'll tell you what I'll do.....

I'm setting up an engine in my shed around Easter 2009: on a stand, with full exhaust / fuel setup, etc...

It's part of my megasquirt development work...

So...I'll have an engine I can run under constant load, and I'll be able to log everything.....

Easy, then, to simply connect several filters to the inlet, run several rev bands, and see which one flows the best..?

I'm not TOTALLY sure WHY its necessary to go to these lengths, but its no skin off my nose doing it, really....

Once you have a figure for flow for each filter, then you can take the total surface area of each, and see which is (theoretically) best....

I'll be back......

[Fab4MR2]

Having read all this v. interesting post, I'll tell you what I'll do.....

I'm setting up an engine in my shed around Easter 2009: on a stand, with full exhaust / fuel setup, etc...

It's part of my megasquirt development work...

So...I'll have an engine I can run under constant load, and I'll be able to log everything.....

Easy, then, to simply connect several filters to the inlet, run several rev bands, and see which one flows the best..?

I'm not TOTALLY sure WHY its necessary to go to these lengths, but its no skin off my nose doing it, really....

Once you have a figure for flow for each filter, then you can take the total surface area of each, and see which is (theoretically) best....

I'll be back......

WHY?! Why?! Why you say?! I'll tell you why! Because it's there!!!!
That and some of us are just stinking purists at heart.

I think we would all be happy to see what you come up with. By the way, what kind of measurements will you get to measure the flow?

I will be measuring the surface area of all the filters I have, once I come out of the stupor that the bizarre cold front we are under here has passed on. We normally only get a few inches of snow all year here, but we have gotten about a foot and a half within the last week or so and I'm still trapped like a rat. I unfortunately live on a roundabout, which is uphill in either direction to get out of it. Not good for an AW11. Temperatures are supposed to finally rise above freezing starting today or tomorrow, so hopefully I'll have something more to say soon.

[Firestick]

Yeah hurry up Fab I need to know whether to stick with the stock or get an aftermarket filter!!!





Have a good Christmas.