UOA: 2011 Mazda2 OEM filter vs K&N SRI

[flatlander757]

So I have a 2011 Mazda2 that is autocrossed regularly and sees commuting duty 500mi per week between VA Beach and Newport News, VA.

The stock intake setup is very restrictive. It makes several 90 degree turns and runs air past the ECM.

The stock filter is a very good woven fiber type, my first UOA had about 25k on the air filter, so it was very efficient if anything by then.

I had concerns with going to a K&N filter because of all the horror stories, but bottom line they show a real 4-6hp increase on these already anemic cars and for autocross its needed. So I did UOAs to make sure silicone levels didn't get out of hand.

As you can see, the new filter is just a hair above the universal average(which as per my last UOA was based on ~4200mi).


So given that the ppm is only a bit over the universal average, with ~1000 more mi on the sample, and it was JUST installed(and that is supposedly when most grit is introduced), and its brand new(and will gain efficiency as its used)... I think it's a perfectly good fit for my situation and needs without risking engine damage.


Hopefully someone finds this useful.


I seem to have lost the pics of the filter in question but I'll update this once found...

 

[circuitsmith]

What I see is silicone more then doubling.
No thanks.
A better plan is to reduce restriction to the OEM filter.
On my ride I re-routed the stock filter box to a colder air zone.
Colder air increases torque and hp across the range, not just at high rpm WOT.

 

[flatlander757]

Originally Posted By: circuitsmith
What I see is silicone more then doubling.
No thanks.
A better plan is to reduce restriction to the OEM filter.
On my ride I re-routed the stock filter box to a colder air zone.
Colder air increases torque and hp across the range, not just at high rpm WOT.



Yes. More than doubled. On the first UOA. With a new filter. VS what was a 25k OE filter.

I suspect silicone will trend downwards the next 1-2 UOAs.


And on any other car I agree I'd mod the stock filter box.

Not really possible on a Mazda2.

The $800 filter box(because its only available with the ECM it houses) has multiple 90 degree turns inside it, and is rather thin where is passes the ECM. There really is no improving it.

It's not a cold air intake that went in, but because the bottom of the car is so open, multiple logs show the IAT is within 3 degrees of AAT by the time I hit redline in first or turning at the first cone. There isn't much of a gain to be had by putting a water sucking intake on my car(remember I live about 20ft from sea level and 5min from the ocean, flooding is a potential concern). I'll do it if/when its no longer a daily.

On the Mazda3 I used to have I never did an intake because it was nowhere near as restrictive. On the 2 I'm seeing a consistent 4-7 more grams per second of airflow above 4.5-5k.


I was mainly doing this experiment to just make sure the K&N isn't too horrible for it as this is needed for competition purposes. And this UOA put my mind at ease.

 

[DoubleWasp]

Questions:

1. Does that ECU need the airflow to cool it?

2. Why K&N? They are not a leader of any aspect of cone filters.

Also:

I think you need an oil filter analysis of what your oil filter caught before you declare victory. You might find that your oil filter has been catching garbage your air filter missed.

You are right about cold air intakes. Once you hit about 20mph, IAT Temps are going to match ambient. I've tested that myself too many times.

 

[flatlander757]

Originally Posted By: DoubleWasp
Questions:

1. Does that ECU need the airflow to cool it?

2. Why K&N? They are not a leader of any aspect of cone filters.

Also:

I think you need an oil filter analysis of what your oil filter caught before you declare victory. You might find that your oil filter has been catching garbage your air filter missed.

You are right about cold air intakes. Once you hit about 20mph, IAT Temps are going to match ambient. I've tested that myself too many times.


1. I don't think so. There are many people who've done the same as me with no failures, a few near 100k many have had this same filter setup for 50k+

2. It came with the DDMWorks kit. I mainly needed the tube with MAF mounting point and have considered switching to another type of filter. It's hard to sort through all the marketing [censored] and find actual evidence of what is and isn't efficient(filtering-wise). Any recommendations?


I don't have a filter analysis done from before so I have nothing to compare to in reality. My thought is the UOA is good enough... If big particles are being shed, then ill see more small ones too(in UOA).

This car is raced. The engine is a wear item. Rebuilding to run E85 or 110+ in street prepared is a real possibility, or go full retard with 12:1 pistons and big valves in street modified. Or turbo. It's a lot of undecided but it won't be stock for more than a few years.

It will be getting redline bumped from stock(about 6300 IIRC) to 7600 soon enough. I'm interested to see how that affects wear numbers. Granted it will only see redline about 5-10x per month. The bump will be needed to avoid a 3rd gear shift on course and also to help the 1-2 shift... Instead of dropping out of power shifting higher will put it right near peak torque. Which isn't much to begin with

 

[DoubleWasp]

If you need a whole kit, I guess there's no way around using what they push.

I'm a big fan of Donaldson Power core and the AEM Dryflow. Donaldson being a major leader in filtering, the Power core being a proven design used in OEM, and the Dryflow having been proven many times in independent testing to ISO standards.

 

[flatlander757]

Originally Posted By: DoubleWasp
If you need a whole kit, I guess there's no way around using what they push.

I'm a big fan of Donaldson Power core and the AEM Dryflow. Donaldson being a major leader in filtering, the Power core being a proven design used in OEM, and the Dryflow having been proven many times in independent testing to ISO standards.



Yeah, I actually looked into the Dry-flow stuff before, the problem is they don't make them small enough.

My setup uses a K&N RD-0710.

2.5in ID flange
3.5in diameter
5.0in tall


I may eventually try routing a duct further down where more room is available. The 3.5in diameter is my main limit due to the battery/tray/wiring right nearby.


Those Donaldson filters are interesting, I hadn't heard of them before.


This is probably the closest fit I've found:

http://www.aemintakes.com/mobile/product.aspx?prod=AEM-21-202D-AK

I can get a rubber gasket to go between the 2.5in MAF housing and 2.75dia filter. And the +1/2in diameter is probably manageable.

 

[FastLane]

I think that just shows how [censored] K&N filters really are. For 4hp that's not worth it. How do you know it actually makes more power? Did you run your car before and after on a dyno? I would be willing to bet you lost horsepower since you are sucking in hot engine bay heat now. Your factory air filter would have no troubles supplying air to that little engine plus it drawing in cold outside air.

 

[flatlander757]

Originally Posted By: FastLane
I think that just shows how [censored] K&N filters really are. For 4hp that's not worth it. How do you know it actually makes more power? Did you run your car before and after on a dyno? I would be willing to bet you lost horsepower since you are sucking in hot engine bay heat now. Your factory air filter would have no troubles supplying air to that little engine plus it drawing in cold outside air.



Your reading comprehension needs some improvement.

Literally every thing you just mentioned was gone over in my posts above, and you chose to ignore it.

Read all the above again.


This is the first UOA, certainly a worst case scenario as supposedly(according to this forum) most silicone contamination occurs when the filter is checked or replaced.

I'll be updating this when the next UOA is done, good or bad. If you can find a better filter that works with this setup I'm all ears.

For the time being I'm merely posting this for others to be informed.


And 4hp on a 2200lb car with 100hp stock is for sure noticeable. Mine has not been dyno'd, but others who have used this same kit have done so. And my MAF readings indicate more flow at higher RPMs, consistent with the flow needed for another 4hp or so.

 

[circuitsmith]

While it's true that under hood temps can drop to near ambient on the highway I do a lot of stop-and-go driving in the city.
When I need a burst of mid-range torque at I've confirmed the difference by monitoring the intake air temp sensor with an OBDII scanner.
While your ECM survives without the air flow I'm sure the manufacturer wouldn't have gone to the trouble if they weren't concerned about stress and thermal fatigue under worst case (think Death Valley) conditions.
For those of us who think of an engine as a life-of-the-car deal vs a wear item the less dirt getting in the better, period.

 

[flatlander757]

Originally Posted By: circuitsmith
While it's true that under hood temps can drop to near ambient on the highway I do a lot of stop-and-go driving in the city.
When I need a burst of mid-range torque at I've confirmed the difference by monitoring the intake air temp sensor with an OBDII scanner.
While your ECM survives without the air flow I'm sure the manufacturer wouldn't have gone to the trouble if they weren't concerned about stress and thermal fatigue under worst case (think Death Valley) conditions.
For those of us who think of an engine as a life-of-the-car deal vs a wear item the less dirt getting in the better, period.



I suspect it may be more of a cost and weight-cutting measure than anything. Shorter harness since the ECM is right on the engine, no weight of a dedicated ECU box. Mazda took a LOT of their weight saving measures on this car. Stock it's 2300lbs and meets 2011-2014 crash regulations. The door speakers are featherweight. [censored], there's no armrest.

The ECU is incredibly similar to that of a Mazda3(base components, etc)... Which is mounted independently. This has been confirmed with Dynotronics who I had tune my 09 3... I was their Mazda3Forums guinnea pig for testing that platform bone stock with only a tune.


And again, the Mazda2 is a bit unique in that this is by far the coldest engine I have ever experienced. The engine does not throw off enough heat to keep front tires warm after auto-x runs. You can put your hand on the intake manifold without it even being warm. A lot has to do with how wide-open the bottom is. You can literally drop a 6in diameter ball through the engine bay right where the filter resides.


I agree better filtering would be great, just need to find something with useable dimensions.

 

[FastLane]

Without putting the car on a dyno who do you know it made 4hp more? It probably makes more noise but such a small engine wouldn't require much air flow compared to so high revving V8. I'm sure the stock filter can flow more than enough air. Without putting the car on a dyno before and after you are just guessing.

Your air filter doesn't even have a heat shield of some sorts around it. Like I said, I bet you actually make less horsepower.

 

[Eddie]

The Mazda intake is a true cold air intake compared to taking air in from the engine compartment. I'm sure it sounds more powerful but, doubt it is. Ed

 

[flatlander757]

http://www.mazdas247.com/forum/showthread.php?123788503-CorkSport-Mazda-2-Short-Ram-Intake

I've not dynoed my own car because plenty of others have done the same already and proven it. I'm not wasting $150 for dyno time on something already proven.


This is a Corksport intake, same exact setup as DDMWorks. CS does have an available cold air duct, but it wasn't even available when this was done:

I know the pics of the setup are missing in the above link. This is their product link... Same setup as DDMWorks:
http://corksport.com/corksport-mazda-2-short-ram-intake.html



I can assure you guys that I've done my homework on this. The K&N being the only real thing I wasn't thrilled about, but now not as worried about(pending another UOA).

 

[edhackett]

If you would have done your homework, you would have looked into the reproducibility of a Dynojet dynamometer. Here's three back to back runs with no changes. The variation is greater than you show with and without the K&N. You've got two runs within the reproducibility of the dynamometer, not proof the K&N increases power.

Ed

 

[flatlander757]

I'm aware of how questionable a dyno is.

But that's all that tweedle dee and tweedle dumb above are harping about.


I have logged more g/sec on my MAF. I have confirmed IATs drop to within a few deg of ambient in a VERY short time.





YOU guys do not have personal experience with this particular car.

YOU guys do not autocross - where you need to be able to discern changes. National events are won or lost by 0.001sec.


I'm a pretty objective person and will not fluff something up for no reason.



Also FWIW the sound didn't change all that much, which I was sort of disappointed about, since the car is so freaking quiet to begin with. I suspect the long intake manifold with variable tumble valve is partially why.

 

[flatlander757]

My last reply was a bit harsh, I apologize about that.


But to get an idea of where I'm coming from... I BUILT my own coilovers to accept some good Koni road racing cartridges at about $2k in materials just because I wasn't happy with the available stuff on the market, mostly cheap Chinese coilovers, Bilstein B-spec stuff(which does not have a coaxial spring seat and is nowhere near the spring rates I need, while taking proprietary springs). 700# front and 550-650# rears are needed to maintain the contact patch without sway bars to prevent lifting the inside from sway bar force killing exit speed. They're downright silly rates.

I'm sorry, its just frustrating as [censored] when I've spent considerable time doing the work and research SPECIFIC TO MY APPLICATION only for some people who have zero experience with it in particular to come in and question it.


Bottom line it works.

It does heat soak up to 25-35F above ambient once all hot(1hr commute) and stopped, and takes 10-15 sec to dissipate. BUT for auto-x the hood is open between runs, it doesn't get more than about +15 over ambient, close hood right before pulling out of grid to the line, and it is back to within 5deg of ambient by the first cone.


Cold air would be great, but there is lower hanging fruit to improve on now. Tune being next and possibly exhaust, but there are not any real gains to be had there aside from weight loss(which is always good).

 

[splinter]

Originally Posted By: flatlander757
But to get an idea of where I'm coming from...I BUILT my own coilovers...

^ This gent gets it.

Well done, sir.

 

[wemay]

Originally Posted By: splinter
Originally Posted By: flatlander757
But to get an idea of where I'm coming from...I BUILT my own coilovers...

^ This gent gets it.

Well done, sir.


+2

 

[flatlander757]

So silicon continues to trend downwards.

Latest sample was with PP 0W20 again(like all of them), this time with Fram ToughGaurd.


I'm now giving Castrol 0W20 Edge(black bottle) with a Fram Ultra a shot. I've actually done one run of 5k on it already, and drained it and kept the filter on, doing the second run now at which point I'll do another UOA.

The truth is so much has changed since this last sample was taken my little experiment is essentially done as far as this thread goes.

For anyone that cares:

I picked up a used Corksport cold air duct cheap for the intake. It's not a sealed box but it routes some cooler air toward the filter. It helped a bit with lowering intake temps after heatsoak and car starts moving.

The car is now tuned and revving to 7200rpms, stock is 6200. I'm fairly certain it's either floating valves or cavitating the oil pump based on a weird noise it makes when you lift at that rpm. Everyone who tunes these experiences this same noise. I'm not concerned about longevity, I know several who've been doing this for a few years, but I'd like to get to the bottom of this. Dynotronics(the tuner) who also tunes all the BSpec cars and World Challenge cars swears it's not floating the valves, they've evidently watched the valves with a slo-mo camera and valve cover removed. Supposedly oil pressure is also fine per a mechanical gauge. Maybe a timing chain tensioner is collapsing or VVT actuator makes a crazy noise when the load goes from 100% to 0 at those RPM levels?

Next time I'll be interested to see if any noticeable amount of wear shows up.

It doesn't make any power at those engine speeds, it helps with the 1-2 shift because the gear spacing S U C K S... it doesn't bog down shifting to 2nd when you run it over 7k in first.

There are going to be probably 50+ auto-x runs on the next oil change UOA alone since we have a test and tune and several events coming up soon.

A friend in the Mazda 2 Owners(M2O) Facebook group got a UOA done of his own car, he was running Castrol 0W20 Edge(same as what I have in it now), and after only 3900mi his car was showing 34ppm silicon. His driving is much different, more short trips. His UOA was with an AEM dry flow type filter. THIS was what I was trying to watch out for when I set out to do this little experiment myself. He checked connections and is going to do another run and see if it was from when it was installed or whatnot. Hopefully he posts his information here at some point.

So in conclusion to this thread I'll say if you want absolute best filtration absolutely I'd stick with an OEM Mazda filter. Properly installed the DDMWorks intake with K&N filter is perfectly adequate. I was just careful with install, and DO NOT TOUCH IT when done.