"Effects of OEM vs K&N air filters on various engine parameters"

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Dyno runs usually incorporate a baseline run with a stock car. The runs, be they stock or modified, are an apples to apple comparison since each is done with the hood open and the fan blowing into the front of the vehicle. So the gains are accurate in my opinion.
 
Originally Posted by wemay
Dyno runs usually incorporate a baseline run with a stock car. The runs, be they stock or modified, are an apples to apple comparison since each is done with the hood open and the fan blowing into the front of the vehicle. So the gains are accurate in my opinion.


What's accurate is to run them like they would be on the street. You don't run the 1/4 with the hood open, so if a hot air intake is actually a net loss with the hood down, it would be prudent to be aware of that.
 
Originally Posted by OVERKILL
Originally Posted by wemay
Dyno runs usually incorporate a baseline run with a stock car. The runs, be they stock or modified, are an apples to apple comparison since each is done with the hood open and the fan blowing into the front of the vehicle. So the gains are accurate in my opinion.


What's accurate is to run them like they would be on the street. You don't run the 1/4 with the hood open, so if a hot air intake is actually a net loss with the hood down, it would be prudent to be aware of that.


That's a different discussion altogether. Plus we've seen recent videos from both Engineering Explained and PF that conclude the K&N alone contributed to faster times.
 
I prefer my own performance data - 1/4 times in the real world. Plenty of folks have shown improvement with a K&N in conjunction with (important!) other intake modifications.
 
Originally Posted by TiGeo
I prefer my own performance data - 1/4 times in the real world. Plenty of folks have shown improvement with a K&N in conjunction with (important!) other intake modifications.


Agreed, and even though I went back to a paper Fram9711 since I've changed my mind on tuning the Passat, I will always go the K&N route if further modifications are planned.
 
Originally Posted by TiGeo
I prefer my own performance data - 1/4 times in the real world. Plenty of folks have shown improvement with a K&N in conjunction with (important!) other intake modifications.


Yup, and there are plenty of setups where it shows no improvement or a CAI provides no benefit over a silencer delete on the stocker. I had a crazy WAI on my '87 Mustang and eventually swapped it back for a silencer deleted stock setup when I did my MAF conversion. The E/T and trap didn't change. What DID make a difference was an underdrive pulley setup and an electric fan.
 
Originally Posted by OVERKILL
Originally Posted by TiGeo
I prefer my own performance data - 1/4 times in the real world. Plenty of folks have shown improvement with a K&N in conjunction with (important!) other intake modifications.


Yup, and there are plenty of setups where it shows no improvement or a CAI provides no benefit over a silencer delete on the stocker. I had a crazy WAI on my '87 Mustang and eventually swapped it back for a silencer deleted stock setup when I did my MAF conversion. The E/T and trap didn't change. What DID make a difference was an underdrive pulley setup and an electric fan.


I run a drop-in K&N with modifications to the stock closed intake system on my Golf. Proven #gains.
 
Originally Posted by TiGeo
Originally Posted by OVERKILL
Originally Posted by TiGeo
I prefer my own performance data - 1/4 times in the real world. Plenty of folks have shown improvement with a K&N in conjunction with (important!) other intake modifications.


Yup, and there are plenty of setups where it shows no improvement or a CAI provides no benefit over a silencer delete on the stocker. I had a crazy WAI on my '87 Mustang and eventually swapped it back for a silencer deleted stock setup when I did my MAF conversion. The E/T and trap didn't change. What DID make a difference was an underdrive pulley setup and an electric fan.


I run a drop-in K&N with modifications to the stock closed intake system on my Golf. Proven #gains.


Yup, as I said in the other thread, it will depend on the design of the stock setup. I had no problem feeding a ~325HP (270 to the tires pig rich, later rectified with a more appropriate injector/MAF setup) 302 with the stock Ford airbox and a paper filter with the silencer deleted. It used a very large panel filter and the factory plumbing was all significantly larger than the 75mm throttle body I was using. I don't expect my 6.4L 392 is starving for air either and the airbox setup on the SRT's are all quite similar whether it is feeding the 475/485HP 392 or the 707HP hellkitty mill. I believe in the cars, the airbox is the same actually and the hellcat filter is just deeper IIRC.

On the Mustang, the purpose of going back to a stock airbox/plumbing from the WAI/CAI was to eliminate the consumption of hot engine bay air and instead have it breathing the much cooler air from inside the fender.

Probably my favourite stocker setup was the big dual setup on my M5. Obviously grossly oversized for the 400HP 5.0L V8 it was feeding, but it looked really neat having that symmetry to the engine bay.
[Linked Image]
 
I have a huge k&n breather for my Oldsmobile but I won't use it anymore after seeing tests showing how much more dirt got through compared to every other filter in the test. It did flow slightly better, but the difference in filtration was huge, I'd rather use the cheapest one in the test than the k&n now.

My cars won't win many races either way but they have most vehicles beat when it comes to longevity, not going to compromise that with an air filter.
 
Attached the graph showing filter efficiency difference. It seems to be similar to the other test result I saw very recently.

Every time the guy in front of me goes off the road and throws a cloud of dirt up that I drive through I'm glad I don't have a k&n. Even more so in my work truck that spends most days in extremely dusty construction sites, the engine bay is filthy with dust, giving me OCD just trying to change the air filter.

Screenshot_20200319-100418.jpg
 
About 450+ hp in the Ford EcoBoost V6s all on stock paper filters. In fact the Ford Fusion Sport 2.7 EcoBoost stock paper air filter is the same one used on each of the turbos for the Ford GT.
 
Originally Posted by metroplex
About 450+ hp in the Ford EcoBoost V6s all on stock paper filters. In fact the Ford Fusion Sport 2.7 EcoBoost stock paper air filter is the same one used on each of the turbos for the Ford GT.


And I'm sure Ford Racing has aftermarket intakes for it that use high-flow filters like all the OE performance divisions.
 
If the stock air filter puts no restriction(as shown by a air filter restriction gauge) how can a filter that flows more cfm make more power?
If the engine is getting 100% of the air it wants with no restriction, putting a larger filter on it won' t get you more hp.
If someone on here can show me how a filter that causes no restriction cost the engine hp I'd like to hear your theory on that.

Rod
 
Originally Posted by rrounds
If the stock air filter puts no restriction(as shown by a air filter restriction gauge) how can a filter that flows more cfm make more power?
If the engine is getting 100% of the air it wants with no restriction, putting a larger filter on it won' t get you more hp.
If someone on here can show me how a filter that causes no restriction cost the engine hp I'd like to hear your theory on that.

Rod


All air filters (and intake systems) have a "restriction vs flow CFM" curve. There is no such thing as an intake/filter that has "no restriction". The whole intake system (including the air filter) with least flow restriction will let more flow into the engine at WOT and give more HP.
 
Sure there is. If you can't measure any restriction because of the air filter(not talking whole intake) there is no loss of hp at wot even at red line. I could put a K&N on my car and not get any more power. I could mount the air filter off my old 14L diesel on same car and not gain any hp even though that filter will flow 2, 3 maybe 4 times the air that the K&N would flow. I can take the a/f off my car and not gain any hp and I have done this on the dyno. In fact my 90,000 mile a/f on my S2000 got the same hp(within normal hp variance from back to back runs) as the new air filter.

Rod
 
Originally Posted by rrounds
I can take the a/f off my car and not gain any hp and I have done this on the dyno.


That's probably because your intake system/tract is the main restriction between the ATM and throttle body, and any small changes in air filter restrictiveness can't be distinguished on a dyno (the HP delta is in the dyno's +/- measurement noise).

Like has been discussed and shown in other similar discussions, if a less restrictive air filter is dropped into a stock air-box (and the intake system/tract is well designed and is not the choke point), then HP gains are seen with a less restrictive air filter which gives more air flow at WOT because it reduces the overall delta-p between the ATM and the throttle body.

There are literally thousands of dyno tests done over the years showing added HP gains from a drop-in filter that have less flow restriction. Then one step beyond that are dyno tests that show pretty big HP gains on some engines from swapping out the entire intake system/tract and filter. Look at the HP gains on Vettes with the Halltech intake systems: https://www.halltechsystems.com

I'm assuming you've read this thread?
https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/5315441/1
 
They took the entire airbox off the SHO and dyno showed 1-3 hp variation, the air filter and air intakes were not restrictions. The 0.1-0.2 psi pressure drop from a K&N isn't worth it on EcoBoost. For the track, I wouldn't mind running a K&N panel just for a possible extra edge but on the street it is quite silly.

The aftermarket intakes for the S550 Mustangs are basically stock airboxes with a cone filter in it instead of a panel filter.
 
People have some good ideas on here, but get hung up on numbers. Like the 5.887 versus 5.995 secs acceleration test above. .001 secs resolution and .118 secs difference. Really? It's accepted a used air filter filters better up to a high restriction point and that's what I want. The power difference is meaningless to an average person driving a car.
 
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