Has anyone replaced the OEM air filters with aftermarket? if so, was there a noticeable performance difference?

 

I think someone here said it made a difference to the ability to hear the supercharger whine.

But in a modern car with airflow sensors and oxygen sensors and an ECU that modifies fuel flow and airflow and timing etc in real time do we really think that it is likely to make any difference at all to performance except possibly if you are replacing a clogged OEM filter?

I personally doubt it very much.

 

Theoretically it could, since the freer airflow (as detected by the sensors) would cause the ECU to deliver more fuel at full throttle. With forced induction the additional fuel mixture may be minimal. I have always questioned whether it generates a detectable performance increase. At best a few horse improvement that really can't be detected by the butt dyno. That said, I have always upgraded to the K&Ns. With or without a supercharger, the sound coming from under the bonnet is enhanced. At $130 for the filter pair, it's not a risky investment.

 

After 40ish years of involvement with high performance cars and bikes, I cannot recall one demonstrated case of a power increase through the installation of a K&N filter.

The OEM filters don't leave much power on the table to grab.

 

Make sure you dry it up some before installing. Filters come over saturated and can destroy your MAF sensor. Porsche's were especially sensitive and I know more than a few who ended up with a costly repair.

Honestly I have not looked into the F-Type filter size and placement but the XKR-S has two, one behind each front wheel and a K&N or any other high flow filter would not add anything, the engine is getting more than enough air..

 

I agree that the HP increase is negligible and the benefits would be reusability if you are in a dusty environment. Over oiling the filter after cleaning could inhibit the MAF (mass air flow) meter from performing its function properly. The air filters on the F Type appear to be hidden in the fender well which means removal of the wheel and liner to gain access.
I used this type of filter on my previous car (BMW M3) for 145K miles which was a speed density system and yes the induction sound increase is very noticeable.

Schwabe beat me to the reply.

 

At this point, just gonna say what others are saying here too.

Used to be a fan of aftermarket washable air filters. But, despite what the filter manufs said about their filters, and the attractiveness of a low-cost mod, I could never detect a performance increase from my "seat-of-the-pants" dyno, though I saw mild increases on a dyno that could just as easily be attributed to the variances of air density on that particular day. Nothing dramatic--just a few HP's. Nice whine from my turbo rides.

I eventually went back to OEM paper filters over both washables and foam. Why? I wanted to avoid the possibility of contaminating my MAF sensor due to overaggressive oiling (I cleaned my MAF on several occasions--whether there was actual oiling contamination was debatable, but the performance was smoother from idle on up). Gaining negligible HP--factory intake systems (including the air filter sealing design itself) are decent nowadays. Also, I didn't want to have to make an argument to a SA who might want to trace an electronic miss to my non-OEM air filter. (I have a very good handle on where some major auto manufs stand on after-market mods based on my past experience. Not sure on Jaguar's corporate "flexibility." Others here may know.) Yeah, I lost the whine. Oh, well.

All this said, if (and that's a big "if") there was sufficient evidence that the Jag's airflow was compromised, I might reconsider. But, I don't see that happening though. Heck, I haven't even checked out my R's OEM air filter design as I write this!

 

I have tried them on my 4x4s, and here are my thoughts
- on modern fuel injected turbo diesels they don't make a noticeable difference in power
- in very dusty environments they do mean you can clean and reuse, but it is a messy and fiddly job to do while you are travelling and it it easier to just carry a spare paper filter and throw it in if you need it.
- over oiling can cause MAF issues

The last time I really loved a reusable foam filter was in the 1980s on a 1960 s naturally aspirated Ford Cortina with a Webber carby. The Webber made some difference to the power, but the induction noise from the uncovered (and pretty much unoiled) foam air filter made it sound much faster and cooler to a teenagers ear

Looked a bit, but not quite like this

 

Unlike the MAF system, a speed density system does not expose the air flow to a sensor situated within the intake.

 

Deleted

 

An indy Jag mechanic once told me that they give 1 and 'maybe' 2 hp increase...

 

I just installed a pair in my car over the weekend. The job was a little time consuming lowering the splash shield and gaining access to the OEM air boxes, but not difficult. Just ALOT of screws! No "sound difference", but the car pulls much stronger about 3K RPM than it ever did with the OEM paper filters! My OEM filters were brand new, not dirty or clogged....before you could feel the car "choke" or "bog" on launch or in between shifts like it was starving for air....couldn't pull it in fast enough....now there are no problems and it cant stop pulling!!! That has always been the case with any K&N filter upgrade on any car that Ive had in the past. NA, turbo, Supercharged, you name it....I have always felt a little bit of power "unleashed" with K&N drop in filters over OEM paper filters. I have also never had an issue with MAF sensors being messed up by oil caked up on them from these filters either.....
To each his own....for me.....a great "upgrade" for $100.00!!

 

Thanks for the firsthand comments - which F Type model do you have?

 

I have used a K&N cone type filter in the past, however I think it is generally recognised that K&N's (and other oiled filters) let through more dirt than regular filters.

So, it would be a tradeoff between engine wear and whatever the benefit is supposed to be.

Can the 550hp V8 'out suck' the stock airbox? If Jag engineers know what they're doing - then no, (otherwise performance would tail off as the engine became starved of air).

 

As long as the K&Ns are washed and re-oiled as often as filter changes are specified by the manufacturer, the cotton K&Ns have been shown, using ISO 5011 lab testing methodology, to meet or exceed the filtration ability and capacity of the OEM paper filters. Airflow obviously is also improved. It's just a lot easier and cheaper for the automakers and service people to throw in a new paper filter.

The trade-off is more labor, not more wear.

 

I think there is a fairly close correlation between flow of air and flow of dirt, no matter what the mfrs state.

This gentleman did some testing, including pressure drop due to reduced airflow and dirt collected in a secondary filter, I think the results may be of interest:

Air Filtration Test

 

1 % less filtration and .14% more flow. Certainly not the cost/benefit ratio advertised by K&N. Thanks for enlightening me.

 

I've seen similar tests before.

I used to drink the K&N Kool-Aid too, years ago. Feeling a difference is very much similar to a placebo effect. If you think a sugar pill is going to make you feel better, it probably will, because the mind is a powerful persuader.