Put in a K&N drop-in panel air filter today and noticed immediately the engine was getting a ton more air. Right away I could tell I was barely having to step on the pedal to drive normally. The car didn't feel any faster at first, just more "airy" but I was in slow traffic. I did notice more engine sound. It has a mean growl now when you step on it and when it's idling it sounds a little bit like a hot rod muscle car, the way their engines kind of chug when they idle. Anyways, it's pretty cool. I've just been tempted to race around with it but I am trying to drive normal to get better mpg. When I passed a car today I pressed the gas kind of hard and was surprised how mean the engine sounded, like it was supercharged or something. People who say K&N air filters don't add hp don't make sense. I noticed the horsepower right away. Probably about 4-5hp, ok I made that figure up but let's just say it's a noticeable horsepower gain. I guess some people just don't know what horsepower is.

 

Ok so I keep driving with a heavy foot trying to hear the sound it makes. I don't think the computer has adapted to the extra air flow. I could feel it wanting to rev and use the extra power but it shifts too soon. I unhooked the battery a few days ago before I installed the filter so maybe it's still learning my driving.

 

There are conflicting reports on the effects of those drop-in filters. Here you see a 5hp gain with any filter other than factory, while here you see nothing at all (the difference is easily within margin of error).

I guess it all depends much on the car & engine in question. In some cases, at worst, the factory filter may be old which alone corrupts the comparison.

 

It definitely lets more air in. It feels almost like I have a cold air intake. My old filter was not new but not terribly old either. I'm just hoping the ecu learns my driving style because right now it seems like it's shifting too soon and wasting gas. I had to disconnect the battery over the weekend though when I was doing the transmission fluid so it reset the ecu. Before it was more used to my driving. Anyways, maybe it added 3 or 4 hp, I don't know. It is noticeable to me though. Many people say they don't notice a difference, but to me the difference was apparent the instant I put it in and drove away.

 

People that are deaf or hard of hearing seem to notice no power increase.

 

I noticed the mellow sound as well when I had an X Type. Didn't notice an increase in gas mileage.

 

If you look at those graphs from the Scion that showed a HP increase it was all ABOVE 6500 RPMs. I know, it was not a Jaguar that was tested, but I would guess that the graph might look similar, in that any "actual" gains would be very high in the RPM range where you might be there for a split second. In the real world at lower RPMs, not so much. I know when I put a K&N soon after I bought my car I didn't notice any real difference in performance or MPG. The filter that was in the car at the time that I replaced looked almost new. I can't say that I noticed a real difference in sound either. I can't say I noticed any real performance gains when I put on Borla mufflers either. They sounded much better to me, but performance-wise my butt dyno didn't notice a difference.

 

O4Xtype...

I am glad you are enjoying the gains from your K&N..there is some that will quibble about how much if any and others swear by the seat of their pants they feel a difference...I'm sure every ones personal experiences will differ...But as long as you are satisfied and happy..enjoy it, I did when I had mine in..but my improvements were slight, only in the responsiveness of throttle action is all..which I guess by some measure equates to somewhat of a HP gain..who knows..?..Just an FYI: since the K&N is oiled as you know and sometimes when they are brand new they will put an oily film on the MAF sensor..just pull the MAF out in a while and spray clean it off with MAF cleaner..

 

I have heard conflicting stories from 5 HP boost to oil (over oiling)screwing up the MAF and IAC . They work great for carburetored engines on your 350 400 hi HP engines cause they let in more air. In a electronically controlled engine they let in more air also then the 02 sensor see the imbalance and stretches out the pulse width and dumps in more gas to maintain 14.7:1 ratio then there goes your gas mileage, alot like the Jag chip that increases HP by changing the parameters of the MAF.You can control the amount of oil in a K&N at cleaning but I think the gas mileage will suffer. I put one in a 1998 Nissan Sonata and it did nothing(I used rice oil to reoil and it was happy,JUST KIDDING). My brother-in-law swears by them but they set a CFL in his Dodge LHS 3.8 but he didn't care, he had 280K on it when he sold it but the CATS were probably toast also. He's got 260K on his Dodge Magnum.So you see It's what you like and want to live with nobody is wrong if it works for them. Just my two cents worth.

 

Drop in a cone filter set up and you will really hear a difference. Heck the sound alone makes the car feel faster.

Remember it's not the speed that decides if it is fun to drive, it's the experience it delivers to its driver. This is the precious thing the X Type has taught me. Every time I drive it, the way I have customized it and made it sound, makes a theatrical experience that not even a car with 200 more HP can replicate.

 

I just checked out the link to that article! My guess of 5hp was reasonable then. I could definitely feel more potential for horsepower but I can tell the engine hasn't adapted to it yet. The ecu's need a little time to reprogram, but I am getting used to how it drives with it now. It's tempting to floor it constantly with this filter, but you'll waste all your gas if you do that.

I was about to do a cone filter but as I started reading the threads on it, the heat seemed like a big problem with that set up. Summers here can get up to 110 degrees too, so you really don't want to be drawing in air right on top of the engine in that kind of heat. I think for winter it would be fine, but I figured in my case the factory box was probably a better option because of the front air ducts. I was almost thinking of figuring out a way to route a cone filter down to the bottom of the engine, where it could get cold air from the ground, but even if I could in California that's not even smog legal, where in any other state it would be perfectly fine.

 

The factory box is good, because of the ducts. However, when the car is at speed, there is a massive amount of fresh air rushing through the front grille & radiator anyway. One day I opened the bonnet immediately after stopping (hadn't even driven at highway speeds) and my cone filter felt cool to touch. The only real difference would be when stationary, but you never need power when stationary anyway.

My fuel economy went slightly up after installing the cone filter, but then proceeded steadily further down than before over the next few months, as the new 2000-3000rpm growly goodness has altered my driving habits to be slightly less economical. The sound has a big psychological factor; it sounds more powerful but I doubt it actually is. There's no way of reliably telling that with just a butt dyno, you'd need a real one for it.

I didn't really notice any difference after fitting the sports exhaust (Adamesh or Mina Gallery) in anything but the sound. Then again, intake and exhaust modifications should mostly affect high-rpm performance, since any of the small restrictions they remedy are far more significant at high flow rates.

 

...And you never want to have you intake anywhere close to the road or near the underside of the car...Because the road heat will magnify the hot air you think you are trying avoiding, not to mention the dust and dirt close to the road surface as well you would be sucking up..Just don't do it!

 

FWIW,, I had my car on a dyno(not the Jag) & dropping in the K&N w some fine tuning gave 7rwhp over baseline.
......Hardly improvement one would feel, tho.

That X-Type looks very classy in white, how bout some more pics?

 

K&N with "some fine tuning"? What sort of fine tuning?

 

^you don't dyno your car every time you change the air filter??? haha
I updated the EFI, & we were tuning boost fuel & spark.

 

Just wondering how much of the measured 7whp increase could be attributed to the drop-in filter if it wasn't the only change, the other ones sound more significant to my amateur eyes.

 

From the outside looking in, i would tend to agree.
But the filter did help the motor increase its peak power.

To give a deeper insight,,

The mechanical fuel injection was converted to EFI about 20yrs ago.
A few years back I replaced the old EFI unit with a more modern digital unit, that why the car was on the dyno. We did a baseline run w the old unit, then after the install, we chased the safe baseline numbers w/ the new unit.
Now,, we couldn't read the old unit as it was antiquated so the tune wasn't 100% the same. Thats why I typed 'some fine tuning'. There was a difference as the midrange power went up significantly with the more precise EFI unit, but not peak power as the only parameters that were apparently different were the fuel & timing curves. But not total timing, or fuel & boost pressure.
I'd hight doubt any increase in mid range had anything to do w the air cleaner.
But when we dropped in the stock replacement filter after the new units preliminary tune, the peak # went up 7hp. I think everyone @ the shop were surprised.
From there we made adjustments for real hp increases

Would it have the same results on the Jaguar?? Hard to say. As the Ferrari's stock airbox works as a ram air system off of the passenger side air duct. The motor is a deeper breathing, higher revving, higher compression engine that is turbocharged on top of that. On the dyno, you could actually feel the suction of air from the duct. So I am sure the paper element air cleaner is more of a restriction on that car than on the Jag.
.....but the K&N did live up to the manufacturers claim.

btw, I am not an automotive engineer, this was done by a professional.

 

I found in my car, I switched off Sport mode which I had been driving in constantly and now regular mode feels nice and torquey with the K&N, where before normal mode seemed more like granny mode so sport mode was all I drove in. I heard someone else say this too about their K&N filter and it is true.

 

Thanks for the explanation. I see in your garage page that the Ferrari is up there at 440 hp, amazing & looks pretty too!

If the boost is higher, especially if significantly higher, than normal, wouldn't that mean the turbo requires more air than normal? In that sense a slightly better-flowing filter gaining 7 whp wouldn't sound too outlandish. I can't help thinking that on a NA car the difference couldn't be so drastic since the airflow demanded by the engine is far lower than with such a turbo engine.