Hi!
K&N's website list an air filter for the XJS V12 but nothing for the 4.0 engine. I am just wondering if both engines use the same filter. If not, does anyone know of another year/make of a car whose air filter will fit the 4.0?
As also thanks!
Jomo

 

It is weird that its not listed, because that is a pretty generic shape for an air filter. I would try measuring it and seeing if you can find a list of K&N filters by size, or sending an email to them and asking if that have something similar to that size.

Idk about the 4.0 but a quick look at some charts reads out that K&N flows a bit better but reduces cleaning by very high percentages. So over time that increase in horsepower would lead to lower horsepower through the life of the engine as it is damaged.

some light reading if you want to know what im talking about. I mean think about it, if more air can get in more debris can also get in.

K&N Air Filter Review - Debunking the Myths (and why OEM is better)

 

wow I never realized this. I read the whole article/test report and am surprised about the results. I mean think about it, if more air can get in more debris can also get in. Actually sound logical to me. I just never thought about it that way.
Thanks,
Jomo

 

Lol yeah man np. Race cars don't use filters but A. they are on a race track not a dirty public road and B. The engine gets rebuilt within a few hundred miles.

I have personally reached a point in my life that I don't get much out of modifying cars and I think its pretty cool to have an older car in nice condition and leave it stock. Of course restomod type things such as better brakes or electric fans can be different, but I'd rather have a really nice XJS than a modified one, especially if it means trading restoration/maintenance funds for mods. At the end of the day there is always someone faster, so who cares.
I have personally had some of the most enjoyable times in a car inside a 1965 morris minor with 30hp. Sorry to rant, it just surprises me at times that I have reached this point at 22 while so many others are hot rodding fox bodies into their 60s.

 

Jomo,

There is no K&N filter made for the 4 litre XJS that fits into the standard air filter housing. It's a strange omission from their range, but that's the way it is.

If you want a K&N, you'll need to fit one of the type that mates directly as an external filter to the MAF. In my limited opinion, it's not worth the effort to do this.

Good luck with your choice

Paul

 

Ive always used K&N filters and will continue. Ive never had a problem.
I wonder if it was a paper filter company who wrote this.

 

"The test was independently performed under controlled conditions using a $285,000 machine at Testand Corp of Rhode Island (manufacturer of the machine)."


sounds pretty unbiased to me.


I wonder if it was a K&N fan who has only purchased one because of marketing who wrote this

 

Your right. I only bought one for each car Ive had. If properly maintained I believe its a better filter.

 

Based on what? You have literally been presented with information proving that is wrong and you are still saying otherwise.

 

it may be possible if the car is driven 200K miles!

i dont think its worth worrying about in our life time, tests also say K&N does give slightly more power/mpg.

side; i'v used K&N since before you were born!

 

Wow, reality check, I am not saying your engine will blow up if you use K&N air filters. I am saying you trade the point of an air filter for an impossibly small power gain. The only reason you get more power is because the air is less filtered and over time the K&N gets exponentially worse at passing air as it fills with dirt, meaning you have to clean it more often than you have to change paper filters.

Even if you gained 2-5hp, that isn't something you can feel amid 250hp

Also my uncle and dad both used to have mid 90s broncos, only difference in them was one had a K&N and flowmasters and the other was maintained stock. The stock one ran strong until he got rid of it at 300k miles. The one with the K&N ran like a total pile of crap at 200k.

I just don't see the point in paying 90 dollars for air filters for an XJS to get a unnoticeable amount of power that will cause increased wear on the engine. Also a point I previously made, at the end of 200k miles I can gurantee you the K&N car would have less power and less efficiency as a result of more wear. I am not saying it will catastrophically damage your engine, just that over time the whole point in your filters that cost 5x a much is defeated as it created the opposite effect.


P.S. I dont care how long you have been overpaying for crappier filters, only took me this long to figure out its a waste. Why don't you just use foam? Its cheaper and gives a bigger airflow increase. I used to have one on my MGB for ***** and giggles because I was going to rebuild it soon.

 

If you do your mathes, a K&N filter will just cost you more money than standard filters as well.

I did the calculation with my C30... I drive around 30.000 km/year. My car is serviced every 20.000 km. Every 60.000 km it gets a new filter. The original Volvo paperfilter costs €11.89 (with taxes). The suitable K&N filter costs €78,99. If I work it out, I need to replace 7 filters, to break even with the purchasing costs. That means 7 x 60.000 km = 420.000 km. After 420.000 km, the car is a wreck and not even worth the price of a K&N filter... That is a lot of money for something factually not offering enough to justify it...

My V12 has gotten original MANN filters for €15/side. The K&N filters cost a whopping €65/side here... And then there are the horror stories of the filters breaking up and being sucked in through the throttle body...