Evening all. I have a problem with the induction on my 2007 XK 4.2 n/a. The car has had a minor front end collision, and on the air filter box, the right-angled pipe that the air intake horn mounts on to has been snapped off. Everything else is fine.

The problem is that the air intake is now just a large round hole straight into the air filter box itself. Not a problem in the dry, but if I drove through a really deep puddle, the air intake could easily suck in rather a lot of water, which would go into the cylinders and wreck the engine. My wallet really REALLY wouldn't like that...

A new air filter box is £400 or so, and of course, it's only sold as a complete assembly (C2P5975), MAF sensor and all. It seems a lot just to get a box with the intake pipe undamaged, and my wallet wouldn't like it all that much either. I can fit a K&N cone air filter kit for less than half that, and cleaning the cone filter itself is not a problem. Has anybody fitted one of these kits to an n/a 4.2, and if so, did it cause any problems?

Any and all advice welcomed..

TN

 

Considering the location of the airbox that is out of the engine bay and in the wheel arch a kn pod style filter would work perfectly

 

It is possible to glue together the broken piece - use J.B. Weld. It will hold.
I have tried using a K&N pod filter (#1040). I tried it with a kit for an XKR, which was a mistake. The intake tube from the filter box is smaller in diameter on the XKR than the XK; and it was virtually impossible to shim the smaller tube sufficient for an air tight seal. You need a special fixture for the mass airflow sensor that fits the larger XK intake tube; and I don't know if one exists. Pls tell us if you find one.
Not to worry about water intake with an "short" intake minus the OEM "snorkel". I live in Oregon (same climate as UK) and have been using a short intake for five years now. The likelihood of ingesting rain water is really remote. You'd have to be fording a fairly deep water for this to occur.

 

Thanks gentlemen. Due to the problem of relocating the MAF sensor, I've decided against a K&N pod filter unless all else fails.

Rey, regrettably, the thick-fingered numpty who bodged the "repair" threw all the broken bits of plastic away...

I'll take the airbox off and see if I can find something that will do the job. Cheapest option will be a right-angled bend of plastic plumbing pipework, if I can find something the right internal diameter, then glue and cable (zip) ties will hold it OK. Doesn't need to be a perfect seal, as it's upstream of the air filter.

If there's nothing in the plumbing area, a firm like Samco that supplies all sorts of aftermarket induction pipework will surely have something that will do the job (he said hopefully...).

 

Check out Pacific Motors via Ebay. They are a dismantler and might have what you need. There is another Coventry 800-331-2193. Also there are several in southern California.

 

It should be simple enough to find 'something', form it and silicone it in place or even hold it there with a couple self tapping screws. The something can be anything plastic or aluminum as needed. You are only limited by your imagination.

 

That's what I think. I'll get the airbox off tomorrow to see the diameter of the intake orifice, and take it from there.

One final question. Is the intake horn, that attaches to my missing right-angled section, plumb vertical in front of the aircon condenser, or angled?

 

It's convoluted, Google 'jeep snorkel' for some idea on how it looks. Comes out the side with an oddball small opening, turns vertical and at the top it turns again so the opening is flat. Really looks restrictive.

 

It looks quite straightforward in the parts diagram - part no. C2P5974. Just a rectangular-section horn that becomes circular and turns through about 70-80 degrees to mate with the airbox inlet.

 

Took the airbox off, and the intake orifice in the end isn't round; it's oblong. Nothing easy off the shelf, then.

Solved it, I think, though. The perimeter of the orifice is 37.18 mm, and a 5" tube is just a fraction larger. I thought of heating a length of 5" plastic pvc water pipe - it's quite pliable at 80 degrees C - and forming it in the orifice. Possible, I suppose, but tricky; it cools quickly and goes hard again, and the bend would need to be at exactly the right angle, or it wouldn't fit.

The solution? A length of 5" flexible aluminium foil ducting pipework, I think. It can be easily bent into shape to fit into the intake, then silicone sealant to hold it in place, and the loose end can go anywhere I want it to.

Fingers crossed it will work...

 

And so it was done, though I used epoxy putty to hold it in place. Some surgery on the radiator splash shield was needed, and the end result is not pretty, but it's in place and does the job. I sprayed it matte black, and with the bumper back on it's not really visible anyway unless you crouch down and peer into the lower grille aperture. Result!

Total cost? About £20/$25. Even more result!!

 

XK intake is well designed. I would look used parts and make it as it was... Jaguar air filters are good too. Would not switch to something other.

 

Is that your opinion, or based on technical knowledge?

[QUOTE] Jaguar air filters are good too. Would not switch to something other. [QUOTE]

Perhaps my post was not clear. Apart from the ducting of air into the air filter box, everything is standard.

TN

 

I sincerely disagree. The longer the intake plumbing the larger diameter it should be to reduce surface friction induced pumping losses. From the inlet to the blower to the air inlet under the bumper cover on my '07 is at least 6' long which is ridiculous. That the inlet is necked down to a small oval is similar to a wrestler breathing through a straw. Good for short burst of energy but runs out of air quick. The engineers also seemed to be conservative on the packaging, making the plumbing over the valve covers far more constricted than it needed to be. The silencer nodes don't help either as far as I'm concerned regardless of frequency induced pulses. I think they are just there to suck any blower noise out of the inlet tract.

 

In terms of the air filter; the shop that worked on my Jags (biggest indy around New England), and how well they work at staying clean. Jags run best with OEM parts and reflect a well maintained car. In general, the only other style filter better would be a foam filter, but not sure if ITF or BMC make one for the XK. If so; that would be neat. I doubt you'll gain anything you'll notice. Will there be a MAF issue? Why bother creating issues when what is easy can be easy.

 

I think almost every shop will endorse using oem parts exclusively - it is a no-brainer, no risk to the shop decision. Quality and fitment of aftermarket parts varies - some better and some worse than oem.
K&N makes a direct filter replacement for the oem. I have one installed with no MAF issues whatsoever and 15K miles on its clock. There are several no-name mfgs which make filters that look like K&N. There is an urban legend to the effect that K&N filter oil will migrate and contaminate MAFs. At one time many years ago K&N filters were delivered without filter oil and the buyer had to apply filter oil personally. This legend probably grew out of over filling by some buyer. Personally, I have added filter oil to "clean" K&Ns over the years with no problems. Nevertheless, in the last fifteen years or so K&N has pre-oiled all their filters, and any problem no longer exists.

 

The problem with K+N was they compared their new filter to a grungy old filter to get their advertising claims. I'd be surprised if the OEM Jag filters are restrictive, especially on an XKR with the twin A/C's.

 

BMC and ITF are only other air filters beyond OEM I would consider for any car.