I am posting this thread to summarise my experiences with my XJR, in terms of airflow, intake temp etc. some of this will be applicable to the non-supercharged cars.

firstly:-
my manual-gearbox XJR has Andy's revised EPROMs, and the Powerhouse 10% bigger drive pulley, so is not standard. I have replaced the ailing original Hella electric intercooler water pump with the Bosch unit, which has really reduced heat sink and power loss.
On a hot day, on a second run on coarse chip road, I have done an accurate 0-60mph time of 5.5 secs. I have not repeated this to try to improve times, as it gives the drive train hell, and I am more interested in acceleration at open road driving speeds, rather than drag racing.

AIRFLOW:
Using a Kiwi3 OBDII bluetooth device, I can graph two variables on my iphone whilst driving, and (in warm summer, approx 25'C) my airflow meter is maxed out at about 4000-4500rpm at wide open throttle of 96%. This is the same whether using a K&N pod filter or standard airbox and paper filter. So I do not think the pod allows more airflow, at least in the supercharged engine. And the pod filter requires regular cleaning/oiling, and probably lets a lot more fine particulate rubbish into the engine. So I just use the std Jaguar filter box and paper filter.

INTAKE TEMPERATURE:
I bought a cheap digital thermometer with a wire, designed to be in a house with the wire outside, so gives 'inside' and 'outside' temperatures.
I taped the 'outside' sensor wire on the mouth of the standard Jaguar air intake trumpet, and it at open road speeds it reads the same as ambient temperature on the car's dashboard. So the air intake behind the lights once moving is 'cold'. If idling in traffic, underbonnet temps can easily rise 30'C above ambient.
If, for example, I have run the car hard for a few miles at speeds of 80-100mph, then sit idling in traffic, then temp under the bonnet (sorry, 'hood', I've just remembered to translate for Americans!) can rise to 60'C on a hot day. However once moving again at 50-60mph, it comes down to ambient within about 1.5-2 miles.

So as far as I am concerned, the standard paper air filter in the standard Jaguar plastic intake box with snorkel, gives full air flow and cold air intake, and can't be improved upon, at least for the supercharged car.

(I may take my car to a local dyno tuner, just to run it up and see what bhp I have at the wheels, but haven't got around to this yet)

 

That’s very helpful thank you.
I have the same setup with an auto, and like you, I’m more interested in overtaking acceleration then 0-60, and it’s pleasing I don’t need to change the air filter to improve this!

 

Cafcpete, I see you are in London. Have you ever taken your XJR down to the A25 for a Sunday drive? The twisty bit from Dorking heading west up the hill from Shere to Newland's Corner would be a great drive ... (I lived for a year in the Abinger area, alas no Jag in those days)

 

Sadly wrong bit of London for me, but will bear it in mind

I haven’t had the car all that long and a fair bit of that time has been fettling the car. Wheels refurbed, SC pump etc.
Currently the car is in Nottingham with David Marks Garage, well know Jaguar specialist where it’s having some bodywork repairs and full rust protection to hopefully last another 26 years.

I have had some enjoyable drives around the lanes in Suffolk and down to Southampton.

In fact on the drive to David’s the extra urge that the upgraded pump has bestowed saved me and the car! Some sleeping idiot in a BMW tried to pull across into the side of the car but I was able to swerve and accelerate out of danger thank heavens.....