I just purchased an 2001 XJ8 with the 4.0 engine,she has45,000mi, a beautiful car in every way except the POWER!
she just need more! I'm used to American muscle power, so I need your advice, so far my ideas are.....

1. install an free flow performance air intake tubesystem, capped off with a large K&N filter

2. change the center 2 into 2 muffler into an "X" pipe, ditch the resonators,
and cap off the system with a pair of Magnaflows performance mufflers

3. install a "PERFORMANCE ECU CHIP"

Any tried all or some of these mods? with GOOD or BAD results?

TIA Alex

 

I'm not familiar with Jags yet, but on any modern car that you care about - don't use K&N!!! I'm assuming these use a MAFS, not just an AFS, for air flow, and any oiled filter is just begging you to kill your MAF. I know K&Ns work well on older muscle cars, but they don't flow that well, don't clean that well, and they have that damn oil.
I'm partial to Apexi filters, because I found them to flow almost tops, and they have been tested to be the first or second top cleaning filter.
That said, an air filter is never gonna give you a huge increase. It will probably make it sound a hell of a lot meaner, though.

X-Pipes are almost always effective. With an FI vehicle, increasing the air filter and exhaust *can* help you greatly, but you won't see nearly as big of gains until you upgrade the pressure the supercharger is putting out, anyway, at which point the gains from the I/E are just because they were greatly restricting the upgraded performance of the supercharger. I doubt the I/E is holding much back in stock trim.

Again, chips can be good. I doubt the eBay special will do any good (probably cause harm, actually....), but if there is a good company that makes a proven, quality chip for this chassis, then go for it.

 

uh. i have used k&n filter for years and installed, not only on my mafs truck, but my wifes Jag, and many customers too. And a K&N filter will not kill a mass air flow sensor, and has been proven time and time again, and wont void warranty either. Now if someone doesnnt know how clean and oil a K&N cause they cant read or follow instructions then thats their problem not the products

 

Brutal,

I've seen it happen time and time again, to several different makes and models. In fact, I know a friend who put his K&N on the car as it was from the factory (pre-oiled), and it killed his MAF.

Rather play it safe than sorry. Besides, there are much better products than K&N anyway - why take the risk?

 

do they have higher flowing cats for these cars. I live in Cali so don't have the option of dumpin them. Never knew that about k&n, i wanted to get a drop in k&n filter for my jag. GUess ill look into apexi, do they make drop ins? My jag is supercharged so not in diar need of more horsepower just a little more and a meaner sounding exhaust. You should of went with an xjr for the power my man, they are amazing 1stjag.

 

BRG, They probably do. Check your local exhaust shop, I think they'd be the best bet for them. Also, I've been told in 09 in CA you can't replace your cats with ANYTHING other than OEM or it's illegal. Of course, you could always find a smog shop that will pass your visual for you, for a....fee.

Apexi only makes cone filters, and you'd have to run your own ducting for the air (sucking in hot air from the engine bay does you no good), so that would be the benefit of the K&N, but for me I'd take the Apexi any day.

 

I had a K&N on my '99 Roush Edition Mustang as part of the MAC Cold Air Intake system and never had an issue, even after cleaning it a bunch of times. If you don't follow the directions properly (which is why people tend to really screw it up) of course there can be problems. I have never heard of an issue with the pre-oiled filters either. As far as exhaust www.jaguarxp.com has some Arden products. I have a stock '99 XJR right now and am about to replace the intake system but don't plan on doing anything with the exhaust. I had the stock three chamber cat back on my Roush, upgraded to Bassani X-Pipes and thought that I really wasted my money. They were really damn expensive..... As for Jaguar exhausts I'm not really going to try anything since I am now in California for the next couple years and they are **** about everything. As far as a chip, I would definitely go for a chip before I replace the exhaust. Again, I replace my '99 Roush chip and noticed much better performance compared to a buddy of mine who replaced his stock GTs exhuast with Bassani before his chip. Be carful though, I would also not go with the eBay special. Do some research and find a good chip. A couple hours of research, a little extra money will keep you from totally destroying your engine. Compare how much extra you would spend on the chip to how much a new engine costs and it is pretty much self explanatory.

 

Damn CA, cant have any fun out here. I heard the same actually i think its been in effect allready. i looked at jaguarxp.com and looked at their setups, they look very nice and all but seem a little steep. would it be a bad idea if I would take the jag to a muffler shop and had them weld on some mufflers?.

 

The best way I know to get real power is to replace the O2 sensors, clean the MAF, flow match the injectors, change the plugs, change the air filter and fuel filter, and flush the tranny . This will add more dependable power than the other stuff, just getting the worn out stuff up to par.A typical seven year old car is usually down 15-20% on power, you can get it back if the compression is still good. I never thought K&N was good for anything but racing, letting too much crud get through for a street car, and I did use them for racing for years, they are made to stop rocks while covering the velocity stacks on your Webers, not 2 micron particles. Dropping the exhaust backpressure is always nice, but breathing changes without cam and timing changes are not worth much, and itcould contribute to a confused maf, with corresponding mixture confusion and possible check engine lights if the change is more than the sensor can handle. I know of no chips for the car since its a 4400 lb powerful luxury saloon with soft springs, not a sporty car, but somone may have something. You might try AJ Engineering, they specialize in these cars.

 

brgxjr,

Honestly, ifI were you I wouldn't do anything. Just replacing the mufflers has the potential to creat a meaner sound but you never know what you are going to get in terms of sound and I personally don't think that it is worth the money. You could really take the cost of that and do other things to the vehicle. Replacing the mufflers is what guys with Civics and other matchbox cars do to try to get a meaner sound. My Roush had a great sound but of course it was an American Muscle car. The XJR though fast (faster than most guys in a stock Mustang GT thought before they saw my tail end) is elegant. Of course, I am more of a traditionalist when it comes to autos. I guess what I'm really getting at is, the car should be as accurate as possible with respect to the style and nature. Anyways, I would take the money and look at cosmetic items that would really add some style and class to an already classy car. Of course your money do what you wish. Again, the previous is just my opinion and that is why we have such a great forum for discussion.

 

jagmarine,
You are very true. I love the car as it is. I never thought i would be driving a car like this at 23 years old, definately wont do anything to the car to demine its class, that was my biggest concern. And you are right about saving the money and using it for something else. I think im better off just saving the money for regular tune ups and preventive maintanance. There are some nice sounding exhaust out there that keep the european sound but they are way to pricey for me, go from 700 to way over a grand. I too had a mustang, tho it was a early 90s 5.0 it had a full exhaust with flows, definately mean sounding. But the jag is just a totally different experience. Thank you for your opinion jagmarine.

 

I, like you want to increase the power and have a meaner sound and more roar from the V8

so far i have only changed the exhaust



So far i have had the far rear silencers removed and it does have a much more noticeable noise. much more throaty when accelerating. I am going to remove the far front silencers just leaving the middle ones so make it a little more aggressive. I have noticed no change however with regards to performance. Also no problems with any warnings

 

man i have not seen a jag in that color at least not an xj. looks pretty nice from what little i can see. thnx for the info tho.

 

Rob, welcome to the forums. I did the same thing but haven"t had time to get the new pipes attached. Right now I just have the stupid empty cut-outs. Going to fix that over winter break.

Gorgeous, gorgeous color. Any more pics? Is that OEM? I"ve never seen it.

Edit, I just noticed the spare tire well is that same color. I guess it is OEM? Oh, and DAMN those taillights looks great! Did you do that yourself or buy them? If you bought them, do you have a link?

 

yes nice color indeed. there's a lot of chat here about upgrading the intake. I've toyed around with this a bit. I tried the K&N cone filter intake with a heat shield, and personally, I think that the stock is better. The stock air intake (at least in the xjr, not sure about xj8) is an ideal cold air intake setup. You might gain some horses when the engine is cold with a cone K&N, but once the engine warms, I think that you can't beat the stock setup. Currently, I just have a K&N rectangle filter in the stock air intake setup, and I'm happy with that,

 

trying not to hijack the thread. cheers for the comments, when i bought it i was looking for a black one but when i saw it i loved the colour and yeah not seen it around but ye its OEM colour

sadly the lights cannot be bought like this. they are the OEM lights but i took them to a body shop to have them tinted. they spray tinted them and lacquered them

here are some pics


with lights on still show up bright

 

looking good. havent seen those rims either. where did you find this thing?

 

cheers, they're Jaguar Celtic's 17". They alright although i want to change them like most bits on the car.
I found the car on autotrader in january and it was just outside of Birmingham, UK.
It was £5000 with 65,000 miles and ye was/is immaculate and looked after well.