I'm looking for affordable performance upgrades for my 2004 XJR.
I have been reading on the forums and have seen different opinions. Some people say a cold air intake (like the one on Mina Gallery) is good, other say its not much of a benefit if you have a super charger. I read a thread on the K&N filter (not specific to XJR) and some people said they noticed a difference and others didn't. I have also read threads on the pulley upgrade, several people have done it, some say they really notice it, others say its probably not worth the effort. I have also read a thread on someone saying an ECU tune was amazing, claiming 60HP gain, while another said his HP went down. A poster said that the Jaguar XJR was already very well tuned from the factory and shouldn't be messed with.

I know a user on this forum makes a stainless steel intake tube that has been recommend on this forum but a mechanic I know said this would be a bad idea as the metal would get hotter then the stock plastic one.

So, I've been trying to do my research but its hard to get concrete answers. Does anyone have Dyno evidence of these air filters, ECU tunes, pullys and exhausts?

What upgrades can I do that don't cost several thousand? I read some of Avos posts on his car but from what I can gather hes an expert and spent a lot of money to get his gains on the XKR. I'm a novice and don't have a huge budget.

Any suggestions from people who have done the upgrade and seen results would be appreciated, thanks.

 

I have done the following to my X350 XJR;

3lb upper pulley from Powerhouse in the UK
Intake tube aka the Caldoofy one
K&N filter, and removed the solenoid operated flap from the airbox
Fitted the Bosch 010 intercooler pump

Those are relatively cheap mods & get you measurable gains. although the I/C pump is not power adder, it does seems to help with the temperatures. The intake tube has been proven to get you at least 10hp at the wheels.

Next step for me is to replace the cats with some 100 or 200 cell ones (check out Nameless Performance for ideas) but then you are looking at some major $$$'s

I would not go for the Mina intake, removing the flap from the airbox does the same job.

I also fitted a Quaife LSD, which although not cheap, has transformed the car in my opinion. Well worth the money.

My XJR has done the fastest 1/4 mile for an X350 on any of the forums, except for the guys in the UK running nitrous...

Also get in touch with MoscowLeaper here on the forum, he is working on a flash-tune that will remove some of the limiters in the stock ECU...

 

Thank you for the reply, interesting stuff.

I have done some extra searching and found people saying that its bad to lose the box for the open Mina cold air intake, as once the engine gets hot or on hot days (I have a lot of these in GA) you lose any gains you had. I think plopping in the K&N filter and keeping the box might be the best bet.... how do you remove the flap, or even check that its working properly?

As for Caldoofy's Intake tube, it seems to get good results for everyone.

How much money would you say it would be to fit a 3lb upper pully and the intercooler? Again I'm a novice, trying to learn all I can but I'd rather pay a mechanic to do it then ruin my only car. Later in life when I have more income I plan to get a car that I can work on and learn to do myself.

 

If you get the intake tube powdercoated it will not soak up the heat. Forum member 34by151 did some tests measuring temperatures before & after he had his intake powdercoated, as well as the old "touch test" the coating makes a big difference in terms of heat.

The smaller 3lb pulley requires some machining of the snout of the supercharger, so that adds to the install costs. As I recall, Deuce2000 here on the forum made a special tool to machine it properly in-situ, have a look through his posts.

 

I actually had my tube ceramic coated which is the best but most expensive option powder coating is very good and is cheaper to do and is enough for road use. I need to take off the s/c soon and will get the inlet manifold, coolers and headers ceramic coated at that time

I will also put the pulley upgrade on while I have the s/c off

Ceramic coating the headers is a good choice if you are doing the cats
The 100 cell cats made a big improvement on mine

Also check out the fan mod.

Cheers
34by151

 

How much does powder coating and ceramic coating cost? How much of a difference does it make?

 

I watch Power Nation on Sun mornings when i can and saw this one last season. They used two coats and tested over and over and will seal the header and withstand 1800 deg F. So far, it's the best stuff they have used for High Temp ceramic coating... $20 max for a couple rattle cans.

VHT FlameProof? Coating

Once you get through the Summit commercials, they show it.

https://www.google.com/url?sa=t&rct=...1dGZsI2o1hGELw

Avail in all sorts of colors... If it'll coat headers, then it'll withstand the heat of anything else.

I had the tins on my Harley Powder coated. $500. Not too bad. The wait was 3 weeks for the shop to get to them tho. I had them do the rear pulley and the brake rotors the same color the following winter. $50 each. So there's a price comparison as well... Hope that helps!

Rags

 

Dont bother with the pressure pack can stuff and dont believe the miricle claims

Either get it power coated or ceramic coated. Both processes are much the same but ceramic coat has an unercoat layer. You can also have the ceramic powercoated to give it a tough exterior and colour coat the part

Both are baked after application

from memory it was $120aud to have it ceramic coated but that included a semi gloss black powercoat over the top as well

I expect to get that a lot cheaper when doing more parts at the same time

also preperation plays a factor. If you do the prep the price comes down. Polished stainless is not good to coat, rough it up with a scotchbright first to save them doing it

as a comparison just power coating would cost around $30aud

I'd expect to pay about 500 to do the intake, manifold, intercoolers, supercharger case and headers all that the same time

cheers
34by151

 

Thanks for the helpful relies. I have removed the little trap door on the airbox like Cambo did, I'm going to order the air intake from Caldoofy. Im going to have to have a chat with mechanics in the area about putting on that 3lb pulley. That might be down the road a bit.

Another question, how much would wider rear tires help for acceleration? I am looking at getting some Coventry Wheels (prob 20" Whitley, not positive yet) and was considering getting 275mm+ for the rear tires, I currently have 255mm on all 4.

 

You can stick all the rubber you like under the back, but if drive is only going to one wheel then you won't get all the power onto the tarmac...