I've been searching the forum the past few days with limited success finding exactly what I'm looking for, perhaps searching the wrong areas. So just a few questions.


1) What size is the factory exhaust diameter (2.25 or 2.5??)
2) What are the center resonator dimensions?
3) What is the outlet side of factory manifolds and does anyone make a flange that can be used to create a new exhaust
4) Has anyone fitted a 3" exhaust
5) What size is the factory MAF and has anyone tried using a slot type maf?
4) What HP level has been achieved with factory pumps and injectors.
5) Any luck with tunes? (I generally tune my own vehicles) Who and how do they do it. Is it all reflashing? Canned tunes? Dyno tunes?
6) Ported blowers, coated rotors. What type of gains. Hard to get a good feel for it after what I've read
7)Has anyone modified the cast inlet piece successfully and what diameter is it?
8)Stock TB..I know it can be bored. And I know there may be a 95MM unit available somewhere. Any additional info? I may look into a cost affective alternative for this.
9) Any dimensions on SC heat exchanger and what size can possibly be fitted
10) Sure im missing some stuff:O)


Basically I want to see just how far I can go with what Id call minor bolt ons. Work on exhaust and air intake side of blower. Id likely add an SC pulley, new IC pump and heat exchanger. I don't want to experiment with things that just haven't worked yet or waste money for 8hp. That's just silly. Anyway any and all help is appreciated. Is there a build section here where I can document progress? I have a bunch of ongoing projects now but I want to get this rolling as its really just minor stuff( Plus I need to beat my buddies s600 TT....It runs a 12.4 so I MAY be dreaming....But help a guy out will ya!


Thanks!

 

OH....And the thing about the N/A exhaust manifolds being better. Has anyone actually tested this theory? I figured if im doing an exhaust nows the time..Ill be going for quiet aggressive) Ive had a lot of experience reducing drove in V6 cars..Lets see what happens here!

 

Hi XxSlowpokexX

Generally speaking, not a lot of people modify these cars for performance, as the stock XJR is normally completely adequate for those who like to "dump rubber".

You may get some advice here, but what you want to do is very uncommon, but wait around to see if anything turns up.

 

I agree it is a well refined combination as is. Any mod that I wind up doing that ruins that experience will quickly be changed back. But I certainly don't mind a little extra noise or power. Hopefully some of the guys that do have this same obsession I do chime in:O)

 

Hi XxSlowpokexX,

Welcome to the forum!

I've seen a number of performance upgrades offered for the XJR, including smaller upper pulleys and larger lower pulleys for the SC, free-flowing exhausts, etc. One vendor is Mina but there are others (typical disclaimers):

Jaguar XK8 XJ8 XKR XJR X-TYPE S-TYPE Performance Parts Upgrades and Accessories

From what I have read, the principal limitation is the IC, and that for more than minor HP gains (maybe 15 hp), the surface area of the IC (not just the depth) would need to be substantially increased, so you would have to modify the front end to accommodate a much larger IC.

You may not want to go there, but often the fastest way to improve performance is to follow Colin Chapman's advice and "add lightness." Do you really need a spare wheel/tire, rear seats, interior trim, carpet and sound insulation, a radio, AC compressor, power seats, wood trim, sunroof motor, etc? I can think of all sorts of parts you could remove. In fact, I'd be happy to pay the cost of shipping them to me to keep as spares....

One place you can start on this forum is by searching for a thread by caldoofy describing his revised air intake pipe for the XJR, which is a very attractive piece of kit and has received positive reviews from members of this forum.

Regarding the exhaust and other dimensions, you could probably answer most of those questions yourself in about 5 minutes with a caliper....

We'll be watching your progress with great interest to see what choices you make and the results you're able to achieve.

Cheers,

Don

 

Don,


I just about read all I can I believe. Thanks for chiming in. The front mounted heat exchanger among other things is on my list of changes, the intercoolers themselves..Nahhh I'd add a meth injection kit first.


I have to admit I cant stop driving this car. I love it. Even its cute little rumble that you expect to get louder when you punch the gas.....and doesn't! Once I start DOING mods I'll start a post with results or whatnot. I have a few projects going currently so not sure how deep ill go right awy..But for sure pulley, heat exchanger/pump,intake and exhaust....Hopefully I am pleased with the results

 

Can't wait to see what you decide and the results you're able to achieve. I love our XJR too, and I have to admit, there are times when I wouldn't complain about another 100 each of hp & ft. lbs..... :-)

Cheers,

Don

 

My biggest quandry is what size pipes I want to go with exhaust wise. I am thinking 3" which many will say is too big however in my experience with what I want to do it should be just about right. I am planning a full three inch stainless mandrel bent with no cats, a muffled x pipe (Dynomax ultra x) and either two dynomax ultraflows or possibly the Dynomax VT with no rear resonators. IF I dont like that sound I can always add some rear resonators. Ive used this combo on V6 engines which tend to drone alot to great success. I smaller system may sound better but I think this sizing with these mufflers will be about right

I dont however want to do the exhaust untill I do the intake system. And to that extend I know Im going to be limited to the trottle body unless I can figure out a good alternative to boring the stock one. The 2004 cast intake peice to the TB Is also probably an issue and im just not sure what can be done ther either till I rip it apart......Hopefully someone will eventually chime in that has been modding these cars. Till then Ill talk to myself and Don B! (im also keeping my eyes on that potential stage II carbon fiber intake I keep hearing about:O))

 

You 4 door guys just love embarrassing kids driving Mustangs.

 

I almost bought an xkr however I was trying to do the responsible thing and get a 4 door. That being I recently embarrassed my buddies 2008 gt..Very sad indeed