My 2007 xkr has an aftermarket exhaust fitted (milltek). I have the standard 4.2 engine with no other mods. Have been thinking of getting it tuned to suit the car for some time, think it needs to be done. A top tuning company here in Ireland say they can do it, giving me an Extra 30bhp and 40NM of torque for €350 done at my door. As i don't know anything about whats involved, is this remap the normal for results, and does the difference be so great. Is it ok for the car. Any answers wellcome, should i go for it.

 

I had a remap done to an s60R. I dont know how it works with a supercharger, but with the turbo it essentially made it build up more pressure from memory. I didnt have any issues with it at all although the next tune overwrote the remap until they got an ECU that couldnt be written over. It also made the acceleration a bit lumpy, i.e. there was a much more noticeable surge. It was awesome. The difference with the turbo was bigger, from memory the KW went from 220 to 240 and the torque from 400Nm to 480, though I never dyno'd it.

 

It might be worth changing the supercharger pulley first so that you can take full advantage of the remap. Your namesake on EBAY sells them at a reasonable price:

Jaguar XKR 4.2 Supercharger 10% 2.5lb Upper Pulley Upgrade 2006 2007 2008 X150 | eBay

Jaguar XKR 4.2 Supercharger 6% 1.5lb Upper Pulley Upgrade 2006 2007 2008 X150 | eBay

I had the 1.5lb one fitted to my car last week and you can feel some difference. It seems to rev quicker now and is more prone to breaking traction when I floor it. There is more mid range punch now as well.

Other people have fitted the 2.5lb pulley and been happy with it although I did see one post where the standing quarter times got worse on a car that went from the 1.5lb to the 2.5lb pulley but a tune may fix that issue.

The nose on the supercharger has to be ground down for the 2.5lb pulley because it is so much smaller which was one of my reasons for going with the 1.5lb. The 4.2 XKR also has enough issues with traction as it is so I didn't want to go too mad.

 

Might take your advice and get the pulley first. Would go for the 1.5lb as you did. Had you any other parts to get to fit, it says the drive belt can be used again. Does it effect your exhaust note.

 

The exhaust does sound a little louder but I think that is psychological. The only difference in sound I would attribute to the pulley change is more whine from the supercharger as it gets to the red line, I assume because it is spinning faster.

The only part you should need is the pulley. My mechanic decided to smooth the end of the supercharger snout in the end. It shouldn't need it but I understand that he would rather be safe than sorry. If the new pulley rubbed once it was on, the only way it was coming off again was by being cut off as he didn't have a suitable puller.

 

Thanks will let you know how i get on. Did you buy you pulley from the e-bay seller you gave me or someone else, his is made from stainless steel which he says is the best.

 

Do the pulley! It does make a huge difference in acceleration. Initially fuel consumption was horrendous, but after several hundred miles I am getting over 20mpg.

 

jahummer How horrendous was your fuel consumption. There isn't much motorway over here and i never get more than 19.5 mpg. What made yours increase after more mileage.

 

Yup, another member recommended them and I have had no issues.

 

So going to order this week the 1.5lb or 2.5lb pulley, but can't decide, anyone any thoughts on which one to go for as u102768 says its straight forward fitting the 1.5lb. But as i'm am getting it tuned and doing it only once want to fit the best one. Any more views wellcome. The tuning on it's own is the extra so i was told 30bhp and 40nm torque, so what would each pulley give me in extra performance.

 

I have no ideas about pulley's but do tell about your STAGE 3 Milltek exhaust... Super loud!?!?!

 

Yes it's loud, high flow cats, one center box, all 3" piping, non valve rear box with twin perforated pipes each side. Never got round to taping it, must get it done.
Here's a wee sound off it, go to 10.12 on the video and you'll get an idea, nice on down shift then acceleration.

 

I was getting 11-12 mpg due to the ECU running too rich. I assume it readapted itself but I could be wrong. I still want to do a tune but no one has convinced me via the vague answers I have received so far as to how it is done.

 

Car booked in for 2.5lb pulley and remap in 2 weeks time, can't wait to see the difference. Bought the pulley from Powerhouse Uk, just coincidence it's my member name.
http://www.powerhouseautomotive.co.u...er-pulleys.php

The owner Lawson is a pleasure to deal with and has great knowledge about what is involved. The 1.5lb is a straight fit. But as i'm doing a remap he said i should go for the 2.5 10%. There is a bit more work involved in fitting, but worth it he says. He told me that people who have fitted the 2.5 have come back and said they can't believe the difference.

Jaguar XKR 4.2 Supercharger 10% 2.5lb Upper Pulley Upgrade 2006 2007 2008 X150 | eBay

 

I am anxious to hear your review. I chose the 1.5 because I could not find anyone I felt confident enough to whittle away at the supercharger snout which is what it takes to fit the smaller pulley.

Who is doing the re-map?

 

The guy that's doing the pulley is doing the remap and is also doing my transmission service. He lives in Dublin and services and fixes on top makes such as ferraris ,Porsches , lambos, astons and of course jags. He had contact with powerhouse uk and discussed all the issues and has no problem to do fitting. Great reviews on his work. He also was our mobile mechanic on the cannonball trip we did round Ireland. He had to put a clutch in a Ferrari outside a hotel on one night. was amazing to watch.
https://www.facebook.com/pages/Ken-P...56674844367059

 

2.5LB 10% pulley came today, it is small in size. Looks very well machined, now just to get it on. 4mm has to come of the supercharger snot. Put a tape measure on it and it seems to be 65mm diameter.
Just a few pictures,