Jaguar XKR 2007 (ecu, pulley, intake and exhaust done) vs BMW M3 2003 manual. Every stop light we had a go. 0-60, I was hanging on to his back bumper. By 120 I was more then three car lengths ahead. 0-60 stats for both cars stock is about 5 seconds... What does this tell me? I don't know how to launch this thing. What's the best way to launch for fastest 0-60? RPM, gear, manual mode, dsc setting?

 

Who knows, maybe the M3 wasn't stock either! Also could be your tires!

 

The M3 is bone stock (it's a buddy of mine) and my tires are Bridgestones. I know I need to practice launching the car from stop but does anyone know the setup for best 0-60 (ex. drag strip). RPM, gear (1 or 2), manual mode or auto, dsc. setting???

 

yes manual mode, palette, dsc settings off, but if your tires are used you will do better with dsc and new tires..traction is important from new tires. with or without dsc. but more traction without dsc, just be carefull.

 

The 4.2L X150's have open differentials, an LSD would certainly help in this case.

The Quaife ATB diffs are a direct bolt-in solution. Contact Tom at TL Jaguar in the UK, best price out there.

 

Is the outer diameter of your tire larger than the stock tire? I'm sure that would negatively impact acceleration.

 

+1

Different vendor but I've got one on mine. Improved launch and accelerating out of corners.

 

How much do these LSDs cost including labor? $6000?

 

The diff was $2000 grand and $300 to install by my coworkers who are professionally trained Mechanics. Lucky circumstances on the install part but call around you may find someone to do it for under 500 I would believe.

 

Really! That seems cheap! It would be a nice upgrade for sure!

Does it interfere with the DSC system's ability to keep the car stable in slippery conditions, etc.?

 

Actually I've been told by a Jag mechanic that the open diff in X150 has sensors and uses the brakes to mimic a LSD. He told me it would hardly make a difference on acceleration maybe better for drift and such... I was actually looking for a more precise answer to my initial question. Do I launch in S manual, S auto or D? If I launch in S manual, what gear do I use 1 or 2? What mode do I put DSC in, DSC off, DSC Trac or just leave it on?

Btw, for those you interested in getting a Quaife LSD for our cars the cheapest on the net is :

Quaife Rear Diff - Jaguar XKR – Jacks Transmissions LLC

I've shopped around for install also for the fun and $350 seems good...(not at Jag

 

I'm sure the brakes do mimic an LSD. However, the accompanying cut in throttle does not. So I think getting an LSD would still be worth it as for best launching, you probably still want a small/moderate amount of wheelslip. I would have to think that turning DSC off completely is the fastest way to accelerate from a stop. Maybe you should do some experimenting and use one of those smartphone apps to estimate your acceleration!

 

FYI I just found this with Google:

Jaguar Quaife Differential Install – Jacks Transmissions LLC

Pretty interesting!

 

Maybe I'm not understanding what the differential is. Isn't the stock differential like... 4X the size of this?

 

Stock diff and Quaife look identical in size and everything, once you see the gearing inside you recognize the difference.

I got new bearings by Timken that where the same spec as OEM. The drain plug is a great idea but we just vacuumed it out the fill hole kinda like the 2010 xk/r oil change process.

The best part about the LSD is the DSC comes on later and you get more freedom/control before the nannies cut power and apply braking.

Best Launch: DSC Off, in Auto S, left foot brake, hold rpms at 1800, release brake foot and roll on the throttle (don't floor it), with practice your roll feel will improve (feeling the slippage limit).

I did the Dynolicious and managed a 4.92 0-60 with a 13.1 1/4 mile on past mid-life Hankooks, local highway with a touch of sand and a questionable gradient (maybe 1-2% upward). Unfortunately the GP Tuning event I did with drag wars didn't provide times for some idiotic reason...

The biggest lesson from the Dynolicious was I always get slower times on subsequent runs. This shows how we suffer from heat soak and major gains could be made with water/meth or a killer chiller.

I just mounted new Michelin PSS and plan to do some early Sunday morning (cooler temps) Dynolicious runs. I let you know how the times come out.

PS: Great article!