I was wondering if anyone here could assist me with alignment specifications for a 2013 XKR that are a little more performance based than the stock alignment settings. In the past with 911 and Corvettes I've owned I always had street performance/track alignment set ups to optimize handling in each driving environment. These cars had coilovers so I was able to adjust corner weight, ride height, toe in/out, camber etc. I'm not going to have that adjustability with the XKR but with the modifications that have been made I'm sure there is a more optimal street alignment configuration then stock.

So far (will be done at the end of the week) I've lowered the car with H&R springs, installed Michelin Pilot Super Sport F 265/35/ZR20 on 20x9.5 wheels and R 305/30/ZR20 on 20x10.5 wheels with custom offsets, and am considering the XKRS-GT rear stabilizer bar. I'm trying this set up first and may move to the Spires coilovers if I'm not happy with the H&Rs. This all goes along with a custom exhaust, 3lbs SC pulley and tune.

So my question is what alignment settings have you tried and is there any difference in setup on the stock XKR, XKR-S or XKRS-GT? With the suspension compressed 1.2" and the wider tires I'm sure I'll need chamber changes but I'm also wondering about front and rear toe settings. Tire wear is also something I'm not worried about but want the car to track well in a straight line but have a crisp turn in. I know this isn't a 911 or serious track car, I'm just looking to improve over stock which I've always done with every car I've owned. I think the XKRS-GT may be a good starting point but have not been able to find the settings.

I'm not looking for a track/race setup I'm just putting together what I want in high performance "GT" car that is a bit more performance oriented than the stock XKR/XKR-S. I think the XKR/XKR-S series of cars are absolutely incredible cars from a performance/visual standpoint and have been incredibly happy with mine so far.

Any insight you guys can provide would be greatly appreciated and thank you in advance for any feedback.

 

I've always changed the alignment with a specific goal in mind, which you don't seem to have. Usually it has been to maximize cornering grip on the race track and even out wear across the face, and that's been accomplished by adding negative camber. I haven't been able to determine any handling trait that needs improving with alignment, even when pushed hard on the race track. Since hard cornering isn't your goal, and crisp turn-in is already excellent, perhaps you should have the alignment reset to factory specs now that you've done your suspension mods. If you then find you have a handling problem with your custom set-up that is in need of a solution then that can be done. The XKR-S front suspension is different from yours, as is the damper valving, spring rates and ride height, so using its alignment spec may not be optimal for your car.

Bruce

 

Nicely done. I look forward to the input. Consider this a neighbour's bump.

 

You probably know that there are no camber adjustments for the rear wheels. I used to have a couple of XKs in the past and both were set up with more rear camber than front. Makes sense for a safety setup which promotes understeer. If I remember correctly I measured the factory non-adjustable rear cambers at close to -1.5-1.7 degree which, I would say, is plenty enough for wide, low profile tires. On the other hand the front wheels were adjusted to near 0. The factory suspension tolerances seem to be wide and unequal in my experience, as in my present XF, where the adjustable front camber is maxed out at -.3 degree. Kind of ridiculously insufficient for the front for spirited driving over winding roads.

It is quite possible, given the geometry of the rear suspension, that after lowering the car you could end up with even more negative camber, which would not be correct for those planned wide rear tires. Those tires need to sit quite flat, with the short sidewalls they do not distort enough to warrant more than max 1.5-2 degrees neg camber even for track usage.

As to toe settings, again, depends on what you end up with. If you install the larger rear swaybar that will cancel out some/much of the understeer. If you still have too much understeer, give it a slight toe-out in the back, something like 1/16 - 3/32" total. For street usage I prefer my front toe to be 0 or maybe 1/16 to-in. For track you may want to have a slight toe-out for better turn-in.

I would generally want my front camber more negative than the rear. Not sure if you will have the range to adjust, just like I do not have it on my XF. Your likely issue will be the rear camber, hoping that the lowering, together with the factory camber settings will not introduce too much camber where you will have too much inside tire edge wear and reduced handling due to the tire not planted flat in the corners. Any qualified racing shop should be able to evaluate your setup, look at the suspension geometry and come up with exact suggestions.

Good luck,

Albert

 

Bruce- I'm really looking for a maximum grip setup for cornering with a fairly neutral balance maybe leaning towards a bit of understeer to be safe. I agree with you on the XKR-S setup I was just wondering what the differences may between the cars. The XKRS-GT has 305 rears and does not seem to exhibit as much negative camber as I've seen on lowered XKRs but that is also due to different ride height and as well as different rear suspension components. I was thinking one of them may offer a good starting point as they are more performance oriented than the XKR. Its going to take some adjusting over the next few months to get it right.

Albert - The lack of rear camber adjustment is something that I was concerned about as all the lowered XKRs I've looked at seem to have too much negative camber in the rear and with wider tires this issue will only be exaggerated at the outer edge of the tires. I'm not sure how the rear suspension control arms are mounted is it possible to use shims or eccentric bolts to adjust the rear camber on these cars?

Thank you all for your input, I'm really looking to come up with a decent baseline setting to start with which for the first week will be stock as the springs "settle" in. Its going to be interesting to find the right set up as there is more information available on most performance cars on the market. Although the rarity of well modified XKRs is why I chose to go down this road.

If anyone knows of good performance/race shops in south florida that really understand proper alignments or has experience with Jaguars please let me know.

 

I just spoke to a good race/performance alignment shop here in Miami that sets up a lot of winning SCCA track cars, high end performance cars and had experience with Jaguars. He didn't balk at the ~1.7 degree of negative camber in the rear and was recommending close to 2 in the front. He also mentioned if the car has more than the possible 1.7/1.8 in the rear there are ways to adjust some of that out. The toe will be the interesting part, and I will post the final alignment settings next week when its complete.

 

I'm headed to a race/performance alignment shop this afternoon so I will post the results when this evening.

 

This I'm looking too...

Subscribed!

 

Cancelling all my evening plans

 

Common' Bruce, do numbers really get you that excited



Looking forward to the results myself.

 

Count me also into the very interested group. Looking forward to finding out if the lowering has caused extra negative camber and if so, how much and, even more interesting, how can anyone adjust the rear camber on a Jag non-adjustable rear suspension.

The toe setting is a piece of cake front or rear, been there done that. The rear camber is the real issue so solve for anyone wishing to lower the car.

Albert

 

Numbers, and letters too...like OCD It's officially evening, and waiting!

 

MaximA-

Can you fit 305s on your rears with H&R springs and still not rub? What brand wheels are you running?

For what it's worth, with the H& R springs I was able to get back to factory specs all around at an alignment shop. Turn in is razor sharp as it is, and push is minimal at the speeds I've been hitting on "back roads." But no track yet, and that's where the rubber hits the road, so to speak. That opportunity will be a function of some serious domestic diplomacy.

 

Good thread. I had a '94 Miata, and there were many different alignment specs floating around the Miata forum. I had one of the sports alignments done, and it was AMAZING. Totally transformed the car! The dealer who did the alignment said that the alignment was the most whacked up alignment he had ever done.

 

Hi Guys I apologize for the delay I was at the alignment shop for a few hours. I have to say this was the best alignment experience I've ever had.

Soon as I arrive at Apex Alignment, I'm greeted my Alex the owner whose first question is what are you looking for in handling and what is your experience in racing and driving high HP cars. I tell him a raced SCCA autocross for 10 years in Corvettes and P Cars and also did a lot of track days in both. He asks which tracks, I tell him Sebring, Robling Road, Road Atlanta, Homestead..

Then he gets in the car drives it normally then asks if he can drive it aggressively, which I agree to. We pull back into the shop and he says the car feel sluggish on turn in, and is a bit unsettling when exiting turns under power, and feels like it wanders a bit.. Just not planted as it should be, but keep in mind I've been driving a week on H&R springs with no alignment.

So it goes on the rack and the initial alignment is not that far off from stock other than the rear camber. The initial settings are on the sheet with the 1 and the new settings are on the sheet marked 2. he sat down with me using a model and clearly described every setting change he was going to make and why. Asked if that was a desired effect and I also discussed my uneasiness about suspension geometry(thank you Bruce H for bringing this up) with him as far as the H&R springs. Keep in mind this guy has raced and set up race cars for 25 years. He said he sees no issue with the lowering and associated geometry change that can't be fixed via PROPER alignment for intended use.

So he wrenches away for a 1.5 hours and the below settings are what he ended up with. Afterwards he drove the car in the same fashion as before and I could tell a difference from the passenger seat the car was on rails and sharp. Then I drove it and WOW, the car is glued to the road and extremely responsive. Don't steer with your knee while looking for something in the car or you'll be in another lane. The car feels like its on rails and I can accelerate(within reason) hard in sharp corner exits and the rear just clamps down where before it would break loose.

Take a look at the settings and let me know what you think. We cant do anything about the negative rear camber difference but it doesn't seem to make a difference. He said we could go with a camber kit later if need be. At this moment I'm happy and will autocross the car a few times and come in for any other adjustments afterwards.

 

Great post. One concern I have about performance alignments is tire wear issues, Then again, with a car like an XKR, you're probably not expecting to keep tires on there for 60k miles...

 

I doubt soft performance tires will last 12k miles on a 600HP car so I wasn't worried about that fact.

 

The changes appear relatively minor so, I am surprised how much better it feels. The rear cambers were unchanged and the front cambers were hardly changed. I'd say that you will not be able to feel much of a 0.4 degree additional neg. camber in the left front wheel. The thing that you probably describing as crisper handling is the removal of the front toe-in values and setting the front to a total toe-in of 0. That will produce a crisper steering response all by itself. In road racing we tended to put a slight toe-out into our front wheels for better turn-in. That is effectively what was done on your car.

With all my Jaguars I found that the factory tended to set the front cambers to less than 1 degree negative while they set the rear camber to 1.3-1.7 negative. I understand that as safety issue, introducing understeer to keep customers on the road. Looks like your lowering effected the cambers more on the front than on the rears. It is a issue of suspension geometry. So, the good news is that lowering does not produce a wild negative cambers on the rears.

Seem like he either did not find a reason to change the rear settings or, given the non-adjustable nature of the rears, could not adjust it. 2.2 degrees of negative camber on the rear is starting to look too much. In my experience the wider and lower aspect ratio tires you use the less negative camber you want. Those wide tires of yours need to be planted flat for best performance. I would "GUESS" that ideal camber for the 305 tires would be closer to 1.0 negative. For the narrower fronts 2.0 looks reasonable for hard driving.

So, you may get early inside edge tire wear on the rears and they may not plant ideally for most street driving but, they may be close to be OK for hard track driving. The main thing is what you are feeling and, reading your description, you are very happy with the setup. That is pretty much all that matters.

Thanks your for the very useful info and enjoy the new setup,

Albert

 

Thank you for your feedback Albert its always appreciated.

You're dead on about the toe thats what he mentioned about the crispness of the steering, as well as the rear tow allowing it to grip more under acceleration. Not much can be done about the rear camber and I expect the site wear so no surprises there.

I can say I'm happy with how it feels and the feel in tight corners. They true test will be an autocross, which there is one in a few weeks so that will tell me how it really feels compared to a stock XKR which drove the hell out of during the Jaguar Performance Academy.

 

I don't think you can tell much from the numbers, but I do like his approach to improving the alignment for your performance oriented needs, and using your feedback for future adjustments. There's always going to be some street vs track trade offs with camber and tire wear, but you accept that. If you went with a coil-over set-up you'd be able to adjust ride height, corner balance and adjust alignment more than is possible with just the shorter springs, but hopefully you'll be satisfied with this alignment and not feel the need for a more dramatic change.

Looking forward to more driving impressions on both the street and track. Enjoy!

Bruce