Bruce,

I have to agree from a reliability standpoint maybe its best to run the car with a stock or close to stock tune on the track. I'd just like some resolution as to why the car looses all or most of the power from the tune just weeks after its tuned.

 

I have solid data that the boost will no longer exceeds a soft 9LBS. Meaning you can see it hit 9.4-9.6LBS but then it is quickly brought back below 9LBS. after the tune it would hit 11LBS around 5k RPM with no problem. I haven't been able to get the car to 155 on the track since I've had tune issues although the car had no problem hitting that speed on the same track immediately after the tune.

That is all proof enough that its no longer running the same way as it as after the tune.

 

I addressed the suspension with Coil Overs and and went to Alcon 6 piston calipers so the car could handle the extra HP. We are talking about 1.5LBS of boost here, not 15 or 20+ that I see on other track cars. From a platform perspective the car was perfect with the tune as it had better responsiveness out of corners and the top end on the straights that the stock tune lacks.

Agreed HP is never a substitute for talent, and if you think so you will get yourself in trouble very quickly. It was what the car needed after the other modifications were made not a crutch.

 

I would have recommended a 94 or higher octane gas "if" the switching of tune was an ECU knock response to detonation, and water-injection if it was a response to out of range intake air temp or exhaust gas temps. Not actually sure in anyone has successfully done a WI system for the Jag yet. And upgraded rads and auxillary engine oil and tranny coolers are needed on some cars to control those temps and keep them within ECU sensor range. Lots to upgrade sometimes when you push hard on the track, especially as you increase engine output.

I'm headed to Virginia International this weekend for a two day Chin event and a 10 day tour with a track buddy in his new C7 Corvette with GM's recommended options for turn-key track use. He put it on track once to see how it was and wore out one front tire and all rear brake pads completely, over heated engine, tranny and diff, siezed both exhaust by-pass valves, and his A/C wouldn't work until the car fully cooled. This is a car that was stress tested by GM for track use. I'm preparing for the trip with an oil change after 5 track days in the Viper, with original pads and tires at probably about 75%.

I hope the XKR is robust enough for your track use, but the example of the newest and best Corvette ever failing miserably with a single track day points to the high level of stress on many components that even some high performance and track day marketed cars just can't handle.

Bruce

 

I'm running 98 or 100 octane on the track as I try to show up empty and buy gas at the track to be safe. My stock brakes could not handle the track ans I had to upgrade to full race endurance pads and even those can overheat on this 4k lbs car. Other then that if the car is driven smoothly I have not seen any numbers that are out of the correct parameters. After what you just said about the corvette I'm surprised! This just tells me the XKR is really well built car as I flog it hard. I'm turning 1:42s at Homestead using banking and not over driving the car, the XKR loves that track.

My XKR is usually one of the top 5 production cars on a familiar track. The only cars I was getting passed by were full on race cars, Star Mazdas, Porsche RSRs etc.

If your doing some Chin events I may run into you at an event one day. Your Viper is a BEAST, I want one

 

Thanks, and that would be fun to do an event together. If I ever see an XKR on the road course again it's likely to be yours...they're rare as hen's teeth there!

To tracking

 

Which US tracks do you usually make it to? I may plan a trip up to VIR at some point just now sure when.

I never see another Jag at the track unless someone racing drove it to the track. Some of the Pro Ferrari guys came over and were surprised the car was as fast as it was. They were surprised and happy to see a Jag on the track.

I'm a really shocked that the C7s are having the issues they are, like you said it should be a turnkey track car.

 

Just VIR next week at this point, and will probably add a Watkin's Glen in the fall. I'm generally staying closer to home this year to learn the new car on the tracks I know best. It'll be my 4th time to VIR over 11 years, and I'm very confident in the car at this point. Hopefully a trip next year to pair up Road Atlanta again with either VIR or Barber, and one to Road America and Mid-Ohio again would be awesome. Nothing planned for Florida unless I do it in a rental!

Bruce

 

Max, Bruce

Have you guys ever checked your running coolant temperatures on the track?

I was surprised now that I use that Torque Pro app with my Android phone, how quickly the temps rose from the flat land 195 F to 220 F just from going uphill for about 3 miles in traffic, doing only about 20 MPH. All with very light accelerator. It was 82 F degrees outside.

Just wondering how high the temps go when you constantly revving the engine to redline on a hot day? The OBD II does not give out engine oil temps, which I would also be curious about under track conditions.

 

I love Road Atlanta and Road America, although the latter is a hike and a half for me. I may have a dedicated race car by then if I can figure out what I want... I can also do VIR as my mom and good friend live in NC and I know he will come with me as well.

Florida for you would be a LONG drive but you have drive Sebring one day.. Its a wonderful track and one of my favorites.

 

My temps with the tune running properly were in the 215-220 range. Now they are in the 202-210 range but also keep in mind thats at homestead where I'm running about 100-120ish in the banking and just barely on the gas so the car has time to cool off.

If you're hitting 220 is that with the A/C on? It makes a huge difference in these cars as I left it on my accident once and got the high temp warning.

I've also started turning on the heat to the top vents, closing the center and blowing the sides out the windows. Some of the guys in high HP street cars have been doing this just to be safe.

 

Albert,
No experience on the track with either of my XKR's (although I will be taking the 2010 coupe later on this year), however, I can tell you with my ancient Pantera, that when I drive it on the street, if I am in any kind of traffic or waiting at an unusually long stop light, the water temperature will rise above 220 and sometimes come dangerously close to overheating. This is even though I have done the cooling system upgrades (fluidyne radiator, fans, etc.). But, on the track, it will run all day long at 195-205 even in 100F weather. The contant airflow is critical in keeping the temp down in the Pantera and on the track, since it is continuous, it actually runs much cooler than on the street where it is stop and go. I would suspect your experience with the XKR is related.

 

Are you running the track at the same time as the Star Mazda open wheels cars?

 

If your interested in a dedicated race car, may I suggest that you take a close look at a Formula F1000. It is one of the best classes of race cars within the SCCA organization.

Here's what I raced.......Home Page

There is a large contingent of F1000's in Florida and the Southeast SCCA regions. These guys predominently run at Sebring, Road Atlanta and VIR.

US F1000 :: Main

There is no better thrill than driving an open wheel formula racing machine like an F1000 (FB Class).


Enjoy the ride.......

 

Edit: I never noted temps of the XKR on track.

I see a max of 92C/197F for coolant and 103C/217F for oil, as seen on this video from the last lap of a 30 minute session of hard laps that saw 145-150 mph top speed consistently.


A friend in a C7 Z51 hit oil temps of 127C/261F for reference on a 3rd platform.

Bruce

 

Glad you brought that up as thats exactly what I've been looking at or maybe a Formula Mazda or Radical SR3/SR8. I love tracking street cars but I'm to a point where a dedicated race car makes sense to me. Now I have to watch the video of Road America I really want to move to downforce cars to get into the 2G range as far as grip.

What is the cost and maintenance of the Formula 1000s? What kind of speeds and adjustment is possible in the suspension?

 

Perfect line around RA and Bruce Mosport looks like an amazing track!

I have to wait until the 6th for my next track day, you guys are killing me with the videos I accidently deleted the SD card from my last day at Homestead but will post a few videos of the XKR after the next track day.

 

I'll look forward to seeing that...and by then I may have a VIR vid ready too.

 

I was in the middle of building a new PC for myself and accidently formatted my SD card with all my telemetry in stead of the flash drive(and I'm an IT guy LOL)... I'm so pissed at myself as there were some really good laps on there. I did save one test lap as I was getting the Vbox setup for this track but the quality isn't good as the video feed was loose and it has no audio.. Definitely not my best lap as I was 5 seconds off my normal pace.

 

oh wait I just found some more that somehow didn't get deleted