Here a short video of my XJR launch training session. Rear tires were drag radials with quite high 23PSI pressure. That's why launch happened from low 1200rpm. Spare wheel set and 55lb of macadam as extra weight in the trunk. Hope to see low 12sec on Saturday's drag race event. Tire pressure down to 16-17PSI and launch from 1400-1500rpm. Unfortunately the track will not be the very best one for fast 60ft ( normal slippery airfield without glue ), but let's see. Will post the results to the Motorsports section.

XJR launch testing - YouTube

 

Holy Launch Batman!!! That is a fast launch!

So will it be you or Steve M that first breaks into the 11s ?

You see this Steve? Your fans need the next episode of "Fast Jags and the furious BMWs chasing them"

Are you able to floor it with no traction control in this video?

I gotta get me one of these LSDs!

 

Yes I see. I'll try to make it to the drag strip sometime in the next few weeks, weather permitting.

 

I think my own target set last year: 11.99 is a bit too optimistic to reach on Saturday. Need a bit more power, real drag strip = less weight in the trunk. I try to do that after four weeks if Corvette guys accept a heavy, slow British saloon to their track/drag day. That's the last possibility here this year.

It's possible to floor immediately if the launch is made after a good burnout. The launch in the video was with cold tyres.

 

The Angry Cat is prepared to be ready for tomorrow. Stay tuned.

 

 

Details on Motorsports section.

 

Do you think the problem could be as simple as heat soak? I'm asking because you are running what...20 psi? and the power fade comes on after 1/8th mile at full throttle.

May I humbly suggest you rig up a decent water spray on the inter cooler radiator, similar to this to try it out. The cost would be less than $100 to know if that is your problem or not. The inter cooler spray is not a magic bullet, but if heat soak is your prime issue, you would notice a large difference, and then know where to focus your efforts.

Here is a post that shows the parts I used on the one I made: https://www.jaguarforums.com/forum/j...system-101209/

Steve M is running a similar set up, Steve, did you notice any heat soak on your runs? or is this issue isolated to only XJR-99s car?

 

I am running many PSIs lower. Heat soak is very much possible - but is it reason for all the troubles - hard to say. If I go to real grag strip the 60ft, 330ft and 660ft will drop about 0.1sec and then the 1/8mile would be 7.68. If you check this conversion table, 7.68 should give my target 11.99, if the rest of the run goes as well as first half.
eight-to-quarter

 

No I didn't notice heat soak during my runs. I don't think you would get heat soak after only a few seconds of WOT.

 

Maybe it is even simpler then....like an inter cooler circulation pump failing to move enough volume?

I'm curious because it launches like a Fire Breathing Beast, then falls flat.

It would be worth checking the flow of the inter cooler pump, that should only take a few minutes.

 

Maybe I have to focus just for 330ft races: 4.83sec

 

Maybe the intercooler pump is not working?

 

This is the difference between a dyno sheet and 1/4 mile runs.

It will be interesting to find out what the problem was when your issue is fixed.

Given how well it launches, you have a very good chance if getting into the 11's when all is sorted out.

 

These videos tell the reason for mixture problems:

XJR fuel trims. Bad bank 1 O2 sensor. - YouTube
XJR O2 sensor output voltage. Bad bank 1 sensor. - YouTube

 

O2 sensor replaced. Stable voltage/fuel trims for both banks.

 

Excellent!

Now, given your car launches like it was rear ended by a freight train, and you have this fixed, show us a video of a 11.9X- 1/4 mile !!

You might go even faster.

When can you go to the track again?

 

Season is basically over here. Only one chance before next May.
I guess SteveM can do very good time when go back to the strip.

 

You twin screw guys are not going to let me beat you all to the first 11 second 1/4 mile with a "lowly" Eaton.....are you?


Now get out there and show us what those new fangled twin screws can do!


Update. NEWS FLASH
STOP THE PRESSES!

Steve M runs a 11.92 @ 118.8

First man on the moon!

 

Tomorrow my snake soup is ready to be eaten. Waterdragon: Stay tuned.