Might have the fastest 1/8mi time in the world for 4.2 supercharged XKR. Mods and the tune do pay off
Ran with street tires, temperature in the 70s
There was lots of interesting cars there , 2009 1.Aston Martin Vantage v8, stock, ran best of 8.8 83mph 2.0 60ft( a little slower than I expected for this car)
2.Infinity q50s red sport, exhaust , best of 8.26 86mph
3. 2015 5.0 Mustang stock auto, best of 9.0 (way slower than expected)
4. Jaguar XJR 4.2sc with exhaust , 3lb pulley, ran best of 8.5 83mph





cant wait for the 1/4mi results
Stay tuned....

 

Looks good but it depends what you mean by fastest, Cambo's 1/8 mile mph was 91.210 so you have a little way to go

Will be interested to see what your 1/4 mile results are. The highest terminal speed I saw in my 4.2 was 113.19 but Cambo pipped me with 115.36.

 

I didn't say trap speed ,😊 1/8 mile time appears to be the fastest that I know of to date 😊

 

I assumed that is what you meant but you did say fastest, hence my confusion:

https://www.dragimportnews.com/tech/...quick-vs-fast/

 

Ok so I have the quickest although I thought is was the same

 

Interesting that a 4.7 Aston only posted a 8.8 Ive regularly locked down 8.7/8.8 in a 4.2 N/A

Alex a 8.0 1/8 is really moving should be good for a 12.4

 

Yes I was surprised how slow the Aston was, might be due to lack of proper mechanical maintenance.
I agree about the 1/4mi time I should easily be under 12.5 or better..
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Unfortunately the track I use didn't list 1/8 mile times when I had my 4.2 litre but I have just had a look through the ones for my 5 litre XKR and none of the 6 runs I did when it was stock were under your time for the 1/8 mile although they were mainly 6 mph or more faster which I guess highlights my traction issue.

Out of the two visits with my current config, 3 out of 9 runs were better on the first visit and 3 of the 5 runs on the other were so yours is a pretty quick time. I think that the 5 litre comes in to its own though in the second half of the 1/4 mile because that is when I catch and pass most of the cars I am racing so it will be interesting to see what you 1/4 mile times are.

You must have very good traction so what tyres are you using and I assume you have an LSD? Also, what technique do you use to launch?

 

Actually this is with stock open differential and my tires are nothing special: Hankocks ventus v12 . Don't have any launching techniques , I tried to avoid the water box as much as was possible and just briefly spun the tires to shake any sand or rocks off. Never took the traction control off, and just tried to ease into it from the first gear to avoid much spin although it was impossible to go without spining. best 60 ft time was 1.89 and rest were in the 1.99-2.05 sec range

 

That is an amazingly quick time then. My old 4.2 XKR with open diff was hopeless off the line, even after getting Michelin Pilot Super Sports the best 60 time I did was 2.2. Before changing the tyres it was usually in the 2.4 to 2.5 range. It also used to bog down unless I partially took the traction control off.

 

Mine was boging down pretty bad after I got high flows installed, felt as if I lost torque at lower rpm. I had to mess around quite a bit in the tune to get rid of the bogging down of the line. Now it's flying 😊😊