Andy Stodart was one of the original team members who developed the X300 XJR at Jaguar, so the chances are that he knows these cars better than anybody!
In fact, the hugely respected and vastly knowledgeable Jaguar Specialist, David Marks turns to Andy Stodart when he needs advice on particularly problematic X300’s!
Andy currently runs two X300 XJR’s of his own and when he wanted more performance, one of the first things he did was to design and manufacture a revised crank sensor bracket which advances the ignition timing by 5 degrees.
I purchased one of these revised crank sensor brackets from Andy 5 years ago, but before doing so, I asked Andy to explain a little about it, in simple terms, as I would not want to risk damaging Brucie’s engine for the sake of a little extra performance and economy.
Andy explained that the team performed various tests and put the results forward, the setting that was deemed best for the market in which the X300 is placed was chosen, but by advancing the ignition timing by 5 degrees the performance of the AJ16 is clearly enhanced, and possibly therefore, advantageous to the longevity of the engine?
After trialling the bracket on his own car, Andy asked David Marks and Rob Jenner to fit one to their personal XJR’s and these tests resulted in improved fuel economy of approx 2mpg in normal driving.
This modification will also provide increased performance, both at part throttle and full throttle. The improved performance is as a percentage of the original performance, therefore, you can expect a far greater improvement from a 4 litre supercharged engine than from the 3.2 normally aspirated version.
As stated above, I had one of these brackets fitted to Brucie in 2013. Nothing detrimental appears to have happened to the engine. I have kept a monthly record of Brucie’s average mpg since purchase in 2010, and can therefore reliably state that the fuel economy improved immediately after it was fitted, the average having been 26 mpg in 2012, rising to 29.0 at the present time. The performance also improved, and this is not in my imagination, as we have a two manual X300 XJR’s, one is fitted with the revised bracket and the other is as original.
Our low mileage ex-Jaguar Heritage car, P760NRW is completely original but our equivalent everyday, high mileage car, K44XJR is fitted with a revised bracket and the performance is astonishing, as anyone who has seen the car on the track or at hillclimbs will know, even when being driven by an amateur like myself!
The AJ16 version of this bracket, priced at £75.00 including postage, is a simple to fit modification which could soon pay for itself (£36/year saving assuming 3000 miles per annum, an improvement from 28 to 30mpg and fuel @£1.10p/litre).
The same revised bracket can also be fitted to late AJ6 engines, after engine number 161586.
Earlier 3.6L engines (after engine number 108834) and 3.2L/4.0L engines (up to engine number 161586) need a different revised design of bracket. As these brackets are produced in smaller quantities, the price is £90 including postage.
Fits all engines listed above, as fitted to XJ40, X300 and XJS
Will not fit 2.9 or V12
*Crank sensor not included in price of bracket
For more information, or to order a bracket, please email Helen Stodart