Is a fuel injection system flush any different for the 1994 XJS?

(Other interests)
- Daily XJS driver at 450hp (without going chevy) (suggestions?)
thanks

Don
94 XJS 6.0L
San Antonio, TX

 

Simple yes. But scary. FIRST You need to replace the stock ECU. With an aftermarket one, like Megasquirt or MAXXECU.
In fact if you want any power increase the stock one needs to go. Oh, there are a few people in England willing to modify your stock ECU. AJ16 comes to mind. The problem is no body over there understands E85. ( where real increases can happen that won’t hurt your engine).

The simple part is fitting a pair of turbochargers.
Anybody who can weld up an exhaust system can do the install on a pair of T2’s. Run the exhaust under the engine compartment and up on the other side of the panel. ( they will fit inside the front fenders behind the tire) be sure to wrap the hot side in a blanket made for that purpose.

Cut a hole for the intake straight in front of the throttle body and clock the pressure side forward to turn on a 90 degree turn into the compartment. 6-8 PSI should get you where you want to be.
The minimum mileage on your engine needs to be 30,000 miles. ( that wears the piston rings enough to open the needed ring gap). If you go over 8 PSI. up to say 12 psi the rings need to have 60,000 miles on them and if you’re going over 20 psi they need 90,000 miles on them. ( that’s using E85).
If you insist on using pump premium 6 psi is your absolute limit. (400 hp maybe? ) And don’t plan on anything longer than a street drag race.
I’ll explain full details if you’re seriously interested.
A pair of T2’s will max out around 800 hp. On an otherwise stock engine. If you’re looking for more power than that you’ll need to go to a pair of Hybrid T 3/4’s

 

Rings or cylinder walls should not wear so substantially by even 90k miles for there to be much impact to the ring gap.

 

Stock end gap varies from the factory from .014 to .020.
In my experiance 30,000 miles opens up end gap by about .010, less if freeway driven more if short trips.
That is sufficient to keep ends from butting together at 6-8 psi. ( using E85 which burns significantly cooler than gasoline) etc.
once rings butt together they start prying the top land off as heat goes up.
The numbers I’ve used are safe in my experience.
Remember it’s not only enlarged cylinder bore but also ring wear. Rings wear the most on initial start up before the bores are lubricated.
My Chevy pickup with 371,000 miles on it didn’t wear enough to use oil because most of those miles were freeway driving.
Most use of Jaguar V12’s has been short trips seldom fully warming up fully. Where wear on the rings is the highest.
That’s based on the 35 V12’s I took apart for scrap metal.