I wonder if anyone could describe the differences between the Jaguarsport 6.0 engine that went into the XJR-S models ('93 in the US) and the later 6.0 XJS engines. Are there improvements in the XJS engine that should be incorporated into the XJR-S engine? Special concerns?

 

i wasnt aware that the U.S. recieved any of the 6.0L engines.

 

They were different engines. The block is different between the 2 engines Jag modified the 6.0L block for the mounting of the 4L80. The Jag 6.0L heads have larger combustion chambers to lower CR for the additional capacity.

The TWR XJR-S originally came with a 5.3L engine (although I don't think these made it to US shores) and Zytec ECU instead of Lucas. It was in the 1989-90 model that TWR stroked the unit to 6.0L

The later 6.0L engines used a version of Fords EDIS distributorless ignition these were available in the later XJ12's this would be a good upgrade would need the later cars ECU or an aftermarket I know Wolf3D and Megasquirt have been used to run the V12 distributorless.

If you are interested in building a high performace engine quite a lot has been done here in Aus using GM and Holden (GM) pistons and Rods on a re-ground crank. There is a guy in South Africa who has engineered Fords EDIS6 to run the V12 ignition with great success combined with a Megasquirt.

There are 3 twin turbo XJS's that I know of here in Aus, 1 is a dedicated race car and the other 2 road cars. There is also a V12 running around with 2 Toyota SC14 superchargers bolted to it.

 

Thanks. I just purchased a '93 XJR-S coupe so I'm investigating what issues I can expect to deal with.
I had heard the Zytec system can be problematic so I wondered what was done by the Factory for their 6.0 liter's engine management. Good to know there are options.

 

You lucky bugger, is it the facelift?

 

Yes. One of the 50 coupes and 50 convertibles that came to the states in 1993. Those were the only XJR-S models we got. 49k miles with only 2k since 2005 - used since then just for car shows etc. I purchased it through Ebay so I'll know in about ten days whether I did well or not. Planning to use it as a part time track car with some minor (and reversable) modifications and after going over all the mechanical systems.

 

EPIC. i want pics and track vids.

 

Hope all goes well. What upgrades are you planning?

 

Nothing too radical right now. I want to focus on making sure the electrical and cooling systems are perfect. Some interior weight reduction and see how that affects handling. I expect I'll get an aluminum radiator if the original is due for replacement. (Not convinced about the advantage of single pass system though). Better pads and some track wheels/tires. Stable energies roll bar. Eventually swap in a 5-speed manual transmission.

 

the tko 600 sounds like the one you want for a track car. then some 3.54's

 

Definintely want to ensure the cooling is up to it. The V12 will take quite a bit of punishment even overheating but who want to push it eh....

2 pass radiators are far more efficient than single, hence why dedicated race cars use 2 pass - F1, Indy, NASCAR and the list goes on. I have a new Alloy full 2 pass ready to go in. Had it custom made but it is so big I need to modify the AC and oil cooler as they will not fit between the rad and the bumper mounts.

If I had my time come over I would stick with the stock radiator, especially after speaking with Bruce who owns the XJS TT race car I posted on another thread. He had overheating issues and went back to a standard rad and said the car will now lap Bathurst with no overheating. So think twice about an Alloy

Not sure what sway bar came on the 93 but I have upgraded my front from 19mm to 25mm and that made a huge difference, another upgrade that is definitely worthwile is upgrading the rack bushes either PU or I have seen some use other methods. I like the PU easy to replace and work straight out of the box. I also have a rear bar to go on and this will happen in the next few weeks as I get the rear end back together and in the car.

cheers
Warren

 

Idiot I meant to post the pic

 

It seems the 1993 TWR 6.0 came with the 2.88 differential while the later Jaguar 6.0 came with the 3.54. That limits the conversion options possibly ... Robert Hall recomends the 5-speed TKO 500 trans for its 3.27 first gear. His other conversions require the 3.54 ... not sure I want to put the extra money into changing the differential for a car that won't spend a great deal of time on the track.

 

The 3.54 was fitted to all 4 speed V12 cars, 3 speed HE+ had the 2.88.

The TKO500 is rated at 500ft/lb so is more than up to the task of handling the TQ from a TWR 6.0L. ou would really only need the 600 if you plan on major modifications.

BTW you can install 3.54 (or any other Jaguar) gears in the 2.88 XJS diff. I have just had 4.09 installed in mine with the use of a crownwheel spacer. I figured if it is good enough for a race car runnning around it would be ok for a street car.

cheers
Warren

 

That's serious low end torque. Since the driveshaft needs to be modified, I suppose it really wouldn't be much trouble to switch to the 3.54. I've got some time before I need to cross that bridge.

 

BTW, there are three Zytek XJR-S computers on UK Ebay at the moment. That's one potential problem I won't need to worry about. (Of course, when I fry mine, there will be none in sight.)

 

Here's an Australian racer with a 4.11 mated to the TWR 6.0 liter. And the source.

Preparation for the Targa Tasmania 2008

 

Yes I know the car the guy who built it did the spacer for my diff.

 

Pre HE ( 1981) started out with either the 3:07 or 3.31 mostly 3.07’s we Racers quickly replaced those with 3.54’s and then swapped the whole rear end when the outboard brakes became available.
I’m relatively certain the XJR-S has the outboard brakes and the 3.54 posi.

 

The XJRS used the same diff ratio and brake setup as standard XJS cars. That is inboard pre face lift and outboard afterwards. The diff ratio was also the same and since the 4 speed 4L80E did not appear until after the XJRS had stopped production they were all fitted with a modified TH400 and never fitted with the 3.54 diff.