Greetings,
Some videos/articles mention about the minor power upgrade on the USA 06 - 08 model years.
Can anyone elaborate on the below pieces of info, thanks
- the Eaton roots-type blower used in the S-type R spins 5% faster than the blowers in the XKR and XJR of the same year, allowing it to produce slightly more hp and torque.
Total boost is 13.1 lbs fed through two air-to-water intercoolers
- While it was never officially advertised by Jaguar, multiple sources claim the 2005 model saw a 20hp bump due to a revised supercharger pulley system

 

Lots of claims but any differences were/are too small to worry about. I had a 2005 STR and the revised tensioner/pulley was because of noise complaints and squeaking belts when cold. The biggest change they made was the addition of VVT on the 2006 and up models. I have sometimes seen a 420HP rating on those engines but have also been told it was mainly added for emissions reasons as the NA V-8 had VVT all along anyway.

No measurable performance difference either so it's like losing the Brembo brakes after the 2005 model year. The 2006 and up STR's stop just as well as the Brembo equipped models but I sure did like the look of the brakes on my STR!

I think we need to remember the S Type was on it's way out and was being de-contented every year. You can easily see this in the year to year changes. They really never did refresh the STR as the performance was constant from 2003-2008. Lost the Brembos in 2006 and not much if anything changed until the S Type died in 2008.
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thanks clubairth1
I prefer the pre-facelift with fog lights and the rear styling. But the logical choice would be the recent year

 

Didn't know it spun quicker than the XJR and XKR, probably needed to as it was much heavier, the others made in aluminium.
Aside of the body in steel they did get the design nearly right in the first place for this model. The main upgrade in 2002 hit the target very well.
Being a specialist car company compared to it's rivals, the S-Type had a very good run for Jaguar; quite a successful model, sold nearly 300,000 units.
Most of the huge initial money invested by Ford and the UK government that was ploughed into the Castle Bromwich upgrade was specifically for this model (and of course for subsequent models). Ford virtually rebuilt the whole plant and it was one of the largest investments in urban redevelopment in the UK for many years.
They were then able to stamp out a whole side of the car in one pressing, 13 feet/4 meters.
Surprisingly, the biggest noise later in the cars life was the release of the diesel. Certainly not in the USA but made the rest of the world seemed to make a big fuss of it.
Not my cup of tea but was very economical.
I'd have the Brembo's any day!

 

no difference at all between the two except for the ac compressor lol



the car was upcontented every year until 2006

 

The air flow through the blower is limited by its physical design not how fast it spins. Once past it optimal speed there is no more air flow no matter how fast it spins. In standard form it reaches this max boost rpm before the engine gets to max RPM.

Mellow

 

I have worked for Jaguar dealerships since February 2002 and the only version of the 4.2 S/C that I remember ever being advertised with 420 BHP was the XKR ? (X150)

We were told that the extra power was only due to the better induction setup on the XKR, it has twin air filters and induction pipework, unlike the S-TYPE R and XJR that use the same engine ?

 

That one does seem plausible.

I think I saw it called AJ34S.

 

AJ33 is X350

AJ34 is X100 and X150. intake is rear feed AJ26/27 style, X100 oil pan is modified AJ27 type but the X150 went to later style

AJ35 is Ford Lima 3.9L. reduced cost version of AJ33

AJ36 is SType. same as AJ33