fueleconomy.gov says here that the 3.0L 6-cylinder S-type gets worse gas mileage than the 4.2L 8-cylinder S-type. Isn't that wrong? What should that say instead?

Wikipedia says the manual transmission gets significantly better mileage (like, 3mpg better) than the automatic. Is that right? I don't think I've ever seen a manual trans S.

 

I am averaging about 21mpg in mixed driving and have gotten as high as 29mpg on the highway with my 3.0.

 

Hey, I don't know...except that the 3.0 S-Type is a heavy car (3850 lb.), recieves 3.30:1 rear gearing. and has 60 less hp and trq. to "Move the Mass". The 1980 Ford Econoline full size van came standard with a 140 hp @ 260 lb/ft trq. 300 cu. inch 6 cylinder that provided less mpg's than the 185 hp @ 300 lb/ft trq. 302 cu. option.
Perhaps the 310 hp @ 320 lb/ft trq. S-Type "Moves the Mass" more efficiently?

 

I think we need to start another I get better gas mileage than you thread.

 

Lol!

 

I win!

 

I followed your link and it says the 4.2 and 3.0 are equal not that the 3.0 is worse. Where did you get that information?

Yes, the 5 speed 3.0 was available here up through 2004. It was dropped in 05. If you do a used car search in say the UK you will see a ton of them. They were never a solid seller. In fact, the 3.0 / 5-speed stick is the rarest S Type in the US. Much rarer than the STR even... Sorry Supercharged folks, don't flame me. Remember, I said rarer not "more desirable".

Now this is a reoccurring theme and will also prove to be very interesting here in the US as CAFE standards keep going up...

Driving Style is the greatest factor in MPG

Yes, I know there are people out here in this forum that will start posting up there "30MPG" numbers.. (LOL Mikey).. yet, me and other close family members have had similar experiences.

I got better MPG out of a V8 S-Type and V8 (5.0/385hp) XF than I ever got in my 3.0.

I actually average the same MPG in my 5.7 Hemi 300 than I did in my 3.0 S-Type. The 300 is larger with one less gear in the trans...yet I average 20MPG in it, including driving it pretty hard. Hmmm.. I used to get 20 in the Jaguar as well.... Why??? It had to work much harder under my driving style..

Here are other examples as well.... My cousin gets better mileage in his V6 Accords than he got when he had a 4cyl Accord.
My wife gets better MPG in her heavy @ss R350 4matic than she got in her Grand Caravan... again, more HP and 3 (yes 3) more gears.

So my other point... notice everyone (car companies) moving to forced induction small motors?? Heck, they are going to be offering a turbo 4cyl in the XF!!!! So, what they are doing are putting motors in their cars that can be advertised to have enough HP and also turn high MPG numbers in the controlled government tests. The reality on the street? A bunch of high strung cars getting crappy mileage... Just like the Chrysler Turbo's from the 80's... LOL

 

Should I also mention again that the 30.7 mpg was on 87 AKI (regular) gas?

Maybe not.

 

I don't understand the question. I got the information on that link. It says:
So it says the 3.0 is worse.

 

The 6-speed transmission in the 4.2 is a major factor in the better highway mileage.

 

Thank you all. Again, let's go back to the jist of my original post...For a similar mass: MPMME or "More Power Moves the Mass More Efficiently".

 

In your original post...and I quote.... fueleconomy.gov says here that the 3.0L 6-cylinder S-type gets significantly worse gas mileage than the 4.2L

Last time I checked a one mpg difference on the highway number is not "significant". In fact on that EPA site both the 4.2 and 3.0 are listed as the same combined MPG and identical fuel costs.

Brisk wind or a fat friend along for a ride can account for more than one MPG.

But these numbers all the more prove my point that if you are looking to get a 3.0 over a 4.2 for fuel economy reasons, don't bother. Most drivers won't see a difference. Now if you choose a 3.0 because of cost and availability it will satisfy most. Me personally would have been much happier with a V8.

Kind of a mute point since the ZFHP26 is applied to all automatic S Types. So, the 3.0 and 4.2 cars have the same transmission. That said, yes the ZF transmission is definitely a factor in all the cars MPG performance.

 

Absolutely agree with this. As an example, for my typical morning I can typically get about 26-28 mpg. On the way home, I'm lucky to get 20 mpg because the traffic is a lot heavier and there is usually an accident 2 days a week during the evening. Don't get me started on why that is though.

 

In the UK people seem to find that the auto gets better mpg than the manual, but they're differently geared and we are allowed to drive 70mph on many roads which suits the auto.

The diesel auto is listed as better mpg than manual, I understand.

 

Not forgetting that the UK uses real gallons when converting from litres, not the little US versions.

 

You are right. For some reason I thought the 3.0 was only mated to the 5 speed auto, but I see it was upgraded to the 6 speed in 2003-4.

 

A bit of an hypothesis: If we assume that the 4.2 S-Type gets a bit better gas mileage than the 3.0 S-Type, can we make the assumption that a 4.2 XK will get better gas mileage as well? AFIK the XK has the same engine, transmission and rear end but better aerodynamics than the S-Type.

 

My wife averages 27 to 28 mpg on her solo trips to and from Tampa in her 2006 XK8 4.2. She averaged right at 33 mpg on those same trips when she was driving our 2005 S-Type 3.0. Same route, same driving habits, hauling the same payload. Our S-Type simply does this trip more efficiently than her XK8 does....

 

Have you compared the average MPH, though?

LOL

 

75 mph in the S-Type, 90 mph in the XK8. Good luck getting her to admit it though.