i'm about to purchase a 2003 v8
Is there really a big difference? what is the KM per litre for v6 and also v8

i wont be doing any highway driving at all, maybe once every 3 months

 

My 2004 4.2L drives mostly city and consistantly reads average consumption 13 to 14L/100km but I read somewhere that on the highway you could expect to get 8 to 9L/100km

 

I've owned 2 V6 Jags - an 03 X Type 2.5 and a 06 X Type 3.0. In town my 4.2 does as well as they did. On trips my 4.2 S Type does better than either of the X Types by 3 - 5 MPG(US). After I took my S-Type on its first long trip, I was amazed that it was consistently getting 30 MPG running at interstate speeds.

Regards:
Oldengineer

 

Interesting.... I always thought V8 4.2l had worse mpg than V6 3.0l.

 

This keeps coming up and people keep on posting that their 4.2 has the same mpg as the 3.0 but somehow it needs saying again and again!
Er, it's not particularly good mpg but then they're heavy cars.

 

The basic science behind it has not changed. That said, I had forgot that when shopping for my car. The main decision behind the 3.0 vs the 4.2 was MPG and I was wrong. To put it as simply as possible, when the power to weight ratio reaches a certain point a smaller engine will actually yield lower MPG than a larger more powerful engine.

Here is a link to a kind of funny test between a Prius and an M3 on Top Gear. While a bit extreme it does show the science I talk about.

http://www.youtube.com/watch?v=dKTOyiKLARk

My experience with a 4.2 was an 06 loaner. I had it for a few days and found that at the same average MPH I got the same combined MPG as my 3.0. And the "driving" feel was much better to say the least.

 

Yes.
We have owned both 3.0 and 4.2 engines. It was a nice surprise to see how the two get similar mileage. Just more fun with the 8.

 

The OP asked me this and similar questions in a PM. I responded that I easily attain 7L/100Km on the highway and that I average around 11L/100Km overall. Interesting that you average 13-14. Must be a much heavier mix of city driving than me.

 

Hi,
Comparing the EPA ratings for the 2003 S-types you will find:
3L V6: city 16 mpg, hwy. 24 mpg, combined 19 mpg
4.2L V8: city 15 mpg, hwy 24 mpg, combined 18 mpg

in liters/100 km:
3L V6: city 14.7, hwy 9.8 , combined 12.4
4.2L V8: city 15.7, hwy 9.8, combined 13.1

This should give the best science-based comparision between the fuel economy of the engines tested in identical circumstances. The V8 is close but the V6 is still better in fuel economy. My 2000 3L V6 averages around 28 mpg per tankfill with bests of over 36 mpg tanks achieved on long, mostly freeway trips. I haven't tested a V8 S-type but I bet I could do pretty good with it also.
Good luck in your search for an S Type and I hope this info helps you. Both are great cars.
VMV

 

i can't believe this crap, i would have had my car long time ago if i had known they get the same gas mileage

 

It's not exactly news for anyone who does some reading.

What on earth do you mean by "gets"?????? I despair.

 

CSM,

15.7/100 is less mileage (kilometerage) than 14.7/100

 

loool i know, i realized what i said after i posted. thats what happens when you post early in the morning

 

From what I've read, the 3.0 is marginally better than a 4.2 mileage wise. However, your driving habits will make a bigger difference in mileage. As Jeff said earlier, the 4.2 will drive better, but will be more expensive to buy and they aren't as plentiful as the 3.0 cars. Since I'm stuck in crappy DC area traffic much of the time, the extra power isn't of much use to me.

Mike

 

So, bottom line..... CSN, go buy the grey one with the 4.2 then do donuts in the snow!

 

everyone is saying that the 4.2 is more rare and expensive, that isn't the case here in toronto
the 3.0 is more expensive, and they are much harder to find. of all the jags i seen about 65% have been 4.2/4.0

i'm going to purchase the jag this Wednesday

 

Good For You!

 

My Jag's stablemate is now a 2010 Honda CRV 2WD with the 180 HP 2.4 4 cylinder I-VTEC engine. EPA highway for the Honda is 28 MPG. On business trips the best the Honda has done so far is 25 MPG. My Jag with the 4.2 smokes this Honda on fuel economy.

Regards:
Oldengineer

 

sure makes mine look good, as it does about 28 mpg (UK) on a run,on the old G/Box without trying to be economical lol

 

28 mpg (UK) = 35 mpg (US)

(because UK pint = 20 fl oz, US pint = 16 fl oz)

but you're still right because which car would you prefer LOL