I had a sneaking suspission that Jag is very conservative also in the claimed engine power.
I read somewhere stock XFR dynoed at 460 RWHP. This should translate to at least 540HP at the crank.
We know also they are very-very conservative on the 0-60 claim.

 

I too would like to know that especially for the S/C and R versions. I have read the estimated 0 to 60 times and they are very conservative. The only magazine that I could find that tested the S/C said that the 0 to 60 was 4.3 which was the same as the XFR. Seems the XFR would be a tick or two better. What have you all heard on performance numbers for XFR and S/C?

 

I'm the one who recently posted about getting a dyno done on my stock XFR before I do some mild mods. The guys at the shop were very impressed with how strong this motor is.

As far as 0-60 times I have only read about an XFR doing 4.3 to 60. Jag claims 4.7. I havent read or seen anywhere about a Superchrged times.

I'm on vacation in Aruba and wont be back till the 5th of May so wont have the mods done till the following week. I have another thread about that which I will post on when those are completed and another dyno pull is done.

 

Actual output will be affected by ambient air temperature and humidity as well as fuel quality. Supercharged engines, whether by turbo or mechanical supercharger, will always demonstrate more significant differences from spec than naturally aspirated engines.

After Oldsmobile and Mazda got into trouble misstating their engine spec no manufacturer is going to spec a higher HP than actual for any sales in the USA. All manufacturers are going to spec the lowest horsepower produced by the worst engine, not the hp the best engine produces.

The Nissan GTR is reputed to have upwards of 50hp more than the Nissan spec, straight from the factory with no additional run in.

 

That's got to suck

 

Just an insight , one of the reasons why you can see different timings is you could look at 0-60 but those could indicate acceleration for km/h rather than mp/h , correct time table should indicate 0-62 mph to match up 0-100 km/h .

 

Still, from marketing stand point, Jaguar 'needs' the higher HP numbers fighting against BMW-M, MB-AMG. This is also because again and again we hear many people are surprised how fast and powerfull the XFR really is. Meaning many would have considered it, but may have not been educated and bought the Germans.

Take Cadillac - they are not shy to say the CTS-V has 556HP. - They advertize it all over the place and get a lot of buzz.

Nissan GTR was by itself , with zero direct competition in the price bracket.

 

The power delivered by the engine depends on the barometric pressure and air temperature (and some other factors), and that is what will influence the 0-60 times (including if you have already a heat soaked engine/intercooler or not).

Usually when you go to a dyno they filter this out by correcting the actual measured HP either via SAE or DIN HP method. So on a day with low temperatures and high pressure, the actual HP output can be higher than the corrected SAE number (or vica versa on hot days).

 

The power delivered by the engine depends on the barometric pressure and air temperature (and some other factors), and that is what will influence the 0-60 times (including if you have already a heat soaked engine/intercooler or not).

Usually when you go to a dyno they filter this out by correcting the actual measured HP either via SAE or DIN HP method. So on a day with low temperatures and high pressure, the actual HP output can be higher than the corrected SAE number (or vica versa on hot days).

 

It was tested in Car and Driver

2010 Jaguar XF Supercharged - Short Take Road Test - Auto Reviews - Car and Driver

 

Of course it is the torque that accelerates the car, and the torque curve and gearing which determine how a car with a given weight will accelerate. Horsepower is just a shorthand for torque in this context and can often be very misleading where modern supercharged engines are concerned. Supercharged engines with modern ECU programming and knock sensor technology (which now can be in the spark plug itself) can produce huge torque low in the rev range and produce an engine which accelerates a car much more quickly than its rated horsepower might suggest.

 

I was just thinking the same thing. I have an XF Premium with the 385 hp engine. I have had cars with more power, advertised, and this feels more like those cars according to my "butt dyno". I realize that weight, fuel and ambient tempreature play a role. No matter what the car is a "gas". The next one will be an R guaranteed.

There has been a rumor since the introduction of the 335i that BMW has purposely understated the power. A friend, who has one of those cars, believes that to be the case, no real proof, dyno, etc just a hunch. Clearly force inducted engines can generate more power with a few "simple" changes.

 

One has to remember that production cars today are seriously encroaching on power levels once unheard of except for racing. Manufacturers are edgy about power claims and have to be mindful of insurability by the average John Q. Public. Insurance companies and DOT aren't really thrilled about these cars like we are.

Lawyers, ya gotta luv 'em..........NOT!

Cheers,