4.2 or 5.0 engine

[Dave Old]

I'm thinking of getting an XK coupe, my budget is approx £20K. Should I go to the newer 5L or the tried and tested 4.2?

[Old Peter]

Welcome to the club, David.

There will be strong opinion on both sides  --  there a quite a few XK owners who will speak from experience.

I  would go for the tried and tested, personally, as a safe bet.  But having said that, both engines are tremendous.

Regards,

Peter.

 

[woodsy]

Is it not the same engine bored and stroked ?

[JOE-DOT-COM]

Hi

If I was picking, I'd go for the 5.0L

The 5.0l has the newer gearbox and later spec engine

I would say the 5.0l will be more sought after and hold better value

I have the 4.2 supercharged unit in my S-type R, Which is a superb engine, but would love to upgrade to the 5L, Just for the extra power and torque

cheers

Joe

[Dave Old]

On 3/19/2017 at 9:16 AM, Dave Old said:

I'm thinking of getting an XK coupe, my budget is approx £20K. Should I go to the newer 5L or the tried and tested 4.2?

Thanks for the advice, I'm going to test drive a 2009 XK 5.0L Portfolio tomorrow, so fingers crossed it'll be my 1st XK

[DO55MAC]

Hi. I am trying to convince myself that an XK is the next step from my XF 3.0 S D, but am torn about what model/year to look at. I really like (no, REALLY like) the XK-R (it's those vents in the bonnet!!) but am trying to justify the extra expense of the 5.0 engine over the 4.2. I was wondering if the same 8-speed gearbox as my XF is used on the 2011 XK, and if so, what year did they introduce it to the XK. It's such a beautiful gearbox that I'd like to stick with it if possible.

Thanks for any advice.

Mac

[Leo]

I moved from the XF 3.0 S D to my 4.2 XK, and have never regretted it for a moment!

My XK is plenty quick enough for me, though it is always nice to have even more torque. I can't comment as to the 8 speed gearbox.

[JOE-DOT-COM]

Hi

Yes its the same 8 speed ZF box, but not sure what year they started

Personally if I could afford it it would be the 5L for me, though I love the 4.2L V8 Supercharged in mine

I thought the 4.2's were 6 speed and 5.0 were 8 speed, usually looking at them J-gate, 6 speed and pop up gear selector 8 speed

cheers

Joe

[DaveMech]

Sorry to contradict, but all  X150 (aluminium) models, even the exclusive, track focused and last hurrah XKR-S GT, were equipped with what I believe is the broadly the same 6 speed box. The presence of the puck gear selector is the most obvious modification but there were certainly changes to control software and presumably gearbox internals to suit the characteristics of the 5 litre engine. Oh, as far as I'm aware the 5 litre was/is a new engine not a 'bored-out' 4.2 (which itself is already a 'bored-out' 4.0 litre), the most significant change being direct injection into the cylinders for improved performance and economy. 

I have an 4.2 XKR 2008 Portfolio, am a member of the XKEC and  a bit of an XK nut!

Any XK is a great car, just smiles and no regrets

Cheers, David

 

[Guest]

I have a 2011 5 litre and can confirm that it is fitted a six speed gearbox.

I am also a member of the XKEC and yes I'm also nuts.

[Jhdee]

I had a 4.2 XK and then changed to a 5.0 XKR - there is a significant performance difference between the two. Fuel consumption is noticeably different too. Would I go back to a 4.2 ------absolutely no way ..... having way too much fun. 

Seriously though - it depends on what you will use the car for. When I had the 4.2, it was my daily runner and went everywhere throughout europe. My 5.0 is used for pleasure driving only - not sure I would be prepared to use it as a daily runner - just a little too expensive on fuel for me.

Either way - they are both fantastic cars  

[Peter Hopper]

On ‎18‎/‎12‎/‎2017 at 6:40 PM, Jhdee said:

I had a 4.2 XK and then changed to a 5.0 XKR - there is a significant performance difference between the two. Fuel consumption is noticeably different too. Would I go back to a 4.2 ------absolutely no way ..... having way too much fun. 

Seriously though - it depends on what you will use the car for. When I had the 4.2, it was my daily runner and went everywhere throughout europe. My 5.0 is used for pleasure driving only - not sure I would be prepared to use it as a daily runner - just a little too expensive on fuel for me.

Either way - they are both fantastic cars  

I have just bought a 2014 XKR 5.0 ltr and it has a 6 speed box and it also goes like stink. I also have a RangeRover Sport Firenze red 2013 3.0 lt and a Porsche 911 996 1999 Carrera 2 and the KXR is way faster than the porsche.

Driving dow to Spain in it come July and looking forward to it

Peter Hopper

[jag77]

I have 5.0 xk with six speed box great car, finding mpg great in normal driving, when in sport it only uses 5 gears but what a song and power delivery so much better than the 4.0 xkr I had

[grabberbluee]

Looking to purchase a 2011 5.0L N/A with 11:5.1 compression or older 2008 xk 4.2LN/A  11:1.0

can I run 87 octane without pinging the engine and destroying it? and or do I have to run 91 octane 89?

[N6 JMX]

Hi Kevin, the short answer is that you "should" be able to fill either car with the petrol of your own choosing and the car's brain will adjust the settings of the engine to cater for the fuel in use - especially the case with the newer 5.0 litre car. However, for peace of mind, the car will definitely run better and return a healthier MPG if you use the higher octane fuels.

Here in the UK, we get the choice of E10 or E5, with the number representing the percentage of ethanol contained within the fuel. Some folks have experienced fuel system issues when using the E10 fuel, e.g. leaking fuel lines, as the higher ethanol content can easier exploit weaknesses in the system.

In my own case, running the the supercharged XKR (2010), I use E5 fuel, which is generally 98 or 99 RON (octane), occasionally 100.

Ultimately, it is your choice, but opting to use the lower octane / cheaper fuel, may well turn out to be a poor choice with problems down the line.

N6 KMX