I was in a mates 4.2SC not so long ago and was amazed at how much of a spring chicken it was. The throttle response was brilliant right from take off. It was a 08MY.

Now mine is a 07MY and while it has the grunt when it's got going the initial throttle response is not as lively and free spinning.

Not sure if the SC is spinning right, if it is just being driven by air or the belt as it should be.

I've got a scheduled all belts, tensioners and pulleys change coming up shortly along with SC oil refresh.

Is there anything else that I need to be looking at? No strange errors on OBD the last time I checked.

Ta.

if you replace the pulley with a smaller one then you will find it pick up better.... ... - .- -.




Y. O. L. O.
.

Thanks Stan. Which pulley ?

Does that mean the 08 came with a smaller pulley

have a read here,

http://www.fullfatrr.com/forum/post414978.html#414978

and here,
http://www.fullfatrr.com/forum/topic14188....ger+pulley ... - .- -.




Y. O. L. O.
.

Thank you Stan. That is more a SC pulley "upgrade"

The one I drove had a lot more poke than mine in standard trim.

Just curious to see if I've got a broken element somewhere on my motor which I need to investigate before thinking of upgrades.

Cheers
Sam

Sam does your by any chance run lpg? as throttle is a little less responsive when on gas.

Nah mate. On full fat diet.

Try pulling the MAF sensor. If it makes no difference, then replace it as that is likely your problem.

Might be worth having any codes read first as I'm sure a dicky MAF sensor would throw a code. 2017 5.0 Autobiography Supercharged
2005 Merc SL350
2005 Disco HSE 2.7 oil burner

Probably worth double/triple checking your mates for standard trim, especially if he purchased it used. What you notice in your mates sounds exactly like I would describe mine after the pulley upgrade.

Also, May be worth while searching the jag forums to see if they experience any knock sensor issues.