Hi,

Im looking at a 01 XJR 120K on it.
Runs nice except when you step on it , it taps a bit, like lifters or valves..
I heard this was normal with the supercharger. Does anyone know if this is true?

Thanks in Advance

 

It most certainly is not true!

 

Thanks...
It could be just some low octane gas, but probably a good idea to get it checked first..
I know NOTHING about superchargers!!

 

I'd deffo try some premium gas, it'll be the cheapest solution in the long term, if it's pre-ignition due to low grade fuel it will harm the engine in the long term.

 

Sounds like somebody has been dumping cheap gas in it. You might want to pass this one by. Reminds me of when I worked in a gas station (many moons ago). This guy used to come in there to get gas in a Dodge Charger with a 426 Hemi. This car was an icon. I saw very few of them. But to my great disappointment, the guy bought it as a family car. I guess he just wanted the biggest engine. But anyway, he would pull in in front of a fog of blue smoke and say fill it up with regular and dump in two quarts of your cheapest oil. It was enough to make a car guy cry.