I can only get 88mph out of mine - then the flux capacitor cuts in and it vanishes

My Satnav has the capacity to store my top speed and so I never reset it unless I specifically want to check my top speed on a set piece of "tarmac"
I'm not disclosing it on here though

and especially not disclosing where I did it

JBS did 146mph (satnav) whilst testing it, which equates to around 160mph on the speedo.