Odd that you mention 1989, unmarked Police cars, Vauxhall Senators and speeding all in the one post! If you remember car-jacking had just started to be "popular" where hoons would run you off the road, drag you out of your car, whacked over the head and nick your car.
One night traveling back from seeing my girlfriend, i was tailed by a dark coloured Senator - midnight blue for want of a better description. I was in the aforementioned Mk1 Cavalier 2.0.
Anyhow, this Senator kept coming up behind me, dropping back, coming up behind, going to overtake, dropping back. I'd been doing about 55-60mph but had edged up to about 70-75mph and they were still doing it.
By now i was thinking they were going to try and force me off the road as there had been plenty of opportunity to overtake so i floored it and watched the speedo and rev counter both go off the scale. Speedo finished at 130 and rev counter ended at 7000 and at a guess was reading about 7300-7400rpm. Was a 4-speeder and about 20mph in top, i'll let you do the maths!
When they had disappeared from my mirror completely and with a rigorously enforced 50mph limit coming up soon, i let go of the loud pedal.
They clocked me on the over-run (when they eventually caught up!
) at 106mph and when i slowed to 49mph for the 50mph limit, a blue strobe appeared on the dash of the Senator.
Nurses and warty curds muttered i. Pulled in to the lay by and was given a bo77ocking by them and it went to court. Meanwhile after the nasty chat, i said to them "What's that then a 3 litre Senator?" - "Yeah, bit quicker than a 2 litre Cavalier" came the reply to which i responded "Bloody wasn't a while ago, was it???"
Probably not the best thing to say as they insisted on seeing the engine bay and straightaway spotted the 38DGAS sitting on a drilled and tapped manifold. I explained it was a budget standard conversion using second hand parts and offered no performance gain but was much better on fuel than the OE Varajet. Thankfully they either didn't know the difference between the sequential twin choke DGAV and the synchronous DGAS or they didn't care, either way they were satisfied it wasn't there for performance.
Poor deluded people!
I didn't have the heart to tell them there was an experimental profile Piper Magnum 285/2 cam and solid lifters inside with a few more tricks
that helped the engine to about 160-170bhp, nearly as much as their Senator but in something 2/3 the weight.
When it went to court i got a heavy fine and 3 points, escaping the usual ban for being 30mph+ over the limit because of the circumstances and fearing for my safety due to the threat of being car-jacked.
About 6 months later the first GATSO in the area was installed in the village with the 50mph limit. It made shed loads of money in its first year apparently.
A year or two later i moved down south and could quite often be found in the oustide lane of the M27/A31 etc heading to Bournemouth, Torquay or similar at 135+ in an SD1 V8 - they didn't catch on to unmarked cars or GATSOs down there as quick!
Somewhere in Suffolk with a Jeep, 2 Rovers and a V6 Volvo