The 20V I-5 in the Quattro has got to be up there.
How many engines could be on this list? Volvo's white block, Audi's old and new I-5, Acura 5-cyl are already mentioned. All were very good. There's Mercedes' diesel and VW's current 5-cyl as well; they're not bad either. Any others? Hard to come up with a list of best/worst.
I honestly don't think there was a bad 5 cylinder... they were all very good in their own way. Each of them have an almost legendary reputation. Even the I-5 from GM in the Colorado, I know three people with one, and they love their truck/engine combo.
Power of a four and gas mileage of a six! Oh wait
For anyone interested, there's a great writeup/history of the Audi inline 5 cylinder 20vt here:
Then there's the Fiat 5 Cylinder. You never got it, but it was available in the Bravo/Brava and later on in the Stilo (and was nothing special, a torquey engine albeit a bit thirsty); but its turbocharged variant in the Fiat Coupé will be remembered. Sounded excellent and made the car really move. Maybe not as tough as the Audi 5 cylinder engines; it still could be mildly tuned without giving problems.
And finally (?) there's the Td5, which is the 5-cylinder turbo diesel engine developed by the Rover group for use in the Land Rover Defender and Discovery models. I don't know anything about this engine other than that (reliability/performance)
In that case, you'd think that the nuclear holocaust has already struck Vermont.
Anyway those old Benzs will still be running because they use an electric solenoid to cut fuel to the engine. And with the effects of the EMP, they might not actually be able to turn them off.
1975 Honda CB400F Super Sport
1986 BMW 535i
1984 BMW 745i turbo - FOR SALE
2002 Passat 1.8t
1990 Saab 9000 turbo