Classic Mercedes 300 SEL 6.3 Packs Big V8 In Midsize Sedan

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Gorgeous 300 SEL 6.3 might not be an official AMG but with a big V8 and more horsepower than necessary, it fits the ethos.

If you wanted to trace the history of AMG back to one particular car, the 300 SEL 6.3 would be a good starting point. Cheshire Classic Cars founder Iain Tyrrell had this classic Mercedes in his shop recently and explains why this early version of the S-class was more than just a big motor.

Tyrrell explains how things got started, saying, “a chap called Erich Waxenberger, who was very senior in Mercedes, decided to just do a bit of mischief one day.” Waxenberger’s idea was to take the large V8 from the 600 series and put it in the SEL. The mischief mentioned was the fact that Waxenberger did this without Mercedes actually knowing about the project.

“What Erich Waxenberger did was try to quietly, almost secretly, transplant that big engine into this body,” Tyrrell explains. It follows the old adage of begging for forgiveness rather than asking permission. The top brass at Mercedes drove this vehicle, knowing that it was special, but not knowing what had been done to it. Thankfully for Waxenberger, the management in Mercedes thought the performance of the car was phenomenal, and deemed his creation to be excellent.

Mercedes Benz 300 SEL 6.3

Tyrrell explains the secret behind this engine’s performance. “What made the acceleration so fast? Because the in-gear acceleration is still impressive to this day. Well, it’s all to do with something called the fueling curve.” Modern fuel systems tend have efficiency in mind. The 6.3 in the 300 SEL uses a mechanical plunger pump for fuel injection, and that pump was happy to move high rates of fuel. “It’s sort of a blunt instrument,” Tyrrell explains. “They like running a bit rich. They like over-fueling a bit. That’s why, when you snap open the throttle on this car… it opens up the taps on this car, and up she flies.”

Mercedes Benz 300 SEL 6.3

In the real-world, that leads to neck-snapping performance, even from a very heavy sedan. On some open roads, Tyrrell takes the 300 SEL out for a test drive. In-gear, he hits the throttle and even the camera holder has a tough time keeping the camera steady with the rate of instant acceleration. Tyrrell exclaims, “That’s what you call throttle response!” Compared to modern cars, he says, “to the modern turbocharged, eco-boosted, whatever whizzy names they call them all, you just will not get throttle response like that.”

Mercedes Benz 300 SEL 6.3

Of course, we all know AMG‘s best-selling and highest performing models carry the “63” designation. If you were wondering why they carried “63” despite being a 6.2-liter engine, now you know.

Patrick Morgan is an instructor at Chicago's Autobahn Country Club and contributes to a number of Auto sites, including MB World, Honda Tech, and 6SpeedOnline. Keep up with his latest racing and road adventures on Twitter and Instagram!


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