Drag race: Mercedes-AMG A45 S vs tuned CLA 45 S

Engine remapping is one of the most popular car mods out there. After all, paying someone with a computer a few hundred quid to connect to your car’s onboard computer and dial-in a few extra horsepower sounds pretty dreamy, right?

But how much difference does a remap really make? Well, that’s what today’s drag race looks to find out.

Lining up here are two cars that, mechanically speaking, are twins. The Mercedes-AMG A45 S and CLA 45 S both use a 2.0-litre turbocharged engine which, as standard, produces 421hp and 500Nm of torque.

Both send that power through an eight-speed dual-clutch automatic gearbox to all four wheels and weigh about the same. The A45 S tips the scales at 1,635kg with the CLA 45 S nudging it up to 1,675kg.

The yellow A45 S we have here is completely standard, but the CLA 45 S has a remap trick up its sleeve. An £800 ECU tune has seen power boosted to 490hp and 660Nm of torque. That should wipe the floor with the A45 S then, right?

Ah well, it’s never quite that simple. The rain has come to play and that throws up a few wildcards. See, the gearbox on the CLA 45 hasn’t been reprogrammed, so it’ll be ready to deal with 421hp but nothing more — so may find itself rather confused in these slippery conditions.

Could that play a factor in the race, or will the 490hp saloon wipe the floor with the standard hatchback? Watch the video to find out…

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