The other day I had the good fortune of being able to drive an i8. It’s not the most expensive car I’ve ever driven, but far more exclusive than anything I get a chance for a go in. Okay, so I didn’t drive it that far. About two miles to be precise. I did, however, ride in it for about 20 miles. Thing is, I only needed those two miles to know that cars like the i8, these ‘performance hybrids,’ do indeed work.
Let’s talk about this because that’s what it feels like when stabbing the accelerator. Not all hybrids are your neighbor’s Prius, that is, cars that use electricity for the sole purpose of achieving higher fuel mileage. Those cars make such little horsepower and rely mostly on a washing machine of a little combustion engine. Not the i8.
The i8 has a much more powerful electric motor, making 129 BHP. Couple that with a 228 BHP 1.5L three-cylinder fed by almost 2 bar of boost, and you’re looking at 357 combined peak horsepower. The 129 from the electric bit is so substantial that when tottering around in EV mode with no gasoline being consumed, it has plenty of pickup and gets up to speed as quick as realistic necessity beckons.
Flick the shifter into the left position for Sport mode, and it all changes. The three-cylinder comes to life and- actually, let’s talk more about that engine. Sure, it’s three cylinders, and that sounds lame. But it doesn’t sound bad. From the outside it’s akin to a certain horizontally-opposed air-cooled German motor with it’s clatter emanating from the engine compartment. It’s really not as bad as you’d think. In the cabin, it’s no match for a V8, sure, but it does it’s best sportscar sounds rather well. Anyway, once the petrol engine ignites, this is a seriously quick car. About as fast as the M2 flat out. But the character of this power unit is in the low and mid range.
See, gas engines on their own make peak power at a high rpm. That’s always been their deficiency. BMW classics like the S54 from an E46 M3 is a screamer, but you have to rev it for it to deliver. Down low, where you actually drive everyday, it doesn’t have much.
Turbocharging somewhat solves this. Compressing air into an engine allows it to develop peak torque at incredible low RPM, usually under 2,000 even, to increase driveability and makes for an encompassing flat, power curve. But, turbocharging introduces lag, the time that’s needed for the turbo’s to spool up and deliver that air when flooring it. Having driven cars that have been said to ‘virtually eliminates turbo lag,’ no, they haven’t; they hide it through clever automatic gearboxes. Lock a new 330i in gear manually below 3k and floor it. Yes, that’s lag for you.
This is where electrifying works. And also where it doesn’t. In a full electric car, you get this immense torque and throttle response, creating an almost ‘whiplash’ effect when nailing it. A BMW i3 even does it. Travel under 30, hit the electron pedal, and smash your passenger’s skull back into the head-restraint. But, electric cars have the disadvantage of gearing, being only a single speed. This righteous momentum cannot be maintained. Even a Tesla Model S P-Whatever can’t maintain the acceleration it has to 60. That’s why McLaren’s and such post trap speeds 10 MPH+ faster through a quarter mile, even if they’re identical time wise. Cars like that catch up quick after 60MPH.
So here’s why the i8 and it’s propulsion system works. By combining gas and electric, you get the best of both. That turbocharged engine’s problem of lag? Because the electric bit makes peak torque at zero RPM, and has instant response, there is none. Zilch. Even in a higher gear, say fourth at 30, foot the floor and it’s gone. And about electric motors running out of puff at higher speeds? The combustion engine keeps pulling hard so there is no real drop-off in the rate of acceleration. It keeps pulling and pulling. The six-speed auto ‘box also receives praise for it’s quick shifts and responsiveness, keeping the engine right in the power band to ride the wave of thrust.
Okay, it doesn’t have the zing and reward at the top end like that mentioned S54 gives, but for a modern, tiny turbocharged engine, it’s pretty damn good. It makes for a much more interesting driving experience than a just another humdrum appliance moving you. This is more like a hi-po microwave on the nuke setting.
Of course, I still prefer a high-revving naturally aspirated engine. But how many of those are left? Ferrari and Lamborghini discounted, there’s not many. As far as the new breed of small-capacity turbo engines go, this improves upon them. Let’s make it easy here: in the case of the i8, electrification improves the driving experience. Think of it as a bargain Porsche 918. They’re both hybrids, made of carbon, and four-wheel drive. One is a tenth of the price though.
So when I read rumors that the future M-cars will all be performance hybrids, I am welcoming the stage with open arms. If it’s done right, it’s exciting as heck. And I can’t imagine how much fun it’d be to, say, add 200 horsepower of electricity to BMW’s twin-turbo v8. I’m onboard with the notion of the performance hybrid. As long as they come with manual transmissions…
