A reader on our Danish ViaRETRO site recently commented: “Once you have driven a turbocharged car, suddenly normally aspirated engines aren’t all that fun”. I thoroughly disagree.
Granted, I’ve only ever owned one car with a turbo engine. However, I’ve also owned another car which was highly comparable – only it was naturally aspirated. On this basis, I’ll claim that reality is much more complex than suggested by this reader.
My own experience stems from my 1986 Renault 5 GT Turbo held up against my 1986 Honda CRX 1.6i-16. They were two of the very quickest cars in the GTi segment anno 1986, yet they utilized very different ways of achieving this. As suggested by their names, the Renault used a turbo to up the power output of their well-known 1.4-litre engine, while Honda went down the path of a 16-valve head. Renault managed 115hp and Honda 125hp – see below for graphical illustrations of their power output (illustrations from automobile-catalog.com):
All of the Honda’s horsepower isn’t at your calling until a heady 6500 rpm, while the Renault only requires 5750 rpm. But it’s actually the torque which differs the most. Where the Honda manages 142 Nm (or 105 lb ft) at 5500 rpm, the Renault beats up an impressive 165 Nm (or 122 lb ft) from as little as 3000 rpm. As most readers will of course be fully aware, it is torque that is of most importance in 95% of driving on public roads. In that light, one could easily argue that this Danish reader was right: The turbo engine is a clear winner.
However, the graphs do not create a perfect illustration of what it feels like to drive the two cars. The Honda engine in my CRX was an utterly amazing machine, which regardless of situation, gear or number of revs, was always alive and ready to deliver its power. No matter what the numbers might suggest, it always felt more than adequate. It would happily pull from low revs, and the power delivery was totally linear all the way up through the rev-range: More revs, more power.
Hondas engineers used all the latest and fanciest tricks they knew, and the fuel injection system was even called PGM-F1, as it supposedly was a development from their Formula 1 engines. Marketing and trickery aside, it was in every way a delight to drive, and to be honest it might very well be the best engine construction which I have ever owned.
Quite the opposite, the Renault engine doesn’t have fuel injection, but instead relies on a good old-fashioned carburetor. Which the turbo force feeds. It’s really a rather primitive solution, in particular when compared with the state-of-the-art engine in the Honda CRX. The old-fashioned Cleon engine with pushrods is a much simpler and low-tech engine. But it works. Surprisingly well even. The Renault has – like just about every other turbo car of that era – a reputation for turbolag, yet I find it particularly better than its reputation would have you think. No, it can’t match the Honda’s immediate power delivery, but it’s also not anywhere near being the big problem which some people try to make of it. Of course you feel it as the turbo wakes up, and the little 5 starts to fly. But it’s not an on/off button: It delivers turbo pressure from a couple of thousand rpm and maximum as available from just below 3000 rpm. Simply keep it spinning north of 4000, and you ensure that there will always be plenty of power – also after shifting up.
Just to be clear: The Renault is the quickest – at least when it comes to acceleration, where it’s claimed 7.6 seconds to 60 mph beats the CRX by a tenth of a second. But then the Honda’s 126mph top speed outruns the Renault by a single mile-per-hour. In all fairness, let’s just say they are very evenly matched.
So in reality, it’s probably more about their character. And let it be said, the Renault has bucketloads of character. Behind the wheel, you are left in no doubt that you are piloting an early turbo engine, as you are never left wondering whether the turbo is up and spinning or not. And that is of course a fabulous experience. The Renault also sounds better. Though I need to confess that my R5 is fitted with a sports exhaust system – nothing extreme and perfectly easy to live with, but I’m sure it delivers a few decibels more than the stock system. But the Honda’s silk-smooth turbine sound wasn’t without its appeal either. Quite frankly, the Honda engine can simply be described as better than the Renaults in every single discipline!
So for me at least, it’s not just a simple choice between suck or blow. The engines also weren’t the deciding factor that lured me into buying either of these two cars – not directly at least. Both are fabulous specimens from the prime of the GTi era, and it was their overall character – their charisma – which I fell for. And that’s where there is no way around recognizing Honda as an engineering-driven manufacturer that always favours the exquisite high-tech solution. Renault on the other hand was one of the pioneers of turbo development. As such, both manufacturers let their technical heritage filter through to their prime candidates in the GTi arms race, thereby giving them both a healthy dose of F1-image to help them flex their muscles.
And both are tremendous fun. If I really had to choose one, I would have to say the Renault is the most entertaining – but that’s really more down to the suspension set-up than it is the engine. And that is of course a totally different story.
Dear readers, what are your experiences and preferences when it comes to naturally-aspirated versus force-feed?