Tangled Metal wrote:Limiting power to 100bhp? Interesting!
Domestic use of vehicles isn't the only use, there's trade, commercial and industrial use. Take trade use, which means vans. There's often power break points at 90, 100 and 115/125 bhp depending on the van. Looking at vauxhall vivaro for example the standard powers are 89/90, 99/100 and 114/115 bhp. There's also a biturbo at 120bhp.
Which is the most fuel efficient and least polluting option? The 120bhp not the 90bhp van. The 90bhp van is actually the highest carbon emissions and lowest fuel efficiency. The best on both counts is the biturbo.
I read an article on the website of a fleet car trade journal that's highly relevant here. The fleet manager for the whole of BT wrote about serious fuel efficiency and emmisions reductions that are possible by remapping vehicles. By remapping for more power, savings of 15% on fuel costs / use in vans and 8% in cars. Crazy right?
In fact the guy wrote that it could be advantageous for large fleets to mass remap their vehicles and then put them through type approval. What that means is the remapped vehicles become recognised as a new model with better fuel / emmisions figures. Advantage being lower personal tax for company cars. They don't because it's really only an advantage to the employee.
I'm no car expert but this guy was so I've no basis to dispute his article. I just think power isn't a good measure for limiting cars. There's evidence that it's a bad measure to use.
I completely see your point and of course arbitrary limits rarely make complete sense, they are (or are best treated as) but a line in the sand from which to work. Of course, in some small defence of my comment, I did specifically say cars and did not mention vans. Commercial vehicles do need considering too but that’s a more complex conversation for another day.
BHP is to an extent a false indicator anyway - it’s meant to be a start point - because what matters more to the user is the amount of torque produced by an engine. (For the reference of others Power = Torque x engine speed, the maximum torque available can vary considerably through an engines’s operating speed range). To my mind 100 BHP is quite a generous limit; whilst 100 isn’t much these days it was in the past and cars of half that power and less have covered very large mileages. Here’s an example of what was a very popular family car that had under 100 bhp : https://en.m.wikipedia.org/wiki/Volkswagen_Golf_Mk3. And here’s an iconic vehicle that mobilised masses of people and yet must have had less than 50 bhp under its bonnet: https://en.m.wikipedia.org/wiki/Renault_4.
I’ve always wondered about engine (performance and efficiency) mapping and am not surprised that after market improvements are possible. Whilst typically manufactures want to make good products they make products for sale and profit, ultimately their goal is to make make money and if product efficiency suffers along the way then that’s businesses as we allow it to function. At the moment we don’t know why the more powerful engines you mentioned are more efficient, but my instinct is that they are more recent designs funded by customer desire for more power. It’s a nice thing for the Marketing Team too that the most expensive model happens to be the most fuel efficient and have the lowest emissions .......
Power might or might not be a useful indicator but it is easy for Goverments to use and so is engine size (eg. 125 cc motor bike of less than ‘15’ bhp is deemed acceptable for a learner to use and 400cc? of less than 33 bhp is OK for recently qualified motor cyclists to use). In general cars with smaller and less powerful engines are more fuel efficient than more powerful vehicles, what’s needed is a trend effect and sometimes, for the greater good, you have to carefully and selectively set anomalies to one side.
