World champion Lewis Hamilton believes Formula 1's move to a three engines per season limit in 2018 "sucks", because it will further force drivers to race conservatively to achieve reliability.
Next year the power unit limit drops from four to three per season for 21 races, with some elements – the MGU-K, control electronics and energy store – restricted to two.
Hamilton stated recently that he has often been driving to protect his engine this season.
He was in the unusual position in Brazil of having a brand new engine which only had to do the Interlagos race and the Abu Dhabi weekend, and the low mileage requirement meant he was able to push it much harder, and run higher power modes for longer, in Sunday's race.
"This is the first time I've pushed an engine like that!," Hamilton said. "It was nice, normally you're managing it.
"I often turn the engine down and they keep telling me to turn the engine up, and I'm 'no, no, no, I prefer it to stay down', and I'll figure out a way to catch up in another way.
"I guess that's just through fear of pushing it a little bit too much, like the engine blowing up in Malaysia last year.
"I don't like the idea of going to three engines, I think that sucks. We should be able to push more. Sprinting is what we're missing in F1."
2018 cars "like a bus"
Hamilton is also frustrated by the current high F1 minimum weight limit, which increases further with the addition of the Halo next season.
"The fact that nowadays we've got this 100kgs [of fuel], the car is going to be a bus next year, it's going to be so heavy, it's going to be like a bleedin' NASCAR next year.
"So heavy, the braking distances get longer, the brakes are always on fire, on the limit.
"I know it sounds negative, but just as a racer who wants a fast, nimble car, that I can attack always, every single lap, unfortunately that's not what we generally have.
"If you look at the front guys, they were managing, and that generally what we are doing when we are in front. I don't think that's exciting for people to watch.
"That's why if you look at the most exciting races, particularly when it rains because you don't have those limitations, the races where Max [Verstappen] has been coming through the back, or a driver has been, those have been the most exciting ones.
"How do we provide that for the future? I'm not sure that cutting down the engines is helping it in that direction."
Hamilton made it clear that he enjoyed the chance to run flat out in Brazil, and he expects to be able to do the same in the final race.
"Yeah, I'm going to give it everything in Abu Dhabi, which is cool, I'm excited for that. It's obviously an unusual position to be in.
"But I really, really loved racing today, I've loved driving this year's tyres, I kind of think, why did we not have these big tyres before?
"What's the next step? Can we make them bigger, do we get more grip from them in the future? Ultimately more mechanical grip means we can do more on track and we get more racing, and that's what we need."