When will petrol engines come back to the bigger stuff?

When will petrol engines come back to the bigger stuff?

Author
Discussion

irfan1712

1,244 posts

155 months

Monday 23rd July 2018
quotequote all
Nanook said:
irfan1712 said:
The 3.0 supercharged v6 has 330 lb ft of torque. Not only that, its delivered at 3k revs. So you'll have to ring its neck to get it moving in comparison to the SDV6, which has less bhp granted, (40 if that?) but has 516lb ft of torque, delivered at 1500rpm.
it'll use more fuel
You've just noted the whole point of the debate on petrol engines in a large car... it''ll use more fuel, because they need to have higher engine speeds to move it compared to a diesel.

In such a big car, 3k isn't ringing its neck but your missing the point - why would anyone want to 'rev out' their huge luxury car to get it moving at a good pace?



Tim bo

1,956 posts

142 months

Monday 23rd July 2018
quotequote all
irfan1712 said:
diesel scare mongering morons in the general public who buy into this whole Diesel will kill us propaganda,
Nitrous oxides are neither scare-mongering nor propaganda.

mrbarnett

1,091 posts

95 months

Monday 23rd July 2018
quotequote all
Remember when LDV put a Rover V8 in a van? Sounds fast, at least...
https://www.youtube.com/watch?v=EyXebDVGna8

captain_cynic

12,320 posts

97 months

Monday 23rd July 2018
quotequote all
Large petrol engines that produce little power just aren't cost effective for manufacturers. We're at a point where a 1.0L turbo can easily produce 100 HP. Long gone are the days where a V6 engine was needed for 150 HP, NA 4 bangers have been doing that reliably for decades now.

I don't think we're going to be seeing 4L V6's and 6L V8's in average cars these days because you simply don't need large engines to make power these days. We will probably see more NA petrol engines in 2L and 2.5L range as downsizing engines hasn't had the effect on fuel economy manufacturers wanted.

Ninja59

3,691 posts

114 months

Monday 23rd July 2018
quotequote all
Doubt it makes sense in honesty. Any large saloons or larger SUV's will go from diesel to electric (with a few phases in between like hybrids).

Ultimately as said above the bit here is torque, some of these larger SUV's just need more of it to get moving. I would not want to really rev out a large saloon or SUV it is just not really the "right" car.

Downsizing has really failed as you now have a generation of engines that whilst good in labs, are really not great in the real world. As said by another poster engines in development now are going back to slightly larger capacities as these engines need to work less in the real world.

Sheepshanks

33,072 posts

121 months

Monday 23rd July 2018
quotequote all
sjg said:
VW do a 2.0 TSI in the UK Transporter now, but they’ve offered it on the continent for ages so not a big deal to expand that.
Missus has a Tiguan that was only available in diesel when she got it (towards the end of the mk1).

Interesting to read the mk2 forums and see comments from buyers who switched to the 2 litre petrol and are absolutely horrified by the MPG!

sjg

7,467 posts

267 months

Monday 23rd July 2018
quotequote all
Plug-in hybrids seem the right short-term solution for the big SUVs and luxury saloons. They have the space, they're already heavy so the weight of battery isn't such a big deal (RR P400e is very close in weight to the V8 diesel), lots of torque with the electric side helping out, brilliant low-speed refinement without the diesel engine noise, low tax & low running costs if your journeys are mostly shorter ones.

bobfather

11,172 posts

257 months

Monday 23rd July 2018
quotequote all
sjg said:
Plug-in hybrids seem the right short-term solution for the big SUVs and luxury saloons. They have the space, they're already heavy so the weight of battery isn't such a big deal (RR P400e is very close in weight to the V8 diesel), lots of torque with the electric side helping out, brilliant low-speed refinement without the diesel engine noise, low tax & low running costs if your journeys are mostly shorter ones.
Only if you are using it for local commuting, Pulling anything with a towbar uses the torque supply quickly ans if you're travelling any distance the electrically supplied torque will run out after around 60 miles leaving you with a low torque petrol engine running at a high and inefficient rev range to maintain roadspeed. Hybrids are good at pulling themselves along but when you add mass the low torque petrol engine cannot provide the required pulling power. The caravan and camping club did a 300 mile test of all the main stream hybrids, they all performed admirably until electric power ran out, generally around 60 miles into the trip. Thereafter they all failed to maintain speed on simple motorway inclines and MPG went through the roof

swisstoni

17,184 posts

281 months

Monday 23rd July 2018
quotequote all
I don't see big petrols (ie 3 litre +) making a comeback. They will stay in the cars that have always used them, but even they will shrink with hybrid help.
2 litre turbo will probably be the best most can hope for IMHO, while we wait for the electrics to take over.

irfan1712

1,244 posts

155 months

Monday 23rd July 2018
quotequote all
Nanook said:
irfan1712 said:
You've just noted the whole point of the debate on petrol engines in a large car... it''ll use more fuel, because they need to have higher engine speeds to move it compared to a diesel.

In such a big car, 3k isn't ringing its neck but your missing the point - why would anyone want to 'rev out' their huge luxury car to get it moving at a good pace?
How much fuel is being used is a bit more complicated than purely engine speed, but yes, generally, going faster uses more fuel. The petrol version is faster than the diesel version, and it uses more fuel.

I'm not missing the point, unless the point is something you haven't made yet. 3k rpm is not 'revving it out' as you put it. The car will still make decent progress without having to be red-lined in each gear.

But if it was, why would anyone want to? Because they want to. That's their choice. It's why some people buy the smooth petrol engined version over the rattly diesel version.
I quite understand If someone wanted to 'rev out' their petrol SUV then they would yes.

the fact is most ( in the example of an RR) don't want to. Because they haven't bought them, they've bought the smoother, refined, torquey, economical diesel instead. which is what the sales figures clearly show. Its quite simple.

As for 'rattly diesel' - you should try an SDV6 in the Range Rover because rattly it is not in any shape or form..in the slightest. I'm not a fan of diesel cars but driving this most days has certainly changed my mind set and makes perfect, perfect sense in an RR to me.