Petrol engine progression
Discussion
Is it me or have petrols not improved in the way diesels have over the last 20 years?
I had an 86 escort van with a 1600 n/a derv in it and it was nasty. Smelly, noisey, harsh and painfully slow. On a winter morning I woke half the street as it clattered into life.
I've had company diesels since and a new Astra petrol recently. That's now gone and I have a new focus titanium x with the 2.0 tdci dura torque. I'm quite impressed so far. All the toys and ample go go for a daily. Privately I have an Audi A4 Quattro 1.8t.
So, my view is that diesel cars have been hugely improved in every way possible but petrols don't really seem to have kept up?
I had an 86 escort van with a 1600 n/a derv in it and it was nasty. Smelly, noisey, harsh and painfully slow. On a winter morning I woke half the street as it clattered into life.
I've had company diesels since and a new Astra petrol recently. That's now gone and I have a new focus titanium x with the 2.0 tdci dura torque. I'm quite impressed so far. All the toys and ample go go for a daily. Privately I have an Audi A4 Quattro 1.8t.
So, my view is that diesel cars have been hugely improved in every way possible but petrols don't really seem to have kept up?
Depends. There is a massive difference between a 1.2 litre, 60 bhp Polo and a 1.0, 125 bhp Fiesta petrol, for instance.
So the improvement is there, but while there is no market at all for the very cheapest, simplest diesel engines, as people will be motivated by a combination of performance, economy and upfront cost, there is a market for 90s-vintage, multivalve, torqueless, naturally-aspirated base models laden down with emissions equipment and blunted by the heavy weight of modern cars, purely so they can sell for a grand or two less than something that can actually move under its own weight while returning over 30 mpg.
So the improvement is there, but while there is no market at all for the very cheapest, simplest diesel engines, as people will be motivated by a combination of performance, economy and upfront cost, there is a market for 90s-vintage, multivalve, torqueless, naturally-aspirated base models laden down with emissions equipment and blunted by the heavy weight of modern cars, purely so they can sell for a grand or two less than something that can actually move under its own weight while returning over 30 mpg.
BFG TERRANO said:
Agree. That's not the norm though for most 1.0 petrols is it?
Compare most 2 litre diesels and your probably about 150bhp now.
About the same as a decent 2 litre N/A petrol engine from the mid eighties and a lot less than the current crop of 300bhp petrol turbo engines.Compare most 2 litre diesels and your probably about 150bhp now.
Toltec said:
About the same as a decent 2 litre N/A petrol engine from the mid eighties and a lot less than the current crop of 300bhp petrol turbo engines.
OK, an Astra 16v or Golf GTi 16v was 150 bhp, but your typical mid-80s 2.0 petrol four cylinder was around 100-120 bhp.And yes, you can get 300 bhp petrol turbos, but you can also get 2.0 turbodiesels with 215 bhp and 2.0 turbo petrols with 220 bhp, so I think you're overstating the case a little, especially as almost anything with a 2.0 petrol turbo will intentionally be at the performance end of the range and the distinguishing factor in relation to power outputs is often more marketing than technology.
diesels are so much better because so much money has been invested in them. The price of fuel combined with the low co2 tax ratings has seen to that.
you mentioned the astra 16v with 150bhp. That was an engine built to go touring car racing with. Again lots of money invested to reach a goal.
The pendulum is now swinging back to smaller petrol turbo engines. Already 180-200bhp is available from 1.4-1.6 petrol engines. That will increase if the car buying market continues the trend for small turbo petrols.
you mentioned the astra 16v with 150bhp. That was an engine built to go touring car racing with. Again lots of money invested to reach a goal.
The pendulum is now swinging back to smaller petrol turbo engines. Already 180-200bhp is available from 1.4-1.6 petrol engines. That will increase if the car buying market continues the trend for small turbo petrols.
(
Drive Blind said:
diesels are so much better because so much money has been invested in them. The price of fuel combined with the low co2 tax ratings has seen to that.)
Only driven by tax regimes though, and now everyone seems to have finally realised NOX and particulate emissions are the biggest issue.
(you mentioned the astra 16v with 150bhp. That was an engine built to go touring car racing with. Again lots of money invested to reach a goal.)
But a 2 litre engine with 150bhp is not that special - how about a 3.2 litre M3 with iirc)343bhp - more like it!
(The pendulum is now swinging back to smaller petrol turbo engines. Already 180-200bhp is available from 1.4-1.6 petrol engines. That will increase if the car buying market continues the trend for small turbo petrols.)
Sadly this may be true but I wonder if in a few years time we will see any advertised for sale with over 100k miles recorded like you regularly see for naturally aspirated 6 cylinder petrol Mercs and BMs.
Only driven by tax regimes though, and now everyone seems to have finally realised NOX and particulate emissions are the biggest issue.
(you mentioned the astra 16v with 150bhp. That was an engine built to go touring car racing with. Again lots of money invested to reach a goal.)
But a 2 litre engine with 150bhp is not that special - how about a 3.2 litre M3 with iirc)343bhp - more like it!
(The pendulum is now swinging back to smaller petrol turbo engines. Already 180-200bhp is available from 1.4-1.6 petrol engines. That will increase if the car buying market continues the trend for small turbo petrols.)
Sadly this may be true but I wonder if in a few years time we will see any advertised for sale with over 100k miles recorded like you regularly see for naturally aspirated 6 cylinder petrol Mercs and BMs.
Don't judge petrol engines as a whole by the petrol engines Vauxhall are putting in their cars, Vauxhall has some real relics among it's options list or at least it did when I last drive one.
Insignia 1.8 with ~140bhp, ancient engine which I'm pretty sure has been with us since the old shape Vectra and is coupled to the most awful set of ratios I have ever come across. 6 speeds, none of them right.
Insignia 1.8 with ~140bhp, ancient engine which I'm pretty sure has been with us since the old shape Vectra and is coupled to the most awful set of ratios I have ever come across. 6 speeds, none of them right.
The whole reason that diesel have moved on in the last 20 years is ALL to do with the haulage industry. Big trucks forced the manufacturers to improve the fuel consumption of trucks and EU legislation did the rest so far as emmisions were concerned. As most large trucks only do circa 7 miles to the gallon - even a 5% improvement had a big effect concidering the mileages these big trucks do. The same can't be said for petrol driven vehicles as no large trucks use petrol engines.
It was left to the car industry to take on the requirment that the engines were cleaner and more efficient. NO manufacturer can defy the laws of physics and given all the criteria that ALL manufacturers have to feed into the computer - they ALL come to the same fuel consumption conclusions.
It was left to the car industry to take on the requirment that the engines were cleaner and more efficient. NO manufacturer can defy the laws of physics and given all the criteria that ALL manufacturers have to feed into the computer - they ALL come to the same fuel consumption conclusions.
Axionknight said:
Put simply and IMO, diesels were s
tter and had more room for improvment.
Pretty much this. tter and had more room for improvment.Most of the technology that has improved diesels so much is also finding its way into petrol powered cars, it just tends not to have such a pronounced effect because petrol engines were better in the first place. In fact I'd argue that some of what has made diesel engines so much better, has actually made petrol engines worse.
Edited by kambites on Thursday 19th March 11:21
There is lots of tech on the horizon which should dramatically help to improve petrols in terms of emissions and fuel economy. The next 10-15 years will be quite interesting in that respect.
That's the boring stuff.
Specific outputs are only going to get sillier. 200hp/l won't be uncommon before long now the tech to support the transient response etc is coming through thick and fast.
That's the boring stuff.
Specific outputs are only going to get sillier. 200hp/l won't be uncommon before long now the tech to support the transient response etc is coming through thick and fast.
MG CHRIS said:
Can anyone explain what the hell he op is talking about. Or has he been in a cave for the past 10 years.
Quite. There have been phenomenal improvements. A turbocharged 3-litre, 6-cylinder engine making 315bhp, yet is only halfway down the list of VED bands (175g/km) and will do high 30s mpg on a run? In a 30k hatchback? Staggering really. Even in the mainstream, things like the VAG 1.2 TSI in the Fabia, Polo, Golf etc are fantastic for day-to-day driving. Torquey but rev out nicely, very economical, near silent in traffic - I'd have one over a 1.6 TDI any day.
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