Small engines in large cars
Discussion
PistonheadRob said:
Small turbo engine cars should be fine, the problem is a large majority of car the car drivers do not know how to care for a turbo engine. For example allowing it to warm up and cool down, combine this with extra long service intervals and things are not great for the engine and turbo.
A lot of drivers dont even know the basics of how a turbo works, they have no interest they just turn the key and put their foot down, then trade in/hand back after 3 years for a brand new one.
Should be fine... that is the problem here. These cars need to be reliable with normal (ab)use by the average driver. If it requires special treatment and shorter service intervals to last the course then surely it isn't really fit for purpose. A lot of drivers dont even know the basics of how a turbo works, they have no interest they just turn the key and put their foot down, then trade in/hand back after 3 years for a brand new one.
I would much rather buy an a old fashioned NA 2.0 petrol with 100k on it then one of these newer 1.2 turbos being forced to haul around increasingly lardy cars.
Willy Nilly said:
If you use 100hp, it will take 100hp worth of fuel, the size of the engine will become irrelevant. Where smaller engines score is that they have less parasitic losses so when they are not wide open they will use less fuel. They are also physically smaller and lighter so take up less room, should be a bit cheaper to make, have less fluids, so a bit cheaper to service.
All engines are getting more power extracted out of them now. Look at the big diesels. Not so long ago if you wanted 400hp, you'd need a 14-16 litre engine, now you can get the same power from 8-9 litres, it's all good and reliability is not an issue.
People seem to love their turbo diesels and it's now petrol engines turn to get some more wind. Bring it on I say.
I know, But I think the NEDC needs to be changed to reflect real life more, or just more info on the matter. All engines are getting more power extracted out of them now. Look at the big diesels. Not so long ago if you wanted 400hp, you'd need a 14-16 litre engine, now you can get the same power from 8-9 litres, it's all good and reliability is not an issue.
People seem to love their turbo diesels and it's now petrol engines turn to get some more wind. Bring it on I say.
Hybrids can go through part of the test on battery power. Turbocharged engines probably use little or no time on boost. Take the ecoboost or the twin air for example, and the amount of owners who are disappointed who thought they were getting a 70mpg car, that in the real world does about 35mpg.
That said for people on about reliability, I've haven't had any problems with the engine at all. Now on 45K, nearly 6 years old.
Edited by Noesph on Sunday 8th March 12:43
poing said:
Quite the opposite I would say, tuning turbo cars is really easy! The tuners will have to take into account the new tech and turbos but I think in a few years once the cars get into the hands of younger drivers they are going to tune the hell out of them. There are plenty of upgrades available for them already.
I doubt that tuners can get much more out of say a small ecoboost without compromising reliability.Not knocking the engine, but there's a lot less headroom as far as boost is concerned.
Back in the day a quick port and cam / carb change would get you an easy 25-50% power gain : by the late 80's / early 90's, it took a lot more work to gain 15% or so.
The same thing with turbos - the days of just winding the boost up are going, as the manufacturers do that in the factory.
My wife has a Polo with the 1.2 Tsi 105ps engine. It is a great little unit, very smooth and pulls really well in all normal driving. Even in 6th gear at normal a-road crusing speed, there is plenty of poke for hills and keeping up with traffic. As someone mentioned earlier, it seems to behave quite like a Diesel in its delivery - strong mid-range, but not much point going up to the redline (5.5k rpm feels like a sensible time to change when accelerating hard).
The only exception is 1st gear on small ish throttle (i.e <50%) openings. It feels as though the torque is being articifically limited. It's not from initial pull away, so not turbo lag but from around 2000-4000rpm. If you do the same in second gear, it actually accelerates more strongly. Similarly, if you floor it in first it picks up as you'd expect, but it's a bit all or nothing and you'll find yourself flying towards the back of the person in front when pulling away from lights etc.
Must be some throttle mapping going on to limit power on part throttle in 1st gear, probably for emissions reasons.
Just realised that I'd been busy reading other's responses about small engines rather than small engines in large cars that the OP asked about - oh well, ignore me!
The only exception is 1st gear on small ish throttle (i.e <50%) openings. It feels as though the torque is being articifically limited. It's not from initial pull away, so not turbo lag but from around 2000-4000rpm. If you do the same in second gear, it actually accelerates more strongly. Similarly, if you floor it in first it picks up as you'd expect, but it's a bit all or nothing and you'll find yourself flying towards the back of the person in front when pulling away from lights etc.
Must be some throttle mapping going on to limit power on part throttle in 1st gear, probably for emissions reasons.
Just realised that I'd been busy reading other's responses about small engines rather than small engines in large cars that the OP asked about - oh well, ignore me!
Edited by plfrench on Sunday 8th March 14:20
plfrench said:
My wife has a Polo with the 1.2 Tsi 105ps engine. It is a great little unit, very smooth and pulls really well in all normal driving. Even in 6th gear at normal a-road crusing speed, there is plenty of poke for hills and keeping up with traffic. As someone mentioned earlier, it seems to behave quite like a Diesel in its delivery - strong mid-range, but not much point going up to the redline (5.5k rpm feels like a sensible time to change when accelerating hard).
The only exception is 1st gear on small ish throttle (i.e <50%) openings. It feels as though the torque is being articifically limited. It's not from initial pull away, so not turbo lag but from around 2000-4000rpm. If you do the same in second gear, it actually accelerates more strongly. Similarly, if you floor it in first it picks up as you'd expect, but it's a bit all or nothing and you'll find yourself flying towards the back of the person in front when pulling away from lights etc.
Must be some throttle mapping going on to limit power on part throttle in 1st gear, probably for emissions reasons.
Just realised that I'd been busy reading other's responses about small engines rather than small engines in large cars that the OP asked about - oh well, ignore me!
I've always noticed exactly as you describe with the throttle in an Audi A1 1.2 TFSI which I have the use of. First gear definitely feels limited but once your in second it pulls strongly.The only exception is 1st gear on small ish throttle (i.e <50%) openings. It feels as though the torque is being articifically limited. It's not from initial pull away, so not turbo lag but from around 2000-4000rpm. If you do the same in second gear, it actually accelerates more strongly. Similarly, if you floor it in first it picks up as you'd expect, but it's a bit all or nothing and you'll find yourself flying towards the back of the person in front when pulling away from lights etc.
Must be some throttle mapping going on to limit power on part throttle in 1st gear, probably for emissions reasons.
Just realised that I'd been busy reading other's responses about small engines rather than small engines in large cars that the OP asked about - oh well, ignore me!
carparkno1 said:
Wife was intrigued by the new 1.2 petrol qashqai. God only know how hard that would have to work with two adults a teenager and a dog.
Wonder what the mpg would be.
5 of these at work as company cars and all used by differing age drivers and doing different journeys to and from work, yet none of them have got above 33mpg. Hateful engine and really a manufacturer should be ashamed of fitting something like this. Wonder what the mpg would be.
carparkno1 said:
Interesting. There's a 1.6 with 163bhp available as well. Given the choice I'd take that for the extra overtaking shove. I suppose if you mainly drive it around town then the 1.2 is fine but if you're on the motorway a lot would you want the extra power?
You have to drop to 4th on a mild incline at 70 to maintain the speed. It truly is crap. We have a mk7 golf 1.4 Tsi
I've tried driving it to get the quoted high mpg and it just doesn't happen. Tend to leave it in sport and it it gets about 10-12mpg more than the impreza. So mid to late 30's.
Have to really concentrate on Eco driving to get it to get anything decent.
Rather a 2.0 lazy n/a engine. Wouldn't go near any of these even smaller turbo'd things
I've tried driving it to get the quoted high mpg and it just doesn't happen. Tend to leave it in sport and it it gets about 10-12mpg more than the impreza. So mid to late 30's.
Have to really concentrate on Eco driving to get it to get anything decent.
Rather a 2.0 lazy n/a engine. Wouldn't go near any of these even smaller turbo'd things
skyrover said:
Willy Nilly said:
skyrover said:
Lets not forget the parasitic loss from driving the turbo...
not sure if seriousWilly Nilly said:
Turbo chargers use the energy from the waste exhaust gases exiting the engine to drive turbine to blow more air into the combustion chamber. I fail to see much in the way of measurable losses from driving the turbine.
They aren't usually considered "parasitic losses", but there's an enormous amount of combustion chamber evacuation efficiency lost due to the fact that you can't scavenge properly with a turbo in the way. Doens't really matter given that you have almost unlimited volumetric efficiency due to having control over the intake pressure. I suspect if you compare a turbocharger and a crank-driver supercharger producing the same intake pressure on the same engine, the difference in final power output will be much lower than the parasitic losses of the supercharger (although the turbocharger will obviously still generate appreciably more power).
Edited by kambites on Sunday 8th March 19:09
Driving a turbo takes energy - the fact that you have a restriction on the exhaust means that power is consumed to overcome that restriction - granted its not in the realms of what is required to turn a supercharger but it is still a loss and one that is measurable.
http://www.hotrod.com/how-to/engine/turbo-tech-q-a...
We have come a long way with engines and reliability is up there now - design tolerance and years of knowledge are behind some of the newer engine tech. Saab was a leader in small capacity blown fours to produce similar powers to low stressed V8 engines in the states. Look at the 9000 compared to some of the run of the mill American cars back in the 80 90's and then you have fuel economy saab was way ahead as they knew that turbos gave the power but when not working your engine was the same as a non turbo car so it would give pretty decent consumption. a 2.3 four pot against say a 5 litre V8 ? no comparison. People just had to get with the lower number of cylinders. Product placement rally and plugging the turbo as a trend setter.... it worked and it appealed to the professionals. Saab were on a roll.
Come forward to present day and we have small capacity engines that can produce decent power 125 hp from 1 litre ? that's good. saab were doing 260hp from 2.3 litres. if the engine is properly constructed and use is made of ceramics and modern materials there is no reason why such small capacity engines wont cover huge miles. As long as they are built to withstand the forces generated by producing that sort of power on a regular basis. We have cleaner fuels now with additives that keep engines clean - we have oils that protect and we have an engineering resource that has learned from the past. A small three cylinder engine of 1.5 litre produces 225hp in the i8. and there is scope for more. Some of the newer 4 cylinder engines are producing 350 hp reliably and it looks like were going to get a horsepower race with 4 cylinder engines which is good for development and for longlivity. You have an engine capable of producing 500hp regularly then you will have had enough research and engineering done on that car that it would break the company through warranty issues.
What is the limit for a small engine do you think we will see 200hp from sub litre engines. I hope so. I hope that we will challenge the emissions and the co2 and keep cars interesting and fun to drive.
http://www.hotrod.com/how-to/engine/turbo-tech-q-a...
We have come a long way with engines and reliability is up there now - design tolerance and years of knowledge are behind some of the newer engine tech. Saab was a leader in small capacity blown fours to produce similar powers to low stressed V8 engines in the states. Look at the 9000 compared to some of the run of the mill American cars back in the 80 90's and then you have fuel economy saab was way ahead as they knew that turbos gave the power but when not working your engine was the same as a non turbo car so it would give pretty decent consumption. a 2.3 four pot against say a 5 litre V8 ? no comparison. People just had to get with the lower number of cylinders. Product placement rally and plugging the turbo as a trend setter.... it worked and it appealed to the professionals. Saab were on a roll.
Come forward to present day and we have small capacity engines that can produce decent power 125 hp from 1 litre ? that's good. saab were doing 260hp from 2.3 litres. if the engine is properly constructed and use is made of ceramics and modern materials there is no reason why such small capacity engines wont cover huge miles. As long as they are built to withstand the forces generated by producing that sort of power on a regular basis. We have cleaner fuels now with additives that keep engines clean - we have oils that protect and we have an engineering resource that has learned from the past. A small three cylinder engine of 1.5 litre produces 225hp in the i8. and there is scope for more. Some of the newer 4 cylinder engines are producing 350 hp reliably and it looks like were going to get a horsepower race with 4 cylinder engines which is good for development and for longlivity. You have an engine capable of producing 500hp regularly then you will have had enough research and engineering done on that car that it would break the company through warranty issues.
What is the limit for a small engine do you think we will see 200hp from sub litre engines. I hope so. I hope that we will challenge the emissions and the co2 and keep cars interesting and fun to drive.
Did you know that you can get a 7-seat MPV with a 900cc two-cylinder petrol engine in it? http://www.parkers.co.uk/cars/reviews/fiat/500l-mp...
I've not driven the 7-seat version, but the 5 seat version is perfectly suited to the small engine. It produces 105bhp and 145Nm of torque after-all, which is way more than the old-skool 1.4 petrol you can also spec it with. No-one would ever accuse it of being fast, but it's happy and relaxed both in town and at motorway speeds. It's not the sort of car you'd expect to be fast anyway. 50mpg is easily achieved over the course of a tank.
I've not driven the 7-seat version, but the 5 seat version is perfectly suited to the small engine. It produces 105bhp and 145Nm of torque after-all, which is way more than the old-skool 1.4 petrol you can also spec it with. No-one would ever accuse it of being fast, but it's happy and relaxed both in town and at motorway speeds. It's not the sort of car you'd expect to be fast anyway. 50mpg is easily achieved over the course of a tank.
All the gnashing and wailing at a small turbocharged engine only putting out 125bhp to pull along the shopping cart. I thought this thread would be more about how these 80s bad boys...
...were sold with the old Peugeot 2.5D pushing out a massive 70bhp or thereabouts. Weighed around 1300-1400kg, so 0-60 in around 20s, and couldn't crack 100mph from memory.
...were sold with the old Peugeot 2.5D pushing out a massive 70bhp or thereabouts. Weighed around 1300-1400kg, so 0-60 in around 20s, and couldn't crack 100mph from memory.
ruggedscotty said:
Driving a turbo takes energy - the fact that you have a restriction on the exhaust means that power is consumed to overcome that restriction - granted its not in the realms of what is required to turn a supercharger but it is still a loss and one that is measurable.
Yes, but it is fundamentally no different to the "loss" associated with driving the "compression" stroke of one piston from the "power" stroke of another. The main advantage comes when you don't want the power, the losses on the turbo drop as you drive it lesd, whereas for the na engine you end up working against the throttle lossesPomBstard said:
All the gnashing and wailing at a small turbocharged engine only putting out 125bhp to pull along the shopping cart. I thought this thread would be more about how these 80s bad boys...
...were sold with the old Peugeot 2.5D pushing out a massive 70bhp or thereabouts. Weighed around 1300-1400kg, so 0-60 in around 20s, and couldn't crack 100mph from memory.
Or 70s diesels. Our first diesel in the family was a Pug 504 Family estate in 78 and it had a max speed of 89mph, a 0-60 of about 20s and the glowplugs took a whole minute to get the car ready to start....were sold with the old Peugeot 2.5D pushing out a massive 70bhp or thereabouts. Weighed around 1300-1400kg, so 0-60 in around 20s, and couldn't crack 100mph from memory.
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