Is torque really relevant?
Discussion
Equus said:
AC43 said:
I find the narrow, sudden-and-over-too-soon torque band of irritating, especially with a manual box.
Have you driven a modern diesel?That certainly used to be the case in the early days, where you would get nothing, then a 500rpm band of turbo, then the rev limiter - I briefly had to suffer an Escort turbodiesel as a company car back in the '90's that was like that.
Modern diesels have come a long way, and will pull strongly and seamlessly from pretty much tickover to a rev limit typically close to 5000rpm - producing over 100bhp per litre in the process (I remember when the Lotus Esprit Turbo was considered highly strung, with a lower specific power output than that!).
Equus said:
ddom said:
As most gearboxes mated dl diesels are auto your point is even more daft that it first appears.
Not at all, because autoboxes have fixed ratios too.I'm sorry, but you clearly don't have a clue what you're talking about.
MC Bodge said:
Torque on demand, whilst at cruising rpm, is desirable.
That's what drivers need/like during normal driving. Revving out the engine through the gears is a different matter.
Is it a difficult concept?
5 of cars that I own/previously owned have this specific characteristic. I like nippy/fast road cars and as is evident from my list petrol or diesel fun is easily achievable. That's what drivers need/like during normal driving. Revving out the engine through the gears is a different matter.
Is it a difficult concept?
Fiat Coupe 20V Turbo
E90 330d (auto)6 speed
C5 RS5 (auto)5 speed
F10 535d (auto)8 speed
S205 C63 (auto)7 speed
Then looking at some of my wife’s cars 1 does two others don’t.
Seat Leon Cupra 1.8Turbo
But the below cars she has /does own are not torque on demand
Honda Accord estate 2.2TDCI
S Max 2.0 TDCI
LimSlip said:
Equus said:
ddom said:
As most gearboxes mated dl diesels are auto your point is even more daft that it first appears.
Not at all, because autoboxes have fixed ratios too.I'm sorry, but you clearly don't have a clue what you're talking about.
RobM77 said:
I've found BMWs the most revvy by far.
I moved directly from AC43's favourite - a large petrol engine in the form of a 5.5 litre V8 Mercedes S-class - to a Jaguar 3.0 V6 diesel, and the delivery of the two engines is close enough not to be noticeably different in the real world.Certainly much closer than the big V8 petrol and a 'normal' (<2.0, 4 cylinder) petrol engine.
Equus said:
Not at all, because autoboxes have fixed ratios too.
I'm sorry, but you clearly don't have a clue what you're talking about.
As usual you think your opinion is the only one that matters. Clearly you haven’t driven that many larger capacity petrol engined cars, or you are just being argumentative as is the norm. A fixed ratio automatic, what are you on about? A well set up engine with a wise spread of power and linear delivery is perfect. FI and modern auto boxes try to do this but it’s still no substitute IMO. I'm sorry, but you clearly don't have a clue what you're talking about.
RobM77 said:
LimSlip said:
Equus said:
ddom said:
As most gearboxes mated dl diesels are auto your point is even more daft that it first appears.
Not at all, because autoboxes have fixed ratios too.I'm sorry, but you clearly don't have a clue what you're talking about.
If you drive a modern autobox like the ZF 8 speed, you won't be aware of any 'slush' at all, really. It's a quite remarkable bit of kit, compared to the prehistoric 3-speed jobs that I get the impression that most PistonHeaders are still regurgitating received wisdom about.
Even without torque converter lock-up, a conventional autobox still has fixed ratios - the torque converter merely 'blurs' the torque delivery a bit.
Edited by Equus on Wednesday 8th July 09:40
Well this has become far too beardy for me.
While I basically understand and appreciate what everyone is saying, and both sides of the argument have valid points, I think the major factor for the OP is what sort of driving profile he has.
For the last decade for daily driving I choose diesel & auto (have had a few modern BMWs in this configuration - currently 640d GC) and for weekends will always choose petrol (gearbox will depend on how I feel at the time, what is available in the car I'm looking at and how often/where I intend to use it).
If in my daily and a long way from home I may occasionally wish I had more power. At the weekends when climbing out of a tight corner I may wish I had more torque. Ultimately each suit my needs better 99% of the time than swapping for the other.
I agree with the whole 'large throttle response for small input leaves you dissatisfied' discussion on modern electronic controlled cars though!
While I basically understand and appreciate what everyone is saying, and both sides of the argument have valid points, I think the major factor for the OP is what sort of driving profile he has.
For the last decade for daily driving I choose diesel & auto (have had a few modern BMWs in this configuration - currently 640d GC) and for weekends will always choose petrol (gearbox will depend on how I feel at the time, what is available in the car I'm looking at and how often/where I intend to use it).
If in my daily and a long way from home I may occasionally wish I had more power. At the weekends when climbing out of a tight corner I may wish I had more torque. Ultimately each suit my needs better 99% of the time than swapping for the other.
I agree with the whole 'large throttle response for small input leaves you dissatisfied' discussion on modern electronic controlled cars though!
Equus said:
This.
If you drive a modern autobox like the ZF 8 speed, you won't be aware of any 'slush' at all, really. It's a quite remarkable bit of kit, compared to the prehistoric 3-speed jobs that I get the impression that most PistonHeaders are still regurgitating received wisdom about.
And why is the ZF8 a better match for something like a 320d......because it’s got a narrow powerband and needs to be kept at threshold to make it enjoyable. If you drive a modern autobox like the ZF 8 speed, you won't be aware of any 'slush' at all, really. It's a quite remarkable bit of kit, compared to the prehistoric 3-speed jobs that I get the impression that most PistonHeaders are still regurgitating received wisdom about.
Ron99 said:
John Locke said:
One quality which a diesel, indeed any turbocharged engine doesn’t have is good throttle response. For that a naturally aspirated or supercharged petrol engine is needed, or better, an electric motor.
Generally speaking the more an engine depends on a turbo for power, the worse the throttle response.For example, a 1.6T with large turbo to attain 270hp has a lot more lag than a 1.6T with small turbo for 170hp.
ddom said:
And why is the ZF8 a better match for something like a 320d......because it’s got a narrow powerband and needs to be kept at threshold to make it enjoyable.
The ZF8 is a good box, period. I've never driven it on something with as small an engine as a 320d, but on the bigger capacity cars I've experienced it on, it works well with both petrol and diesel.What is your experience? Still being remarkably tight lipped, whilst spouting such obvious bulls
t that I'm almost tempted to believe that you don't even hold a licence.As a general rule I much prefer lots of torque and a turbo in a daily, but I'm happy enough with high revs and not much torque in a weekend fun car though.
For example I didn't like my E92 M3 as a daily, but I'd be very happy with it to use occasionally on nice clear roads though for sure.
For example I didn't like my E92 M3 as a daily, but I'd be very happy with it to use occasionally on nice clear roads though for sure.
ddom said:
In this instance dozens of hire cars. All modern diesels.
But your implication was that you have much greater experience than me of large capacity petrol.You already know that I used to have a 5 litre TVR, and the post immediately above yours tells you that I also recently owned a 5.5 litre Mercedes. There have been many others, but I'm interested to know what your experience is?
Can we discuss all the people saying diesels have a narrow powerband? Because the opposite is my experience.
If you look at a torque/BHP curve on most dyno cars I've seen the torque curve has long domed torque curve and a rapidly rising bhp curve which cuts the torque curve at midway and then reaches a narrow peak before falling back down.
Generally in diesels the torque curve is predominant, and in petrol the peak is predominant.
I really don't understand then how people keep saying the power band in a diesel is small as it is represented by the area under the long domed curve. It certainly looks like its the petrol with the narrow powerband not the diesel.
Which explains why diesels change gear less often. I think people are being fooled by the fact that the petrol engine rises steeply to a narrow power band and the diesel never has that and and relies on less power but over a longer powerband.
I guess turbos disguise both to an extent but you can really tell on discussions like this people who have no experience of any cars prior to the modern ones.
If you look at a torque/BHP curve on most dyno cars I've seen the torque curve has long domed torque curve and a rapidly rising bhp curve which cuts the torque curve at midway and then reaches a narrow peak before falling back down.
Generally in diesels the torque curve is predominant, and in petrol the peak is predominant.
I really don't understand then how people keep saying the power band in a diesel is small as it is represented by the area under the long domed curve. It certainly looks like its the petrol with the narrow powerband not the diesel.
Which explains why diesels change gear less often. I think people are being fooled by the fact that the petrol engine rises steeply to a narrow power band and the diesel never has that and and relies on less power but over a longer powerband.
I guess turbos disguise both to an extent but you can really tell on discussions like this people who have no experience of any cars prior to the modern ones.
ddom said:
Equus said:
This.
If you drive a modern autobox like the ZF 8 speed, you won't be aware of any 'slush' at all, really. It's a quite remarkable bit of kit, compared to the prehistoric 3-speed jobs that I get the impression that most PistonHeaders are still regurgitating received wisdom about.
And why is the ZF8 a better match for something like a 320d......because it’s got a narrow powerband and needs to be kept at threshold to make it enjoyable. If you drive a modern autobox like the ZF 8 speed, you won't be aware of any 'slush' at all, really. It's a quite remarkable bit of kit, compared to the prehistoric 3-speed jobs that I get the impression that most PistonHeaders are still regurgitating received wisdom about.
Which model of 320d have you driven? My two E90s had pretty wide power bands for diesels.RobM77 said:
Which model of 320d have you driven? My two E90s had pretty wide power bands for diesels.If you look at his posting history, his comments on almost every topic are extremely non-specific and look a lot like opinions that have been picked up by reading stuff on the internet.
Equus said:
The ZF8 is a good box, period. I've never driven it on something with as small an engine as a 320d, but on the bigger capacity cars I've experienced it on, it works well with both petrol and diesel.
What is your experience? Still being remarkably tight lipped, whilst spouting such obvious bullst that I'm almost tempted to believe that you don't even hold a licence.
Which is fine if you are going to choose an automatic, personally I’ll take a manual. And a manual IME is not well suited to a modern diesel. If you had driven smaller engined modern diesel cars you’d be better placed to understand torque, and this topic. Try something like the 1.4 TFSI in manual and auto. It’s night and day. What is your experience? Still being remarkably tight lipped, whilst spouting such obvious bulls
t that I'm almost tempted to believe that you don't even hold a licence.Gassing Station | General Gassing | Top of Page | What's New | My Stuff