Is torque really relevant?

Is torque really relevant?

Author
Discussion

nomis36

429 posts

163 months

Tuesday 7th July 2020
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Equus said:
But in the real world, it almost always does.

Proof of the pudding is in the driving. I defy you to drive a diesel against a petrol of similar BHP and say that it makes no difference.
Exactly! I’ve had a 3.0 m54 bmw (petrol) and a 3.0 M57 (diesel) both have the same bhp but the torque figures are vastly different. The diesel feels a hell of a lot faster and in an effortless way.

anonymous-user

53 months

Tuesday 7th July 2020
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Yeah right, diesel is the answer...

Not in my garage!!

Gary C

12,312 posts

178 months

Tuesday 7th July 2020
quotequote all
nomis36 said:
Equus said:
But in the real world, it almost always does.

Proof of the pudding is in the driving. I defy you to drive a diesel against a petrol of similar BHP and say that it makes no difference.
Exactly! I’ve had a 3.0 m54 bmw (petrol) and a 3.0 M57 (diesel) both have the same bhp but the torque figures are vastly different. The diesel feels a hell of a lot faster and in an effortless way.
Thats because your driving the petrol wrong !!!

wink

But slightly seriously, people do tend to thing cars with a turbo torque surge lower down do tend to feel the car is faster than when working an engine uptowards its rev limit, where actually, they are delivering similar torque to the hub of the (same size !) wheel.


Equus

16,766 posts

100 months

Tuesday 7th July 2020
quotequote all
Gary C said:
But slightly seriously, people do tend to thing cars with a turbo torque surge lower down do tend to feel the car is faster than when working an engine uptowards its rev limit, where actually, they are delivering similar torque to the hub...
But they're not.

The peak torque to the hub may be the same, but the total through the range of revs as the car accelerates in gear (ie. the area under the curve if you plot a graph of the torque) is greater.

ddom

6,657 posts

47 months

Wednesday 8th July 2020
quotequote all
Equus said:
But they're not.

The peak torque to the hub may be the same, but the total through the range of revs as the car accelerates in gear (ie. the area under the curve if you plot a graph of the torque) is greater.
I'd never take a 3.0 diesel over 3.0 petrol. All of the diesels are FI for a start, and they have a much, much more narrow power delivery. Peak torque over a condensed range is no match for a linear delivery across the rev range.

nomis36

429 posts

163 months

Wednesday 8th July 2020
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Equus

16,766 posts

100 months

Wednesday 8th July 2020
quotequote all
ddom said:
Peak torque over a condensed range is no match for a linear delivery across the rev range.
Come back when you understand how gearboxes work.

MC Bodge

21,551 posts

174 months

Wednesday 8th July 2020
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nomis36 said:
It's PCP rather than HP these days.

anonymous-user

53 months

Wednesday 8th July 2020
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Equus said:
Come back when you understand how gearboxes work.
What an odd thing to say, unless your idea of a great driving experience is a CVT transmission with a computer to run it. An infinite number of gears and steady rpm would lack a bit of character, I feel.


Equus

16,766 posts

100 months

Wednesday 8th July 2020
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rockin said:
What an odd thing to say, unless your idea of a great driving experience is a CVT transmission with a computer to run it.
Not at all - you don't need a 7,000rpm rev range when you have 5 (or more) gears, so having a broad spread of gutlessness just gives you more scope for being in the wrong gear. It's actually peaky petrol engines that benefit most from CVT's, and torquey diesels that are most flexible when there are gaps between the ratios.

The rev range of a modern diesel is more than adequate for anyone with the vaguest idea how to use a fixed-ratio gearbox.

anonymous-user

53 months

Wednesday 8th July 2020
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Heaven help us. I'll stick with my petrol engines and a bit of in gear flexibility thanks.

MC Bodge

21,551 posts

174 months

Wednesday 8th July 2020
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Gary C said:
But slightly seriously, people do tend to thing cars with a turbo torque surge lower down do tend to feel the car is faster than when working an engine uptowards its rev limit
Because when you are driving along, not revving the nuts off the engine (doing 10mpg) , the ability to immediately use the available surge to overtake on the motorway or climb a hill is a good thing.

It might not be ultimately faster, but at the moment you press the throttle down it is, and unless you intending to keep it there until maximum speed is reached.

Ps. Yes, I can rev match, heel & toe, double de-clutch.
....and break in a bronco, shoe a horse, lasso a cow, hunt a mammoth etc. wink

Edited by MC Bodge on Wednesday 8th July 09:02

Equus

16,766 posts

100 months

Wednesday 8th July 2020
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rockin said:
Heaven help us. I'll stick with my petrol engines and a bit of in gear flexibility thanks.
Then you're another one who doesn't understand gearing or torque.

There is greater 'in-gear flexibility' with a diesel, because it has better torque.

That's kind of the whole point of this discussion...

Welshbeef

49,633 posts

197 months

Wednesday 8th July 2020
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rockin said:
Heaven help us. I'll stick with my petrol engines and a bit of in gear flexibility thanks.
So you like big rev range and lots of gears.

Does that mean the AC cobra 427 isn’t for you or the Bentley Turbo R or any of the countless 4 speed sports cars of yester years.

Some cars only have 4 gears and have enough grunt that they can pull away in 4th all the way to v max

AC43

11,433 posts

207 months

Wednesday 8th July 2020
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Equus said:
rockin said:
Heaven help us. I'll stick with my petrol engines and a bit of in gear flexibility thanks.
Then you're another one who doesn't understand gearing or torque.

There is greater 'in-gear flexibility' with a diesel, because it has better torque.

That's kind of the whole point of this discussion...
I find the narrow, sudden-and-over-too-soon torque band of irritating, especially with a manual box. I don't mind peaky petrols so much but agree they can also be irritating, especially in traffic.

My favourite is relatively low stressed n/a petrols which have decent torque low down AND a proper top end. Add in large displacement and now you have something that pulls hard from 1500 RPM to 6500 or 7000.

That's my ideal way of getting the job done.

Mouse Rat

1,798 posts

91 months

Wednesday 8th July 2020
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Welshbeef said:
The problem is with all this “get in the right gear” view is less and less relevant on the public UK roads.

As any petrol head knows LEGAL speed limits you can only get MAX power in 1st and second gear whereas 3rd is in the 80-120mph range depending on how much grunt your car has as such changing down a few gears isn’t really that doable - unless of course do many here nip into 1st for the maximum attack out of a corner.
This sums it up why torque is relevant as you have the power most of the time. Petrol's have more power but less of the time.


V8RX7

26,762 posts

262 months

Wednesday 8th July 2020
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Welshbeef said:
Does that mean the AC cobra 427 isn’t for you or the Bentley Turbo R or any of the countless 4 speed sports cars of yester years.

Some cars only have 4 gears and have enough grunt that they can pull away in 4th all the way to v max
They certainly aren't for me - A Bentley is relaxing and a great cruiser but few call them fun.

I've driven many Cobra replicas a mate owned a 7 litre one and as I predicted, he soon tired of it - any gear, any revs it just goes for a few seconds before you worry about your licence, that's not fun.

Wringing the neck of a smaller engined car is fun (to me) although I didn't get on with the Integra R as it was too peaky for a daily driver

Equus

16,766 posts

100 months

Wednesday 8th July 2020
quotequote all
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!).

MC Bodge

21,551 posts

174 months

Wednesday 8th July 2020
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Mouse Rat said:
This sums it up why torque is relevant as you have the power most of the time. Petrol's have more power but less of the time.
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?

ddom

6,657 posts

47 months

Wednesday 8th July 2020
quotequote all
Equus said:
Come back when you understand how gearboxes work.
As most gearboxes mated dl diesels are auto your point is even more daft that it first appears.