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Discussion Starter · #1 ·
my tickover seems very high around 1000rpm at rest is this normal for this engine? i have had a honda civic 1.0ltr 3 cylinder previous and that ticked over around 8000 ...be grateful for any input on my query ...thanks
 

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belknap said:
my tickover seems very high around 1000rpm at rest is this normal for this engine? i have had a honda civic 1.0ltr 3 cylinder previous and that ticked over around 8000 ...be grateful for any input on my query ...thanks
Sounds about right, is that rpm from cold or warmed up? I would of expected a range of between 900-1000 rpm at tickover TBH.
 

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belknap said:
that's warmed up 1000rpm ...yes on cold slightly higher ...thanks
No issues there, don't forget it is a small capacity three cylinder 1 litre, so off boost has low torque and power, hence higher tickover. At the same time being a lower size/CC engine it will be using less fuel on tickover.
 

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Discussion Starter · #5 ·
many thanks ..that's reassuring .i love the car not as quick as the honda three cylinder but a much better car all round
 

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belknap said:
many thanks ..that's reassuring .i love the car not as quick as the honda three cylinder but a much better car all round
It is a good engine but agree also not the best, better than the Ford and Vauxahll 3 cylinder but the Honda and slightly larger PSA 1.2, 3 cylinder (we have the PSA 130 in our Grandland X - very impressed so far) do seem to be better performance wise. I think the biggest element is that max torque is not reached until 2000 rpm where similar engines are 1500 rpm.
 

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Cyberbob said:
I think the biggest element is that max torque is not reached until 2000 rpm where similar engines are 1500 rpm.
I questioned your figure in this
Arona max torque.

SEAT figures indicate max torque is more likely around 2700 r.p.m.

Cyberbob, where are you getting this figure of 2000 r.p.m.? SEAT say this is the low end of the max torque range. Where is the information regarding max torque for "similar engines"?

Sorry if I come across as a little confrontational but on car forums you do get a lot of hearsay or conjecture pushed as fact. People need to be able to back up their figures or they will be challenged by fellow enthusiasts.
 

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The Vauxhall Grandland X 1.2l engine gives max torque of 230Nm at 1750 rpm
https://www.vauxhall.co.uk/cars/grandland-x/engines-and-data/engines.html

The ford 1.0l ecobost engine appears to have max torque output of 170Nm that is flat between 1400 and 4000 rpm see graph on last page of
https://media.ford.com/content/dam/fordmedia/Europe/en/2013/Features/The%20Ecoboost%20Engine/Focus1.0-litre%20EcoBoost_TechSpecs_EU.pdf

The Arona according to the link below has max torque of 200Nm between 2000 and 3750rpm . I am still looking for a graph.
https://www.seat.co.uk/new-cars/arona/technical-data/fr.html

Because these are turbo engines the torque curve is essentially flat within a rpm range.

The links above seem to agree with Cyberbobs assertion that the VW 1.0l TSI engine reaches the start of the max torque band at a higher engine speed than that of similar offerings from some other manufacturers.
 

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Here is a power/torque graph for the 115PS (85kW) 10l TSI engine. Showing max torque from 2000 rpm. Although it does start to build from 1750.
 

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Dunkelmann said:
Cyberbob said:
I think the biggest element is that max torque is not reached until 2000 rpm where similar engines are 1500 rpm.
I questioned your figure in this
Arona max torque.

SEAT figures indicate max torque is more likely around 2700 r.p.m.

Cyberbob, where are you getting this figure of 2000 r.p.m. you keep wrongly stating? SEAT say this is the low end of the max torque range. Perhaps you are not familiar with torque curves (then see the reference in the post referred to above). Also where is the information regarding max torque for "similar engines"?

Sorry if I come across as a little confrontational but on car forums you do get a lot of hearsay or conjecture pushed as fact. People need to be able to back up their figures or they will be challenged by fellow enthusiasts.
I never take offence or gate for that matter as that would be theft :lol:

TBH, I know very little about cars in the wider scheme of things... I just use manufacturers figures found in their brochures 'tech spec.' I wrote the below some years ago for Seatcupra.net as fits in with your post on the last thread you redirected to.. Although derv v n/a petrol!

One person I do know has said they thought the 110 1.2 TSi they had prior to the 1 litre 115 was more 'driveable' they put it down to where max torque hit, compared to 1.2. As they have owned a 1.2 110 then 1 litre 110 MK4 Toledo.

"In reality it is the torque that reaches the drive wheels that dictates both acceleration AND max speed. This figure is comprised of engine torque and gearing.

Higher engine torque = higher torque at the wheels = higher acceleration.
Lower gearing = higher torque at the wheels = higher acceleration.
Remember that TORQUE is the only engine output a driver feels. Power is a kind of esoteric measure that is simply calculated from Torque and Engine Speed. If we are talking "BHP" and "lbs.ft" then the equation is:-
Power= (Torque x rpm)/5252

But the power on most cars is rated at the flywheel and not the wheels so the power loss through various transmissions is:
FWD 15%
RWD 20%
4WD 25%

Power dictates how much advantage you can make of gearing. I've seen a few analogies before, but the best one I've have ever seen is the analogy of the human body as we all now the basics of how we work don't we? So I shall use this analogy of Bill and Ben on their bikes.
Torque is what your legs generate. If you press harder on the pedals you'll accelerate harder. You use the gears on your bike to multiply the torque your legs generate. In 1st gear the bike wheel may only rotate once for every 5 times you spin the pedals. In this gear you can zip up a hill (or accelerate really quickly), as this has the gearing has the effect of multiplying your leg power by 5.
If you maintain a steady force on the pedals, the bike accelerates at a steady rate. The torque you are generating stays constant, but the faster you spin your legs the more power you muster. Eventually you discover that you run out of steam and cannot peddle any faster, and you can't really get any force into your leg strokes. This is like your engine going up to and beyond its' peak power point.
Higher gears allow you to move along quickly whilst your legs go round at a comfortable pace. Nice one. Try to pull away from a standstill in the same gear however and (without enormous multiplication of your leg strength) it'll take you significantly longer to get up to speed.
Bill and Ben are out two examples of engine. Bill has very strong legs. But struggles to pedal very fast. So whilst he can put allot of force into each revolution, he can only manage slow rotations. This is the good old TDi

Ben conversely has very athletic and supple legs - . He has however very flexible and fast moving ankle muscles (think Variable Valve Timing VVT) that helps him to peddle very fast. Although his legs lack power he can pedal very fast.
We line them up on the drag strip and the light goes green and Away!! Bill storms into the lead, his rear tyre barely able to contain the thrust created by those strong legs. But he soon cannot peddle any faster, and he's quickly forced to change up into second, then third…and look at this! Ben is staging a comeback, still in first with his legs going round allot faster than Bills. Whilst Bill is producing major leg thrust, he's currently using 3rd gear, which only doubles the torque his legs generate before it reaches the rear wheel. Bill is still in first, so his supple legs continues to be subject to 5-times multiplication…and he's reeling Bill in!
It's a similar story when they are up to maximum speed. By enormous coincidence they appear to have an identical flat-out pace. Bill is pumping his top gear firmly and steadily ~ wind resistance and friction conspire against him - he can go no faster. Ben is right up there with him, but he's still in 3rd his legs pedaling faster than Bill.

Back to the world of cars. You should now be able to understand why TDI's are often quoted as having "massive in-gear thrust", whilst it's acknowledged that they are not quite as good when it comes to both "0-60" and top speed although they are catching up in BMW 335D or 125d. Most TDI's barely get to 60 in third, so in addition to requiring an extra gear change over most petrol models, they pass "the magic 60" in 3rd ~ which is by definition higher geared than 2nd, so torque is multiplied to a lesser extent before it gets the chance to arrive at the drivewheel and "do the business". This gearbox multiplication is the real important factor and why two engines of the same power output can seem faster.
As diesels operate using compression ignition they don't require spark plugs. This omission unfortunately makes advancing the spark somewhat difficult the main cause of their high rpm torque deficit. Also needing a longer stroke for compression reasons also inhibits high RPM.
Because ignition cannot be adjusted like a petrol car they cannot rev to such a high level as a petrol engine.

A VVT engine with 140lbs.ft max torque CANNOT punch as hard as a BM Diesel with 290lbs.ft. In a VVT engine however you will choose to accelerate with a lower gear than the derv, so the torque it does have is multiplied to a greater extent before it reaches the wheels. A TDI might feel impressive in 4th~ certainly more impressive than a petrol in 4th, but the petrol driver would undoubtedly pop it into 3rd (or even 2nd) to make better progress. The TDI has no such option. So high RPM means that we can stay in a lower gear for longer!!
As a rule - lower gearing makes better use of what torque you have available, but leads to unfashionably (and often uncomfortably) high-rev cruising.

This gearbox multiplication is the real important factor and why two engines of the same power output can seem faster. It is also why some people say this engine feels more tourqey even though engine A has the same power/torque as engine B.
Another note needs to be made of chipping, most engine re-maps will increase the power but it is the torque that they concentrate on.
As the increase in Power for a diesel comes from an increase in fuel/air density which comes from the injection pressure currently at 2000 for a common rail system. The increased pressure gives more torque at any set engine speed for a like for like engine capacity. This leads to smaller more powerful engines able to match Petrol via the Gearbox/torque ratio.
let's look at a F1 car example:

Assume 800hp at 18000rpm. Using the equation at the start (Power= (Torque x rpm)/5252), we can see that it is only producing 233lbs.ft at this point. Not a lot really….a 1.9TDI VAG unit produces up to 235lbs.ft.
However if we want it to do 210mph, then our mega-revvy F1 engine only needs a top gear pulling 12mph per 1000rpm. Which is barely higher than 2nd gear in most road cars. Hence the "torque multiplier" from the gearing is massive, and you can still spin those fat rear slicks in top gear. Massive power allows vast exploitation of gearing. (I would guess gearing ratio in top is approx 6.5:1. So the engines' 233lbs.ft becomes 1500+ lbs.ft to be shared between the rear wheels).

What if you could extend the rev range further? Let's double it to 36000rpm. With this, the same car could use gearing of only 6mph per 1000rpm (about the same as 1st in a road car) and still manage 210mph. All 800 horses are still required (and produced), although only 116.5 lbs.ft torque is required to create it at this astronomical engine speed. Has the torque arriving at the wheels changed? (No). You can see why F1 engineers love engines that rev."
 

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OK, Nigel and Bob, I get it now. It is the turbo that makes the difference in that it forces a constant mix over a rev range, unlike normally aspirated engines. This constant mix determines the torque.

There is a lot more detail here.

On my daughter's Fabia the turbo does seem to kick in at lawer revs.
 

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Dunkelmann said:
OK, Nigel and Bob, I get it now. It is the turbo that makes the difference in that it forces a constant mix over a rev range, unlike normally aspirated engines. This constant mix determines the torque.

There is a lot more detail here.

On my daughter's Fabia the turbo does seem to kick in at lawer revs.
Thanks for the link - really interesting :mrgreen:

I never stop learning something new on forums thanks Dunkelmann!
 
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