Horsepower versus torque

[ShootMyMonkey]

Better mileage and a more efficient engine, less displacement is required to get the same overall HP.

Under the assumption that all else is equal. But if you're given the option of various types of powertrains, that isn't the case.

 

[Frank]

From another forum, a comparison of the same cars based on the closest kilogram per Kilowatt ratio available. All in metric units.

Weight kW   0-100 Top  Fuel      Car

1030   66   10.7  175  diesel    Toyota Yaris 1.4 D4-D Linea Terra
1000   64   13.1  170  gasoline  Toyota Yaris 1.3 16v VVT-i Linea Sol

1215   78   11.2  186  diesel    Renault Mégane Sedan 1.5 dCi 105 Privilège
1120   72   12.5  183  gasoline  Renault Mégane 1.4 16V Accès
 
1245   80   10.8  186  diesel    Mercedes-Benz A 180 CDI Avantgarde
1095   70   12.6  175  gasoline  Mercedes-Benz A 150 Classic
 
1718   110  11.3  180  diesel    Hyundai Santa Fe 2.2 CRDi VGT 2WD AV
1547   99   12.2  174  gasoline  Hyundai Santa Fe 2.0i 16V 2WD AV

1263   81   11.5  183  diesel    Ford Focus 1.6 TDCi 109pk Trend Automatic
1154   74   10.9  185  gasoline  Ford Focus 1.6 16V Futura

1244   80   12.4  192  diesel    Citroen C4 Coupé 1.6 HDi 16V 110pk VTR
1249   80   14.6  188  gasoline  Citroen C4 1.6 16V Ligne Prestige

The Ford diesel is the only one with an automatic transmission.


Edit: the kg/kW header should read simply kW. Corrected.

 

[Frank]

Only really the corvette z06 since it has a 7k redline and has enough torque to allow for a huge first gear.
A viper btw has to shift and still manages 3.9 seconds.
Besides, with clutchless manuals and DSG trannys there's almost no lag between shifts.. and for DSG there's none at all.

Nah, there are actually plenty cars who go 60 mph in first gear. There are much less who can come close to 3 seconds while having to shift. But I don't know what I would count as the best performance. Having to shift and still be that fast is VERY good.

 

[RobertR1]

A good driver can powershift a car within a 1/10-2/10 of a second. It's not that big of a deal really. Controlling wheelspin during launch are much more critical. Also, a street 0-60time is a lot slower than mag tests due to less traction available.

 

[Frank]

A good driver can powershift a car within a 1/10-2/10 of a second. It's not that big of a deal really. Controlling wheelspin during launch are much more critical. Also, a street 0-60time is a lot slower than mag tests due to less traction available.

Yes, I agree. The better heel-and-toe work combined with revving the engine as high as it needs to go will make you accelerate up to a quarter faster than the factory figures. But not many people know how to do that.


Then again, with those diesel engines you have less reason to do so, and they only burn about half the fuel.

 

[MPI]

Yes, I agree. The better heel-and-toe work combined with revving the engine as high as it needs to go will make you accelerate up to a quarter faster than the factory figures. But not many people know how to do that.

What the hell is heel-and-toe good for on the quarter mile?

Then again, with those diesel engines you have less reason to do so, and they only burn about half the fuel.

Bollocks. Diesels by their nature have a narrower powerband overall compared to petrol engines, all else equal.

Why do you think manual diesels often comes in 6-speed? Or that diesel lorries/buses have 1152 gears? Now, I think TDI's have come a long way in the past decade, but all this praise is getting a little out of hand...

 

[Frank]

What the hell is heel-and-toe good for on the quarter mile?

For enduring less stall while shifting. It increases your score.

Bollocks. Diesels by their nature have a narrower powerband overall compared to petrol engines, all else equal.

Why do you think manual diesels often comes in 6-speed? Or that diesel lorries/buses have 1152 gears? Now, I think TDI's have come a long way in the past decade, but all this praise is getting a little out of hand...

Well, for starters, non-turbocharged diesels have almost gone the way of the dodo by now in consumer cars. And second, those turbo-diesels are that good.

Then again, you might state that turbocharged gasoline engines are even better. But they are limited to the high-end segment here in Europe, because they consume three or four times the amount of fuel of a comparable turbo-diesel engine. And they're not that much better.

 

[MPI]

For enduring less stall while shifting. It increases your score.

Do you even know what heel'n'toe is?

Well, for starters, non-turbocharged diesels have almost gone the way of the dodo by now in consumer cars. And second, those turbo-diesels are that good.

And yet they have 6 gears, like the 170bhp Golf TDI... Why is that? Inquiring minds want to know...

Then again, you might state that turbocharged gasoline engines are even better. But they are limited to the high-end segment here in Europe, because they consume three or four times the amount of fuel of a comparable turbo-diesel engine. And they're not that much better.

Now you're just pulling crap out of your ass... three or four times? Now, diesels ARE more efficient, but COME ON...

 

[RobertR1]

Yes, I agree. The better heel-and-toe work combined with revving the engine as high as it needs to go will make you accelerate up to a quarter faster than the factory figures. But not many people know how to do that.


Then again, with those diesel engines you have less reason to do so, and they only burn about half the fuel.

Heel and toe is a downshifting technique not upshifting. Power shifting = staying on the gas in between shifts instead of letting up. You can't really do on high HP cars though as the surge of power from powershifting will create too much wheel spin. The point is to lunge/launch the car forward to make up the time lost in shifting. The over rev from powershifting gives it another launch from the speed the vehicle is already traveling at. Necessary disclaimers about oversteer apply

 

[Frank]

Do you even know what heel'n'toe is?

Well, yes, I think so. Keep pressing the gas pedal while braking and clutching. Which you do to reduce the time it takes your car to get back up to speed after shifting gear. Right?

And yet they have 6 gears, like the 170bhp Golf TDI... Why is that? Inquiring minds want to know...

Most recent cars have six gears. It increases the fuel efficiency when cruising on the highway, and it allows the shifts to be a bit shorter, thereby increasing maximum acceleration.

Now you're just pulling crap out of your ass... three or four times? Now, diesels ARE more efficient, but COME ON...

Do you have different figures?

 

[Frank]

Ah, yes. Stupid of me. Yes, heel-and-toe only works when downshifting. Sorry about that.

 

[RobertR1]

Well, yes, I think so. Keep pressing the gas pedal while braking and clutching. Which you do to reduce the time it takes your car to get back up to speed after shifting gear. Right?

Yes but why would you be braking when you're tyring to 0-60, 1/4mile? Heel toe is only for downshifting to match the revs (bring your rpms up to where the downshift would bring them at) when you're coming into a corner to not upset the balance of the car.

Edit: nm, I see you just posted right above no worries.

 

[thorny]

Most recent cars have six gears. It increases the fuel efficiency when cruising on the highway, and it allows the shifts to be a bit shorter, thereby increasing maximum acceleration.

Do you have different figures?

Actually it's interesting how similar the fuel consumption figures can be between modern petrol and diesel engines. They can be very similar unless you need a big car (from a European perspective):

Toyota Argo 1.0 61 mpg, 1.4 diesel 68 mpg. 11% less efficient
Golf 1.4TSI 39 mpg, 2.0 tdi diesel 49 mpg. 20% less efficient
Honda Civic 1.8vtec 44 mpg, diesel 55.4. 20% less efficient
BMW 3 Series 330i 32.5 mpg, 330d diesel 43.5. 25% less efficient

In all case except the Civic the petrol has a faster 0-60 time.

 

[scooby_dooby]

Yes, I agree. The better heel-and-toe work combined with revving the engine as high as it needs to go will make you accelerate up to a quarter faster than the factory figures. But not many people know how to do that.

lol, Heel-Toe is when you're braking!

But, on the topic of powershifting...it's bad..mmkay?? It works damn well, but if you have any love for your drivetrain you won't do it.

 

[RobertR1]

But, on the topic of powershifting...it's bad..mmkay?? It works damn well, but if you have any love for your drivetrain you won't do it.

My ex-flywheels agree with you

 

[KimB]

But, on the topic of powershifting...it's bad..mmkay?? It works damn well, but if you have any love for your drivetrain you won't do it.

Well hell, man, if you're driving for max performance, you can't care much about keeping your car in good shape for long without maintenance.

 

[Frank]

Actually it's interesting how similar the fuel consumption figures can be between modern petrol and diesel engines. They can be very similar unless you need a big car (from a European perspective):

Toyota Argo 1.0 61 mpg, 1.4 diesel 68 mpg. 11% less efficient
Golf 1.4TSI 39 mpg, 2.0 tdi diesel 49 mpg. 20% less efficient
Honda Civic 1.8vtec 44 mpg, diesel 55.4. 20% less efficient
BMW 3 Series 330i 32.5 mpg, 330d diesel 43.5. 25% less efficient

In all case except the Civic the petrol has a faster 0-60 time.

What does it mean? I don't understand. Can you explain that a bit better?


Anyway, while turbocharged gasoline engines have factory mileage figures which aren't that bad, to have a comparable mileage figure yourself, you should drive it really gentle. In which case, I would wonder why you bought such an engine in the first place. Otherwise, you could expect 6-10 miles per gallon.

 

[RussSchultz]

DiGuru,

Where do you pull this stuff from?

I have a turbo-charged gasoline engine (250 hp), and I get well within the EPA estimates.

18 city, 26 highway is what the sticker says. On my normal day/day driving, I get about 23 if I'm gentle, and about 22 when I jackrabbit around. And I live in a very hilly city. On a full tank on the freeway, I get better than 26.

 

[Frank]

DiGuru,

Where do you pull this stuff from?

I have a turbo-charged gasoline engine (250 hp), and I get well within the EPA estimates.

18 city, 26 highway is what the sticker says. On my normal day/day driving, I get about 23 if I'm gentle, and about 22 when I jackrabbit around. And I live in a very hilly city. On a full tank on the freeway, I get better than 26.

Ok, that sounds pretty good. In that case I'm sorely mistaken.

It might be the difference between using them to commute every day, and test-driving them. Because I (and many journalists) are close to or below 8 MPG when they get to drive such a car for a few hours or days.

 

[RussSchultz]

Yes, if you put the computer on instantaneous mileage, and you accelerate from 0-60 in 6 seconds, you see your mileage drop into the single digits.

Its kinda hard to do a full tank of gas that way, though.