An unimportant question about lorries

asbokid

the horse power of truck engines is surprising modest for such huge vehicles..

This £200,000 Mercedes SLS driven by the odious Jonathan Ross can push 563 hp..

Flying-High_2

asbokid wrote: »

the horse power of truck engines is surprising modest for such huge vehicles..

Jonathan Ross's £200,000 Mercedes SLS can push 563 hp..

Its not all about BHP though is it.... Lets Torque..:D

marksandsparx

Torque is king!!

asbokid

According to Wonkypedia, horsepower and torque are related by the formula..

BHP = torque * 2π * RPM / 33000

which simplifies to

BHP = torque * RPM / 5252 or

torque (lb ft) = BHP / RPM * 5252

Returning to the BBC parasite, Jonathan Ross, and his obscene £200,000 Mercedes SLS AMG...

The Merc's 6.2 litre V8 engine produces 563hp @ 6800 rpm (1)

torque = 563 / 6800 * 5252 = 432 lb ft (585 Nm)

However, its peak torque of 480 lb ft is achieved at just 4750 rpm, when

BHP = 480 * 4750 / 5252 = 434bhp

According to a press release from Volvo Trucks, the engine in its FH16 truck has 700 hp and 3150 Nm (2323 lb ft) of torque. (2)

So the Volvo has just 20% more horsepower than Ross's Merc, but nearly six times its torque!

(1) http://en.wikipedia.org/wiki/Mercedes-Benz_SLS_AMG

(2) http://www.volvotrucks.com/trucks/global/en-gb/newsmedia/pressreleases/pages/press_article.aspx?pubId=5952

Flying-High_2

Or a more smilar BHP/Torque comparison would be Scanis 560 motor.... 560bhp and 2700Nm between 1100ish & 1400ish RPM....

Hammyman

asbokid wrote: »

the horse power of truck engines is surprising modest for such huge vehicles..

This £200,000 Mercedes SLS driven by the odious Jonathan Ross can push 563 hp..

BHP counts for absolutely nothing when you're trying to move 44 tonnes of lorry. Although some of the lorries I drove only had 420BHP, they had in excess of 2000Nm of torque. Somehow I doubt that Mercedes comes even close to half of that torque figure.

Hammyman

asbokid wrote: »

So the Volvo has just 20% more horsepower than Ross's Merc, but nearly six times its torque!

Not only that, in Ross's Merc, the max torque will typically be around 4000RPM or higher whereas on most lorries its under 1000RPM.

skiddlydiddly

The Ferrari might pull 44 tonnes....once, for about a foot.Then it would be new clutch time and a few grand bill.

Look at this for power.

http://www.liveleak.com/view?i=c2b_1296324091

fadetogrey

marksandsparx wrote: »

Yeah they can! to be honest some of the 420 hp ones can shift with a trailer!!

not really they are all governed to 55 mph.

Flying-High_2

Hammyman wrote: »

Not only that, in Ross's Merc, the max torque will typically be around 4000RPM or higher whereas on most lorries its under 1000RPM.

Out of Interest which Trucks are making peak Torque at under 1000rpm?