Luke Kay

Before I had my 2006 STi, my dad had a fair bit of work done to the engine. He had forged pistons and rods and generally anytiing short of a fully closed deck block and turbo upgrade he had done. 21psi of boost, 660cc injectors, and a tune later, the car made about 330hp and 470ft-lbs of torque. He said he asked for it to be mapped for "max torque" as opposed to making max power.
The car is stupid quick and when it gets to 3500rpm it absolutely pins me back with a car full of people. Just curious as to what other guys on here are running, and seen as though torque is useful for low end driving, why have most people I've seen on here who daily their car got less or equal torque compared to their power? If my car made same power but with only 340ft-lbs, would it be/feel slower than the car as it stands now? Just curious because I swear this car can do mid to high 3 second 0-60s if you're quick enough shifting, and 60-100mph on a straight road takes about 4.7 seconds. I've only seen one dyno graph of it and it made a little less of Both power and torque figures, but is an 8-9 second 0-100mph possible at this power level? Me and my mum both think the car has more power than my dad says it has, but is that just the torque giving the illusion of it pulling harder? Sorry for rambling but the power and speed of the car doesnt really add up, unless I'm a complete muppet, which I could be, with me coming from a 90hp citroen Ds3 to my second ever car being a 330hp sti, I don't really think I have a lot of experience

JDM_Stig

iTrader: (3)

Was the work done at Scabby so Scoobyclinic ?

Luke Kay

It was mate yeah, scoobyclinic did the work for him

JdmSti2006

torque is "by-product" of power
2.5l engine owners myth to cover its failures
power and revs are things to chase

domino46

power is for pub talk ,, torque is what wins races lol

if your building a track car then you will be sat at the top of the rev range the whole time so wanting it to rev loads will be better ,,, but road cars rely on torque to get them going as the rev range will be a lot lower and who drives around with there car sat at 5k waiting to race someone lol ,, you want to be able to put your foot down and the car move on , not sit there stiring the gearstick trying to find a lower gear to get the revs right to push on lol

Don Clark

Power vs Torque

Torque refers to the capacity to do work, while power is the rate of completing work in a given amount of time. The primary use of torque is to make the car accelerate in the initial stages of movement, while the horsepower determines the rate of the acceleration of the vehicle.

For better understanding, let's take two imaginary vehicles (A and B) with the same weight and size. A has 100 bhp of power and 250 Nm of torque, while B has 150 bhp and 200 Nm on tap. In this scenario, B has more horsepower than A, which means B will be able to move at a much faster rate.

Now, let's load both A and B with four passengers and some luggage. In this scenario, it is the torque which will play a more crucial role in maintaining engine's performance. Because of less torque, car B's engine will be more stressed and performance (especially initial acceleration) will deteriorate as compared to A's engine which generates more torque and can carry the load with relative ease. Vehicle A, on account of higher torque, may also find it easier to maintain engine speed even at low rpm range.

In a nutshell, horsepower (bhp) affects a vehicle's speed while torque (Nm) impacts the load-bearing capacity. This is why most SUVs and load carrying vehicles use diesel engines as they are capable of generating more torque as compared to petrol counterparts.

TECHNOPUG

iTrader: (1)

Power (BHP) is an expression of torque at a given rpm, using the formula BHP = (Torque × RPM )/5252,where torque is lb -ft and n = revolution per min.

As such, 2 engines can have wildly different torque figures and perform very differently and intended for different uses yet have the same power figure.

eg: an engine with max torque of 600lbs/ft @ 3500rpm will have the same power as an engine with max torque of 230lbs/ft @ 9000rpm.

Luke Kay

So essentially that's why it FEELS just as fast when it's carrying an extra near 200kg of people, as opposed to when its just me in it? Cause it has a bunch of torque and it has the capacity to do the work and keep the car moving if I'm getting this correct

Luke Kay

[/QUOTE]eg: an engine with max torque of 600lbs/ft @ 3500rpm will have the same power as an engine with max torque of 230lbs/ft @ 9000rpm.[/QUOTE]

Yeah it makes peak torque at like 3800rpm, drops off a fair bit after that. Same with power, that picks up a little bit but still anything past 5k is really dropping. Cause you can feel it launch forward until about 5k and it slows down. Still pulls hard, just not as hard. So pretty much car would be able to accelerate faster if it had more power towards the top end correct?

ALi-B

iTrader: (1)

Go and do your A-levels!

BHP is a calculation derived from torque measurement ...it is impossible to measure BHP alone. You must measure torque and revolutions.

Derived from the mathematical power of work done over a given distance (basic maths): Power = (Force × Distance ) / Time. Where power is the energy dissipated (watts or horse power), and force is torque or pressure or amps. You need to add a few thing in to convert distance into rotary motion.

This is also why converting HP to KW is a straight forward conversion as both are measurements of dissipated energy.


Hence the equation: BHP = (Torque × RPM )/5252

There is also a quirk in the maths results in any rotary device (engine/motor etc.) that revs below 5252rpm will show poor BHP values, which is why diesels have much lower BHP, as with any engine where torque falls off below 5252rpm.

However if a engine revs much higher with low torque, as rpm is a multiplier , 5252 will divide into it more, resulting in low torque engines producing big bhp...like motorbike engines. Bottom line rev higher=more BHP.


Edit: missed Technoplugs post. It's obvious who did physics at school/college