pHEnomIC

iTrader: (14)

I have a hard time understanding what is going on when people refer to a modification saying that it will gain hp but lose torque. Since the two are correlated in some way, don't they always increase and decrease together?

Also, how can a modification add horsepower at one rpm (higher) and lose horsepower at a lower rpm? i just dont understand it completely. Can someone enlighten or explain it?

Sales2@Texas-speed

iTrader: (5)

By the math and physics, if you gain torque at any given RPM you will also gain HP there. HOWEVER, what people mean when they say that is you can move the powerband up so high that you get great peak HP numbers, but the bottom end torque (what gets the vehicle rolling) is weak and can actually be lower than it was before a certain modification. At that low RPM though, the engine will have lost or gained both HP and torque, not one or the other.

That help?

fuel

iTrader: (13)

a 5500 stall can fix a low tq problem

custm2500

iTrader: (11)

HP is a calculation of torque vs. time.

1000 ft. lb. of torque can be made in 1 second or 10. in 1 second you have 1500 hp, in 10 seconds you only have 500 hp. Simple real world explanation is gas vs. diesel. Gas typically make similar hp and torque, diesel make gobs of torque and much less hp.

Sales2@Texas-speed

iTrader: (5)

^^Not exactly. HP is calculated from torque at a given RPM in an engine.

Torque = (5252 x HP)/rpm

That is why you always see the HP and torque curves cross at 5252rpm

Fireball

iTrader: (21)

actually, he's dead on...1hp is 32,572 ft*lb/min...it just happens when you consider the time aspect in an engine, revolutions/min is whats taken into acount so you end up with the relationship you showed

WS6TransAm01

iTrader: (13)

As said before, most people are refering to the graph shifting to a higher RPM so you loose low end torque.

If you have more torque at a higher RPM you will more than likely have more HP at the peak, but since your torque peak shifter right, you will more than likely have less in the lower rpm range.

Not that it matters, since you make it up with higher RPM.

True dat!



Unless you are doing it in metric... I think, [NM for torque and KW for power] they they cross at 9090... if you ever get there lol

I think the formula is Torque (NM) = [Horsepower (KW) x 9090] / RPM

custm2500

iTrader: (11)

The calculation that Matt posted is correct but that is to calculate torque.

I knew it was a relationship between time and torque but couldn't find definitive proof. The 5252 some from calculation of rotation vs time if I figured it out correctly.

Again The easiest way for an example is diesel making 1000 ft lbs but not revving very fast wile a gas makes 350 ft lbs but revs fairly quickly.