MONTE 01&97 SE

iTrader: (1)

With all the talk of the 02/03's not making their full 255 Hp do you guys think that the 04 will be in the same boat. You think Nissan is going to over rate it as well, I cant wait to see a dyno on it when its claimed horsepower/torque shows up vs its actual numbers.

PeterUbers

There is no CONCLUSIVE scientific proof (w/ multiple runs on multiple dyno's w/ the exact same methodology used) that the current hp ratings are in fact overrated. The Max auto tranny may just sop up more juice than the altima tranny, despite the fact that many say they're the same tranny. (just an example, I welcome all hotheads to claim I'm wrong, power to you)

RyRy

I wouldn't be surprised if Nissan said it would 280HP, then bumped it down to 275 before it's release..

Dany

iTrader: (1)

Maxima is overrated in hp, but underrated in torque
My friend dynoed his 350Z 6-speed and got 225-230hp and got same torque as what 6-speed Max is getting, I think this is no where close to 287hp Nissan is claiming. Nissan is just playing with numbers.

JJS MaxInf

I frequently dyno my Corvette. It is well known the Six Speed Corvettes have 15% loss to Rear Wheel Horsepower (which is what a dyno measures), and an automatic has 18% loss.

zerofighter

how much torque does the max really have?

MaximaPower

iTrader: (3)

i think nissan will overrate some of their cars and underrate some.
the G35 sedan with the auto 5spd is putting down some good numbers. i've seen dynos graphs of 213rwhp - 225rwhp. i also, believe that the g35c 6spd and Z 6spd should be rated at around 270 or 275 hp..not 280 and 287.
if the 04 is rated at around 270 hp then i dont think it would overrated, but i wouldn't be surprised if it dynos the same as the g35 and the Z

they can overrate the hp #s cus they underrate the torque. that's one reason the car is still pretty quick.
oh and i think the torque in all the 3.5L is about the same even tho nissan rates them differently.

vqman

I don't claim you're wrong, but how do you explain that the exact same tranny would "sop up more juice" ?

because I just don't understand?

-vq

maximase86

iTrader: (24)

I thought I'd make a point. When your dyno'ing a car, the hp your getting is the hp at wheels. One guy posted a dyno from a 350Z being at 225-230hp. That would be rear wheel horsepower. The numbers nissan gives is the amount of power at the crank, which is different. It has always been a given that you will loose power through the powertrain, because there is hp needed to turn all that weight. So I highly doubt that Nissan is merely throwing numbers around. There is away to calculate whp to bhp though I don't know what those calculations are, but they take into effect the distance from the motor to the wheels, gear ratios, weight, etc. The only other way to see if nissan is telling the true is to remove the motor, and dyno the motor. Hope this helps some.

S

MaximaPower

iTrader: (3)

i believe everyone knows that.
the point we are trying to make is, "why does the max, Z, etc. lose sooo much power?"

if a 6spd Z dynos at 225rwhp, that's almost 22% loss. i dont know about u, but that's a bit much to me

maximase86

iTrader: (24)

On a RWD set up, a lot of the loss is contributed to the driveshaft. I'll tell you the stock drive shaft on most cars are not very light. Let's say we are looking at a drive shaft, you have one end connected to the tranny, one end at the differential. Now to the naked eye, when one side spins, the other spinning at the same time. In reality this doesn't happen. If you were able to slow down the process, what happens is when the tranny side of the shaft spins, but the differential side does not. Basically the drive shaft is twisting itself a little, absorbing some of the turning energy before the other side turns. This costs some horsepower. The same thing can be said about the transmission, differential, and axles. Also, some of the energy is absorbed by the clutch in manual, and a lot of energy is absorbed by the torque converter on automatics. On top of that you have to consider the accessories the engine drives, including the power steering pump, alternator, a/c compressor, water pump, oil pump, etc. On top of that you have to consider the weight of all these components, and how much energy that is need just to make them turn. 22% power loss may seem like a lot, but when you add the physics to it, then it all adds up. You will never find one single car, that puts out the same amount of horsepower at the wheels as the motor.

Basically to combat this, you can go with lighter shafts, smaller diameter pullys (underdrive pulley's), lighter drivetrain components, etc. People can be very surprised how much horsepower you can free up by just doing that.

Does this help?

S

vqman

i am familiar w/dyno'd hp being less because of drivetrain losses than crank horsepower...thanks for the lesson

-vq