would a stock dyno FWD be higher than a stock dyno RWD?

sidemarker

 

if you ask any Physics teacher or Physics buff they'll tell you it takes more effort/force to push a object or mass (which is weight) than to pull it. so a lets say we have 230 hp at the front wheels. and a camero has 230 at the rear wheels. therefore the camero would not only have to work harder to get the car rolling(which is velocity). therefore it would require a larger motor to do the same thing.

the way I know you lose horsepower going to the rear wheel drive is the more parts and longer distance the actual power has to travel to get to the wheels to spin them your losing power. for example with your crank HP(260 HP) they measure your car and all cars before they put on pulleys(which rob you like 10 hp) the automatic transmission robs (as a rule of thumb they say 10-12%) so about 30 hp. so your down to about 200 hp your putting to the tires and thats front wheel drive

 

so u are saying that it will dyno less???

if so then if the G35 or 350 Z was a FWD car it would be faster?

sidemarker

 

It's harder to pull an object than to push it. For a simple experiment, go outside and try pulling your car..take a little rest. then try pushing it. Come back and tell us which one was easier :P

 

the push/pull argument aside, u also have to consider weight shifts. when u launch a car, the weight shifts to the rear. for a FWD that means significantly less weight on the drive wheels = less contact with the road. with a RWD that means more contact with the road. but u're talking dyno's so none of this means anything to ur question.

technically, just on a dyno, i tcan be argued that a FWD wil dyno higher than a RWD. as was mentioned, a RWD does lose some power through the driveshaft, differential and axles. these components are either non-existent or significantly shorter on a FWD which equates to less loss of power.

 

CAMARO
C_A_M_A_R_O

 

I am no physics expert and it has been 15 years since physics class but I believe you are talking about two different things here. It is harder for a human to pull a car than push a car becuase of they way humans are built.

When you push a car you are actually pushing into the ground. This means that there are two force vectors that apply. One up vector and one parallel with the ground. The trick is to get the most force parallel with the ground by stepping away from the car and getting your body flatter to the ground when you push.

When you pull a car, it is harder to put more force in the "parallel to the ground" vector so you are wasting a lot of force on the up vector.

Now, that is why it is easier for a human to push rather than pull but that has nothing to do with fwd vs. rear wheel drive.

I dont remember if it is easier to push rather than pull. It seems like the force vectors will be the same (only opposite) so it has more to do with overcoming friction. Seems like it should be the same to me but I am not sure.

Also, this push pull thing has nothing to do with a dyno because you are measuring the force the wheels can apply, not the force required to move the car.

My brain hurts now.

 

You're right. If it takes 2000 lbs of force to push a car into movement (hypothetically), then it takse the same 2000 lbs of force to pull it. All the force vectors half to be balanced to keep the universe from exhibiting chaos theory. So where the drive wheels are located has nothing to do with how much force is needed to move the object. Damn, now my brain hurts. I never did like balancing vector equations!

As for the dyno, it depends. Here's the factors that effect it (considering the 6 speed manual with HLSD):
1) The FWD has no driveshaft going to the back, so it has less rotational mass to overcome. Mind you newer cars use aluminum or composite shafts to reduce the weight and rotational effects. So this would give a little more HP to the ground.
2) The FWD with HLSD uses a gear driven differential which is the only way to put a LSD in a FWD vehicle. This sucks up extra HP.

So, at the end of the day, they could come out pretty much the same if it was RWD, and had different differential.

But the benefit: The RWD will probably be faster since it'll have more traction due to weight transfer to the rear of the car on a launch.

 

no one answered this question yet

sidemarker

 

I don't think so. Like somebody said, although RWD is lss efficient, when a car takes off the weight shifts to the rear. In the case of RWD, this is an advantage cuz the weight is on the rear wheel- the driving wheels. The problem with FWD is just the opposite, the weight shifts back and it's harder to get traction, esp once you start modding and making some serious HP.

 

whoa. whered you come from!

 

Damn i jus noticed that was my first post. Ha, guess i registered and only lurked.

 

The weight shift arguments play an important role. But I'm a physicist and there is no reason pulling takes more force than pushing or vice versa.

 

on a dyno they're statistically equal. on the street its a different story. remember that a dyno only measure the HP at a wheel. to say that one car is faster than another u have to factor in things like weight, tires, aerodynamics, transmission shifts (on a dyno the tranny really has no load compared to actually movin a vehicle as is the case on the street). and don't forget the comptech sticker effect.

 

its just hard to understand how they will dyno the same.

since you are transfering power to the wheels wouldnt u have more power going to the wheel if the ouput of the power was closer to the wheels oppose to being on the other side of the car?

for instance if you took a wheel with a short stick on it and a wheel with a longer stick isnt it easier to roll the wheel with the shorter stick?????

so if the cl was a RWD car would it be faster??

sidemarker

 

If the CL-S was a RWD vehicle, it would only be QUICKER out of the hole (from a dead stop) than an equally powerfrul CL-S fwd b/c of the fact that you could produce a more effective launch due to the whole weight shift concept (which actually has a term .. i forget the term at the moment). On the roll, neither would be any faster. You would also minimize wheel hop with a rwd application vs. the fwd drive setup.

 

You need to take into consideration that the front of the vehicle weighs considerably more than the rear. Even with the shift of the inertia, you still have better traction on the front then the rear.

 

no it would not be any faster, i think it would be slightly slower.

first off, it would be a smokey mess trying to get a clean start, and second you would need some chunky 245 series tires to keep from doing a 300 ft burn out.

but with the right tires and lots of weight up front it could be just as fast.

 

i'm not certain about where the stick is relative to the wheel. sorry. i'm not saying they would be exactly the same. they would be statistically similar (i.e. not enough of a difference to make a blanket statement that one is faster than another). u hit the problem on the head with ur question about transferring power. think about all the parts that have to be turned to transfer power in a RWD vs a FWD. this is where u lose power. please elaborate ur stick.wheel scenario...describe the axis of the stick and thatof the wheel please

 

I'm far from any kind of a mechanic, but I can tell you one thing...if I push the "exilerator" to the floor, my car goes like a bat out of hell.