That sounds about right. Some maybe even as low as 20%.

 

 

exsqueeze me? AWD drive losses?

 

The pecentage of horsepower lost from the flywheel through the drivetrain to the wheels. AWDs are the least efficient and front wheel drives are the most efficient with the least amount of hp loss.

 

Drive train losses. Power lost from the flywheel on it's way to the wheels. That's why, best example I can think of, was when SCC dyno'd the WRX, it puts out 222 at the flywheel, but they measured 147 getting to the ground. However, they've seen numbers about as high as 187. It's rough business to dyno an AWD car. I'll try and dig up better numbers for either an FWD or RWD car.

 

Heh, heh, I beat you to it.

Yeah well I can still edit your post! MWAHAHAHAH...but I won't. Abuse of power=big no no.

 

http://www.sdsefi.com/techdyno.htm

That page has some awesome info regarding drivetrain losses. Well written to.

 

thanks pjal. However, I just can't believe it's actual drive train loss due to the reason of AWD. AWD cars are much better/faster from stand still acceration, therefore, I'm thinking it's more like balancing the powertrain for all 4 wheels rather than relying on only two.

 

AWD is quite truly a double-edged sword. Sure, you lose HP since you must distribute it to four wheels, and two gear boxes (i think?) but since that power is nicely distributed to the corners, you're able to launch the entire mass of the car that much more efficiently. Plus there's no doubt in my mind that the quality of the mechanisms involved play a crucial role in power delivery.

 

That is called grip. Here is an example: You have two identical car cruising side by side at say, 50 mph in fourth gear, only one car is FW drive and the other AWD. (Both cars are the same weight too.) If both cars were to floor it at the exact same time, the FWD car would slowly start to pull away from the AWD car.

Here is another example: If you compare 1/4 mile times of an Evo (AWD) with an identical time of a RWD car you will notice the trap speeds of the Evo are usually lower then the RWD vehicle. This is because the AWD car launches harder, but the over the 1/4 mile the RWD car begins to catch up finishing the 1/4 mile at a higher speed. This is not the rule every time, but it is an average.

 

Nice analogy. Makes sense to me.

 

So pjal84, now when I get flamed, I'll blame it on you for changing my post.

pjal84: Nope! It'd say at the bottom, "edited by pjal84". hehehe...the compy doesn't let me be stealthy enough. BACK ON TOPIC!

evo_dan: Now I'm officially calling you the post hijacker.

 

Think of drive losses this way. Every extra gear, bearing, universal, shaft, direction change = loss of power. Try pushing a FWD dsm and then try pushing a AWD dsm...very big difference. Try pushing a FWD dsm on a cold day, like say below zero, now try pushing a AWD DSM on the same day...I bet you cant even do it. Think about how much drag the center differential and rear pumpkin cause from the gear oil alone before they are warm. For that matter, the stock 1G FWD turbo DSM is faster than the 1G AWD DSM in the 1/4 mile. AWD systems also have to spin more mass. Launch an AWD car and you have to rotate the added mass of the rear drive shafts, rear axle, the center diff and transfer case. Not to mention the car has to carry the 300-400 pounds of extra weight of the AWD system. The added weight requires bigger brake rotors which adds un-sprung weight to the wheels. Another problem with Mitsubishi AWD is that the motor is positioned to benefit a FWD transmission. Adding AWD is an afterthought carried over from previous FWD models even in the EVO VII. The transfer case must rotate the power to the rear wheels 90 deg. Take a look at the skyline setup sometime. A skyline uses a front and rear pumpkin and a tranny that point to the rear of the car like an American inline 6.

How does AWD translate to the real world? Don’t pull up next to a C5 or a MKVI supra on the highway at 40 mph and expect to walk away from him. It just wont happen, his RWD is in its element. His 320-406 hp will be used to its fullest advantage. He is not going to break traction unless it is raining. Where is your AWD EVO going to shine? Any TIGHT twisty bumpy back road that will light up his RWD's tires. Also any time it rains and any stoplight launches. Lets talk about RWD cars for a moment. For example the new Mustang. The Cobra comes with a fully independent rear end like the EVO. The standard GT comes with a straight rear axel. Technically the Cobra's rear end has a bit more drag (4 CV's) vs the GT's rear end. In this case a bit more weight, drag and added cost is offset by the increase in handling.

 

Are you and evo dan brothers or something?!

Nice explanation

 

if it's too long i don't bother to read it ...can someone summarize? j/k