[Mongoose]

Personally I don't think that the EVO IX's are under rated, check out the numbers they put down on Buschur Racing's dyno, then compare them to the numbers an EVO VIII puts down, the difference is only like 10 whp/torque...and for the record the IX's only put down about 210 whp on that dyno. Every dyno reads different so it's hard to get an exact number for drivetrain loss IMO. I managed to spin Buschur's dyno to the tune of 275 whp and 303 ft-lb's with just a downpipe and a tune at 19 psi. That is slightly more whp than Buschur's BR350 package on an EVO IX and like 40 some odd more ft-lb's of torque , of course Buschur's dyno is a mustang dyno and an extremely low reading one at that. As other's have stated it's all about how much mass the engine has to spin before the power find's it way to the ground, look into things that others have already suggested like a CF driveshaft, lighter wheels/brakes, pulley's, disconnect your AC if you are a die hard. There are a lot of things you can do to decrease drivetrain losses, I however am more focused on just making more power for now, then when I get bored of that maybe I will look into lightening up the drivetrain.

[Ozer]

Rotating things also drain energy. Heavy rotating things need to store much more (inertial) energy than their lighter versions, which is registered as drivetrain loss.

For your information:
Rotational Energy = 1/2 * I * w^2

w is the frequency
I (moment of inertia) is mr^2 for a filled disk.

In order to accelerate the car, you also need to accelerate all turning parts, thereby using some of the engine power to create enough moment of inertia.

So yes, he was absolutely right about using lighter drivetrain parts to reduce drivetrain loss. Friction is only one type of loss, and definitely not responsible for all of the loss.

(Sorry if I'm mixing up any English terms; I originally learned this thing in Turkish)

Originally Posted by mxpop

You're thinking inertia, not drag, as in a heavy flywheel etc.

Drag is the resistance to move such as gears in thick oil or bad bearings or draggy diffs, low tire press, etc.

Rotating mass (as in flywheel) wont reduce horsepower but it will reduce acceleration. Drag will ruin hp and acceleration.

[Ozer]

If you lighten up your car, not the drivetrain, yes, your car would be a better performer, but the whp and wtq you measure at the dyno would NOT change.

Therefore, disconnecting A/C would NOT change the values you read at the dyno. When the AC is off, it's pulley is disengaged and it is literally disconnected from the system, anyway.

Originally Posted by Mongoose

Personally I don't think that the EVO IX's are under rated, check out the numbers they put down on Buschur Racing's dyno, then compare them to the numbers an EVO VIII puts down, the difference is only like 10 whp/torque...and for the record the IX's only put down about 210 whp on that dyno. Every dyno reads different so it's hard to get an exact number for drivetrain loss IMO. I managed to spin Buschur's dyno to the tune of 275 whp and 303 ft-lb's with just a downpipe and a tune at 19 psi. That is slightly more whp than Buschur's BR350 package on an EVO IX and like 40 some odd more ft-lb's of torque , of course Buschur's dyno is a mustang dyno and an extremely low reading one at that. As other's have stated it's all about how much mass the engine has to spin before the power find's it way to the ground, look into things that others have already suggested like a CF driveshaft, lighter wheels/brakes, pulley's, disconnect your AC if you are a die hard. There are a lot of things you can do to decrease drivetrain losses, I however am more focused on just making more power for now, then when I get bored of that maybe I will look into lightening up the drivetrain.

[Mongoose]

I'll take your word for it, but could you please explain how lightening up the drivetrain wouldn't yield in addtional power finding it's way to the ground? In reguards to the AC, I said if you are a die hard it might be something you would consider, as I have seen plenty of people do it on various makes and models. Also even when the system is off there is still a belt being turned by the engine which is connected to dead wieght. How much of a difference it really makes(probably none power wise, but maybe throttle response) I have no interest in, being that it's something I will never do. I just really don't understand how lightening up the drivetrain wouldn't make a difference, our cars have such a great loss at the wheels as a result of all the bulk the engine has to turn to make the car move. Less bulk (rotating mass) the motor has to move the less power that would be absorbed before finding the wheels. I'm no expert in this category but to ME (and maybe I'm wrong) it just makes sense.

Heck even look at your own post (#17) where you basically say the same thing in reguards to more mass requiring more inertia.

[mxpop]

The AC clutch will disengage at WOT but yes, the belt and pulley will still be turning. You can add this to your total effective flywheel weight calculations if you like.

[Ozer]

Well, there might be a misunderstanding, but anyways, I totally agree with your comments

What I meant about AC is, people delete it because of the weight of the total system (its condensator, lines, compressor, etc.), not because of the weight of its rotating mass.

I'd also imagine, even if you delete the AC, you'd leave the hollow AC pulley turning in the system, not to make any change in the belt design. Besides, when AC is not engaged, only the very light hollow part of the AC pulley is turning, which is no heavier than those other balancing pulleys in my opinion

- Ozer

Originally Posted by Mongoose

I'll take your word for it, but could you please explain how lightening up the drivetrain wouldn't yield in addtional power finding it's way to the ground? In reguards to the AC, I said if you are a die hard it might be something you would consider, as I have seen plenty of people do it on various makes and models. Also even when the system is off there is still a belt being turned by the engine which is connected to dead wieght. How much of a difference it really makes(probably none power wise, but maybe throttle response) I have no interest in, being that it's something I will never do. I just really don't understand how lightening up the drivetrain wouldn't make a difference, our cars have such a great loss at the wheels as a result of all the bulk the engine has to turn to make the car move. Less bulk (rotating mass) the motor has to move the less power that would be absorbed before finding the wheels. I'm no expert in this category but to ME (and maybe I'm wrong) it just makes sense.

Heck even look at your own post (#17) where you basically say the same thing in reguards to more mass requiring more inertia.

[Mongoose]

lol , I knew we were both getting at the same thing .