More_Torque_More_HP

The Damper is designed to reduce the crank tortionals -tortional bending caused by the firing pulses, accessories and transmission inputs, etc. Without it the crankshaft bending goes up and the potential for fatigue issues. When designed they look at multiple orders of bending like: 1st, 2nd, & 4th order

tireman1554

I see a battle of witts in the near future.

Brwbier

Correct me if I'm wrong, but is not the crank supported between each cylinder? Just exactly where will it bend?

The Curly 1

On most cars the underdrive pulley is a good idea. (In my opinion)On the Ecotec I do not think is does much good. The reason for that is most cars have water pump, alternator, air conditioning, smog pump, power steering and other things ran off of the crank pulley. That draws a significant amount of power and you if you can slow those down some and still keep battery up and other accesories going it will perform better. On a vehicle like that I would not be surprised to see a 1 or 2 MPG and noticeable butt dyno gains.

The Ecotoec only has the alternator and the air conditioning running off of the belt so the results of course would not be as dramatic. With the Ecotec I do not think there would be any noticeable gains in mileage or performance. Now a 3Hp gain on the dyno is probably not noticeable in real life so probaby not worth the money. Also 3 Hp could easily be different gas, different weather, car warmed up better or any number of variables.

If the Ecotoec is internaly balanced it should not hurt the motor to run the lightwieght underdrive pulley.

There is a little extra protection from the factory, they try to make the air conditioner, alternator etc. large enough to cover worst case scenarios and most of us could get away with the underdrive pulleys unless you have a huge radio system or other loads.

I was really wanting to do the underdrive pulley system but after finding out it only runs the Air conditioner and Alternator I think it is not worth the money. May help a little but not much.

mistermike

Torsional crankshaft vibrations are twisting motions along the axis of the shaft. Unless controlled, they can lead to rapid deterioration of bearings and even fracturing of the shaft itself, not to mention loss of power. Going to an undamped pulley is generally a really bad idea, but particularly so on an engine that gets no benefit from relieving accessory load. It's almost 100% downside. Virtually all NASCAR and NHRA engine guys use ATI dampers on their builds. There's a reason they pay $400+ to keep crankshaft vibration under control. Yes, ATI make one for the Ecotec.

The Curly 1

While I do not dissagree with you here I think the stock Ecotec pulley is a steel nuetral balanced Non dampening pulley. If the factory had put a damper on it then I would really agree with you. Since the factory did not put a damper on there then I would not think there is much difference between the lightwieght aluminum and the factory steel. But as I said in one of my earlier posts I do not think there would be much improvement iether.

mistermike

I agree. I'm embarassed to say that I have yet to crawl down there and see if the factory pulley is damped. I guess I wrongly assumed it was, particularly because ATI makes one, but that's for 600 HP applications.

Maven

It sure is.


Internally balanced yes, lacking a crankshaft damper, NO. Internal balance and crank dampers arent addressing the same things

Again, the problem isnt strictly the lightweight, its the fact that its undamped(solid)
ATI makes superdampers for the ECO, the underdrive one is only for apps UNDER 600hp, the stock size one is what the factory drag cars run at 10,000rpm and ~1400hp. MIne is on order.

All ECOs have a crank damper(all current GM engines for that matter)

JoeR

Hey, Maven, what brings you over here from the "short bus"??

To add....

The Ecotec is indeed a damped pulley. And, if that dampening didn't matter, why would GM go to the extra expense of manufacturing it that way?? Jeez... they're broke and if they could save a few $$$ with an undamped pulley, wouldn't you think they would??

Finally, to address the shameless hype from those selling these snake oil pulleys.... Do some reading on rotational inertia. One tidbit you find is that the effect of rotating mass increases with the SQUARE of the radius. That means that the smaller the diameter, the effect becomes much less and the crank pulley is small in mass and diameter in relation to other items to follow.

Now, let's consider the total rotating mass of the drivetrain... Start at the engine... crank, lower part of rods, cams, water pump, alternator, all the pulleys, balance shafts (rotating at 2X crank speed), then the flywheel (or flexplate), clutch (or torque converter), trans with all them gears spinning, axel shafts. brakes (X4), wheels (X4) and, finally tires (again, X4). Wow, that's a LOT, isn't it?? When you consider what a miniscule part the crank pulley plays in the total, you should realize what a scam this is. Heck, just getting lighter wheels or even tires of a slightly smaller diameter would make a "huge" difference compared to the pulleys!

Maven

How do you know me when youve got one post on css?

Nothing, I am on a few sites, I love ECOs and have a Balt, the HHR is just a Cobalt station wagaon so I figured I spend some time with y'all.

I wanted an HHR but I am 6'3" and the seat was too high/windshield too low in the HHR, I was always looking out the very top of the window. I returned my half panel after about 50 miles.