While everyone is eager to get basic bolt ons to increase HP & Torque with intakes, smaller supercharger pulleys and exhaust systems I think the most overlooked item that most cars can also benefit is also the least looked at item for this car. An underdrive pulley. Yes, I know the ecotec 2.0L is a free flowing motor and rev happy, the one thing that it can benefit from after basic bolt ons with this is the U/D pulley.

From what I have heard it can also free up an extra 10HP or more (Forced induction only), with this in mind, has any vendor even taken into consideration getting some protypes on the board? I was like looking at the accesories pulley today and damn that thing is big. Def need something smaller in there.

Does the 2.2L ecotec already have one? (From the Cavailer, Sunfire, Grand AM days) and if so.. is the bolt pattern the same where we can just slap it on the 2.0L? or do we need something different all together? That is the cheapest but also most effective mod you can install on a car besides what I listed above. Are we overlooking this?

-Mike

 

I think the #88958631 Billet Crankshaft Pulley on the following page http://www.gmgoodwrench.com/perfpart...284&section=pp is the pulley for the 2.2 Ecotec, but i am not sure yet. I wrote today to GMPP to know if it can fit on a 2.0 SS/SC.

 

you want to be carefull, as running an underdrive pulley will change the speed at which the blower spins if i'm not mistaken. somebody please correct me if i'm wrong.

i think the best bet would be to get lighter pulleys, that way you still have the option of running pulley upgrade kits as they become available.

 

shouldnt change it that much,

but is that pulley for a 2.0 or 2.2 that is the question.

some stuff doesnt work.

 

according to one of the pages I visited for the pulley it's suppose to spin more freely , not drag more. I would think this would be an advantage for the blower with less hesistation.

 

so if you put on a smaller diameter pulley, you'll have more HP?

 

bigger pulleys cause more drag, especially if you runs accessories such as a/c. The purpose of it is to create less drag, allow it to spin more freely and free up extra HP without comprimising the accessories.

 

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88958631, and whether it will fit on the 2005 Chevy Cobalt SS 2.0. We
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Thinking of that, the pulley should be for the 2.2, because a smaller pulley would make the blower turn slower ...

 

running a smaller pulley causes the accessories to spin slower, taking less power from the belt system (the "drag")

but changing the size of the pulley also affects the pulley ratio of the S/C if it's in the same belt system. a good way to see this would be to look at the diagram under the hood.

i'm not saying it would be bad, but it COULD alter the pulley ratio of the S/C. and with the LSJ being so sensitive to mods and wanting to go into limp mode, running a pulley upgrade kit designed for a certain airflow might be hindered by a minor mod like an underdrive pulley. contacting PSI-FI about this would be the best way, as they're the only company that's got something available (if only for local guys while they work things out).

all i know is that it's taken them a while to work things out without the car going into limp mode. instead of spending 100 on a pulley (or whatever it'll be). i'd wait and spend 500 on their kit and get MUCH more power reliably. they'll know best though. should be fine on a stock car, it's just that later down the line you might end up having to get rid of it (don't see the point of getting an underdrive pulley if you don't plan to take things further).

ok i'm done...

 

these are usually crank pulleys, not the SC pullleys
also i would be weary of some kits with water pump/ alternator pulleys

 

Just to bring the discussion back from the dead.... A lightweight OVERDRIVE pulley is what you would want. This would increase boost by a few %. Pretty common for the guys with the Mini's... http://www.altaminiperformance.com/p...ankpulley.html

 

Good example. I am sure we will see something designed in the future for these motors.

 

Why would you want an underdrive pulley system on a car that is dependent on how many RPM's the crank is pushing? Sure you might gain 10HP from a pulley swap on a 2.2L - but this is a motor with a supercharger that is driven off the pulley system. The whole point of going with a smaller pulley for the supercharger is to increase the rotor RPM's thus creating more CFM @ a certain RPM. But lets say you ignore all this, and buy one and install it. Your supercharger spins at a slower rate, thus creating a loss of horsepower. So you try and match it with a smaller supercharger pulley, but you're only going to break even if even that. Then you realize that this was just a waste of money and you could of better spent it on a piggy back system or a stripper.

None of the GM Racing Cobalt's have this done, overdrive or underdrive, and there's a reason for it. It's NOT worth the money.

 

I know RSM Racing has a lightened crank pulley (stock size just lighter) for the 2.2L ECO I had one on my 03' Sunfire...I wonder if it would fit but I no longer have the car nor the pulley..

 

i have the rsm pulley u speak of on my car. it will not fit the lsj. l61 has 5 ribs, lsj has 6. if u gus sparked enuff interest im sure theyd make em for yall as well.

 

except a smaller crank pulley means the supercharger would spin slower too... Pretty much would shoot you in the foot.

 

The RSM crank pulley, if they were to make one for the LSJ, it would be the same size as stock just lighter so the s/c wouldn't spin at a slower rate...

 

IMO if you make the pulley smaller its gonna slow down the belt causing the supercharge to spin slower.

you may gain alittle power but i doubt it will be more than 1 or 2 without other pulleys.

 

the rsm crank pulley is stock sized. its made out of aluminum to shave off a few ounces. the car revs a lil faster with it. not a significant gain but just a piece of the puzzle

 

Like said above, if you change the size of the crank, you'll throw off the superhcarger pulley. Make the crank smaller, you'll have to make the blower pulley smaller too. But you guys are already pushing the limits as to how small of a pulley will fit the blower.

If anything, make it lighter.

 

Good Advise.

 

Do you sell pot

 

 

Add to that the nice dim lights and dash lights at idle because the alternator is slowed down . Ive never been a fan of underdrive pulleys . To many possible issues with voltage and cooling for the miniscule gain in power . jmo .

 

smaller UDP will make the blower spin slower= less power