My MRZ order came in this afternoon too...not the pulley though - the seat braces. I'll be posting pics as soon as my camera finds its' way home...

You got the original size, but lighter, pulley right?

 

Yes
It's the lightweight but same size as stock
Can't wait to find out how it revs

 

How-to and pictures of installed is now requiered.

 

Why would you want to get the same size as stock? Your not going to get any power if its the same size right?

I dont see how it would make a bit of difference besides overall car weight. Isn't it going to spin at the same speed regardless of weight?

 

Rotational mass buddy...think of it like replacing your flywheel with a lightweight one...less rotational mass=less power wasted in turning and more power to you.

 

It won't take as much effort to spin it if it's lighter.

 

ahh makes sense... ty .. You'd think GM would know this and not put a f'in cast iron on it!! LOL

Cheap bastards!

 

A big heavy damper and/or flywheel makes the idle more stable and the car easier to drive at low speeds.

 

so your saying w/ an underdrive pully I should expect a bit less help from power steering?

 

anyone have any kind of surging idle yet with the underdrive pully?


i think i might go ahead and just order it, i have a fairly large system, butttt, it is a pretty decently supported one with larger grounds (BIG 3), yellow top, and cap.

 

yeah i havent even gotten it yet. dont know whats going on i ordered it the 9th and even paid more for the faster shipping.not a happy camper what shpuld i do?

 

have a tracking #?

 

Hey guys check this out ... I dont think i'm going to be getting this anymore. From a very well known name in the cavi / cobalt scene. Name will remain anonymous.

"Would this be a part that would benefit from a tune following install? IMHO I'd at least want to raise the idle up 100 rpm or so to compensate charging system losses."


Hi Ryan,
my experience with underdrive pulleys is: they are a complete waste of time and money, cause nothing but problems and are simply an un-necessary product companies build for the street simply to make money.

I suggest NOT even considering this modification.

That's my personal point of view.

Also, tuning will not compensate for the charging so I doubt there would be any benefit to having Vince re-tune.

I hope this helps.

 

thats underdrive pullies... now what bout just the lightweight pullies?

 

From how it was explained to me. The stock pulleys are set to a certain degree of both mass/rotation and dampening. I've been researching from people who I actually know dyno their cars before and after, rather than just read on the site that it gives 20 horsepower so they calculate their car + 20 horse lol.

Nobody yet besides a few 4.6 Mustang guys have even shown the SLIGHTEST horse power gain, or improved times at the track.

The only thing that it will help is your car to rev faster IN NEUTRAL ONLY.

I've even read that light weight flywheels can actually hurt quarter mile time due to having to dump the clutch at a higher rpm. This last comment is still unsubstantiated, but in a way makes sense.

 

The flywheel didn't hurt my 1/4 mile times.

 

an underdrive pully is just what the l61 needs, it makes no power down low in the rpm range and getting there quicker will definitely make a difference. anyone who launches a modded l61 knows wht im talking about. ill qoute hack "feels like Vtec when my engine gets past 4 k"

 

That's just the drivers fault. Just like when you get all this new power but you dont know how to control it, of course you are going to get worst 1/4 mile times.

 

Not sure if this is sarcastic or not, but......

No your PS assist will remain the same since the Cobalt uses electric power steering.

 

so does the lightweight one make a difference and does it mess anything up????

 

yes. Less rotational mass=more power not wasted.

 

yes i do, it says on the canada post that the item has been accepted into the us, but on the usps website, it says orgin post is preparing tosend delivery......very confused i have been waiting since the 16th

 

mine was shiped on the 11th, came in on the 19th, usps still says is wasnt recieved :p

 

Alright, you guys go ahead and be the ones to buy em. Have dyno b4 and after. I dont see it gaining any hp, it was explained to me as one of those sell it to ya cuz it sounds good kinda parts. Kinda like front strut braces on front wheel drive cars. Always have been spetical about them. I bought into the hype. & wish 65 bucks ago I never did. Similar to an underdrive pulley, the negatives out weigh the positives.

 

i see no negatives from the udp