Went to a dealer today asking about installing pulley and crank pulley! People there told me that the supercharger pulley and crank pulley both will counter-react on a mcs... cause the supercharger pulley spins by the crank pulley. and since the crank pulley is the 2% bigger so it's actually slowing down the supercharger pulley... i don't really understand ... can someone plz help me out here??? what's the good of installing crank pulley???
is it better to install both pulley? or just supercharger pulley.. I know the stock crank pulley weight like hell but it absorbs the vibration since it's rubber inside not solid.. PLZ HELP, I REALLY NEED TO KNOW! GOTA MAKE A DECISION ON THE PULLEYS! THANX

 

It has been my experience that you will get the most power gain with no reduction in driveability with a 15% and 2% pulley combination.

 

The 2% crank pulley makes the SC spin FASTER. Think of the outside diameter of the pulley. If the crank turns at the same rate, the farther away the edge is, the faster it's spinning.
Same principal for the SC. Only it's being DRIVEN, so the CLOSER the pulley edge is to the SC shaft, the FASTER the shaft is spinning.

If you do any cycling, thinking about big rings and small rings will help. When the crank is on the big ring and the freewheel is on the small ring, the tire spins fastest.
The dealer guys need a lesson.


BTW - there's no such thing as 'counter-reacting'. They could counteract each other though.

 

Try to find a person who is willing to help you install the pulley and crank pulley or find a shop other then the dealer that will do it for you. As for the previous statements from gjpundsack and Eric_Rowland. Eric_Rowland has it right on with his analogy! I am going to go the route of 15% or 17% with 0% crank pulley. Seems like the dealer mechanics are not to bright on how things work. But then again that is just my opinion from what you have wrote about the dealer. If you do get it installed, deff. let us know how things go and post your thoughts on the setup!

Garrett

 

thankx Everyone... I've made my decision with M7 16% reduction pulley and M7 2% crank pulley... The machanics at the dealer even said that it is basic physics principles for sure they'll counter-react.. :impatient

Ha Ha.. anyway, I'll be installing them soon this weekend hopefully... I'll post how it goes! Can't Wait...

by the way.. heard it'll vibrate a lot.. is it true? since the crank itself is solid not rubber

 

let us know how the 16% + 2% work.

I already have the 16% and I'm trying to decide between 2% or 0% crank pulley.

 

The cycling analogy is PERFECT here...

The crank pulley on your engine is like the front chainrings on a road bike, just as the supercharger pulley is like the rear cassette (gears) located on the back wheel of your bike.

So, think of your stock crank pulley as the smaller chainring on your bike. Now, shift the chain to the bigger chainring (i.e. the larger crank pulley). If your RPM's stay exactly the same as before, your back wheel is now spinning faster, correct? That is precisely why all the aftermarket crank pulleys are LARGER than stock. They make the belt, (and therefore the supercharger), spin faster than with the stock crank pulley.

The same thing happens when you shift to a smaller gear in the back of your bike--the back wheel spins faster. That is precisely why the aftermarket supercharger pulleys are all SMALLER than stock.

Your mechanics are wrong. Go somewhere else. Would all these aftermarket parts manufacturers be making crank pulleys that are wrong???

NO WAY!

 

Did you tell them the crank pulley was going to be LARGER than stock and the SC pulley was to be SMALLER than stock?

 

Don't let those mechanics near your car even for an oil change. You heard it will vibrate alot & your still going to install one? They don't vibrate at all. rubber crank? (that will )

 

I got both the pulley installed today! DAMN!!! IT"S FAST!!!! all i can say is the POWER GAIN IS SUPER!!!! i use the M7 16% and M7 2% crank! ... the supercharger whine is like the sound from the heaven... now i have the grin back on my face like when i first got my mcs... believe me! the sound that supercharger made is really loud and really it's a sound from the heaven!

 

any drivability issues?

 

I have a 15% Alta and 0% Alta crank and so far no problems. No additional vibrations except my loose exhaust . I have driven about 500 miles now on the combo so I guess time will tell.

 

Makes me want to get it more and more. But I will wait until the spring! Need to put more money away and not spend it on all kinds of goodies! :smile: Glade you enjoy the new upgrades!


Garrett

 

Engrish rules

It's good to hear of your positive experiences with your new pulleys, grats on the new power!

 

Congragualtions SeaTo Sky. Now whatever you do stay away from that dealer that has NO clue what he was talking about.

 

I think I'm still just a tad bit confused about this crank/supercharger pulley issue. It seems to me that installing a larger crank pulley would be equal to installing a smaller supercharger pulley...after all, a larger crank pulley makes the supercharger spin faster (along with all your other belt-driven accessories), correct? Is my thinking skewed (as it often is)? I tend to OVER-analyze things frequently. I can even make very very simple things INCREDIBLY hard. haha
I put a smaller pulley on my supercharger and it's nothing short of spectacular! I don't drive the same kind of vehicle as most of you, but I ran across this post when I was researching the larger crank pulley theory.
I may not even get any replies to this, since this post is a week or so old, but if anyone could answer my question, I'd really appreciate it. Maybe you can UNconfuse me.
Thanks
baron_iv --->

 

A larger crank pulley has the same effect (in addtion to others) as a smaller SC pulley - it spins the SC faster. Due to space limitations though, I believe the largest you can go on the crank pulley is 4%. It also spins all the other connected components (AC, alternator) faster.

 

If 2% crank + 15% pulley = 17% pulley....then why do 2 when you can only do 1 pulley and done with it?

 

because the crank pully weighs only .9 lbs. While the stock one ways 5.5lbs. Rotational inersia and all that fun stuff tells you that less rotational weight = more power. Regardless if you do it in one pull you still should do the lower weight crank pully.

 

Ah, so it's as much of a weight thing as a power thing. I see. Thanks. That makes it a lot more clear to me.
They don't even MAKE a lighter crank pulley for my vehicle, I guess I shoulda bought a mini if I wanted to have plenty of aftermarket things to choose from. hehe
I won't tell you what I drive, I'd probably be flamed right off the board. This place has been a great source of information though, so I figure I'll stay around as long as I can.

 

if both pulleys make the sc spin faster and the engine rev faster, then will it cause small engine breaking when coasting because it will rev the engine down faster as well? just curious

 

lololol just another story showing just how stupid the dealers are lololol

my dealer told me that by installing my supercharger pully i have sped up my alternator and all my other drives including the crank hence voiding my waranty even thoug it was already voided at the time

again how stupid do you gotta be!!!!!!! or worse how stupid do they take us for
the thought is scary:impatient

 

Hey, sea_to_sky and 4GAZM...what dealership are you going to? Names please...so that none of us ever go there!

Hard to believe your dealer techs are this retarded. Simple physics...driving vs. driven. You should print out this thread and take it to them.

 

I think 4GAZM says his warranty is already void because of the # of miles on his car

 

4GASM is well over 100,000k miles

If reduction of 5lbs from the crank is good, then taking 17lbs (Fidanza 12#)from the flywheel must be great