megan racing pullys

[twofourzeroSX]

they are only 100 bucks for the accesory pullys....will they even make the slightest difference tho? my mods are listed in my signature.

[twofourzeroSX]

anyone? are pullys a good mod?

[9240sx]

Yes,But if you want to see gains in power you sould buy the UR Crank pulley,I saw i nice gain in power with it,looks great under the hood to.I did a long review on it.Do a search.Everybody who does the Megan or Greddy pulleys dont see gains with maybe 2-3hp.There mainly just for looks.Get the UR pulley you will be very happy with.

[mallbor240SR]

im also interested in MR pulleys but are those underdrive pulleys ? or just light weigh pulleys?

[codyace]

I'm actually wondering if the Megan Waterpump pulley is different in size to help underdrive it....I can't bring myself to buying a 150 dollar pulley for the water pump ya know???

[9240sx]

Megan Racing pulleys are just light wight,And retain the stock pulley size.On all the pulleys in the kit.The plus to that is you dont have to get new belts.If you want to underdrive the water pump ( which is a Very good on the SR) Again get the UR crank pulley...

[mallbor240SR]

thanks , thats what i had in mind

[240guyNY]

just out of curiousity... Would doing both, the UR crank and megan pullies, cause any negative effects? Im assuming not but just curious?

[Neil]

I wouldnt get a lightened crank pulley under any circumstances...

I would rather lose the 3hp and keep the harmonic dampener than gain 3hp and munch the crank from excessive lateral and torsional vibrations.

[PROJECTRB240SX]

sr's and ka's don't have harmonic dampers... they have a a/c damper to isolate a/c system NVH from the rest of the system.

[9240sx]

Right on!! Sr20's dont have harmonic Balancer's..I hate when people say that.Sure they have a rubber ring on the inside.But its for when you turn on the A/C.Sr20's have balanced crank's,If you look at one you can see the holes in it to balance it out.Iv had a UR crank pulley for a while now.And if any thing its made the engine run alot smoother. I would never put anything on my car if i thought it was going to mess up my engine in anyway.UR knows what there doing.

And your going to get alot more then just 3hp with the UR Crank pulley.

[namwons_240]

Any amount of weight taken off the crank ie. the crank pulley, flywheel, rods, pistons, driveshaft, or wheels, will increase hp, response, and/or acceleration.

[TogueDrifter]

I agree

[tonis56]

I'm actually wondering if the Megan Waterpump pulley is different in size to help underdrive it....I can't bring myself to buying a 150 dollar pulley for the water pump ya know???

Yashio Factory has a pulley like this.. http://www.raretrick.com/index...=6720

[mallbor240SR]

that yashio pulley doesnt undredrive the water pump, it makes it spin faster and you dont want that.

[95lstegman]

correct, the UR crank pulley does remove an important part - the rubber ring inside the stock pulley. this rubber ring helps to deaden the vibrations of the continual impacts on the crankshaft. without this piece of rubber, reverberations go unchecked on the crankshaft, which could have very bad effects at any power level. i've personally seen i believe 8 scored up/trashed crankshafts due to lightweight crankshaft pullies. for the 5hp or less or whatever, i'm not staking my crankshaft on it. i've seen physical research on this, but like an idiot i didn't bookmark the website. it was a cool test, though.

[PROJECTRB240SX]

YEAH THATS CALLED B.S.

THERE IS NO HARMONIC DAMPENING OF THE SR20DET OR KA24DE. THE RUBBER RING IS THERE TO ELIMINATE NVH OF THE A/C COMPRESSOR (ONLY) FROM ALTERING THE CRANK HARMONICS.

THE SR20DET IS INTERNALLY BALANCED WITH A FULL COUNTERWEIGHT CRANKSHAFT WHICH REQUIRES NO EXTERNAL DAMPENING LIKE A SBC OR EARLY ENGINES.

[95lstegman]

try reading before you reply and bash. the stock crankshaft pulley is not designed to balance the crankshaft, it is designed to deaden the vibrations of the combustion events, which create jerks (from a physics standpoint) and accelerations that cause the crankshaft to vibrate. these vibrations can put heavy stresses on the main caps, which of course hold the bearings. i know lots of people say they've never had a problem with their lightweight crankshaft pulley, but from what i've seen in experimentation and from what i know of physics (i'm a mechanical engineer BTW), i wouldn't risk it for a few more ponies. up the boost 1psi and forget about it.

[PROJECTRB240SX]

so how does an external rubber band prevent main cap stress?

You don't make sense, If you are talking about internal stress caused by combustion.... well it has nothing to do with an external pulley.

[Neil]

i googled "crank pulley torsional vibration"

The factory crank pulley has a built-in harmonic dampener, in the form of a split design, with a thick rubber pad sandwiched between two steel sheels. The dampener is designed to absorb torsional and vertical vibrations from the crank. MOST underdrive crank pulleys (with the exception of the Buschur Racing model) do not have a harmonic dampener at all.

Torsional vibration is a twisting vibration caused by the pulses of each combustion event. The force of the piston causes the crank to deflect ever so slightly in the direction of the force, and when that force goes away the crank ever-so-slightly springs back. At certain frequencies the crank can resonate, making the vibration much worse. This is where the harmonic dampener comes into play.

Although many DSM owners have removed the harmonic dampener crank pulley without incident, doing so almost certainly increases crank bearing wear, and COULD lead to early failure of the crank or crank bearings. Just how much the life of these parts is shortened is unknown.

We do have one piece of first-hand experience, to offer, though. We know of ONE instance of crank failure on the 4G63 motor. It was a 2.3-liter motor that belong to an employee of ours. The crank cracked in two -- the only time we have ever seen this happen. That block had an undampened crank pulley on it.

On a race motor, increased risk of bearing or crank problems is insignficant next to the risk of, say, detonation in the cylinder that could blow up the motor. So for a race block, we heartily endorse lightweight undampened crank pulleys.

But for a street-driven car, one that you might want to last a couple of hundred thousand miles, we do not recommend using a pulley without a harmonic dampener.

[95lstegman]

thanks. i really didn't want to get into the thick of it, but that pretty well puts the good stuff into a nutshell. there was a big debate a few months ago on honda-tech about this, and physics were flying all over the place. i can't believe that a nissan forum can be owned by a honda forum

anyways, in reference to the original poster, i believe the MR underdrive pullies only work on the S14 SR, and therefore would require an S13 SR to be modified with the crank pulley off an S14 SR in order to work, like is recommended by some name-brand ones that only work on S14 SR and S13 SR with S14 SR crank pulley.

[PROJECTRB240SX]

THE SR DOESN'T HAVE A HARMONIC BALANCER.....

THAT RUBBER RING ONLY ISOLATES THE A/C CIRCUIT... IF IT WAS A TRUE HARMONIC BALANCER IT WOULD SEPARATE ALL THE PULLEYS FROM THE CRANK.

ALSO THE SR REQUIRES NO EXTERNAL BALANCING BECAUSE IT IS INTERNALLY BALANCED AND FULL COUNTERWEIGHTED TO NEARLY ELIMINATE TORSIONAL VIBRATIONS.

IF YOU CAN FIND ONE ARTICLE WHICH DISPROVES THIS LONG KNOWN BIT OF INFORMATION ABOUT THE SR I WILL GRATIOUSLY BACK DOWN, IF NOT THEN WELL I STILL SEE NO REASON WHY A CRANK PULLEY WOULD BE DETRIMENTAL TO THE SR'S LONGEVITY.

[95lstegman]

it's not a balancer! dammit! it's a dampener. i'm not going to say it again, man. look up the two words in the dictionary for g/d's sake.

[PROJECTRB240SX]

harmonic balancer and harmonic dampener are the same thing, just two different ways of saying it.

[forksquared]

all i want to know is where to get the UR pulley!

[drifter_for_life06]

harmonic balancer and harmonic dampener are the same thing, just two different ways of saying it.

bal·anc·er Audio pronunciation of "balancer" ( P ) Pronunciation Key (bln-sr)n.

1. One that balances.

damp·en Audio pronunciation of "dampener" ( P ) Pronunciation Key (dmpn)v. damp·ened, damp·en·ing, damp·ensv. tr.

1. To deaden, restrain, or depress: “trade moves... aimed at dampening protectionist pressures in Congress” (Christian Science Monitor).

thats from dictionary.com if it makes any sense

as far as the pullies giving horsepower, IIRC they dont GIVE/ADD any horesepower, the power was already there, but due to the fact it had to be sent through more mass it wasnt harnessed, just like a lightweight flywheel makes the engine more "rev-happy"

correct me if im wrong

MR makes good stuff, but I wouldnt buy the pullies, Hell i dont even think id get the UR one, just doesnt seem worth the money to me

[drifter_for_life06]

all i want to know is where to get the UR pulley!

since im in a good mood

http://www.horsepowerfreaks.co...Crank

[PROJECTRB240SX]

THIS IS THE DEFINITION OF WHAT YOU GUYS ARE ARGUING OVER:Harmonic Balancers (also known as vibration dampeners [ dampers] or pulleys) are fitted to the crankshafts of some engines in order to control the torsional (twisting) vibration of the crankshaft. The need for a Harmonic Balancer often stems from increasing the stroke of the engine which makes the crankshaft overly flexible (twisty). If something is not done to keep this flexing vibration to less than 1/2 of one degree of twist from one end of the crankshaft to the other, then the crankshaft may develop cracks over time.. The harmonic balancer consists of the hub (bolted to the crankshaft), an outer weight ring (usually of cast iron) and a sandwiched layer of flexible rubber. This rubber absorbs the energy of the vibrating crankshaft in the form of heat, damping the amount of vibration to within safe limits. The rubber may deteriorate from heat, becoming hard and brittle, or from oil it may begin to soften and decompose. Also often times the rubber begins to move out between the parts so that it no longer provides the proper frequency to dampen crankshaft twisting vibration.

THE SR20DET DOES NOT CONTAIN ONE OF THESE IN ANY FORM.... THE ONLY DAMPENING THE SR20DET HAS IS BETWEEN THE MAIN PULLEY AND THE A/C PULLEY AND THIS IS DESIGNED TO DAMPEN THE EXCESSIVE NVH ASSOCIATED WITH AN A/C CIRCUIT. IF YOU DON'T RUN A/C THE UR PULLEY IS FINE, IF YOU DO RUN A/C USE THE UR PULLEY WITH CAUTION.

[95lstegman]

balancer and dampener are not the same. i've never seen an import using the crankshaft pulley to balance the crankshaft. the guy knows where to get it, he's read the arguments for and against it . . . whatever, man. when i got into this debate the first time [a long time ago], i decided after hearing the argument for the down side that it wasn't worth the risk. we're not talking massive HP here. just a few. so to anyone else reading this, use at your own risk, and enjoy your measly 5hp if you so choose. and good luck; may the main bearing failures i've seen not plague you.

i'm out [of this thread].

[forksquared]

im glad you were in a good mood