DOES CHANGING THE PULLEYS REALLY HELP AND OTHER THAN MARCH WHO ELSE MAKES THEM

 

Yes,

Auto Specialties
Moroso

 

Don't buy just a crank pulley. If you get a pulley set get a 3 piece set, crank, water pump and alternator.

 

ive heard the opposite, the crank pulley is the one which frees up the power, the others pretty much do nothing,, if you get a set get the 2 piece set, crank and alt,
hypertech is another company that makes them

 

I bought a 2 pieece set about 6 months ago and the only real difference i felt from was the from alternator not working to well. You might want to keep that in mind.

 

In theory, it shouldnt matter which you buy, crank, or accessory kit. The principle is simple physics and leverage of the pulleys and belts. What you want to do is slow down the accessories about 20%, therefore reducing drag on the engine. This can be accomplished either by getting a smaller crank pulley, or larger accessory pulleys. If you ask me, it makes more sense to save money and only change one pulley.

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1983 Pontiac Firebird SE
LG4-Based Chevy 400
700R4 Tansmission
Modified 4 Barrel Q-Jet Carb
Accel Super Stock 8mm Wires
Edelbrock Pro-Flo Air Cleaner
3.23 Posi Rear
14X7" Cragar SS/T Wheels
Clarion 45X4 CD/AM/FM Head Unit
100WX2 Amp
2 Pioneer 12" Subs in Custom Box
Third Gen Performance
"A four cylinder is only half an engine"

 

For the March Pulleys:

The crank pulley is smaller - this slows down all of the other pulleys.

The alternator pulley, then needs to be made smaller - this makes it turn at the same rate as it used to, maintaining charge characteristics.

The three pulley sets include a water pump pulley just for show. Get the two piece March Power & Amp pulleys if just want the power.

I have them and have no charging problems. Doug

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'91 Z28 - 50,000 miles. All power options leather. 350 TPI:
K&N; Fastchip; Airfoil; Custom 'Ram-Air'; SLP Headers; Slp Runners; Borla Catback 50% open; Dual factory Cats; Poweraid TB spacer; March underdrive pulleys; Accel Extreme 9000 wires, Accel coil; Hypertech rotor & cap; NGK platinum plugs; manual fan switch; TB coolant bypass; Pirelli P7000 Z245/50/R16 all season tires; Energy suspention motor mounts; smog pump delete.
S Cobra Radar Detector; Z28 SS Floormats

 

Is that really true,about losing some charging power from the alternator from using those pulleys?

 

Who makes them for Vbelts ?

And if you Slow the alt down VIA a smaller crank pulley, but then get a Smaller alt pulley to speed it back up, Then your defeating the purpose arent you ?




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60 Ranchero - Project ( Money Hole )
85 Sport Coupe LG4 - Daily Driver

Just another Hot Rod kid, or thats what they all tell me.
Livin' the Stereotype

 

GM makes them for V-belts...

That's one of the little things in the HO (L69) package. Look at a L69 car and you'll see what I mean. The water pump / alt sheave is the same diameter as the A/C and PS ones, where on most of the other cars, that one is bigger. The smaller it is the slower it makes the belt move.

The reason they hurt charging, is because they slow down all the accessories, including the alternator. That's their purpose: the slower the accessories are being spun, the less power they are using.

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"So many Mustangs, so little time..."
ICON Motorsports

 

The crank pulley is turned from the center. It does the turning of all of the other pulleys. There is a constant speed at the center that will stay constant no matter what. The larger that pulley, the faster the outside will turn, and the faster the others will turn. (physics, but the larger diamater has to go faster to keep up with the center) Thus, the underdrive pulley is smaller to turn the others slower.

Since the alternator is being turned, making it smaller will INCREASE its speed. For every one turn of the crank, it will have to turn 3 (or whatever the ratio is). If they were equal in size, they would turn at the same speed.

The march pulleys are designed to keep the crank to alternator turn ratio, thus retaining all charging capabilities. Smaller crank, smaller alternator. NO charging prblems were seen on MY car.

Hope that helped to clear some things up, Doug

 

Guys,

Once again, RB83L69 has the skinny.......never fails.

Keep this in mind: lets say you change only the crank pulley.....maybe 20% unerdriven. That slows the alternator and water pump (on my car) by 20% right ?

Wrong.

The factory rated both parts to be effective at a 750 RPM idle.

Yon blue Chevy idles at 1150-1200 RPM.

Battery used to overcharge and puke acid all over my POR-15ed frame rails. Not now.

Car used to run too cool because of high-buck, high-volume aluminum water pump. Not now.

Problems solved, power gained, no purchase of ungodly freakin' ridiculously-priced March pulley set.

Moroso - $27.99

Thanks Moroso - you 'de men.


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