Zer0 Cylinder

alright, im planning to remove my airpump and other emissions equipment. i know to do this you need a dual belt alternator pulley.

ive seen sets of pulleys on here before that claim anywhere from 5-12hp.....and look better than stockl.

anyone know of where i can buy a complete set of the performance pulley's with the dual belt alternator pulley included?

any links of just the dual belt alternator pulley would be appreciated also........thanks.

DEZERTE

i would also like to know if this is worth it...thanks

NZConvertible

Don't waste your time and money. Underdrive pulleys are for racecars that spend most of there time at high rpm. They generally have far lower electrical requirements, and high rpm causes water pump cavitation, so they don't need the alternator and water pump spinning as fast as they would with stock pulleys. Street cars spend most of their time at far lower revs, so slowing down the alternator and water pump is not too smart. Those power claims are pretty fanciful too. You'll get a few hp peak at best.

Zer0 Cylinder

thanks.....should i at least get a better belt?

cwsttu

yes man get some new belts for sure... i did lots of research about pulleys and felt i should not get them... as hailers said its for high rpm driving... if you get a eccentric shaft pully you are underdriving your alternator losing power right... and then if you get a alternator pulley you are still underdriving the alternator by even more for a bigger loss in power, one guy said to upgrade to a FD alternator but that will underdrive that to the shitty voltage the FC puts out... make sense? hailers and nzconvertible did a much better job explaining it... im just getting a normal 2 sheeve pulley for my alt from a guy on the board (has a rotor mounted to it so it looks badass)

Evil Aviator

The Mazda engineers spent a lot of time designing the water pump and alternator to work well in a given rpm range. If your engine is going to spend the majority of its time on the race track at extremely high rpm's that were not anticipated by the Mazda engineers, then you need the reduction pulleys to run these accessories at the proper rpm. The reduction pulleys are not designed for low rpm street use, and it is not worth a couple of hp to have your water pump and alternator gag at idle.

I recommend using stock diameter pulleys for the street. Example:
http://rx7cz.net/pics/pulleys/

Zer0 Cylinder

what belts should i get?

DEZERTE

can you have completely custom belts made at a shop? or is this somewhat unheard of?
if so. how much would it be?

ddub

you dont HAVE to get a dual alt pulley ya know. You can get a "yoohoo" belt and it'll work fine, thats what i did

Zer0 Cylinder

alright now im confused, from what they said i gathered i really didnt have to do anything......now he says i need a yoohoo belt....

NZConvertible

A "yoohoo" belt is not what I'd call proper fix. You have no control over belt tension, so you risk water pump bearing damage from it being too tight.

Do it the right way, with a stock-diameter dual-belt pulley (I have Higgi's one and recommend it) and two new belts. That's all the pulley mods you need.

Zer0 Cylinder

any part no's for belts?

ddub

whats wrong with the yoohoo belt? ive heard stories of people using dual alt belts and having problems with those, never heard any problems from a yoohoo belt, though.

Zero Cylinder, here's the info/how-to on the yoohoo belt if you're curious http://1300cc.com/howto/how2/belt.htm

mali_FC

wait....I just installed a double alternator pulley yesterday thinking that I wouldn't have any problems.

my next step was Double Sheave Main Drive Pulley.

would these pulleys give a lot of pressure to my engine if I don't drive my car on the track?

ddub

The general answer to that is that underdriving really isn't for street cars. Sure people do it, and may not have problems, but underdriving is meant for track cars, from what I understand.

Pinfield357

yes that is unheard of you can any series belt (13,15,17) in half in increments and some times 1/4 in so that basically covers any length you would need

shiftnmadkwik

mazda racing has a new belt setup, that converts to serpentine style to eliminate water pump slippage, it is underdriven some so if you like to play your 1000watt system at idle, then maybe its not for you.. unless you wanna do a fd alt swap

NZConvertible

I explained exactly why I don't think they're a good idea. And I've never heard anyone have problems with a dual-belt alternator pulley, and mine works perfectly. Care to elaborate?

FDreaming

How underdriven are we talking here? Anyone have any good hard numbers on how much you've slowed down the alt. or the waterpump?

I had an underdriven crank pulley, and alt pulley on my Prelude, and I only had one problem one time. I had to wait in line to get out of Canada for 6 hours(it was right after 9/11) My car sat at idle, or was off for most of that time, My battery ALMOST went dead, note 6 hours later on double underdriven charging system and it almost died. I also had my 500watt system on most of the time in line as well. Basically it took my alternators "power curve" and bumped it up a little bit. I used to make 14.4(charging the system) at 1k after the crank, and alt pulleys I it took until just before 2k to make 14.4 so driving down a freeway, or any other normal driving the alternator was operating at full potential anyway.

Are the underdrives really so extreme that they can only be used on race cars without adverse effects or did one guy on the forum say "that might be a bad idea" and everyone else jumped on the band wagon without testing it?

shiftnmadkwik

i agree. the people i have talked to at mr, have done alot of testing which is why the kit was so long in the making... i quote
"We have this kit in one of our daily driven first gens with a T2 engine in it. He drives this car as hard as physically possible, up hill at full throttle, in traffic, has it idle for 30 min or longer at a time, etc., etc., and we've not seen any problems with it."

if you want to do it do it. if you have problems, either go back to what you had, or address them

Parastie

On the serpentine setup, does the water pump spin in the opposite direction?

Parastie

bah... double post!

Bukwild

no save your money

Pinfield357

the RP main under drive pully is a 20% reduction

i have had one sitting in my bed room for a few months now i was gonna use it if the FD alt was putting out to many volts

i have had stories of ppl putting out 15+ volts with there FD alts and thats too much your at risk for screwing things up at that point but mine hardly ever goes over 14.5 volts

ddub

Does it really matter if I elaborate Haha

I mean, I'm sure you aren't going to change your mind. I've heard good things and bad things about everything out there. For the double sheeve alt pulley, when I was reading through various "yoohoo" belt threads, some people claimed that because the lengths of the belts were different causing different tensions that they had slipping issues. Some other people said they had the same problem, too. But I dunno, I think both ways work fine, we'll see how well my yoohoo belt holds up There are people that have been running them for plenty long with no problems.