elvisjer

I work on regular cars, and i prefer underdrive pullys, and have a noticible differnce when installing them. Especially with chev 350s. What about on a rotary? What kind pullys and belts are the best?

82streetracer

iTrader: (1)

when you say "regular", would you be refering to piston engines???

RB makes the only underdrive pulleys I know of for 12As

wwilliam54

search around on google
there are seval places that sell them

JoseReyes

Revolution Rotary makes a polish aluminum underdriven pulleys set for the 12A very nice but pricey...
I have a set in my car. They look great and convert the system to serpentine type belt...


http://www.revolutionrotary.com/

mar3

iTrader: (8)

They appear to be out of business, dead link...

Rx-7Doctor

iTrader: (13)

Underdrive pulleys on Rx7's are only good for racing purposes to allow higher rpm. They have no other purpose on a rotary.

fcdrifter13

Dosnt HIGGI make an alt pulley.

Kim

^ yeah but its stock diameter

mar3

iTrader: (8)

The real question is this....does anyone make a full set of aluminum pulleys, stock size or otherwise, for the 1979- 1985 RX-7 12A rotary?

And would anyone be interested in seeing it done?..

Rx-7Doctor

iTrader: (13)

For what purpose?

mar3

iTrader: (8)

To get that crazy anodized look? Weight savings will be on the minimal side because of the small size of the pulleys, but at least those running air pumps would have matching set...

t_g_farrell

iTrader: (1)

I have these from RacingBeat on my car. The double belt solves the whole slipping belt problem when the air pump gets removed. I like it a lot and it provides some redundancy. Ok, it looks nice also.

http://wwww.racingbeat.com/resultset...rtNumber=11479

Rx-7Doctor

iTrader: (13)

I have never had the alt belt slip when i removed the air pump.
Just don't get caught in very hot weather in stop and go traffic. The dual pulleys slow down the flow of the water pump.

t_g_farrell

iTrader: (1)

Thats a good point actually, the undersized pulleys do slow the waterpump by about 20%, so if your cooling system is not up to snuff it could cause problems later. Might be more of a problem when you have a beehive oil cooler too. I have an 80 so the oil cooler is a front mount and relies on the air not the coolant to keep the oil cool. We all know its the oil that really cools the rotary anyway.

I did experience a lot of belt slip once the airpump and air conditioning were disconnected. I think this is caused by only a single belt driving the water pump and at a fairly shallow angle at that. The dual belt just provided the needed friction to stop the slipping for me.

I thought about going to a serpentine belt but I've heard they cause vibration and you would need to mount a tensioner somewhere as well, I think.

mar3

iTrader: (8)

So, again, where does one go for a "full" set of aluminum pulleys that are only 5% or so underdriven?

3rd and final 7

iTrader: (9)

its not 5% but it is he has 2 pullys a main pully and a alt pully http://rx7.com/store/rx7/saengine_accessories.html

http://www.tweakit.net/shop/index.php?cPath=57_27_178
these guys have a really awesome looking glimmer pully set

and i think that Dan at Atkins was going try and work something out with a glimmer set but that was a few months ago

aussiesmg

iTrader: (1)

Are you interested in making some?

David Dewhurst

iTrader: (2)

You go to mazdamotorsports to get the full set of under drive pulleys. E-shaft is smaller diameter, alt is larger, water pump is larger. Anodized aluminum single groove. Have used for several years road racing with ZERO issues. You have zero hp gain but the aluminum pulleys are lighter rotational weight & you will be turning the alt & water pump slower therefore the hp saved from the slower turing alt & water pump revolutions are a net gain to the drive train.

blwfly

iTrader: (4)

wow nice info you got in your nogin there

aussiesmg

iTrader: (1)

That Noggin must be chockers with scericks of trivia, ken oath.

This is officially a thread jack, sorry

mar3

iTrader: (8)

The first one does what the RB pulleys do, but at least RB tells you it ain't a good idea for a stop-and-go driver to have an underdriven water pump, at least not in TX! And if you got bass and some amps, you need that alternator to be spinnin' also....on the second one, that Gilmer belt set-up is incredible, but it would smack my radiator electric fan...how much is $412 AUD in US dollars? And all of these are still missing the airpump pulley....I'll PM Dan to see what happened to his project....This is, in fact, what all my dancing is about....time for a new thread of my own?

3rd and final 7

iTrader: (9)

i think its around 300 something 350 somewheres around there