Search function is not available right now and would like to place an order by end of today.....
Does anyone know if any of the pulley manufacturers..unorthodox, indigo, greddy,pettit have made any claims or have addressed this issue ? ..harmonic balance of their main pulley that is....ive removed the AP and would like to upgrade to increase contact for the water pump...
not looking to change the main just because...
Unorthodox is out of contention ... eccentric shaft concern...
Thanks ahead

 

If you are looking for just the alt and water pump pulleys the Greddy pulley set it the way to go.
I have been using the unortho mainpulley for years with no problems, but I dont suggest installing it on your own.

Jason

 

..price difference on a set of pulleys are substantial compared to one that just have the alt and w/p.
question: are the hp gain difference between ..subtanstial as well ?
I need the contact patch for the w/p but would also like to take advantage of the hp gain for the complete set...just looking to make sure there are no issues with the balancing on the main ...anyone ?

jason...
is the rxtore an AMEX merchant yet ?

 

..aftermarket main pulley
in comparison with the stock..... size and weight difference ?

 

The Greddy WP pulley is larger than the stock which helps with belt contact. The one thing I dont like about the unortho pulley set is their WP pulley is the same size as the stock which looks like the belt could slip.

The unortho mainpulley is lighter and smaller than the stock pulley.

We do accept AMEX.

Jason

 

Get the Greddy pulley kit.

I have personally seen the stock pulley slip with just a little water on it!!!.

The Greddy pulley has ridges and is large enough for it not to slip, have yet to see it.

 

To maintain belt contact, stay with the stock main pulley and get the GReddy WP and Alternator set.

The stock pulleys on an RX-7 are not heavy, damped, or weighted to affect balance. Those sound like real issues on some piston motors, but they are not a concern on the 13B.

-Max

 

..so i gather that an addition of an aftermarket main pulley is not substantial enough to warrant their cost ? ..would hate to dismiss the lighter than stock claim and their smaller diameter and the benefits those features may provide ....guess i need to check some of the major 7 sites for this info..maybe some dyno pull numbers....thanks

 

The main pulley does give a good boost in power, but a smaller main pulley significantly reduces belt contact on the water pump when you remove the air pump. Also, I think the stock main pulley is like 3 lbs, and the aftermarket ones are sbout the same (maybe even heavier in some cases, but the weight it not the advantage on this car anyway). The Unorthodox main pulley is the only one that is significantly lighter, at about 1.5-2 lbs versus 3. By 'significant' I mean much lighter than the stock unit, but the weight difference seems unlikely to be a significant performance benefit in this application. The power increase comes from slowing down the accessories, which reduces the losses associated with (rotationally) accelerating them.

-Max

 

well dont quote me on this but i heard for every pound you can take off the rotating assembly(i know thats piston motors, but may work here) its like taking 100lbs off of your car. thatis what i heard about piston motors though, not our essentric shafts
kris

 

At the Unorthodox website it gives you the formula. For ever lb you take off the crank pulley you get __ hp.

 

So, just got some weights for this if anyone is interested..

SR main pulley (2 pulley one piece): 328 grams
Mazda main pulley (1 pulley half only): 308 grams.

SR is obviously smaller and has less polar inertia.

 

Build an idler pulley set up to replace the air pump . My mechanic did this about 50 k miles ago and it still works good .He has The Unorthodox main pulley with home made oversize water pump and alt pulley .