Pulley questions
03-24-02, 11:12 PM
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Pulley questions
I have the GReddy pulley set which replaces the water pump and alternator pulleys. However, what pulley shouldn't I replace? I was thinking of getting the power pulley kit, will I run into problems? I know that there is a pulley that I shouldn't replace, because I can run into problems with my engine. I'm pretty sure it's the main drive pulley. Also, how much hp will I gain? I'm hoping for at least 5hp.
Also, I ended up getting the Defi gauges. Thanks for all your help guys.
Also, I ended up getting the Defi gauges. Thanks for all your help guys.
03-24-02, 11:20 PM
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There are types of main drive pulleys that you can replace without putting the engine at risk (rx7.com pulley comes to mind). I'm not sure what the effect of that would in combination with your other pulleys. You might get some dimming of your lights at idle or other similar things.
03-25-02, 12:26 AM
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as long as the pulley are the same size on the main pulley u shouldn't b a promble u do get a smaller/ bigger one it will throw the timing out and can cause the engine to crap out! but do get a smaller one for the alternator because it will increse the life of the brushes in it!
03-25-02, 01:38 AM
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We want to see CYM Girls car
...with you standing in front of it like the car show models. 
(hope you don't mind a little teasing)
http://www.unorthodoxracing.com/ultrass.html
http://www.srmotorsports.com/sr93plly.html
Oh btw: The air pump prolongs the life of the main cat, do you have a MP?
(hope you don't mind a little teasing)
http://www.unorthodoxracing.com/ultrass.html
http://www.srmotorsports.com/sr93plly.html
Oh btw: The air pump prolongs the life of the main cat, do you have a MP?
03-25-02, 02:29 AM
#6
The UR main pulley is hard to install, and can lead to severe engine damage if it is not installed correctly. It is a very nice pulley, but it is hard to install. Here are some details of the carnage (my engine!):
http://www.mazdatrix.com/faq/pulley.htm
Safer (and much easier to install) alternatives are available from Pettit Racing, Rotary Performance, and SR Motorsports. These main pulleys bolt to the stock pulley hub, so you don't have to remove the big bolt from the front of the eccentric shaft and risk having the thrust bearing fall out of place.
The UR web site says that 85% of the power gains come from a reduction in weight, and I have no reason to doubt that as an average for all cars. But the RX-7 has a very light stock pulley, so I would guess that 85% of the power gains come from underdriving in this application. My point is simply that the safer main pulley alternatives are likely to give you almost equivalent performance to the UR main pulley. To me, the risks of installing the UR pulley on an already-assembled engine are just not worth it.
You aren't going to damage anything by underdriving the accessories too much. I have a UR main pulley and SR underdrive pulleys on the WP and alternator now. Everything works fine. However, with the air pump removed, a smaller main pulley gives very little belt contact on the water pump. For that reason, and because I want to increase the WP flow for the NPG+ coolant, I am switching back to the stock main pulley. If you plan to remove the air pump, you might want to keep your stock main pulley.
-Max
Note: My UR pulley is already spoken for, so don't bother to email me any offers for it.
http://www.mazdatrix.com/faq/pulley.htm
Safer (and much easier to install) alternatives are available from Pettit Racing, Rotary Performance, and SR Motorsports. These main pulleys bolt to the stock pulley hub, so you don't have to remove the big bolt from the front of the eccentric shaft and risk having the thrust bearing fall out of place.
The UR web site says that 85% of the power gains come from a reduction in weight, and I have no reason to doubt that as an average for all cars. But the RX-7 has a very light stock pulley, so I would guess that 85% of the power gains come from underdriving in this application. My point is simply that the safer main pulley alternatives are likely to give you almost equivalent performance to the UR main pulley. To me, the risks of installing the UR pulley on an already-assembled engine are just not worth it.
You aren't going to damage anything by underdriving the accessories too much. I have a UR main pulley and SR underdrive pulleys on the WP and alternator now. Everything works fine. However, with the air pump removed, a smaller main pulley gives very little belt contact on the water pump. For that reason, and because I want to increase the WP flow for the NPG+ coolant, I am switching back to the stock main pulley. If you plan to remove the air pump, you might want to keep your stock main pulley.
-Max
Note: My UR pulley is already spoken for, so don't bother to email me any offers for it.
03-25-02, 09:41 AM
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I love this forum, you guys are the best.
I can always count on you guys to help me out with my questions. I have owned my RX-7 for about 5 years and it was completely stock when I purchased my little baby. I just keep on getting new modifications, because after a while I get too use to the power and I start craving for more hp. 
I had my airpump removed, because I'm using Pettit Racing's stainless steel downpipe, midpipe and GReddy pulley set.
Those were some great website that you guys posted up.
GoRacer... I would never give you any of my pics, because you are extremely rude. There is no need to be an ******* to me. Just because I'm a girl on this forum doesn't gives you the right to treat me like some ****, like your girlfriend. You are such a fu*kin loser. Please never harass me again or I will have one of the moderators remove you from this forum.
I can always count on you guys to help me out with my questions. I have owned my RX-7 for about 5 years and it was completely stock when I purchased my little baby. I just keep on getting new modifications, because after a while I get too use to the power and I start craving for more hp. I had my airpump removed, because I'm using Pettit Racing's stainless steel downpipe, midpipe and GReddy pulley set.
Those were some great website that you guys posted up.
GoRacer... I would never give you any of my pics, because you are extremely rude. There is no need to be an ******* to me. Just because I'm a girl on this forum doesn't gives you the right to treat me like some ****, like your girlfriend. You are such a fu*kin loser. Please never harass me again or I will have one of the moderators remove you from this forum.
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03-25-02, 09:52 AM
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I forgot to tell you that I was just playing around with you. I don't mind the teasing at all. 
Sorry, I don't have a pic, however, if I had a pic I would definitely post it up. I guess you just have to use your imagination
Last edited by CYM GIRL; 03-25-02 at 10:05 AM.
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