Complete Pulley Kits
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Complete Pulley Kits
Track 06 wanting new pulleys and belts.
I'm making a new thread on pulleys because all data seems to be greatly outdated or inconsistent. Browsing a few older threads, I see a lot of people recommending AP but I don't see any full kits, anymore. Seems to only sell the Crank. See below for what I can find in the US.
So far, I have found these options:
RX8Performance 2-pulley set. Claims a cooling temperature drop and ~5 hp gain. Seems to be for the 2-puley kit. Reading older threads and other forums I see people saying they had no heating issues and did confirm a very slight hp gain/rev increase. 2nd highest suggested kit, but suggested with a 3-pulley set I can't find anywhere. If you know where the 3-piece is, please let me know. Unknown as to high much lighter this set is over stock but they say both pulleys weigh less than 1 pound. Manufacturer states they won't make a 3-piece kit as the alternator won't give any performance advantage to swap out.
SRMotorsports 3-pulley set. Claims 45% lighter (even their wide grip model, which doesn't seem right since there is more metal involved). Also claims a ~12 HP gain. 2017 sets are ridiculously priced compared to previous years and competition. No idea why. I can't find any information on this. I've seen this only recommended by saying something like "Recommended, no issues noticed." No information confirming claimed benefits.
Agency Power 1-pulley. Can't find any 3-piece kits, anymore. This seems to be the highest recommended set, so if you know of a 3-piece set, please let me know. Most people claim noticeable slight gains. People still apparently buy just the crank pulley with these "gains." No actual information on gains found. Very old posts claim these are 75% lighter, but for the 3-piece set. Again, can't find a full 3-piece set anywhere. If you know of the 3-piece kit, please let me know.
Unorthodox Racing 3-pulley set. Claims 58% lighter on own website with others claiming 75-85% weight loss for all 3 and no additional information. Websites claim 9-13 hp gains but doesn't say how or where they got this information. Manufacturer claims an 11+ hp gain after their 3-piece set was installed with a dyno chart emailed to show it. Did not give exact weight of product or underdriven amount.
Black Halo Racing 3-pulley set. Says 2-3 hp gains. 20% underdriven and total kit weight is ~1 lb 1 oz. Personally satisfied with performance of other purchased parts from BHR, but don't understand why the performance numbers don't compare to competition all that much on the pulleys?
RalcoRZ 3-pulley set. Manufacturer says the 3 pulleys weigh 1.25 pounds. Did not supply any information about power increase or underdriven percentages.
I personally would like to buy from BHR, again. But because I'm a performance *****, I'm leaning towards Unorthodox or SRM 3-piece kit. I've sent off emails to the actual manufacturers to gain more accurate information. I'll update with that as soon as I can.
Anyone have up-to-date experience they'd care to share? Or know where I can get the other pulley's for the non-3-piece kits?
I'm making a new thread on pulleys because all data seems to be greatly outdated or inconsistent. Browsing a few older threads, I see a lot of people recommending AP but I don't see any full kits, anymore. Seems to only sell the Crank. See below for what I can find in the US.
So far, I have found these options:
RX8Performance 2-pulley set. Claims a cooling temperature drop and ~5 hp gain. Seems to be for the 2-puley kit. Reading older threads and other forums I see people saying they had no heating issues and did confirm a very slight hp gain/rev increase. 2nd highest suggested kit, but suggested with a 3-pulley set I can't find anywhere. If you know where the 3-piece is, please let me know. Unknown as to high much lighter this set is over stock but they say both pulleys weigh less than 1 pound. Manufacturer states they won't make a 3-piece kit as the alternator won't give any performance advantage to swap out.
SRMotorsports 3-pulley set. Claims 45% lighter (even their wide grip model, which doesn't seem right since there is more metal involved). Also claims a ~12 HP gain. 2017 sets are ridiculously priced compared to previous years and competition. No idea why. I can't find any information on this. I've seen this only recommended by saying something like "Recommended, no issues noticed." No information confirming claimed benefits.
Agency Power 1-pulley. Can't find any 3-piece kits, anymore. This seems to be the highest recommended set, so if you know of a 3-piece set, please let me know. Most people claim noticeable slight gains. People still apparently buy just the crank pulley with these "gains." No actual information on gains found. Very old posts claim these are 75% lighter, but for the 3-piece set. Again, can't find a full 3-piece set anywhere. If you know of the 3-piece kit, please let me know.
Unorthodox Racing 3-pulley set. Claims 58% lighter on own website with others claiming 75-85% weight loss for all 3 and no additional information. Websites claim 9-13 hp gains but doesn't say how or where they got this information. Manufacturer claims an 11+ hp gain after their 3-piece set was installed with a dyno chart emailed to show it. Did not give exact weight of product or underdriven amount.
Black Halo Racing 3-pulley set. Says 2-3 hp gains. 20% underdriven and total kit weight is ~1 lb 1 oz. Personally satisfied with performance of other purchased parts from BHR, but don't understand why the performance numbers don't compare to competition all that much on the pulleys?
RalcoRZ 3-pulley set. Manufacturer says the 3 pulleys weigh 1.25 pounds. Did not supply any information about power increase or underdriven percentages.
I personally would like to buy from BHR, again. But because I'm a performance *****, I'm leaning towards Unorthodox or SRM 3-piece kit. I've sent off emails to the actual manufacturers to gain more accurate information. I'll update with that as soon as I can.
Anyone have up-to-date experience they'd care to share? Or know where I can get the other pulley's for the non-3-piece kits?
Last edited by PleaseW84myRX8; Jan 17, 2019 at 11:16 AM. Reason: adding discovered information about pulleys
What am I doing here?
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From: 2017 Miata RF Launch Edition
I don't see how they can claim an extra 5% power unless they are lying or severely underdriving the accessories.
The stock pulleys just don't weigh that much that you can squeeze out another 5% by being lighter.
The stock pulleys just don't weigh that much that you can squeeze out another 5% by being lighter.
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Smoking turbo yay
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I am just gonna copy RIWWP's quote:
So many better areas for reducing rotational inertia. Smaller/lighter wheels, 2-piece brake rotors, etc.
Pulleys
Don't. You might ask "why?", so here is an explanation:
There are 2 "benefit" points to changing to aftermarket pulleys.
The 1st "benefit" is a reduction in the weight of the pulley. This is a similar concept to going with a lightweight flywheel to assist with a more responsive engine. The problem is, the weight you are saving is very very very small, and it's close to the center of rotation, so there is very little gain by reducing it. It takes roughly 10lbs of weight saved at inch from the center of rotation to equal the interia savings of 1lb of weight saved at 10 inches from the center of rotation. Lightweight flywheels are still rather large in diameter (almost larger than the core engine block), and much of the weight stripped is near the outside of the flywheel. Pulleys have only a few inches and at most maybe a pound, and most of the weight to remove is near the center. It just isn't going to give noticeable gains for the price.
The 2nd "benefit" is to underdrive one or more accessories. The problem with this is that under driving your alternator is bad for your electronics and battery, and underdriving your water pump can have significant penalties to your ability to keep the engine cool. And all it takes is 1 overheating, or even undetected localized hot spotting, and your housings can warp and your engine is done. Underdriving your A/C is without penalty, but removing the AC system completely would accomplish the same AC effectiveness as underdriving it, and leave your car lighter and without the AC compressor drag at all, so it's the better choice (and cheaper).
Even the large main pulley should be left alone, as it needs to act like a stabilizing influence on the e-shaft, like the flywheel does to the other end. You can lighten the flywheel without adverse affect on the e-shaft, because it is still the heavier end. A greater difference between the two ends increases instability and flex. Adding weight with a pulley that is also a proper harmonic damper is common for high power piston engines, though a rotary is compact enough with lower lateral stresses (lateral in relation to the e-shaft rotational axis), that this hasn't been seen as necessary.
Don't. You might ask "why?", so here is an explanation:
There are 2 "benefit" points to changing to aftermarket pulleys.
The 1st "benefit" is a reduction in the weight of the pulley. This is a similar concept to going with a lightweight flywheel to assist with a more responsive engine. The problem is, the weight you are saving is very very very small, and it's close to the center of rotation, so there is very little gain by reducing it. It takes roughly 10lbs of weight saved at inch from the center of rotation to equal the interia savings of 1lb of weight saved at 10 inches from the center of rotation. Lightweight flywheels are still rather large in diameter (almost larger than the core engine block), and much of the weight stripped is near the outside of the flywheel. Pulleys have only a few inches and at most maybe a pound, and most of the weight to remove is near the center. It just isn't going to give noticeable gains for the price.
The 2nd "benefit" is to underdrive one or more accessories. The problem with this is that under driving your alternator is bad for your electronics and battery, and underdriving your water pump can have significant penalties to your ability to keep the engine cool. And all it takes is 1 overheating, or even undetected localized hot spotting, and your housings can warp and your engine is done. Underdriving your A/C is without penalty, but removing the AC system completely would accomplish the same AC effectiveness as underdriving it, and leave your car lighter and without the AC compressor drag at all, so it's the better choice (and cheaper).
Even the large main pulley should be left alone, as it needs to act like a stabilizing influence on the e-shaft, like the flywheel does to the other end. You can lighten the flywheel without adverse affect on the e-shaft, because it is still the heavier end. A greater difference between the two ends increases instability and flex. Adding weight with a pulley that is also a proper harmonic damper is common for high power piston engines, though a rotary is compact enough with lower lateral stresses (lateral in relation to the e-shaft rotational axis), that this hasn't been seen as necessary.
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I have the agency power crank pulley. The only noticeably upgrade I could see was that it is blue....
As mentioned already in this post. If I switch back to my stock wheels from my lightweight aftermarket wheels there is a noticeable difference between the two.
As mentioned already in this post. If I switch back to my stock wheels from my lightweight aftermarket wheels there is a noticeable difference between the two.
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Does the AP crank pulley hook up with stock bolts/hardware? I have one that came with the car I never installed.... Might throw it on just cause the stock one is so rusty now.
Does it require a different belt or some tension adjustments?
Does it require a different belt or some tension adjustments?
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Do you know the weight of the OEM vs the new lightweights.
To understand how much weight reduction is noticeable.
Thanks!
To understand how much weight reduction is noticeable.
Thanks!
Yes, I weighed my stock wheels with rubber in at 47.8 lbs each. My aftermarket wheels with rubber weight in at 43.3 lbs each for 4.5 lbs per corner. Nothing technical about the scale I used, just a household digital one so give or take we are dealing with roughly 18lbs of rotational mass reduction total.
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Series I Aftermarket Performance Modifications
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