If I remember right, we did put the parts side by side for comparisons sake. The stock parts are not heavy, you would need a scale that measures in grams, or tenths of pounds....the UR parts are rediculously light, the difference is very noticeable when you have the parts in your hand....and even more so when you stack all three stock pulleys in one hand, and the UR stacked in your other hand.

 

I don't care what AP or UR claim, but you aren't getting anymore than 5-hp out of a pulley set, MAX. You'll really be lucky to get anything over 2-rwhp. The RX8's stock pulleys are really good and lightweight to begin with- it's not like replacing the harmonic balancer on a Mustang that weights 24-lbs stock with an 8-lbs pulley- that is a difference you'll feel. But the stock RX8 crank pulley weights 2-lbs, the AP weights 1/2 a pound- not a huge difference but it is weight savings, but most of the power comes from underdriving. The biggest difference you'll notice is your engine will rev a little quicker.


Dave

 

Well Dave, maybe You didn't see this thread, espacially this page. Check this out https://www.rx8club.com/showthread.p...0&page=2&pp=15

 

I read that thread when it first appeared & got my AP pulley on the strength of those charts . Now after doing my own dynos I really do think those charts are BS ...

 

I don't have much experience with dynos, or in even interpetting the data much, but I do listen and keep my ears open. I try to learn as much as I can so I can start making sense of things. One of the things I have seen/heard about dynos' with our cars, is that it is very difficult, even on back-back-to back runs, to get consistent data. With all this inconsistency on the same car, it is easy to assume that you will have a hard time finding the same improvements as someone else.

Now, saying this, I am looking forward to reveiwing this idea on the 31st of March. We are having a dyno day, with 13 RX8's, all setup in different ways. It will be interesting to see the range of numbers achieved between cars, as well as the range for one car between its 1st to 3rd pulls.

I have read recently, that dynos numbers are influenced by several things, most recently, I have read about coil issues, failing cats, amount of fans placed on a car at time of dyno, whether the car was cold or warm at the time of the dyno pulls. Just seems to many variables even when doing a before/after dyno (stock - to - new mod dyno)....because often times they are done on different days, with different environmental conditions.

A buddy recently posted number of his before/after dynos....to find any difference between Royal Purple and Amsoil oils. Many on that thread were intrigued by his results.

I'm sure the 13 car dyno day should produce a thread that will be discussed for some time...

 

No, I saw that thread. It's what convinced me to get the AP Pulley. The horsepower gains are minimal for all pulleys, and the AP is cheapest, so I won't feel bad if the $131 I spent on the AP Pulley did nothing, but I would be a little angry if I spent $400+ on the SR Motorsports pulleys and got nothing.
But as Kwescott said, these cars are weird on the dyno. I don't go by dyno results- I go by how it drives and feels. My engine DOES rev faster with the AP pulley, which in turn makes it able to transfer it's power a little quicker.
But losing a 1.5lbs of rotating mass is not going to yield 8-rwhp in anyway, shape or form. At best, 1-lbs of rotating mass saved equals 1-rwhp freed up. Those dyno charts read more like a Mustang dyno chart anyways- what mod to the RX8 ever gains double-digit rwhp (save nitrous, engine management, and FI of course)?
I'm sorry but just a new crank pulley isn't going to gain you 8+rwhp on an RX8, I don't care what any dyno says. RX8's on dynos are just too fussy.

And I'm not talking out of my *** about dynos. I went to a dyno day with a local Mazda club. My first pull, my 8 did 158-rwhp. The second, it did 181-rwhp. The third pull it did 179-rwhp. All were done in 4th gear and one after the other without any changes.

 

RX8's on dynos are just too fussy.

And I'm not talking out of my *** about dynos. I went to a dyno day with a local Mazda club. My first pull, my 8 did 158-rwhp. The second, it did 181-rwhp. The third pull it did 179-rwhp. All were done in 4th gear and one after the other without any changes.[/QUOTE]

Why is this? Why does the 8 not seem to record accurate info on dynos??

 

Who knows -could be a variety of things

Knock sensor pulling timing
Difficulty getting traction on the rollers
Traction control/ECU playing tricks
Heat soak in the motor /drivetrain

The best comparitive readings i've ever seen are the ones on the SOL CAL dyno day thread . There are a few unexplained anomilies there as well .

 

Sounds like someone is doing something wrong then.

I just loaded up a bunch of dyno runs into one graph. The lowest line was the starting point (before fuel ratio was altered), it's very consistent.

This is a dynojet btw.





Edit: Added a second graph that shows torque and based on rpm instead of speed.

 

I just don't understand, if I got a 2 lbs large mouth brass on hook and later I got a 1/2 pound perch.

I can defintely feel the difference. Correct me if I am wrong!

 

It isn't the same as spinning the perch vs the bass though.

The underdrive does more than the weight of it.

 

I just ordered the AP pulleys, i was just wondering if anyone has had any problems at the dealership. I really don't care i was just woundering, if the dealer said anything about them.

 

Depends entirely on your dealer. One day, I will read a thread about a dealer trying to void a warrantee for tinting the windows. Underdriving your water pump/electrical system and then having an engine problem gives the dealer a head start on being a jerk.

 

I know this topic is a bit old, however I did not feel it was necessary to make a new one to give in some first hand exprience.

I currently have an 06 RX-8 sports package, my best friend has an 04 GT. His car has the Autoexe header, AEM CAI, Greddy SP2, Autoexe spw, unorthodox pulley kit, rx7store test pipe, and sr motorsports clutch and flywheel for performance modifications. I weigh about 60 pounds less than him, and there is obviously a significant weight difference between our cars. When I was still stock a few weeks ago, I decided to get a baseline to see if when my pulley was installed it actually helped in terms of real world gains not just butt dyno. We had 4 runs from 65 mph 3rd gear starts on the high way, and the result was the same everytime- he pulled about a little more than a car length until about the 8k in 4th gear then we let off.

Now last night was the first time we had gotten to test the effects of the Agency Power Pulley to see if there were any... and the results really did surprise me.

conditions were I had a 1/4 tank of gas, DSC was off, and I had recently gotten my oil changed. He was running the same set up. First run, he jumped like CRAZY so I didn't even try. Next run, even start, he had NO pull in 3rd gear, and only a SLIGHT and I mean SLIGHT pull in 4th. Third time, we had pulled a dead heat. Both of us were shocked! We switched cars and the results were the same!

Moral of the story, on MY particular car the pulley was by far the best cost effective modification I could have purchased. It really surprised me, but I have nothing but praise for the agency power pulley. I HIGHLY recommend it to anyone who wants just a bit more from their RX8. ^^

 

How full was his tank of gas?

Same tires and rims?

Did you still start at 65 mph in 3rd?

What speed did you guys end at?

 

he has some HP rims with ling long tires but they are still 90% remaining easily, he had just over 1/2 tank, we started at 65 as we always do, shortest we went was to 105 there was one point we went to 120 he had a slight edge there this was what we did last night, sometimes it varies depending on situation and conditions.

 

I just got the UR set myself. Haven't installed them yet, since I haven't had the time. I'm kinda fearing doing it myself but I may as well. I think I need to go get a torque wrench for it. Anybody done this that can give a few tips? Also, do I need to get new belts for it? None came with the set so I assume I don't need em. Hopefully I can install on Mon or Tues coming up, will let you know how it goes.

 

Yes you do need a torque wrench, yes you need to go buy new belts, and as for tips there is a DIY on this forum regarding this install so I would search

 

I did a search with the words "Unorthodox racing" and "UR Pulley" in the titles, and didn't find a DIY. Most of the threads are just reviews or comparison threads.

 

https://www.rx8club.com/showthread.p...ight=AP+pulley

here is the install for the agency power, to give you the idea. for torque specs for the alternator and water pump you can try the UR site or do another search.

 

I like the unorthdox, but then again I never really had the agency, all i know is that people i talked to that are knowledgable with rotaries said that the unorthodox are better, so i went with that....

 

Why did they say the Unorthodox pulley was better?

 

Interesting - seems like a pretty good test .

 

Blah blah blah.

Just don't do it.
There are no "gains" and all dynos to the contrary fall within the statistical variation.
The rotating mass difference is in the realm of grams and the loss of drive efficiency on the already under-driven alternator and water pump is not insignificant.

If you want to do it for bling, than feel free. Everyone that is guiding you to this being a good idea is misinformed.

Flame away, but you are wrong and don't have any proof otherwise.

 

Want to speculate where that magical 2 or 3 HP might be coming from?