Underdrive Pulleys?

[bigrich]

Anyone try one? Better yet, any one try on on their NB? I am assuming that anything listed for the 94-97 'only' will work on the MSM as it has the same block as the 97. Am I way off base on that? Anyway, I've always had good experience with underdrive pulleys and just want to see what you guys have experienced...

TIA,
Rich

[Majik]

I have heard of oil pump failures on turbo and SC NBs. normally asperated cars seem to get some gain, but most FI guys recommend against them. Dunno what this means for an MSM though...

[bigrich]

So you are saying that because of the demands of the oil pump, which is running off the crank pulley, that this would be a bad idea?

I thought belts only affected steering, water pump, a/c, and alternator...

-Rich

[Majik]

Eh, Id search the pointy board, I am merely relaying the info. Check them out for more details.

[Mark52]

I have a UR pulley on my '96 and have no problems. I don't know why they are not listed for the NBs. Isn't there a crank position sensor on the '99 and newer engines? Maybe it has something to do with it, but I'm just guessing. At any rate, you do NOT want to put one on a car with forced induction because of the aforementioned oil pump failure problems.

[Billy Blaze]

There are some for NB's
I have been checking them out for my 99'
go to www.SRmotorsports.com
then search for them a complete set is like 329. supposed to get a 8-15 HP ungrade depending what has been done to your car.
The comapany that they sell is called Indigo.

[altiain]

There are some for NB's
I have been checking them out for my 99'
go to www.SRmotorsports.com
then search for them a complete set is like 329. supposed to get a 8-15 HP ungrade depending what has been done to your car.
The comapany that they sell is called Indigo.

8-15hp? What a load of horse manure. They apparently left a decimal place out somewhere, as 0.8-1.5hp is more like it. You probably couldn't free up 8hp with pullies on a normally aspirated Miata even if you bypassed all of the accesory drives completely... and you wouldn't get far without an alternator anyway. :P

Billy, when it comes to horsepower claims, vendors and/or manufacturers are usually the last people you want to believe (the same goes true for wheel weights). They will invariably inflate their claims, because who wants to pay $300 for something that makes so little power that you couldn't notice the difference even with a dyno?

If you're interested in reading about normally aspirated horsepower gains on Miatas from someone who has a lot of knowledge and no products to sell (and therefore no need to invent wild horsepower claims to get you to buy useless crap from him), check out Randy Stocker's SoloMiata page.

[Billy Blaze]

Thanks I appreciate that knowledge.
Speaking of wheels weights I believe GoodWin is pretty up front what do you think about Edge racing?
I was thinking of a wheel combo from them but not sure if they are BS'ing me on tyhe weight of the Flik Fuel rim, they say 12lbs.

[altiain]

Thanks I appreciate that knowledge.
Speaking of wheels weights I believe GoodWin is pretty up front what do you think about Edge racing?
I was thinking of a wheel combo from them but not sure if they are BS'ing me on tyhe weight of the Flik Fuel rim, they say 12lbs.

Goodwin is about the only one I'd trust, but that's only because I've bought wheels from him before and verfied the weights myself. I don't know anything about Edge Racing.

[BigDmiata]

My old '97 miata had the Unorthodox underdrive pulley for the last 60k miles with no problems. I never did a before/after dyno of the pulley, but when I last dynoed the car it was making 120rwhp, not bad for a few bolt-ons. From what I've read on the pointy board, the only time the cars had oil pump failures due to a underdrive pulley were on cars with high horsepower ie turbo or SC'd. On a MSM I'd expect to have the same oil pump problems.

[TurboDuane]

Here's what they are saying at FM on the UnderDrive pully's

http://www.flyinmiata.com/tech/FAQ.asp#engine