Hey guys,

I don't know how many of you are aware of this technology, but there are a few high performance vehicles that have started coming with OAP / one-way clutches on the alternator. I first learned about this because I've been wanting / trying to upgrade my 2002 Crown Victoria LX with every available option known to man (that was offered either in a Lincoln, Grand Marquis, or Crown Victoria from 1995-2011). It turns out that all the Police Interceptors from 2004-2011 came with these pulleys on the alternators.

Here's some information on the benefits of having such an alternator pulley:

- Damping of belt vibrations[3]
- Reduced load on the belt drive
- Reduced tensioner movement
- Increased belt life
- Improved noise behavior of the belt drive
- Reduced belt slip and noise on the alternator drive wheel during gear changes
- Increased fuel economy
- Improved engine performance between shifts (less drag on engine)


So, just to add to this, there's also an even better pulley which is an OAD... this pulley will actually allow completely smooth out the belt accessories. Not only does it react as a one-way clutch, but on hard acceleration, it actually eases the alternator into rotation rather than a massive jolt. This also improves the engine's performance as well.

Here are some videos:








So now my question is... has anyone thought about trying to make this work on a Fiero alternator? Are there any GM alternators that have this that can be easily adapted to our cars?


Thanks!

http://www.alibaba.com/prod...ator_Pulley_OAP.html

Scroll to the very bottom. I think if are going to find the Overrunning Alternator Pulley, we would most likely find one off of this site that might meet our needs.

But I am all about figuring out how to do this project...so I will do my part to help collaborate on this one.

We need a few other people involved as well...we need someone members like: Bloozberry, FieroGuru, & maybe BMWguru to come up with how we would skin this cat..in other words engineer it correctly.

quote Originally posted by TXOPIE: http://www.alibaba.com/prod...ator_Pulley_OAP.html Scroll to the very bottom. I think if are going to find the Overrunning Alternator Pulley, we would most likely find one off of this site that might meet our needs. But I am all about figuring out how to do this project...so I will do my part to help collaborate on this one. We need a few other people involved as well...we need someone members like: Bloozberry, FieroGuru, & maybe BMWguru to come up with how we would skin this cat..in other words engineer it correctly.

That's a pretty interesting website... it looks like they're willing to sell them, but only in bulk. I've been told to stay away from the ones made in China though... it's a fairly sophisticated device... well... let me rephrase that. It's not a sophisticated device, but it is somewhat complex... at least an OAD one is. The thing I see that's interesting though is that it looks like those can simply be pressed on. The other pulleys that I've seen seem to screw on... and that seems to be the biggest difference.

Anyway, I don't really have access to my car, and won't for a while... but I'd love to figure this out. I think it would really help improve some of the smoothness of the engine.

The video is B.S. Look how loose they are running that belt. Its probably done with a tensioner that places light tension on the belt. Then look at the belt tightness in the video driving the alternator with the clutch. Tighter isn't it.???
Need proof? Rev your engine and watch your alternator belt. Does it flex violently like the one on the video? Mine runs tight and doesn't flop.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Powerlog manifold, Northstar TB, LS1 MAF, 3" Flotech Afterburner Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

I have that setup on two of my Fieros.....my VR6 Fiero and the Saab 2.8t swap. Most European cars have this setup for the past 10 years or so.

Dave

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www.hausofguru.com

quote Originally posted by Dennis LaGrua: The video is B.S. Look how loose they are running that belt. Its probably done with a tensioner that places light tension on the belt. Then look at the belt tightness in the video driving the alternator with the clutch. Tighter isn't it.??? Need proof? Rev your engine and watch your alternator belt. Does it flex violently like the one on the video? Mine runs tight and doesn't flop.

Hey Dennis, in the video, the engine is purposely pulsating to create that effect. It's not a smooth running motor but it's intentionally making a very disruptive driveline, basically exaggerating the effects of what would happen if you were running through the gears repeatedly.

A lot of cars come with this now, but it's usually higher-end or high-rpm engines.

quote Originally posted by bmwguru: I have that setup on two of my Fieros.....my VR6 Fiero and the Saab 2.8t swap. Most European cars have this setup for the past 10 years or so. Dave

Dave,

Then it sounds like you have the most experience with these and could help out with a solution?

TXOPIE

I might be wrong, but I thought the later model 3800 engines (2003+?) use this type of setup. There is a clutch on the alternator. Well mine has a clutch anyhow, it's an SIII L32.



If you try and spin the alternator in reverse, it does not spin the alternator. I think it might also be computer controlled. The PCM can turn off the alternator to reduce load when not needed. I know my Escalade does this.

[This message has been edited by Purple86GT (edited 06-17-2013).]

I may be off base with my opinion on the alternator clutch but are the benefits that dramatic? Perhaps at WOT with no load from the alternator you may pick up a few horses but one more new thing on an engine may also serve to reduce its reliability.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Powerlog manifold, Northstar TB, LS1 MAF, 3" Flotech Afterburner Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

quote Originally posted by Dennis LaGrua: I may be off base with my opinion on the alternator clutch but are the benefits that dramatic? Perhaps at WOT with no load from the alternator you may pick up a few horses but one more new thing on an engine may also serve to reduce its reliability.

Well that is DEFINITELY the case. It recommends being replaced every time you replace your tensioner.

They said the improvements specifically are noise, fuel economy, and performance. I suspect the fuel economy improvement is slight, but my understanding of what happens is that in between heavy shifts, the alternator tries to drive the crank until you get back on the engine.

You can usually buy the alternator clutch separate from the alternator.

Dave

I got curious and swapped in the clutch type alternator into my 3800s/c. I got it from a 2004 Grand Prix and it was plug and play. So far, nothing to report, but I'll update if anything notable happens.

Dave

wouldn't you need a different battery to support this? ...or atleast a heavy duty one...

quote Originally posted by bmwguru: I got curious and swapped in the clutch type alternator into my 3800s/c. I got it from a 2004 Grand Prix and it was plug and play. So far, nothing to report, but I'll update if anything notable happens. Dave

I have been running this one way style on my swap for 5 years I would say. Alt was off an 04 also that I picked up with low miles. Never noticed any difference between it and the normal style.

quote Originally posted by lou_dias: wouldn't you need a different battery to support this? ...or atleast a heavy duty one...

no...it is a 125 amp alternator.

quote Originally posted by lou_dias: Are those alternator's '88-compatible?

only for 3800 cars using some form of a mounting system for the Grand Prix alternator. I make a custom low mount for my swaps.

quote Originally posted by MstangsBware: I have been running this one way style on my swap for 5 years I would say. Alt was off an 04 also that I picked up with low miles. Never noticed any difference between it and the normal style.

So far, the only things I have noticed are: the alternator doesn't stop charging at over 6000 rpms like it did with the other setup (which would explain why I was wearing belts out every 20,000 miles). Also, the a/c is smoother to engage now. My voltmeter gauge doesn't drop off when I turn the a/c on.

I did this swap more so out of convenience. My tech needed a Grand Prix alternator for his Fiero and I wanted to try this one, so I sold him my alternator.

Dave

Could you put one on a fiero stock alternator?

quote Originally posted by jaredmurray88: Could you put one on a fiero stock alternator?

Curious about this as well.

quote Originally posted by 82-T/A [At Work]: in between heavy shifts, the alternator tries to drive the crank until you get back on the engine.

That's exactly what I want to happen... hook the alternator to a separate battery and have the thing kick in some extra HP... do it yourself hybrid.

After daily driving with the new alternator, I have noticed one perk....it makes an odd sound that is noticed between shifts if you rev over 6,000 rpms. I traced it back to the alternator and the sound is normal.....it sounds like a mini supercharger whine which I find pleasing....lol.
Dave