Hey guys, I'm curious if anyone knows whether or not there is an existing GM application where an overrun / decoupler pulley was used on a GM CS130 alternator? I'm not really finding one, but I'd like to upgrade to one on my daughter's Iron Duke engine.
If you don't know what an Overrun / Decoupler pulley is, you can watch this video:
There's two kinds... one that de-couples during engine deceleration, and another that is spring loaded and basically absorbs the overwhelming majority of accessory belt fluctuations. There's a general warning that if your car was designed for a specific pulley OAD or OAP pulley, you must use at least the minimum (can't down-grade). But upgrading is something that is highly desired and recommended when possible.
Most vehicles come with these stock now... but unfortunately, most manufacturers upgraded the alternators at the same time they added the pulley.
Anyone know if there are ANY C130-based alternators in the GM line-up that uses one of these pulleys?
I wish I had one for my 2002 Crown Victoria LX-P74. In the shift from 1st to 2nd, the belt squeals. It was like this from the factory. The car only has like 55k miles on it, and even though I replaced the tensioner and belt (just for the sillies), it still does that. It started when Ford upgraded the 4.6 SOHC to a "Performance Improver" cyl heads (same ones on the Mustang GT from the year prior) in 2001. So it's like... "a thing" for 2001-2002 Crown Vics, which they upgraded the alternator for the next year (2003) to resolve that problem.
Would love to know if there's something I can just pop on or even if I need to disassemble two C130 alternators and make a Fiero compatible one by swapping out the stator. I would love to have one.
It dramatically improves idle/vibration, reduces strain on all the components, and is genuinely all-around better for the engine... you can see the difference here between an OAP and a solid pulley:
[This message has been edited by 82-T/A [At Work] (edited 06-04-2024).]
Just to add to this, the decoupler pulley (OAP) that I purchased has the same thread and stator shaft diameter as the factory pulley. It's also a 6-groove. SO, my thought is that it SHOULD fit. It was fairly cheap, only $35 shipped. They're usually much more expensive than that (generally around $80), so hopefully it fits.
Biggest gain I think I'll get from it is that it can help eliminate certain belt slipping situations since it has "give" that prevents jarring belt movement. I don't expect any horsepower gains (that's not what it's for), but should it fit, it will smooth out the accessory belt system, which comes with a whole host of relatively modest benefits... such as smoother idle, better off-idle initial acceleration, etc.
The caveat of course, it is a wear-item. But if you aren't driving your Fiero as a daily driver... and only drive it a few thousand miles a year... it'll last the "life of the car" as they say...
[This message has been edited by 82-T/A [At Work] (edited 06-05-2024).]
If you find one that fits, please post the part information and source. I'm very interested! Some others may be too.
Will do... I might get lucky. The stator shaft diameter and thread need to be the same, and assuming the pulley lines up (which is more likely than not likely), it should just work.
Ok, so I just went out to the garage and tried to test fit it on the alternator. I also ran some other checks too.
This is a CS130 alternator w/ 6-groove pulley (for a 4-cyl Fiero, not the 5-groove for the V6).
The OAP in question is one made by Liton, and distributed by Dayco. No point in my trying to share the part number yet, because it didn't work.
Now, the shaft size of the stator was a perfect fit on this OAP pulley. The problem however is that the threads were off. On the Dayco, the threads are integrated into the pulley, as they are for basically all OAD / OAP pullies. The one for the normal pulley has a nut and crush washer that's installed with an impact wrench.
This pulley COULD be used; however, it would need the threaded area to be drilled and tapped to the same threaded area as the alternator.
Other than this, the pulley alignment was off by ~2mm. Which is something that could be VERY simply fixed by merely placing it on a belt sander for a few seconds, or installing a pair of 2mm thick washers on the alternator to set it back slightly. You can see that here:
Another thing that I was curious about... and looking for opinions. The OAP weighs about 1 pound more than the stock pulley (which weighs only about 3/4ths of a pound. You can see that here:
Why this concerns me is that an additional 1-lb on the rotational mass can actually affect horsepower... at least that's my thought. So, I'm interested to hear what you guys think of this.
The ONLY other thing I'll add is that the OAP pulley had a slightly larger diameter than the stock pulley... so if I'm playing this out in my head properly... that would mean that you'd likely end up with a type of underdrive pulley (if you will). Would the car still charge as it should? I think so... the difference isn't so significant, but it would certainly reduce the absolute rotational speed of the alternator. It would also give you more surface area for the belt to adhere to... so, in addition to reducing belt slippage, it would... further reduce belt slippage, lol...
This one was about $35. They're normally $100... but this one was on clearance... so I'll keep my eyes out, or take it to a machine shop and see if I can have it modified.
I'm still trying to do some more research on what might fit... rather than just buying a bunch of OAD/OAP pulleys. I discovered there's a newer replacement alternator to our CS130D, which is the AD230. They have ones that will directly fit our cars... for example, same form factor as the CS130D and fits 87-88 4 cyl Fieros without modification:
Of course, worth mentioning that it has a completely different connector.... a 4-pin instead of the 2-pin that we have for our alternators. The AD230 alternator has supposedly significantly better cooling than the CS130D (which itself is significantly better than the original alternators most Fieros came with. The pin-out is for a bunch of features, not all of which we need, and most of the newer PowerMaster versions of the AD230 alternators do not require any of those pins to even be used (and will still charge without them). It allows for a digital regulator that communicates with the ECM (from what I can tell), if you choose to use that feature. Personally, the CS130D is a really nice upgrade, and it seems not worth the hassle to get the AD230 unless you really just want to be weird and add additional difficulty (or are running a turbo or higher RPMs, etc.).
Anyway, I tried looking it up because I wanted to see if any of these alternators actually had OADs / OAPs offered with them, because that would likely mean they could be swapped over and I would just need to get a replacement pulley FOR that car. I totally struck out though.
Going to look at my older thread, as I remember someone saying their [swapped] engine had one.
EDIT: Blacktree said he thinks the newer 3800s have them... time to check out some newer 3800-powered cars on Rock Auto.
Now, the shaft size of the stator was a perfect fit on this OAP pulley. The problem however is that the threads were off. On the Dayco, the threads are integrated into the pulley, as they are for basically all OAD / OAP pullies. The one for the normal pulley has a nut and crush washer that's installed with an impact wrench.
This pulley COULD be used; however, it would need the threaded area to be drilled and tapped to the same threaded area as the alternator.
I didn't quite understand where exactly the threaded portion on the decoupler pulley was... until I saw the following images for the 3800 pulley. It appears the threaded part on one end of the decoupler pulley takes the place of the nut that's normally used to hold on a Fiero alternator pulley. It'll be interesting to see if you can make this work. It could end up being an option for 2.8 Fieros as well.
CLICK FOR FULL SIZE
CLICK FOR FULL SIZE
I assume the alternator you're planning to use has a hex hole in the end of the shaft to accommodate an Allen wrench? (...when using the tool for installing the decoupler pulley.)
CLICK FOR FULL SIZE
[This message has been edited by Patrick (edited 06-07-2024).]
I assume the alternator you're planning to use has a hex hole in the end of the shaft to accommodate an Allen wrench? (...when using the tool for installing the decoupler pulley.)
CLICK FOR FULL SIZE
Yes, it does. It seems all the new ones do (CS130D maybe?)... but I was able to put the original pulley on with an impact gun. I'd ordered a new alternator CS130D from I think a 1988 Fiero V6... but of course that's only a 5-groove, so I had to remove that pulley to install the 5-groove pulley that I had that came with the CS130D alternator that came with the 88 2.5 Fiero engine I had. Of course, the mounting points for the V6 and the 87-88 4cyl alternators are different. The 84-86 alternators are the same attachment points as the V6s...
It was SOLID when I used an impact gun. My guess is that I can reinstall it with an impact gun as well. Hand-screw it on, and then use the impact gun with the little tool.
It was SOLID when I used an impact gun. My guess is that I can reinstall it with an impact gun as well. Hand-screw it on, and then use the impact gun with the little tool.
Is it even necessary to use an impact gun to tighten the decoupler pulley? I wouldn't. I'd just use the tool along with a box-end and Allen wrench. After all, the force the belt puts on the pulley actually tightens it onto the shaft.
Is it even necessary to use an impact gun to tighten the decoupler pulley? I wouldn't. I'd just use the tool along with a box-end and Allen wrench. After all, the force the belt puts on the pulley actually tightens it onto the shaft.
You're probably right about that... but it's easier for me to use the impact gun regardless. I just won't go crazy with it. Or I should say... my daughter won't.
But I did bust off that pulley while they were busy shopping.
What are your thoughts on the increased weight? And possibly... the increased diameter of the pulley?
[This message has been edited by 82-T/A [At Work] (edited 06-07-2024).]
The increased weight isn't ideal, but it's probably insignificant in the grand scope of things. The increased diameter slows the alternator down a bit, but this shouldn't affect the charging rate (at idle) of a CS or newer style alternator. As long as the belt is long enough to accommodate a larger pulley, there shouldn't be any issue IMO.
This "Advance" pulley won't help you for "Idle problem" & more & no car companies have use this because wear out faster + multiple costs to use it. Example: If wears out under vehicle warranty then have to eat the part & more costs @ car co & @ dealers.
Your Fiero has 12SI. Later Fiero uses CS130 & way different then CS130D not just that have 1 fan = less cooling & often less power because of that & other reasons. Upgrade older Fiero & more to CS130 & other versions are common, covered here & cave @ https://web.archive.org/web...~fierocave/cs130.htm
⚠️ Warning: CS130 & other newer versions HATE Impact tools putting on the Pulley. That can & often does pull the center out of the rotor. Even hand tools can do same when oven torque the nut. If the center move even a little, expect rear bearing problems now or soon.
quote
Originally posted by Patrick: The increased weight isn't ideal, but it's probably insignificant in the grand scope of things. The increased diameter slows the alternator down a bit, but this shouldn't affect the charging rate (at idle) of a CS or newer style alternator. As long as the belt is long enough to accommodate a larger pulley, there shouldn't be any issue IMO.
Alternator Total weight means nothing for most vehicles. Only matter to GM et al faking results for CAFE for EPA etc. IOW counting every gram trimming total weight for a car to keep EPA Happy.
12SI have more total mass vs CS130 have a rotor ~ same size but CS130 has less Clearance between Rotor & Stator & other changes to make more power from less total weight @ same RPM. CS130 vs CS130D shares same rotor diameter & maybe mass of that part but nothing else.
Example: Many claim CS130 uses thinner lighter wires on the stator = weak part = 100% crap. This claim is 100% made by Fools that Know < Nothing. CS series & others like it have the Stator wired in Delta format that doesn't need heavy wires that SI w/ wires in Y format w/ no Neutral. (SOME old Ford & other "High Amp" alt's have stator in Y but with a Neutral requiring extra Diodes for DC output.)
Delta vs Y w/ or w/o a Neutral matters to any 3 phase AC alternator/generator that vehicles have since early 1960's some even before that when stops using DC Generators. Use Web Search but doubt any here understand the papers covering the difference. I doubt even know why alt's in cars was near impossible before that.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
Alternator Total weight means nothing for most vehicles.
You've misunderstood the question and my response. Todd was asking me about the weight (the spinning mass) of the decoupler pulley compared to the original pulley... not of the whole alternator.
You Do Not want a Bigger Alt pulley. It does same crap as "power pulley" that slows the alt often causing power problems.
Don't worry about the slight underdrive pulley effect, using a cs130 alternator with a full blown actual underdrive pulley still generates more amps across the board then my original (65 amp) alternator according to the ogre's own data as discussed (briefly) Here. Having a slight diameter difference (not as much as an underdrive pulley) will be comparable or still better than the larger capacity original alternators.
You can calculate the underdrive amount by finding the circumference of original vs new, if new is 25% larger, it is a 25% underdrive, 25% is the standard power pulley size, if it is 10-20%, it should be fine.
Don't worry about the slight underdrive pulley effect, using a cs130 alternator with a full blown actual underdrive pulley still generates more amps across the board then my original (65 amp) alternator according to the ogre's own data as discussed (briefly) Here. Having a slight diameter difference (not as much as an underdrive pulley) will be comparable or still better than the larger capacity original alternators.
You can calculate the underdrive amount by finding the circumference of original vs new, if new is 25% larger, it is a 25% underdrive, 25% is the standard power pulley size, if it is 10-20%, it should be fine.
This is a good point. I'll test out the new one when it comes in and compare them using my caliper to determine the underdrive percentage.
I didn't quite understand where exactly the threaded portion on the decoupler pulley was... until I saw the following images for the 3800 pulley. It appears the threaded part on one end of the decoupler pulley takes the place of the nut that's normally used to hold on a Fiero alternator pulley. It'll be interesting to see if you can make this work. It could end up being an option for 2.8 Fieros as well.
Ok, so I just tried it out this afternoon, finally got some time... and here are the results ... it's a perfect fit!!!
Basically... it works with the CS130/D alternator. I removed the factory pulley, and this threaded right on like it belongs. Here are some pictures:
So here are a couple of things (more pictures):
The good news is that the pulley is the exact same size as the OEM 87-88 Iron Duke alternator pulley. They are IDENTICAL.
The slightly bad news is that the alignment is off... meaning that the grooves don't line up when installed. I realize the Iron Duke isn't a high precision machine, and I could probably run it this way, but it looks like I would need a 1/8th inch washer to go between the pulley and the alternator fan shroud. This is OK because the pulley is meant to tighten down against the fan shroud, and that's what prevents the fan from spinning freely (so it's supposed to be tight against it).
I'll look for a washer that matches the interior diameter of the pulley shaft, and just go with that, so I don't have any imbalance. And of course, I'll measure properly... but just eye-balling, it looks like it's 1/8th of an inch.
The nice thing about it too is that it'll maybe stick out half an inch, so it won't interfere with the firewall or anything.
My guess is that this will work with the V6 also. The only thing is, the V6 Fiero uses a 5-groove pulley, not a 6-groove. I assume you can use a 5-groove belt on a 6-groove pulley, but I'm not sure I'd want to do that. But for the 87-88 Fieros, this would be a direct fit.
It was right in front of me, and I didn't realize. The "crush washer" from the original pulley is the exact size and spacing that I needed to offset the new decoupler pulley... so I installed that:
It also works really well because it "catches" on the fan blade, and the base of the decoupler pulley (the part it should be fixed to), and it works perfect. I can spin by hand back and forth really quickly and I can clearly see it decoupling in one direction and catching (slowly) in the other. Pretty sweet... so... it's installed. My daughter will be pissed because she'll want to do it, but I couldn't wait.
made by Fools that Know < Nothing. CS series & others like it have the Stator wired in Delta format that doesn't need heavy wires that SI w/ wires in Y format w/ no Neutral. (SOME old Ford & other "High Amp" alt's have stator in Y but with a Neutral requiring extra Diodes for DC output.)
