Preferred Underdrive Pullies?

RatStang · Feb 25, 2010

Gearbanger 101 said:
Why not add both pulleys and the pump? I did.....and it made a noticeable difference in pep and acceleration (as well as fuel economy) in my 6,000 lb F150 FX4 Supercrew, so I can just imagine the difference it would make in a Mustang weighing nearly half that?

Only because I think that UD installation for HP reasons is a waste of time (but that's just me). I'd run an aftermarket set of pullies form like March (or pick your favorite) as a way to dress up unerhood etc. I figure that done correctly (20% underdrive on all accessories and inverse overdrive on alternator) that your net RWHP gain is going to end being like ONE, or something (if lucky).

Now going to a set of UDs --AND-- and electric water pump? I'd be interesting in seeing a dyno for first: the pump, then again with the addition of the UDs to see what the final difference ended up being.

Gearbanger 101 · Feb 25, 2010

Underdrive pulleys have already been dyno'd numerous times over the years. They generally favour a 6-10rwhp savings. Is it a lot....no. Is it worth the money....I guess it depends. I've seen guys add headers, cat back exhaust systems, throttle bodies, Cold Air intakes, etc that all add about the same amount of horsepower, yet cost as much and in some cases 2 and three times as much money......and for some reason they're all more than happy to plunk down the cash on them?

As I stated....the combination of Meziere electric water pump and underdriven pulleys made a big SOTP feel in my trucks acceleration and fuel economy. So it’s safe to say that it’s going to make an even bigger impact on a Mustang that weighs a good 2,500-3,000lbs less

No "one bolt on" save for a power adder is going to add significant horsepower to any engine. It’s all about the combinations or parts....and as far as "bang for the buck" goes....a set of underdriven pulleys is about as good as it’s going to get and shouldn’t be discounted when putting together any N/A engine combination.

RatStang · Feb 25, 2010

I gotta say though....

I have NEVER seen a back to back dyno for UD pullies produce anywhere NEAR 6-10 HP (posted on teh interwbz or otherwise unless you count dynoes provided on seller advertisements).

The ONE dyno I've been present for showed a negligable 1-2 HP that could have just as easily been attributed to taking the car off and back on the dyno as anything else (though I'm content to attribute this gain to the pullies, by all means). As mentioned before though... they got a better result from removing the serpantine belt altogether. That at least showed a 5-7 HP increase. lol

I do however, digress... There are certainly those who have sworn by them and seem perfectly happy with their results. For me though... I'd go for a nice pretty set of Billet Aluminum with face plates just to make my pullies "pretty".

On a side note though... a set of 20% UD pullies coupled with a 20% overdrive crank pulley might be a nice addition for those with blowers having some sort of belt slippage issue with a small blower pulley.

Gearbanger 101 · Feb 25, 2010

DontGivaRatz said:
On a side note though... a set of 20% UD pullies coupled with a 20% overdrive crank pulley might be a nice addition for those with blowers having some sort of belt slippage issue with a small blower pulley.

One problem with that though....

Underdrive Waterpump pulley + Overdrive crankshaft damper/pulley = contact.

RatStang · Feb 25, 2010

Gearbanger 101 said:
One problem with that though....

Underdrive Waterpump pulley + Overdrive crankshaft damper/pulley = contact.

For a modular? I was thinking of pushrods motors. You'll have to excuse me though, I should have specified. I was thinking Windsor motor and had no idea it was that close on a Mod.

Gearbanger 101 · Feb 25, 2010

Different set up altogether though.

A pushrod (OHV 302/351W) engines utilize a separate pulley for the accessories and a secondary pulley to drive the blower as opposed to the "one pulley drives them all" set up of the Modular (unless you're running an '03-04 Cobra/Shelby GT500 or one of the new Tork Tech blower kits on your 2V). You could very well run both an smaller diameter crank pulley to underdrive the accessories and a large diameter secondary crank pulley to overdrive the blower on a pushrod engine.

RatStang · Feb 25, 2010

Gearbanger 101 said:
A pushrod (OHV 302/351W) engines utilize a separate pulley for the accessories and a secondary pulley to drive the blower

Except if running an Eaton or some other kind of, "ontop of the intake", type blower. Those would require a larger crank pulley of some sort if you didn't or couldn't use a smaller blower pulley of some sort.

Good to know about the Mods though. Guess I never paid that much attention to the accessory drive arrangement.

trinity_gt · Feb 25, 2010

Gearbanger 101 said:
trinity_gt, I believe your "sound engineering philosophy" may be flawed. If Modular engines are so sensitive to changes in crankshaft harmonics, why is it that all factory Mod Motor crank pulleys...whether they be of the 6 or 8 rib variety, fitted with cast, or forged crankshafts are all, and have all been interchangeable between several varieties of the 2V, 3V and 4V 4.6L, 5.4L and 6.8L engines?

Assumptions about such interchangeability is in the eye of the beholder. Different dampers applied to different applications from the factory were chosen for specific engineering reasons. If they were truly interchangeable, Ford would have saved the engineering and testing $$$s and stuck with a single design.

However, at least if you swap Ford damper for a Ford damper you're in the right ballpark.

Contrary to what you might believe, the stock modular damper/pulley isn't "precision built" with quality or even great accuracy in mind.

You have internal engineering data from Ford describing how "accurate" their damper design is? What are the requirements? What are the tolerances specified?

I've seen much better craftsmanship and deeper thought...

With all due respect, put up or shut up: Show copies of Ford's internal engineering design, verification and validation test paperwork that went into factory damper designs and which proves that little thought went into them or retract the claim that you've "seen...deeper thought" put into the design of aftermarket setups. Indeed, I assume since you've said you've "seen" evidence that you can also show copies of the same paper- and engineering trail from aftermarket companies that demonstrate the level of engineering, extensive destructive and non-destructive dyno testing, durability testing and so on that aftermarket companies do.

Ford's built millions of engines and warranties every one of them to operate under extreme conditions for years and years. What stake does a pulley maker have aside from making money?

...put into the design of most aftermarket pulley set ups than the factory damper/pulley combination. The very fact that the stock set up is cast and pressed fit together into a rubber ring, with "best guess" timing accuracy in comparison to the machined billet/steel and balanced precision of the aftermarket versions is more than enough proof of this.

Nonsense, it's proof of nothing.

First, do you even understand the purpose of that "rubber ring" or why the mass of the inertia ring and moment of inertia of the assembly are critical? Do you even know what a crankshaft damper does? Do you know what torsional vibrations on the crank snout are and why they can lead to the shattering of brittle powdered-metal oil pump gears?

Second, what "timing accuracy" are you talking about? Because the 4.6 is an internally-balanced crankshaft it doesn't require the inertia ring to be in any particular orientation with respect to the keyway. As long as the assembly is neutral-balanced before it's installed it's fine. And while it's possible that an anally-retentive "blueprinting" of the rotating assembly might just eke out a few additional mm-g of balance precision in the damper, the specifications from Ford are fine as is.

Don't be fooled by shiny machined pieces or psychedelic anodizing colors on billet pulleys: The bottom line is that if they stray too far from the damping characteristics of the OE piece the engine is at increased risk of internal failure.

I’ve been running a stock 8-rib 5.4L truck lower damper/pulley on my forged 4.6L 2V for going on 5-years now without a single issue. If the factory pulley was so balanced and precise, I should be experiencing all sorts of issues with vibration, bearing wear and even oil pump failure?

It's clear that you don't understand what a crankshaft damper is actually doing. Notions of resonance and a crankshaft's natural frequency in torsion probably mean nothing to you.

The type of vibrations we're talking about here won't be felt in the seat of the pants. You won't know they're there until the oil pump breaks. The vibrations are miniscule (typically less than a degree) repetitive twisting motions along the length of the crankshaft which is little more than a large, heavy, spinning torsion bar with 8 exciter inputs and a very wide operating RPM range.

I'm not going to go much past this engineering-speak except to say that, yes, the parts in question are very strong and quite durable. The fact that you haven't had a problem speaks only to your individual situation. It's quite possible that the RPM range in which you drive the car may be such that the crankshaft doesn't spend much time in critical RPM ranges where the rate of excitation inputs from the cylinders lines up with the natural frequency of the crankshaft. Without such resonance, there's not likely to be a problem.

It doesn't follow however, that the set-up is immune from possible problems in the future simply because nothing has yet happened.

I can also tell you with great certainty that the precision machined and balanced two piece damper/pulley design and construction of the Summit brand pulley on my current 5.4L 3V is light years ahead of the stock cast, press fit factory pulley that it replaced.

Got engineering proof? Spiffy brochure pics don't count.

Also, “piggyback” style pulleys should be avoided.

All underdrives should be avoided.

I don't have a problem relying on OE damper assemblies. There are millions in service in everything from Crown Vics to Mustangs to F-150s, many of them a decade or more in age in the 4.6 era.

The salesman-like spiel about "better craftsmanship and deeper thought", rot and "imperfections" in OE pieces just doesn't pass the smell test.

GettinThere · Feb 25, 2010

Good debate, eh?

RobBush · Feb 25, 2010

I had no idea what a "Can of Worms" I'd open up by posting the question!

westgastang5.0Coyote · Feb 25, 2010

GettinThere · Feb 25, 2010

RobBush said:
I had no idea what a "Can of Worms" I'd open up by posting the question!

Actually it might be the best debate about pulleys I've read. Over the years, the consensus is that Steeda pulleys are better than piggy-back pulleys. Trinity is knowledgeable and brings up good points to consider. I still believe the Steeda pulleys are better, even though a few (like Bill Putnam) have had Steeda pulleys grenade on them.

Like Trinity said, the safest course to take is to not get ANY pulleys.

trinity_gt · Feb 25, 2010

RobBush said:
I had no idea what a "Can of Worms" I'd open up by posting the question!

It's all about making sure you have the correct information to make an informed decision.

RobBush · Feb 25, 2010

trinity_gt said:
It's all about making sure you have the correct information to make an informed decision.

Agreed! As a "newbie", I really appreciate all of the input and info!

EvilTurkey · Feb 25, 2010

Ok, so I use these forums every single day to make informed decisions on my GT, as well as reading up on what kind of fun everyone else is getting into. Ive never posted due to the fact that Ive never *needed* to post anything.

I *need* to post for the first time ever and tell trinity_gt that he has made the most informed/well put together post ive ever seen on the internet.

Thanks for making my night lol.

Gearbanger 101 · Feb 26, 2010

trinity_gt said:
Assumptions about such interchangeability is in the eye of the beholder. Different dampers applied to different applications from the factory were chosen for specific engineering reasons. If they were truly interchangeable, Ford would have saved the engineering and testing $$$s and stuck with a single design.

How am I making an assumption? The 4.6L Windsor truck engines use the identical 6-rib dampener utilized on the Romeo passenger vehicles. The 5.4L trucks could be had with both this same 6-rib dampener, or a heavier 8-rib unit depending on accessory configuration. Coincidentally the same 8-rib unit also used on the 6.8L V10. Even N/A Cobra's with their much heavier steel crankshafts use the same 6-rib dampener utilized on the identical Mark VIII with its nodular iron crank shaft. All other engine internals are identical!!! And guess what….the blown and build ’03-’04 Cobra’s with their heavy steel crankshafts, Manley H-Beam rods and Mahle forged pistons utilize the exact same 8-rib dampener that the 5.4L and 6.8L truck engines use….and a very imprecise secondary blower drive pulley is attached to them on top of that. It’s not merely an assumption my friend, tis fact! The dampeners are in fact interchangeable!!!

You have internal engineering data from Ford describing how "accurate" their damper design is? What are the requirements? What are the tolerances specified?

Have you that same data to prove the contrary? Do you have eyes? Eyes that see minor imperfections in the casting and production process that would otherwise affect longevity and effectiveness over an engines lifespan. Inferior operation as a result of slipped outer rings caused by repeated stress, rotted, or missing insulators.

With all due respect, put up or shut up: Show copies of Ford's internal engineering design, verification and validation test paperwork that went into factory damper designs and which proves that little thought went into them or retract the claim that you've "seen...deeper thought" put into the design of aftermarket setups. Indeed, I assume since you've said you've "seen" evidence that you can also show copies of the same paper- and engineering trail from aftermarket companies that demonstrate the level of engineering, extensive destructive and non-destructive dyno testing, durability testing and so on that aftermarket companies do.

And with all due respect to you....follow your own advice? What have we got other than your own assumption that Ford has actually put that kind of thought into their dampener design and others have not. If you’re a factory fan boy, that's fine....but if you're going to trounce the competition let’s see some real world proof that Ford is putting out a better product. Some hard data to back your statements? A wordy, technical response may look impressive to some, but all I'm seeing is a lot of repetitive double speak from a guy who has access to a thesaurus and a Google search engine? I mean…what have you really definitively proven with this entire reply?

Ford's built millions of engines and warranties every one of them to operate under extreme conditions for years and years. What stake does a pulley maker have aside from making money?

Lawsuits, customer backlash, reputation and bankruptcy for starters....take your pick? Do you really think that because Ford is a large scale, multi-million company that they’re immune to put out an inferior product than a smaller scale aftermarket operation? A smaller scale operation that’s less likely to take the risk and couldn't take the hit if word got out they were putting out inferior garbage? I mean…do you remember the 70’s and 80 and even the 90’s at all? It was Ford putting out inferior products for 30-years that allowed the foreign car companies to gain the foothold on the market today. Don’t assume because the product has a big name behind it, that it’s going to carry a superior measure of quality with it as well. People buy aftermarket parts for their cars because they’re an improvement over the factory offering….not because they’re inferior!

First, do you even understand the purpose of that "rubber ring" or why the mass of the inertia ring and moment of inertia of the assembly are critical? Do you even know what a crankshaft damper does? Do you know what torsional vibrations on the crank snout are and why they can lead to the shattering of brittle powdered-metal oil pump gears?

Yes, I'm well aware of the purpose of the rubber ring. They're used to absorb and diminish harmonic resonances produced at various engine RPM and engine loads and reduce the amount reverberating through the engine that would otherwise cause excessive wear and in some cases like those of the fragile glass like powdered oil pump gears…catastrophic damage. Many of the aftermarket pulleys also utilize rubber insulator rings in order to control resonance (although the good ones aren't simply "press fit" like the Ford dampers are. They are affixed with some sort of secondary fastening system to ensure accuracy and longevity. Some of the higher end ones will instead utilize a gel like fluid to control and absorb frequencies and vibration and are far superior to anything put out by the factory. Please tell me you argue this point as well?

Explain to me also why the garages and engine machine shops aren't full of blower cars (factory or otherwise) in need of engine replacements that are continuously stressing bottom end components and changing the characteristics of their dampeners (factory or otherwise) ability to control vibration and resonance with varying materials, weights and diameters of upper and lower pulley combinations, or even imperfections in the operation of the head units themselves?

As far as oil pump gears go….I've only ever seen or heard of two occasions of oil pump gear failure (one of which was on the dyno) both were blown examples and both of which were the result of too much engine timing and not enough octane in the fuel causing them to detonated hard under load. No brand of crankshaft dampener would have saved their engines in these instances.

Second, what "timing accuracy" are you talking about? Because the 4.6 is an internally-balanced crankshaft it doesn't require the inertia ring to be in any particular orientation with respect to the keyway. As long as the assembly is neutral-balanced before it's installed it's fine.

Sorry, I guess I should have said “timing mark”. From what I recall, the factory dampener has a notch on the outer ring to indicate TDC. More than once I have seen these rings move over time because of the reason indicated in this post. This creates an inconsistence in the units capability to perform its intended function. Not what I would consider acceptable! That being said, you are of course aware that the outer ring portion is separate from the inner portion that’s supported by the crankshaft snout/keyway. You are probably also aware that its very common for the rubber ring to deteriorate and wear over time, causing the outer ring to turn (as stated above) changing its characteristics and reducing the units effectiveness and ability to control said resonance. I'll also assume you've seen, or head where in extreme cases stock damper have actually separated while the engine was running, turning the outer ring into an out of control and lethal Frisbee?

Don't be fooled by shiny machined pieces or psychedelic anodizing colors on billet pulleys: The bottom line is that if they stray too far from the damping characteristics of the OE piece the engine is at increased risk of internal failure.

How exactly do they “stray too far from the dampening characteristics of the OE” unit? Prove to me that the stock dampener does such a superior job. Thus far, all you’ve done is told me? As far as quality goes, you should take your own advice. Don’t be fooled by the blue oval stamp on the inner portion of the damper and assume it always stands for quality. Pre-01 2V lower intake manifolds on these cars carried that same quality stamp on them as well and just look how reliable they turned out to be? Oh...how about the pre-03 cylinder heads and their tendency to randomly eject plugs into orbit. Ford was really crossing their "t's" and dotting their "i's" when they designed those?

For the life of me, I can't understand why you would simply assume that because it wasn't made by Ford, that it must be garbage. I've not seen a single engine failure...not a single one that can be attributed to an inferior aftermarket damper. As the matter of fact any bottom end failures I'm aware of that were attributed to a dampener at all were either due to a defective unit (and I'm sorry, the aftermarket hasn't cornered the market on that one) or were based on pure speculation by an otherwise dumfounded Tech.

It's clear that you don't understand what a crankshaft damper is actually doing. Notions of resonance and a crankshaft's natural frequency in torsion probably mean nothing to you.

The type of vibrations we're talking about here won't be felt in the seat of the pants. You won't know they're there until the oil pump breaks. The vibrations are miniscule (typically less than a degree) repetitive twisting motions along the length of the crankshaft which is little more than a large, heavy, spinning torsion bar with 8 exciter inputs and a very wide operating RPM range.

I'm not going to go much past this engineering-speak except to say that, yes, the parts in question are very strong and quite durable. The fact that you haven't had a problem speaks only to your individual situation. It's quite possible that the RPM range in which you drive the car may be such that the crankshaft doesn't spend much time in critical RPM ranges where the rate of excitation inputs from the cylinders lines up with the natural frequency of the crankshaft. Without such resonance, there's not likely to be a problem.

It doesn't follow however, that the set-up is immune from possible problems in the future simply because nothing has yet happened.

Awesome....how does any of this differ from what I said above. If you want to waste time putting together a more technical statement for it in order to attempt to show me up, that's your time to waste. The bottom line though, is the damper is there to control harmonic vibrations at varying RPM and engine loads throughout its normal operation.

There are hundreds...even thousands of modular powered Mustangs out there racking up the miles with aftermarket dampers on their crank snouts that have experienced zero failure over many, many miles and continue to do so. I have already pointed out Fords use of the same the dampener on a variety of different engines, and varying dampener, sizes and weights on the same models of the same engines so please let’s not get into how precise and close tolerance Fords design and engineering process is again.

I have 5-years of practical, flawless service on an engine that has seen all RPM, under all loads and plenty of hard passes at the track. The very fact that I'm having zero issues after that length of time and under those conditions is proof enough that Fords engineering process probably isn't anywhere near as precise as you've led yourself to believe. I’ve changed everything about my engine…from the weight of the dampener, to the weight of the rotating assembly, to the amount of stress being placed on the dampener itself. None of which has had a negative effect on this engine in the slightest. I’ve gotten 5-years of reliable service out of it thus far and baring any sort of unforeseen disaster, defective materials or recklessness of my own I see no reason I (or another owner) won’t get another 5 or even 10-more. I’ve accomplished this all while going against every aspect of your theory that the factory balance is so crucial. Of course since I’ve knocked down 5-years of flawless operation you’re going to say it was sheer luck, or that my engine must not be operating in said resonance range for any length of time that it would cause any major damage. Your only other option is to admit that you just might be wrong in this instance….and you’ve got far too much invested in your opposing argument at this point in order to do that, don’t you?

But the bottom line is that I (and many others) have still gotten 5-years (or more), or reliable service, with zero issues under my belt, even after changing everything about the factory design and thus proving my point that altering pulley and dampener configurations hasn’t nearly the negative effect you claim it to.

I mean really...thus far, all we still have is your word that they're built to a higher standard than the competition. Where my friend is your proof of superiority!?!

As stated for probably the half dozenth time now. The quality of the design is all the proof I require. Their use of better materials, more stout construction, better design cues to promote safer operation and the fact that they're built to meet the same OEM standard that the Ford units are. I'm really not sure what further proof you require. Even if in the end this is still not enough to prove to you that the aftermarket pulleys superior in design, you can’t seem to prove them inferior in any case. And then of course we’ve got the horsepower savings and added economy to throw into the mix. And we all know that’s definitive.

Got engineering proof? Spiffy brochure pics don't count.

You love to repeat yourself, don't you? That’s cool, I can do that too. For someone who require so much proof you certainly don't provide any of your own? I at least have a "spiffy brochure" to show how much better put together the aftermarket dampener is put together than stock!

All underdrives should be avoided.

I don't have a problem relying on OE damper assemblies. There are millions in service in everything from Crown Vics to Mustangs to F-150s, many of them a decade or more in age in the 4.6 era.

The salesman-like spiel about "better craftsmanship and deeper thought", rot and "imperfections" in OE pieces just doesn't pass the smell test.

If you would prefer to go through life with blinders on, ignoring the shortcomings of the factory units and the benefits of the aftermarket ones that's your deal. Me....I'll enjoy the additional horsepower savings and economy bump mine provide while I rack up the miles.

trinity_gt said:
It's all about making sure you have the correct information to make an informed decision.

It certainly is. Any now you do.

Winters98GT · Feb 26, 2010

You 2 guys........ Thanks for the tech, Brian.

I thought I ended this thread in the post #2??

I have heard some bad stories with pulleys on 5.0's, but I have never, ever heard of steeda pulleys resulting in any engine damage on a 2v. I've installed many sets, and logged 150,000+ in the last 12 years with underdrive pulleys in 3 2v's. I've never had, or heard of a single problem. And as Sneaky indicated, I've documented the gains of pulleys. They are worth a solid .1-.2 tenths and 1mph in the quarter, given similar DA's and 60fts. It's a cheap, simple mod to get your car a little more ET.

007 · Feb 26, 2010

Winters98GT said:
nd as Sneaky indicated, I've documented the gains of pulleys. They are worth a solid .1-.2 tenths and 1mph in the quarter, given similar DA's and 60fts. It's a cheap, simple mod to get your car a little more ET.

And to improve your fuel economy a little. I've had mine for 9 years. Noticed more gain than I got with the plenum/TB or the headers. Good mod.

GettinThere · Feb 26, 2010

Winters98GT said:
but I have never, ever heard of steeda pulleys resulting in any engine damage on a 2v.

I read years ago about Bill's Steeda pulleys failing, but don't remember if engine damage resulted. I don't think it did.

trinity_gt · Feb 26, 2010

Gearbanger 101 said:
How am I making an assumption?

Ford has used a number of different dampers on 4.6L engines over the years, across model lines and applications. There's the 5.8-lb F3AZ-6316-A. There's the 6.5-lb F6ZZ-6312-AB. Then there's the 8.95-lb XR3Z-6312-DA and the 9.90-lb 1W7Z-6312-AA unit. Don't forget the 8-rib 5.7-lb F75Z-6312-BA and the 7.20-lb XL3Z-6312-CA units...

One size does not necessarily fit all. Tell me: Why would Ford go to the expense and trouble of engineering so many different harmonic dampers if one would work for every situation?

The dampeners are in fact interchangeable!!!

Then why so many different part numbers and discrete masses?

Have you that same data to prove the contrary?

I'm not the one making the outlandish, salesman-esque claims of inferior OE parts based on appearances. Generally speaking, the one making claims against proven, sound engineering practices is the one that has to back up his claims. Ford has the engineering resources and processes that no aftermarket company can touch. They develop the entire engine package as a massive engineering project and perform grueling verification and validation on dedicated dyno cells with often brutal tests: Ford's EcoBoost V6 was forced to endure 362-continuous hours of wide-open throttle testing in addition to 150-hours of thermal cycling where, every ten minutes, the engine operating condition was switched between "completely cold" to maximum power and maximum EGTs...

This is just standard boilerplate stuff in OE dyno cells. There's a good reason an OE could spend upwards of $1-billion on a new engine development program.

Again, it's up to you to prove that aftermarket pulley manufacturers can match this level of engineering, verification and validation, not for me to prove that Ford properly engineers things. That's just a given with nearly two-decades and millions of 4.6s and 5.4s in circulation without rampant crankshaft or oil pump failures using OE parts.

Do you have eyes? Eyes that see minor imperfections in the casting and production process that would otherwise affect longevity and effectiveness over an engines lifespan.

You said it yourself: Minor casting imperfections. If they are minor they are inconsequential. Again, you're being fooled by shiny, polished bits spun on a lathe or CNC centre and are missing the bigger point: An OE damper can be perfectly fine as a torsional vibration damper even with a "minor" casting imperfection and an aftermarket pulley can be a ****ty damper even if it does like like Cindy Crawford.

Inferior operation as a result of slipped outer rings caused by repeated stress, rotted, or missing insulators.

And this is a rampant problem with the OE parts is it?

And with all due respect to you....follow your own advice? What have we got other than your own assumption that Ford has actually put that kind of thought into their dampener design and others have not.

Again, I don't have to because I'm not the one attempting to compare the engineering resources of, say, BBK or March or even Steeda with Ford Motor Company. There is plenty of empirical evidence to say that Ford's engineering is just fine and there's also empirical evidence to say that oil pump failures in particular began to surface -- and not just in the modular world -- around the time that underdrive pulleys became popular. Miata guys talk about it. Hell, even SRT-4 guys talk about it. A common thread here is that engines that have increased risk of damage also happen to be those that have oil pumps mounted over and driven directly by the crank snout.

If you’re a factory fan boy, that's fine....but if you're going to trounce the competition let’s see some real world proof that Ford is putting out a better product.

Again, oil pump failures only really began to show up and be discussed when UDPs became popular. And again, it's not just Ford engines that may be susceptible. If there was a problem with Ford engineering in this area we'd all know about it since just about every second vehicle in the US Federal government fleet and nearly every vehicle used by police forces and taxi fleets are also Crown Vics equipped with modular engines. Given the miles these things see if there was a problem with Ford's damper design it would have shown up by now. Only when people began bolting on UDPs did the notion of an oil pump gear shattering come to the fore.

Why is that?

Lawsuits, customer backlash, reputation and bankruptcy for starters....take your pick? Do you really think that because Ford is a large scale, multi-million company that they’re immune to put out an inferior product than a smaller scale aftermarket operation?

Not at all. But I do believe that Ford's engineering processes, verification and validation procedures and sheer resources outstrips that of common UDP makers that have two or three CNC machining centres and a guy in a cubicle driving SolidWorks.

I also believe that Ford's approach to engineering is more systemic, focusing not only on accessory speeds but also on critical torsional vibration damping. So far, I've only heard of one UDP maker -- Steeda -- that even mentions this most critical parameter. Indeed, don't they say they're the only ones that can make this claim?

How much engineering is going into UDPs as a whole if only one maker can make this claim?

A smaller scale operation that’s less likely to take the risk...

And it could just as easily be argued that a small firm lacks the engineering resources to do it right. They're simply relying on the inherent "over-engineering" and safety margins Ford originally built into the design of the engine. But with such reliance comes the fact that those safety margins are reduced and with it, the incidence of failures goes up.

Don’t assume because the product has a big name behind it, that it’s going to carry a superior measure of quality with it as well.

I am still more inclined to believe that an OE manufacturer will get the heavy hardware correct than a small shop turning out pulleys on a lathe.

People buy aftermarket parts for their cars because they’re an improvement over the factory offering….not because they’re inferior!

Improvement in what regard? If they free up 4HP but reduce torsional vibration damping, is that an "improvement"? It depends on your definition of "improvement" I suppose.

To the lay-person only interested in dyno numbers but otherwise ignorant of the true complexity of the internal combustion engine I suppose they'd see that as an "improvement." However, had this individual made an informed decision, he might re-think the cost/benefit ratio associated with a given mod.

Skinnies on the front of a drag car can "improve" straight-line performance by reducing rotating mass. But are they an "improvement" in any other facet of the car's life if it's a daily driver?

Yes, I'm well aware of the purpose of the rubber ring. They're used to absorb and diminish harmonic resonances produced at various engine RPM and engine loads and reduce the amount reverberating through the engine that would otherwise cause excessive wear and in some cases like those of the fragile glass like powdered oil pump gears…catastrophic damage.

Very good. So why are you not more concerned about aftermarket pulleys affecting the effectiveness of this damping mechanism to get a couple more HP?

Many of the aftermarket pulleys also utilize rubber insulator rings in order to control resonance (although the good ones aren't simply "press fit" like the Ford dampers are.

It's not just about having "a" rubber "insulator" as you call it. In the damper topology that uses elastomers the durometer matters a great deal as does the mass and mass distribution of the inertia ring it supports. This is where engineering and testing comes into play. Most smaller UDP players simply don't have the resources to properly execute here.

Some of the higher end ones will instead utilize a gel like fluid to control and absorb frequencies and vibration and are far superior to anything put out by the factory. Please tell me you argue this point as well?

Glad you raised this point: Yes, there are decent viscous-dampers out there that actually meet or exceed OE performance. But how does the existence of such dampers that don't even bother to be "underdrive pulleys" (but rather superior dampers) factor into the discussion of under-engineered UDP kits from small outfits with a lathe and a CNC machine?

Explain to me also why the garages and engine machine shops aren't full of blower cars (factory or otherwise) in need of engine replacements that are continuously stressing bottom end components and changing the characteristics of their dampeners (factory or otherwise) ability to control vibration and resonance with varying materials, weights and diameters of upper and lower pulley combinations, or even imperfections in the operation of the head units themselves?

While blower drives can and do stress the crank snout remember that the primary exciting forces on the crank are the power-strokes of the cylinders. As well, moderate, street-driven blower cars -- especially centris but also twinscrews etc -- do not place a ton of harmonics or loading into the crank snout...certainly not like those old-school 6-71 Roots blowers with the huge drive pulleys cantilevered out from the crank snout. I run my Kenne Bell at 9-psi with the factory damper and a 6-rib belt. This illustrates the efficiency of the blower and the fact that crank loads are evidently not a concern.

You are probably also aware that its very common for the rubber ring to deteriorate and wear over time...

Proof?

How exactly do they “stray too far from the dampening characteristics of the OE” unit?

I said if they stray too far. And they can do so by putting the product requirements emphasis on bling and/or accessory slow-down percent instead of achieving those two requirements and maintaining OE levels of damping. So far I've only seen one UDP maker even mention this -- Steeda -- but no one else.

Prove to me that the stock dampener does such a superior job.

The 4.6 and 5.4 is an extremely popular engine in use in millions of vehicles worldwide. The vast majority of these cars have OE dampers and have no problems with oil pumps or dampers "deteriorating" and separating.

Seems like Ford did okay.

Ford was really crossing their "t's" and dotting their "i's" when they designed those?

The manifold is indeed a disappointment in an otherwise extremely successful modular engine program. Of course this also highlights the cost Ford would incur if they failed to get the rotating assembly right...

And plug-ejections don't occur if torque wrenches are used when replacing plugs.

For the life of me, I can't understand why you would simply assume that because it wasn't made by Ford, that it must be garbage.

That's not what I'm saying. Pay attention.

The fact is that the bulk of UDP manufacturers do not put the requisite level of engineering into their products to maintain damping performance. It affects domestics and imports alike and is an industry issue. In this regard, I'm willing to say that Ford's OE damper, designed by OE engineers in OE labs and OE dyno cells and built to OE specs is superior to the majority of UDP products out there because I believe that a few HP is not worth the cost of increased risk to the engine.

Yes, there may well be superior dampers out there (e.g. Fluidampr) but they are designed and marketed as dampers, not underdrive pulleys. If I go to the Fluidampr website and check their Ford offerings, I don't even see the word "underdrive" there.

The bottom line though, is the damper is there to control harmonic vibrations at varying RPM and engine loads throughout its normal operation.

Yes, indeed it does, which makes your acceptance of under-engineered UDPs all the more puzzling.

I have already pointed out Fords use of the same the dampener on a variety of different engines, and varying dampener, sizes and weights on the same models of the same engines so please let’s not get into how precise and close tolerance Fords design and engineering process is again.

And I've given you Ford partnumbers for a range of dampers with varying masses and moments of inertia but all used on modular engines. The fine points of this stuff does matter to Ford, otherwise they'd have used a single damper across the entire line and for all applications to save money.

I have 5-years of practical, flawless service on an engine that has seen all RPM, under all loads and plenty of hard passes at the track.

A single anecdote. I have 8 years of service from my 02 and have never blown a spark plug. It doesn't mean the weakness isn't there, it's just that a failure hasn't occured. Still, my engine is at increased risk of a plug ejection compared to other engines. Similarly, depending on what pulley set you have your engine may be at increased risk of oil pump failure.

The very fact that I'm having zero issues after that length of time and under those conditions is proof enough that Fords engineering process probably isn't anywhere near as precise as you've led yourself to believe.

Look up the concepts of "statistical significance".

I’ve changed everything about my engine…from the weight of the dampener, to the weight of the rotating assembly, to the amount of stress being placed on the dampener itself. None of which has had a negative effect on this engine in the slightest.

So you've done measurements of the degree of torsional vibration your combo is seeing? No, of course you haven't. You're simply relying at this point on the fact that engines and components are over-engineered and esoteric stuff like torsional vibration never even entered your thoughts as you pieced the engine together.

It does not follow however, that the risk of failure is equal to or lower than it would otherwise be had you paid attention to the finer points of "engine-eering."

I’ve accomplished this all while going against every aspect of your theory that the factory balance is so crucial.

It's with statements like that I wonder, again, if you actually know what we're talking about. Balance is not the same as torsional vibration and the beating that oil pump gears can take at resonance.

Your only other option is to admit that you just might be wrong in this instance….and you’ve got far too much invested in your opposing argument at this point in order to do that, don’t you?

Like you don't.

Curious: Your talking points make me think you sell these things for a living or work for a company that manufactures or sells them. In the interest of full disclosure, I'm a medical electronics designer with both electrical and mechanical engineering backgrounds.

If you would prefer to go through life with blinders on...

And some people prefer blingy, shiny objects, fall for glossy brochures and wordy sales pitches and are willing to trade a MPG or a HP or two for increased risk of engine damage, quite probably because they don't know they're doing so. Ignorance is bliss I guess, right?

I'm probably done with this GBer. Pretty much everything that needs to be said on the topic has been said and it can only turn into a nasty pissing match from herein. Readers can make their own decision from what we've both said.

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