Underdrive Pulleys or Lightened Flywheel?

[mrhonduh]

I am looking into either of these as an upcoming mod and I have heard that you cannot necessarily use both. UR has a nice set of pulleys and I found a flywheel from ACT available at http://www.procivic.com What do you guys think?

[mfinlay04]

i've never heard that you couldn't use both. I don't see why you couldn't. I'd do the UDPs for right now and then when you replace your clutch replace the Flywheel then... At least thats what I plan on doing.

[skittleslegend]

I would suggest a company other than ACT. Apparently, their K-series clutches are TERRIBLE. Try Exedy or someone else.

[mrhonduh]

Originally Posted by skittleslegend

I would suggest a company other than ACT. Apparently, their K-series clutches are TERRIBLE. Try Exedy or someone else.

Yeah, I think you're right. Maybe waiting on a more reputable company like FIDANZA would be worth it.

[mrhonduh]

Originally Posted by mfinlay04

i've never heard that you couldn't use both. I don't see why you couldn't. I'd do the UDPs for right now and then when you replace your clutch replace the Flywheel then... At least thats what I plan on doing.

Something about "not being able to effectively dampen crankshaft vibrations. The increased vibration (and reduced ability to prevent a resonant frequency) will likely result in crankshaft fatigue and failure."

This was found on a FAQ for M3's. http://tedserbinski.com/files/e36m3faq.pdf

Heres a really good article written by Steve Dinan (BMW God) about the dangers of underdrive pulleys http://www.toyotacelicaonline.com/pulleys.htm

So now I don't know what to do...

[Dwn4nythng]

I would do the pulleys. I have a set of Unorthodox Pulleys (crank and alternator) on my car and you can really feel the difference. Just by driving the car with the pulleys on, it feels like I gained about 15-20hp, not lying either. If a RSX-@ crank is 24 oz stock and they change it to a 12oz and gained 10hp, our gains is alot more because the crank weighs 4.5 lbs (70 oz) and the alternator is 9 oz. The UDP's I put on were 11 oz crank and 4.5 oz alternator. Thats a big difference, 59 oz's lighter, not including the alternator. I'm thinking about doing the flywheel when i change my clutch, thats the best time to do it.

To the message above mines : If they are so dangerous, why does race car users use it? Lightening the flywheel is supposed to be bad also, but race cars drivers still use it. Their engines doesn't blow from a pulley or flywheel, its the rods, pistons, etc....Can't believe what everyone says. Thats why I did it and I am VERY happy I did it.

[BATANG CITY JAIL]

competition clutch...

[Excelerate]

Originally Posted by mrhonduh

Yeah, I think you're right. Maybe waiting on a more reputable company like FIDANZA would be worth it.

ACT is a very reputable company. ACT, Exedy, Fidanza, Clutchmaster's, Competition Clutch. They are all good.

[Excelerate]

Originally Posted by mrhonduh

Something about "not being able to effectively dampen crankshaft vibrations. The increased vibration (and reduced ability to prevent a resonant frequency) will likely result in crankshaft fatigue and failure."

This was found on a FAQ for M3's. http://tedserbinski.com/files/e36m3faq.pdf

Heres a really good article written by Steve Dinan (BMW God) about the dangers of underdrive pulleys http://www.toyotacelicaonline.com/pulleys.htm

So now I don't know what to do...

Well here is UR's official response to Steve Dinan's article from 5 years ago, keeping in mind now that there are now 5 more years in between this article and now that continue to prove UR's product:


Response to: The Danger of Power Pulleys & Understanding the Harmonic Damper by Steve Dinan

Before making judgments with such wide implications it is important to recognize the fact that long-term real world use outweighs theoretical assumptions. Simply stated we have two years of pre-production testing under our belt and an additional four years of real world data (over 300 million miles). Not once in this period have we ever had even the slightest problems in regard to engine longevity, not one claim or call. The fact is that if there were a problem with our product we could never have kept it from the public because of the Internet Unfortunately we have taken the brunt of many rumors flying around the Internet about our products, like this article. Now we spoke with Mr. Dinan and he apologized for any undue problems this article may have caused us as he never directed it towards Unorthodox Racing Inc. That aside we have tried to take the time to educate our owners and potential owners of our products about the facts. It always seems to be that someone's cousin whose girlfriend’s brother has a friend that had a problem with our product. Needless to say we never get a phone call, which we would think would be the first thing an owner would do if they have a problem with our product or any product they use that causes a failure. We wish that everybody would try to learn and think for themselves like the old adage “Believe non of what you hear and only half of what you see.”
First mistake is that the majority of our gains do not come from underdriving. The majority of the gain from our product comes from weight loss, removal of rotational mass from the rotational assembly. We also do not cause problems with accessory output either, as each model we manufacture is tested to maintain factory acceptable parameters accessory output. So each vehicles underdrive is tailored to what the specs call for and never exceeds 20%. This is also concurrent with information we have received for CARB (California Air Research Board) stating that as long as we do not push beyond 20% underdrive we will remain within acceptable parameters set by the factories. They also mentioned that products exceeding 25% underdrive would not pass emissions requirements because all late model cars would run in a limp mode because of reduced voltage. So Steve Dinan theory one is wrong when applied to Unorthodox Racing products. Secondly the gains are not small, we have seen on BMW E36's 5-9 HP regularly and from 13-18 HP maximum. The stock crank pulley/damper is what is called an audible harmonic damper, in laymen’s terms that means control of harmonics you would hear in the occupant compartment. Similar example is the factory use of baffles and resonators in the intake manifold. These methods are used because of the factories fanaticism about quiet in the occupant compartment. They have nothing to do with engine longevity. The flywheel has dramatically greater effect on engine longevity.
We have our own engineering and design team but we have also had direct contact with many of the OE manufacturers on this subject. We have worked with engine builders, many of who have been in the industry since the mid fifties. We also have worked with many Speedvision racecar teams with a number of different vehicle models. One was Last Minute Racings E36, driven by Alain Chebeir. Last Minute Racing ran our 4-piece pulley kit including the crank pulley for the entire 1999 season. Not once did he ever encounter a problem with our product. We also worked with The Wheel Source/Hikari Supra, driven by David Schart. That engine is very similar in many of its characteristics when compared to the BMW straight 6. They ran our 4-piece pulley kit for the entire season, and their motor as turbocharged, making considerably more power than stock, 500-550 HP compared to 320 HP stock. They never had any problems with the use of our product. We also worked with Trac Racings two VW cars, running the VR6 engine. They have run our pulleys for two seasons now with no problems. We also worked with High Speed Racings two VW's and they have had no problem whatsoever. All of these teams have disassembled their engines at various times throughout their race seasons and have found no abnormal wear or crankshaft cranking. Now those were just the road course teams. We also work with many drag racers and one Pikes Peak car (Rod Millens Supra) and none of these teams have ever had problems. Not only these facts but the fact that we have had over 100+ sets in the field on street and street/strip BMW's including some turbo models without ever having any problems leaves you to believe that Steve did not intend to include Unorthodox Racing. All of our pulleys for other vehicles have never once caused any problems, in fact aside from the examples stated above, we have over 250+ million owner driven miles out there with our product.
Steve's association of the stock crank pulley being the primary damper is incorrect, it is the dual mass flywheel that accomplishes this task. But even replacing this dual mass damper with an aluminum flywheel would not cause long-term damage as long as the flywheel were properly balanced. To give an example lets look at the Turner Motorsports Speedvision cars. Those vehicles were running underdrive pulleys from another source. To regress slightly for historical value, we had originally engineered two designs for the BMW crank pulley section, but both kits were four pieces in total. One crank pulley design was a six-bolt pulley section replacement like the way the factory designed theirs. The other design was a complete one-piece replacement of pulley sections and the hub that mounts to the crank snout. We had sent some pulleys up to Mr. Turner for evaluation. The prototype design sent to him replaced the pulley section and the steel hub section with one unit that attaches directly to the crank, as described previously. This once piece design help eliminate the weight from the heavy steel hub. Unfortunately we could not use this design for production because the aluminum would crack shortly after installation due to the high torque specification for the bolt that attached that hub to the crank snout. Now Mr. Turner instead of working with us decided he would not tell us this, which we found out at about the same time from another local owner that worked with us. Mysteriously the following race season, with other pulleys on his car they began to have crank cracking problems. Multiple motors were broken, all at the main journal before the last rear cylinder from what we understand. It was also amazing to find out that they were also using an undampened solid aluminum flywheel. It seems amazingly odd now that the breakage occurred at the rear of the crankshaft closest to the lack of damping component. But as stated before if a properly balanced flywheel would have been used the failures would not have occurred. This is supported by the fact that all the Speedvision teams, described above, we have worked with use aluminum flywheels and have had no problems whatsoever.
We have seen a few of these products and they would not even pass inspection for factory fitment even if they had the rubber isolator. The machining quality is frightening and the products are also unbalanced. These companies cut the factory timing ring off the stock pulley and remount it, for 95 or older model year BMW's, this assumes the balance of the ring once it is removed. We laser cut our timing ring and check balance during machining and after assembly. Our tolerances are held to .001" in critical areas, where we have seen regular tolerances of .005" or more from these other manufacturers. As stated before we have tried to address these issues at various times over the years through education to our dealers to FAQ's on our web page. It unfortunately comes down to the old adage that you get what you pay for when it comes to quality. There are offshore and on-shore copies of our other pulley models out there. All of these pieces are sub-standard and would not even meet factory specifications. So why do owners keep buying them, unfortunately its lack or education/understanding and plain old dollars and cents. The same problem occurs with cam sprockets with tolerances of other products, even at supposed 0 degree factory settings, not being up to even OE specifications. Meanwhile our own sprockets are held to again .001" tolerances and have timing marks that are down to the minute (60 being in a degree). Its price that drives the consumer, so unawares they are buying product that they cannot properly adjust or product that comes loose. Our pulleys are 60-70% more expensive than the offshore and onshore copies and other underdrive only products offered. Our top of the line sprockets are 60-70% more expensive than these others. We have even introduced an entry-level sprocket, which is 15% more expensive in order to be more price competitive while offering the functional quality of our top of the line without some of the additional lightening machining and extra hardware.
One other important issue is the rather random attack on a specific performance adder without looking at power adders in general. If we wish to get technical about this type of issue then all power adders must be looked at under a more rigid standard. Based on factory testing and design even changing the oil to a non-factory used oil puts the power plant or driveline into a completely different set of parameter results. Lets use intakes systems as the first example. By increasing the intake airflow response parameters are changed to some completely different set of parameters from what the factory tested or designed too. Now this does not even take into account the change in intake resonance frequencies, which again creates deviations from the factory design. This does not even take into account that the engine may make more power from this modification, which again leaves us with a deviation from parameters the factory designed the vehicle to be within. Now to be fair lets look at supercharging or forced induction for normally aspirated cars, which dramatically affects every aspect of engine function. More boost of course means more power, which in turn means more engine and drivetrain stress. This is a product that the factory never designed the vehicle to be used in conjunction with. The drive of the supercharger puts more stress on the front of the crankshaft. Turbos put more stress on the exhaust valves from backpressure and heat. Turbos are also less dependable as far as control goes, tending to spike which causes severe engine strain. Turbos also require additional expensive products like boost controllers and turbo timer. This additional stress was encompassed into the factory design of the crankshaft or the pulley system. If the factory pulley were a damper in the traditional sense the additional stress from any modifications would eliminate any special function that the factory pulley may have had because it was never designed for the additional flex of the crankshaft nor the faster spool up of the engine. Looking at other engine systems the fuel pump was never designed to deliver the amount of fuel needed based on the new demands the supercharger puts on that system. Flow might be adequate as a function of output but is the pump up to the day-to-day stress. Another parameter the factory never designed into that system. We can go on and on with how non-factory parts, even regular service parts which are non-factory can effect a vehicle. The fact is that owners that want more power assume the risks of their desire. All the products they desire to achieve these improvements where never entered into the design equation of the factory designers.

Respectfully,
Shawn Baumgartner
President
UR

[skittleslegend]

Originally Posted by Excelerate

ACT is a very reputable company. ACT, Exedy, Fidanza, Clutchmaster's, Competition Clutch. They are all good.

You would be correct. ACT IS a very reputable company. However, their K-series clutches have been proven among owners to be unreliable. Not sure I would want to trust them to have fixed the issue, since this has been an issue for a few years now. I'd rather do it right the first time as opposed to have to do it then do it over (like most of the folks that have complained about their DCRH failing...also from a very reputable company). Not trying to bash them at all, but sometimes, even great companies put out poor products.

[mrhonduh]

Originally Posted by Excelerate

ACT is a very reputable company. ACT, Exedy, Fidanza, Clutchmaster's, Competition Clutch. They are all good.

Wrong choice of words on my part. I meant a company that is renowned for its flywheels.

Originally Posted by Excelerate

Well here is UR's official response to Steve Dinan's article from 5 years ago, keeping in mind now that there are now 5 more years in between this article and now that continue to prove UR's product...

Excellent article. But you have to consider the source. No doubt that UR makes an amazing product that is proven, but I do think that independent testing is required before coming to a conclusion on how the UDP wil effect engine life. Will this happen? Probably not. I am still searching and reading more articles that contradict the article written by UR and the one written by Dinan.

I guess what it comes down to is when you modify and/or race your car, things will break. And I'll probably buy the pulleys anyways.:)

[mfinlay04]

I've known a lot of my friends that drag race and tune their cars. They all live by UR, and none of them have ever had any issues with their UDPs. That's good enough for me. All the miles that they have put on their cars with zero issues?!? And most of them drive dodge products.

[8civic]

I have used NST, www.NonStopTuning.com pulleys for years and years on several of my cars, including the new civic. I highly recommend their stuff.

I have also personally used both a light weight flywheel and a pulley kit and have not experienced any extra vibrations or problems.

Some people on the internet sit behind computer monitors all day and act as if they know everything about products that they probably have never even used, others go out in the real world and use them to see what happens.

[mrhonduh]

No doubt! I am one of those people who like to learn from other peoples mistakes. I feel you have to question the validity of claims made about products based on its source.

Again, the only way to know for sure would be to invest the time and money in before and after testing, as an unbiased party no less, and see what works and what doesn't.

[bioevolve]

I used them on my EP3 with k20A2 with no problems.
Here is link to my old 2003 thread on it: click me
Here is their side of the story, from FAQ:

3) "Isn't my stock crank/eccentric pulley a balancer, harmonic/torsional, or vibrational damper?"
A common misconception is that factory crank pulleys on certain vehicles are harmonic dampers. The fact is, on todays late model cars the factory crank pulley is designed to reduce NVH (noise / vibration / harshness), which does not affect crankshaft or bearing life. These are noises and vibrations from the engine compartment that may travel into the cabin of the vehicle when the engine is running and the stock crank pulley is used to reduce NVH for the occupants (similar to the use of resonators in the intake to quiet intake noise). We do not manufacture crank pulleys that replace or eliminate a damper in applications where the factory crank pulley is an actual harmonic damper (such as 90 degree V engines).

Our pulleys are lightweight, CNC-machined 6061-T6 aluminum and are by design "0" balanced. Because of this, owners have called to tell us how much smoother their engine feels after installing our pulleys. Unorthodox Racing has been manufacturing and selling pulleys for over 5 years without a single engine failure due to the replacement of the stock crank pulley. This is testament to the quality and reliability of our products.

Owners who have engines that use balance shafts must understand that if they eliminate their balance shafts their engines must be balanced and blueprinted if they expect to have no long-term engine problems with or without the use of our crank pulleys. This balance shaft elimination is rare and only happens on a few models that are modified for racing only (Eclipse/Talon/Laser/Galant VR4/Conquest TSI/Starion just to name a few).

4) "Will the underdrive pulleys cause my engine to have premature bearing wear ?"


This is a fear many prospective owners have and it is a valid concern since we are dealing directly with the rotating assembly. It is, however, a fear with no basis in fact. The fact is that our pulleys have the opposite effect on engine bearings. The combination of tight tolerances, quality control, perfect balance, and dramatic weight loss versus the stock pulleys reduces the stress on your engine extends the total service life you can expect from your engine. Engine bearing problems are purely associated to poor engine maintenance, use of heavier than factory recommended oils, improper engine building practices which includes poor balancing, excessively revving engines when they are cold, and owners expecting their factory oil pumps to handle engine HP outputs 2-3 times over stock HP levels.