Power pulleys safe?

[The Flying Scotsman]

Here is some information from Active's website about their power pulley kit!

It seems like they are using a pretty safe pullley kit that does show a power increase!

"This is a complete bolt on kit engineered using Aircraft Grade Billet 6061 Hard Coat Anodized Aluminum. After months of R&D in house and overseas (various climates & conditions) we concluded that there may be a slight power increase by going smaller than our pulley but the trade off is a chance of making the engine run hotter or possibly overheat (we noticed this in both DCT cars and Manual cars on and off the track), we choose reliability over that extra 1-2 rwhp that we may get from a smaller pulley. Testing in Miami, FL and in other hot climates was a must in our R&D process to take things to the “extreme limits”.

Another key element in the development of the Signature Pulley Kit was to retain the “Factory Crank hex Drive Adapter”, this was important to keep this factory feature for its inherent purpose. The pulley kit does not modify factory harmonics or dampening. Stronger side walls were the last key element in choosing our size over a smaller design.

The Active Autowerke E9X Signature Pulley Kit yields gains of 12+HP on a completely stock car. This is a complete bolt on system that is easily reversible. A must for the true enthusiast."

I have their pulley kit and have never had an issue. I notice a slight power increase within the higher rpm range.

[M3SQRD]

Originally Posted by GIdriver

I was considering a dinan pulley kit but after reading Steve Dinan's article I'm having second thoughts.

As several people have already stated in this thread that old Dinan article (written specifically for the e36 M3) is discussing removing and replacing the harmonic damper, not an under-drive pulley by itself. On the e9x M3 you'll only be replacing the pulley so you are safe - Dinan sells an under-drive pulley so if it wasn't safe why are they offering one for the e9x M3?

[Ateam]

Keep in mind pulleys are not what they used to be in good and bad ways. Power pulleys of the past used to completely take out the harmonic balancer and therefore the gains could be actually pretty big. Much bigger than now since they leave the harmonic balancer in place. Getting rid of that enabled a ton less drag on the system as it was eliminated and power gains were more substantial and thus quite popular. However as the dinan article referred to, this caused the engine to break! So trade-off not worth it.

Nowadays, people learned this and do not touch the HB, at the cost that pulleys no longer produce a substantial noticable difference.

The analogy I think of in terms of "feeling" is the old pulleys that removed the HB are like exhaust systems that removed the CATs-they make noticable power but have more downsides for sound/emissions.

Exhausts that leave cats in place have minimal gains but are safer for smell/sound and emissions.

Not perfect but you get the idea of the difference

[GIdriver]

Thanks dbarnes and Ateam. I understand better now the HB issue.

[kaiv]

Some people in this thread do not understand the difference between crank pulley and accessory pullies.

Accessory pullies: alternator, waterpump, powersteering... not touching or messing with the harmonic balancer/damper/dampener/vibration damper-whatever you want to call it

Crank pulley: bolts onto the harmonic balancer

[Brucewonder]

i still wouldn't do, not much HP gain to worry about the possibility of malfunction/warranty issues

[C|3R1C]

I actually just put in my AA Pulley about two weeks ago. Really easy to do it yourself. It has been a thousand miles and for the first few hundred I was pretty adamant about listening carefully and checking the belts. I had the same questions, IE power steering, overheating, electrical, etc. So far no problems or dimming of the lights. Torqued everything to the right specs also, so that definitely helps. Thread is a few months old so I am not sure how much of this info actually helps. But, if you still have questions, feel free to PM me.

[Kyoshi71]

I am astounded by the amount of mis-information contained in this thread by all the armchair mechanics at their keyboards.

PLEASE stop referencing the decade-old Steve Dinan article that doesn't pertain to the S65. An underdrive pulley is 100% safe for E9X M3 because the factory engineers the stock pulley system to "overdrive" the pulleys to be ultra conservative.

In any given car, do you have an idea what percentage of the time the alternator "isn't" working? A lot...so why spin it faster?

You will not need a trickle charger if you under-drive your accessories. Actually, to be precise, no more than you would with normal pulleys if your car isn't a DD.

My opinion would be to go with the crank pulley only and not a set; and buy from either Dinan, Evosport or Turner. I feel that those three specifically commit research as well as quality when they release a product.

[M3SQRD]

Originally Posted by Kyoshi71

I am astounded by the amount of mis-information contained in this thread by all the armchair mechanics at their keyboards.

PLEASE stop referencing the decade-old Steve Dinan article that doesn't pertain to the S65. An underdrive pulley is 100% safe for E9X M3 because the factory engineers the stock pulley system to "overdrive" the pulleys to be ultra conservative.

In any given car, do you have an idea what percentage of the time the alternator "isn't" working? A lot...so why spin it faster?

You will not need a trickle charger if you under-drive your accessories. Actually, to be precise, no more than you would with normal pulleys if your car isn't a DD.

My opinion would be to go with the crank pulley only and not a set; and buy from either Dinan, Evosport or Turner. I feel that those three specifically commit research as well as quality when they release a product.

[S65V8]

This forum always amazes me on the level and detail of information. Thanks guys, it doesn't sound like a lot of gain for something if not installed properly would malfunction.

[jimmy ny]

Dinan pulley installed with no issues almost for one year. Before i had a Gintani pulley. The car would struggle to turn in cold weather, due to poor design. Dinan pulley is actually 2 different ribs on it. This way you don't have any power steering issues.

[Kyoshi71]

Originally Posted by SROC5

Thanks guys, it doesn't sound like a lot of gain for something if not installed properly would malfunction.

Incorrect

A pulley is actually the most cost-effective mod you can do to our cars.
Where else can you get a solid 10-12 hp for $400?

I know I'm going out on a limb here considering some of the dopey things I've seen, but here goes...It's pretty hard to improperly install a pulley. It either goes on or it doesn't. It's not something that needs tuning or periodic adjustment.

Originally Posted by jimmy ny

Before i had a Gintani pulley. The car would struggle to turn in cold weather, due to poor design.

Why am I absolutely NOT surprised by this?

[Ateam]

Originally Posted by Kyoshi71

I am astounded by the amount of mis-information contained in this thread by all the armchair mechanics at their keyboards.

PLEASE stop referencing the decade-old Steve Dinan article that doesn't pertain to the S65. An underdrive pulley is 100% safe for E9X M3 because the factory engineers the stock pulley system to "overdrive" the pulleys to be ultra conservative.

In any given car, do you have an idea what percentage of the time the alternator "isn't" working? A lot...so why spin it faster?

You will not need a trickle charger if you under-drive your accessories. Actually, to be precise, no more than you would with normal pulleys if your car isn't a DD.

My opinion would be to go with the crank pulley only and not a set; and buy from either Dinan, Evosport or Turner. I feel that those three specifically commit research as well as quality when they release a product.

No offense but before accusing the board of not knowing what they are talking about, you should know your info more carefully. Actually this car and most bmw's now do not engage their alternator at all unless coasting, or braking. Its a combination of their brake energy regen. and IAC (intelligent alternator control). Been around since 09 on most models. So there is absolutely no load coming from the alternator as it essentially has a "clutch" that disconnects when stepping on the gas and then resumes engaging and thus running alternator when decelerating, costing or braking.

Point is underdriving the alernator is pointless for a car with this system. You actually only hurt yourself as you want it fully driven when the car is coasting or braking to make sure you get hte most out of it when you do not need it. So your info is more inaccurate than most other stuff on this thread

So why don't you actually learn your info before critisizing everyone else. I do agree and I said in my post there is no harm to these moder pulleys, but the benefit is questionable and not worth the hassle in my view.

[Dave07997S]

Originally Posted by Kyoshi71

Incorrect

A pulley is actually the most cost-effective mod you can do to our cars.
Where else can you get a solid 10-12 hp for $400?

I know I'm going out on a limb here considering some of the dopey things I've seen, but here goes...It's pretty hard to improperly install a pulley. It either goes on or it doesn't. It's not something that needs tuning or periodic adjustment.



Why am I absolutely NOT surprised by this?

Wait, I had these left over bolts..what now..

[Kyoshi71]

Originally Posted by Ateam

No offense but before accusing the board of not knowing what they are talking about, you should know your info more carefully. Actually this car and most bmw's now do not engage their alternator at all unless coasting, or braking. Its a combination of their brake energy regen. and IAC (intelligent alternator control). Been around since 09 on most models. So there is absolutely no load coming from the alternator as it essentially has a "clutch" that disconnects when stepping on the gas and then resumes engaging and thus running alternator when decelerating, costing or braking.

Point is underdriving the alernator is pointless for a car with this system. You actually only hurt yourself as you want it fully driven when the car is coasting or braking to make sure you get hte most out of it when you do not need it. So your info is more inaccurate than most other stuff on this thread

So why don't you actually learn your info before critisizing everyone else. I do agree and I said in my post there is no harm to these moder pulleys, but the benefit is questionable and not worth the hassle in my view.

I guess the part when I said "ISN'T WORKING" confused you. "ISN'T" is a contraction of "IS NOT." No worries; just look out for that next time, all righty?

Also, when I reference misinformation, It comes from my 6 years of experience as a member here. As opposed to some folks who have been around for a month or so

[LTJohn]

Originally Posted by Kyoshi71

I guess the part when I said "ISN'T WORKING" confused you. "ISN'T" is a contraction of "IS NOT." No worries; just look out for that next time, all righty?

Also, when I reference misinformation, It comes from my 6 years of experience as a member here. As opposed to some folks who have been around for a month or so

Kyoshi, have you ever had any issues with the power steering? I am worried about running out of assist at an autoX?

I like the idea about pulleys since they can add a few HP and maybe make the MPG go up a smidge!

[Ateam]

Originally Posted by Kyoshi71

I guess the part when I said "ISN'T WORKING" confused you. "ISN'T" is a contraction of "IS NOT." No worries; just look out for that next time, all righty?

Also, when I reference misinformation, It comes from my 6 years of experience as a member here. As opposed to some folks who have been around for a month or so

No worries maybe I just misunderstood your wording so I apologize-I am sure you know a lot more than me as I am no mechanic or anything

Either way pulleys have a bit less gain on the m3 due to the fact the alternator is already disconnected and creates no drag, the AC disconnects when at WOT so creates no drag and that really only leaves the power steering pump (oil pump?) So at WOT in this car a pulley will really not do squat. However when not at WOT you can have the stated gains with no safety risk

[Kyoshi71]

Originally Posted by DocJohn

Kyoshi, have you ever had any issues with the power steering? I am worried about running out of assist at an autoX?

I like the idea about pulleys since they can add a few HP and maybe make the MPG go up a smidge!

I personally have never heard of any PS issues. especially if the pulley comes from a reputable source. Increasing MPG would be great right?? I can practically watch my gauge moving!!!!!

Originally Posted by Ateam

However when not at WOT you can have the stated gains with no safety risk

I believe the key to the underdrive pulley working so well on our cars is about reducing the rotational mass of the whole accessory system together with the belt.

While accelerating to redline, just moving the belt over ball bearings consumes energy, let alone actual accessories. I'm telling you man, I'm not the guy who subscribes to all the BS claims of HP gains. Mufflers, charge pipes, air scoops, "carbon fiber foot rests"(that was a joke) all come with BS claims of power. The pulley, on the other hand, actually works. Dinan is the last guy to cuff HP numbers. His site reads 11 hp @8,400

[Ateam]

I am totally with you! No arguement from me that it is one of the few mods that are sensibley going to increase hp. My only point was bmw made some nice improvements such as disengaging the a/c at WOT and disengaging the alternator at throttle, and therefore the drag of these two things is eliiminated while accelerating hard which is a step in the right direction. A pulley continues to help by cutting drag on the rest of the accesories.

Pulleys, shorter final drive and removing your cats is the only 3 I feel are worthy of true power gains. Aside from a supercharger of course

[BMRLVR]

Originally Posted by Ateam

No offense but before accusing the board of not knowing what they are talking about, you should know your info more carefully. Actually this car and most bmw's now do not engage their alternator at all unless coasting, or braking. Its a combination of their brake energy regen. and IAC (intelligent alternator control). Been around since 09 on most models. So there is absolutely no load coming from the alternator as it essentially has a "clutch" that disconnects when stepping on the gas and then resumes engaging and thus running alternator when decelerating, costing or braking.

Point is underdriving the alernator is pointless for a car with this system. You actually only hurt yourself as you want it fully driven when the car is coasting or braking to make sure you get hte most out of it when you do not need it. So your info is more inaccurate than most other stuff on this thread

So why don't you actually learn your info before critisizing everyone else. I do agree and I said in my post there is no harm to these moder pulleys, but the benefit is questionable and not worth the hassle in my view.

Here you go again!!! Remember what I mentioned to you in my last reply? Kyoshi71 is another one of the members who will give you the facts and no BS. If you keep rebutting answers to your questions with condescending remarks no one is going to respond any more, or the people who respond will only be the people who don't know.

I did read your apology to Kyoshi71 so I see you are realizing what we are all telling you.

Now on to the topic:

To touch on what Kyoshi71 was telling you about the pulleys reducing the rotational mass of the accessory drive system here goes: The reduction in mass of the accessory drive system is part of the power gain however the effective gear reduction is where most of it comes from. Think about riding your mountain bike....... The smaller chain-ring the chain is on, on the crankset (same as the crank pulley on an engine for all effects and purposes) the easier it is for you to pedal. The smaller chain-ring will not allow you to go as fast but it allows you to move while exerting much less energy onto the pedals.

So the underdrive crank pulley does two things to gain power. 1)It loses mass and therefore rotational inertia. 2)It gives the crank pulley more mechanical advantage to turn the accessories (and turns them a little slower as a result of that gear ratio change) so there is less drag on the engine regardless of wether the M3 disengages the alternator and AC under load or not.

In a way the underdrive pulley does the same thing as a lower ratio differential gear set. The big difference is that the power gained from a crank pulley is actually the result of less power being used to turn the accessories. This power is instead sent to the driveline through the PTO of the engine instead of being wasted driving the accessories. Differential gear sets don't make any power, they just give the engine more mechanical advantage to turn the drive wheels.

The only possible side effect of an underdrive crank pulley is that a low engine speeds (under 1.5KRPM or so) the power steering pump volume will be less and may make steering wheel effort slightly increased. This effect will most likely be extremely slight and I hear no complaint from members on the forum that use an underdrive crank pulley. A possible plus to this would be lower PS oil temps on the track since the pump would spend less time going over relief since the volume would be slightly reduced. When any hydraulic pump is over relief for extended periods of time the oil heats up.

I hope this helps!

[Ateam]

Originally Posted by BMRLVR

Here you go again!!! Remember what I mentioned to you in my last reply? Kyoshi71 is another one of the members who will give you the facts and no BS. If you keep rebutting answers to your questions with condescending remarks no one is going to respond any more, or the people who respond will only be the people who don't know.

I did read your apology to Kyoshi71 so I see you are realizing what we are all telling you.

Now on to the topic:

To touch on what Kyoshi71 was telling you about the pulleys reducing the rotational mass of the accessory drive system here goes: The reduction in mass of the accessory drive system is part of the power gain however the effective gear reduction is where most of it comes from. Think about riding your mountain bike....... The smaller chain-ring the chain is on, on the crankset (same as the crank pulley on an engine for all effects and purposes) the easier it is for you to pedal. The smaller chain-ring will not allow you to go as fast but it allows you to move while exerting much less energy onto the pedals.

So the underdrive crank pulley does two things to gain power. 1)It loses mass and therefore rotational inertia. 2)It gives the crank pulley more mechanical advantage to turn the accessories (and turns them a little slower as a result of that gear ratio change) so there is less drag on the engine regardless of the alternator and AC being disengaged or not.

In a way the underdrive pulley does the same thing as a lower ratio differential gear set. The big difference is that the power gained from a crank pulley is actually the result of less power being used to turn the accessories. This power is instead sent to the driveline through the PTO of the engine instead of being wasted driving the accessories. Differential gear sets don't make any power, they just give the engine more mechanical advantage to turn the drive wheels.

The only possible side effect of an underdrive crank pulley is that a low engine speeds (under 1.5KRPM or so) the power steering pump volume will be less and may make steering wheel effort slightly increased. This effect will most likely be extremely slight and I hear no complaint from members on the forum that use an underdrive crank pulley. A possible plus to this would be lower PS oil temps on the track since the pump would spend less time going over relief since the volume would be slightly reduced. When any hydraulic pump is over relief for extended periods of time the oil heats up.

I hope this helps!

Again you ignore that wrong information is posted and then post a bunch of long winded rehash of what has been said. The fact is bmw has already figured out a way to decouple the A/C and alternator-which are the two biggest sources of drag on an engine when trying to accelerate. Adding a power pulley will do nothing further to reduce drag from this since its already zero during acceleration.

Point was sure it helps and has no downside but the gain on a car that already eliminates 2 big sources of drag is not going to be much compared to a car that does not disengage those 2 power drainers and thus underdriving the system really does have a solid gain.

[BMRLVR]

Originally Posted by Ateam

Again you ignore that wrong information is posted and then post a bunch of long winded rehash of what has been said. The fact is bmw has already figured out a way to decouple the A/C and alternator-which are the two biggest sources of drag on an engine when trying to accelerate. Adding a power pulley will do nothing further to reduce drag from this since its already zero during acceleration.

Point was sure it helps and has no downside but the gain on a car that already eliminates 2 big sources of drag is not going to be much compared to a car that does not disengage those 2 power drainers and thus underdriving the system really does have a solid gain.

I am done..... you are obviously above all of us "Armchair Mechanics".

How about next time you post a question you answer it yourself because I sure as hell won't try and answer it for you..... I hope everyone else does the same thing too!