Improve bhp & torque: Light weight crank pulley & alternator pulley

[Jerman]

I picked this ad up recently and wonder if anyone has tried this? I was informed that both of these light weight pulleys are only 1.3kg vs the original ones 5kg ie. a massive 74% lighter? The entire package cost RM 880 (E39/E46/E90) excluding installation.

 

[leforte]

you may want to stay far away from this.

FYI a crank pulley is apart of the rotating assembly of the engine and its also fitted with a harmonic damper to dampened the resonance emitted by the engine during its operation. most of this if not all after market crank pulley are not balanced and fitted with a harmonic damper. i have seen the one you mentioned, and a piece of rubber insert DOES NOT constitute it as a harmonic damper. its more like a rubber piece for aesthetic use rather than for its functions. they are all just copied versions of the oem unit, lighten and a groove with rubber inserted for looks only. every oem harmonic balancer is a part R&Ded with millions by the car company for each specific engine type. you think a company can just replicate it?

Since they are underdriving your accessories, you do get the performance from them as promised but its gonna be at a cost of all your other parts failing or the total lost of your engine. a forumer here has tried it on his car. i've warned him before hand however i was too late as it was already fitted. and guess what.. it took only a few days of use and all hell broke loose with major damage to his oil pump, power steering pump and others costing him a repair cost of a few Ks.

my advised to you, is stay far far away from shops that sell this as they are generally clueless about the functions of your car and its only there for profits.

its your choice. buy at your own risk. you have been warned. for more info please check out the link below from a reputable tuner on the subject.

http://www.dinancars.com/bmw/techni...pulleys-and-understanding-the-harmonic-damper

 

[astroboy]

Yes! Listen to leforte, this is his forte..

There's another brand in the market that sells similar thing but mainly for JDMs and local cars. To further lighten the weight, they even build it smaller and with some common sense, you can imagine the damages its going to do to your ancillary components like aircond compressor, power steering pump, alternator and water pump because all these components now will rotate a lot faster due to the smaller diameter crank pulley, thus shortening their life.

Another problem we faced is the material used for its construction, it seems to expend and shrink at a very different rate compare to the OEM cast iron pulley. Result is it will bite so hard onto your crank rod and its a nightmare to pull it out when you need to remove it for whatever reason, and confirm the knocking to get it out will damage the soft pulley. So better keep the OEM as spare in the car.. :wink:

Of whatever mentioned by leforte is the main reason you should not use it, I just tumpang only..

 

[daveseech]

Yes! Listen to leforte, this is his forte..

There's another brand in the market that sells similar thing but mainly for JDMs and local cars. To further lighten the weight, they even build it smaller and with some common sense, you can imagine the damages its going to do to your ancillary components like aircond compressor, power steering pump, alternator and water pump because all these components now will rotate a lot faster due to the smaller diameter crank pulley, thus shortening their life.

Another problem we faced is the material used for its construction, it seems to expend and shrink at a very different rate compare to the OEM cast iron pulley. Result is it will bite so hard onto your crank rod and its a nightmare to pull it out when you need to remove it for whatever reason, and confirm the knocking to get it out will damage the soft pulley. So better keep the OEM as spare in the car.. :wink:

Of whatever mentioned by leforte is the main reason you should not use it, I just tumpang only..

i concur, leforte's forte =).after reading that dinan article i believe thats the whole reason why the better ones from reputable tuners around only has the water pump, powersteering pump pulley and some also have the alternator in their kit. crank pulley is not something they will touch on.

i think this swap brand crank pulley is from the same place and person that does raptor superchargers. i remember i saw this in the SG bmw forum. that place sold a raptor to a one of my friend's car, and it performs like crap with load of problem after. hard to trust a place that sells unproven stuff. this swap brand that the claim to be from australia is also unheard off by any one over there. seems more like china made. sigh. the guy selling it in singapore goes by the nick raptorsc with the same nick here

http://www.bmw-sg.com/forums/bazaar-bmw-parts-accessories/29083-fs-underdrive-pulley.html

 

[pussy]

someone in the forum tried this, caused so much damage to his engine... poor guy, heard it was a e60...

 

[IsaacVky]

Tacoma Narrows Bridge

Collapsed in year 1940 as a result of Resonance. When wind, the driving force natural frequency is almost if not identical to the natural frequency of the bridge, Resonance occurs.

Resonance occurs in the engine crankshaft across the whole RPM range, be it 1500 3000 4500 or 8000.
Amplitude is at its highest when damping is at its lowest.
In our crank pulley case, removing the Harmonic damper resulted in increased Amplitude.

 

[daveseech]

someone in the forum tried this, caused so much damage to his engine... poor guy, heard it was a e60...

heard the damage was closed to 5k vs the cost of that piece of scrap metal at 900rm. there was a x5 that had the same problem too,i saw the car at my friend's mechanic in cheras. same problem after changing the crank pulley.

 

[pussy]

yup... but heard also the x5 owner suffered a stroke from the bill...

 

[ess530i]

i read that the new e90/92 m3's have crank pulley w/out the rubber harmonic balancer... must be real light & fun to drive. wonder what and how they improved on the engine to enable it to run reliably without the harmonic balancer

https://www.turnermotorsport.com/html/project_e90m3.shtml

the seller of SWAP is indeed the same seller of RAPTOR sc kits as the contact # is the same...i believe he is a forumer here too. perhaps he can enlighten us on the technology used for his lightweight pulley w/ harmonic balancer. until then, it is highly NOT recommended for anyone of us (besides e90/92 m3 owners) to 'downgrade' their stock crank pulleys to lightweight ones

p/s: i'm the 'unlucky' e60 owner who got screwed by the lightweight crank pulley (dun ask how). feel real sorry for the x5 owner...

 

[ramsing]

yup... but heard also the x5 owner suffered a stroke from the bill...

hmm....so became shareholder also la....??

 

[B33mEr]

i read that the new e90/92 m3's have crank pulley w/out the rubber harmonic balancer... must be real light & fun to drive. wonder what and how they improved on the engine to enable it to run reliably without the harmonic balancer

https://www.turnermotorsport.com/html/project_e90m3.shtml

the seller of SWAP is indeed the same seller of RAPTOR sc kits as the contact # is the same...i believe he is a forumer here too. perhaps he can enlighten us on the technology used for his lightweight pulley w/ harmonic balancer. until then, it is highly NOT recommended for anyone of us (besides e90/92 m3 owners) to 'downgrade' their stock crank pulleys to lightweight ones

p/s: i'm the 'unlucky' e60 owner who got screwed by the lightweight crank pulley (dun ask how). feel real sorry for the x5 owner...

E90/E92 is a V8 ... Ours is a straight six which is more susceptible to harmonic vibrations than a V configuration engine

 

[ess530i]

E90/E92 is a V8 ... Ours is a straight six which is more susceptible to harmonic vibrations than a V configuration engine

makes sense...but what about those JDM cars with in-line 4-cylinder engines? almost everyone who is into performance i know has lightweight pulleys and most have no harmonic balancers. even one of my fren who drives a wira had lightweight pulleys for 5 years without any major engine problem. they find our 'german' stories quite amusing... google for lightweight crank pulley and you will find the topic very debatable in the JDM world. even reputable aftermarket parts producer like perrin make and sell lightweight crank pulleys. perhaps thats where it makes a difference...just my thoughts

 

[IsaacVky]

makes sense...but what about those JDM cars with in-line 4-cylinder engines? almost everyone who is into performance i know has lightweight pulleys and most have no harmonic balancers. even one of my fren who drives a wira had lightweight pulleys for 5 years without any major engine problem. they find our 'german' stories quite amusing... google for lightweight crank pulley and you will find the topic very debatable in the JDM world. even reputable aftermarket parts producer like perrin make and sell lightweight crank pulleys. perhaps thats where it makes a difference...just my thoughts

Maybe this can answer your question :love: taken from bro leforte's link.

As you can see this is a 4 cylinder engine. The amplitude of torsional vibration increases with increasing distance from flywheel. What would happen to an Inline 6 engine with much longer crankshaft.

 

[ramsing]

makes sense...but what about those JDM cars with in-line 4-cylinder engines? almost everyone who is into performance i know has lightweight pulleys and most have no harmonic balancers. even one of my fren who drives a wira had lightweight pulleys for 5 years without any major engine problem. they find our 'german' stories quite amusing... google for lightweight crank pulley and you will find the topic very debatable in the JDM world. even reputable aftermarket parts producer like perrin make and sell lightweight crank pulleys. perhaps thats where it makes a difference...just my thoughts

back in the ol' days, would remove the balancer shafts in the evo block and blueprint the engine. and then rev the suckers to 9k rpm, boosted. no flying pistons. i guess it applies as what the link says.

i wonder if it works on 4 piston bmw engines... :wink: anyone wants to give it a go...hehehe:top:

 

[daveseech]

back in the ol' days, would remove the balancer shafts in the evo block and blueprint the engine. and then rev the suckers to 9k rpm, boosted. no flying pistons. i guess it applies as what the link says.

i wonder if it works on 4 piston bmw engines... :wink: anyone wants to give it a go...hehehe:top:

i think even for a 4 cylinder they do need some form of balancing or dampening as well. i just remembered my wife's minicooper s has a performance crankpulley installed by the previous owner which i didnt knew about. since having it we had the sc belt tensioner replaced 3 times in just one year. feeling frustrated as on one occasion the belt actually snap while driving, aaron @leforte suspected something wasnt harmonically right as the tensioner has fatigued failures on all occasion so he suggested to have a look at the pulley and sure enough the pulley was a aftermarket unit. i have since replaced it back to the original bmw mini unit and its been almost a year with no issues. the power is minimally less but i felt the engine was much smoother after that. strangely the original unit doesnt have a harmonic balancers or dampers on them too but i guess what was stated by leforte that its balanced as a part of the rotating assembly its true. you change it and you upset the balance.

 

[daveseech]

i read that the new e90/92 m3's have crank pulley w/out the rubber harmonic balancer... must be real light & fun to drive. wonder what and how they improved on the engine to enable it to run reliably without the harmonic balancer

https://www.turnermotorsport.com/html/project_e90m3.shtml

the seller of SWAP is indeed the same seller of RAPTOR sc kits as the contact # is the same...i believe he is a forumer here too. perhaps he can enlighten us on the technology used for his lightweight pulley w/ harmonic balancer. until then, it is highly NOT recommended for anyone of us (besides e90/92 m3 owners) to 'downgrade' their stock crank pulleys to lightweight ones

p/s: i'm the 'unlucky' e60 owner who got screwed by the lightweight crank pulley (dun ask how). feel real sorry for the x5 owner...

i feel your pain.

i would not second anyone to go near those swap pulleys even if he has a e90/e92 m3, to me, the raptor sc fellers know nothing about tuning a car or how a harmonic balancer works and i for that i dont even trust their swap pulleys to be australian made as well, since there is no traceable evidence of it to be of existence by anyone in australia. i would say they are probably made locally justlike their raptor sc kits which they said to be a fully australian made kit.

 

[ramsing]

are the raptors still being sold today? dont really hear much of it anymore.

 

[bimmerdude]

i have an Audi A4 1.8 NA car which uses a lightweight crank pulley. been almost 5 years with no problems. Probably it depends on make and engine configurations. I'm sure that all the negative experiences stated are real. Has anyone used it on their E90/E92?

 

[paultantk]

I have underdrive pulleys from UUC for the power steering and I think the waterpump, not so sure as they were fitted by the previous owner.

No lightened crank pulley or anything of course, UUC doesn't make em and even discourages its use, like DINAN.

Do you guys think I should remove them? Car's been running for nearly 2 years with them so far, no visible/detectable problems.

 

[Guna]

Despite all this negative issues about lighter pulleys I am still very curious la guys.I was talking to a certain reputable aftermarket shop guy that he has fixed it on hundreds of cars over the last 3 years with no major problems.He said he is aware of the risk if you put in the wrong ones but he almost swears by what he has.He mentioned of a particular brand called RUFF and that it would cost somewhere in the region of RM2,400 plus labour to change three though the kit comes in a set of fours.He was about to explain why only three when he had to put the phone down coz he was in the middle of something.I was also talking to some friends who drive some fast cars like Audi Quattros who don't seem to have a problem with the mod.The idea of deriving that much power from a simple and yet not so expensive mod is really tempting guys and I hope some super sifus here could give us the serious pros and cons.But for now,I think I'll hold the plans till I'm assured.