Underdrive Pulleys

[fabianyee]

Originally posted by DanPromote+Mar 16 2006, 01:05 PM-->QUOTE (DanPromote @ Mar 16 2006, 01:05 PM)

Originally posted by Breakpopin@Mar 16 2006, 11:30 AM

 

[Calvin Tan]

:rofl: :rofl: ha ha ha ha!!! never heard before there are a/c compressor underdrive pulley in my whole life. :rofl: :rofl:
Anyway here is the one I and adliz are using
It is p/s pump pulley and water pump pulley. There is nothing call underdrive a/c compressor pulley!
Overall! you can't get any kind of power with this kind of money k: :yes!:

 

[fabianyee]

y cannot have underdrive a/c comp pulley meh???

ok lah.. I 'accidentally' created that...

 

[DanPromote]

Originally posted by fabianyee@Mar 16 2006, 01:16 PM
[have u considered the fact that there are teeth on the pulley for the crankshaft sensor to pick up. Is aluminum teeth provide the necessary pulse signal? iron and aluminum provides different magnetic property. However, u can always be the guinea big to test that.


To be frank, lightened and underdrive pulleys for the accessories are safer than replacing the crankshaft pulleys.

yea I remembered asking u about it that day... since it is a 100% replica the only difference is the material and weight. How does the sensor work? Does it depend on the teeth or the magnetic property? I don't mind being the guiney pig, worse come to worse I can still use back the original pulley if it doesn't work and use the T7 replica as a cup holder

 

[E3six]

Seem like a interesting project.

Kelvin, do you have those pully for my ride ? If not, any1 know

Where to get those pully and how much ?


Rgds

 

[Breakpopin]

Calvin Tan,

AHah thats why i PM-ed u even before i posted this thread!!


So anyway, why cant we underdrive aircond compressor pulleys too? Just curious

 

[Alvin]

Last i got a quote from my machine shop its was like 1k or slightly more. The material is expensive. If you want pass me a sample & i'll get my engineers to do a Autocad drawing with all the proper dimensions. Then send to our supplier to quote. Material recommended will Anodized T7 Aluminum.

 

[teejay]

Originally posted by Breakpopin@Mar 16 2006, 05:30 PM
Calvin Tan,

AHah thats why i PM-ed u even before i posted this thread!!


So anyway, why cant we underdrive aircond compressor pulleys too? Just curious

if you underdrive the phulleys.....


you'd be chillin'......

 

[Calvin Tan]

Originally posted by Breakpopin@Mar 16 2006, 05:30 PM
Calvin Tan,

AHah thats why i PM-ed u even before i posted this thread!!


So anyway, why cant we underdrive aircond compressor pulleys too? Just curious

If you underdrive your a/c compressor you will be driving with a heater.
I think most of you guys here are misunderstood the topic here. Breakpopin is asking for the underdrive pulleys means power steering, water pump and perhaps an alternator pulley if you want. That's it! no nothing fan clutch pulley, a/c compressor pulley or crankshaft pulley.
The underdrive pulleys (I mean power steering pump and water pump pulley) is suppose to reduce the speed (yes, it turn slower). So it is more lighter and easier for the crank / crank pulley to turn them. So lesser burden to the crank, more power to the wheel.

In general a newer generation BMW (eg. E36 and above) are not proven with an underdrive crank pulley.
P/S pulley and W/P pulley is good enough

I have been using it for a month now. I was so sceptical for this pulleys stuff until have tried it out. My experience for this. More power on the wheel all the way from acceleration until max rpm cut ( they don't gain any engine hp, but give more wheel hp), much quicker throttle response... most important it worth every single penny.

I'm now trying out a new product. See you all in another thread...bye now..

 

[Breakpopin]

Wah thanks Calvin for that lenghty explaination heh.

Breakpopin is asking for the underdrive pulleys means power steering, water pump and perhaps an alternator pulley if you want.

Well yeah but its ok, let this thread be a discussion on any kind of pulley mods out there! Including bicycle gear pulleys hahaha..

 

[gwumpkus]

hmm..i'm following this closely to see if it leads to a SUCCESFUL group buy.... let me dig around for some spare pulleys to serve as "guinea pigs"..or rather "models" for alvin's foray into this..

 

[E3six]

Originally posted by Breakpopin@Mar 16 2006, 04:30 AM
Calvin Tan,

AHah thats why i PM-ed u even before i posted this thread!!


So anyway, why cant we underdrive aircond compressor pulleys too? Just curious

The operation of the A/C compressor is cyclic. Depending on various RPM and temperature conditions, it will cycle on and off with varying frequency. Either way, the same amount of work is done to cool the car's interior. Underdriving the A/C compressor would not yield any gains, or any discomforts.

 

[ALBundy]

Originally posted by E3six+Mar 17 2006, 12:13 AM-->QUOTE (E3six @ Mar 17 2006, 12:13 AM)

 

[ALBundy]

Originally posted by fabianyee+Mar 15 2006, 04:41 PM-->QUOTE (fabianyee @ Mar 15 2006, 04:41 PM)

Originally posted by The Necessary@Mar 15 2006, 06:47 PM

 

[pussy]

AFAIK, there main crankshaft pulley is matted into 2 or 3 pieces with a special casted rubber damper.. without it, many problems..

ask me how i know ?

 

[ess530i]

hi guys...time to reactivate this thread with my nightmare! Pussy you’re damn right about the special rubber damper…

about 3 weeks ago i replaced my stock crankshaft pulley to lightweight ones. immediately after the upgrade (i would now call it a downgrade), there was vibration on my gearknob at certain rpm range. YES, there was substantial improvements on engine response which i thought could outweigh any issues i would face but wrong. the very next day, my air-cond belt broke. last week, my power steering hydraulic hose assembly broke and gone with the oil. today, my engine oil pump broke and my mechanic said it was his first time encountering such problem with BMW (also very rarely with the hydraulic hose assy). i can only think of one explanation which is the lightweight pulleys causing too much initial pressure to the belt system causing the components being driven to fail. lack of the rubber damper could also be the main factor as vibration can kill a lot of components.

the car is still in the workshop as i write and have yet to know the total damage. so far its RM120 x 2 (towing) + RM200 (aircond belt) + RM2,200 (PAS hydraulic hose assy incl labor) + RM1,000 (used oil pump incl labor) + RM900 (lightweight pulleys) = RM4,540.00

i will be replacing the lightweight pulleys to my stock one but its unfortunate i have to go through this costly experience. btw my car is supercharged so i'm still researching if the failures had to do with the incompatibilty with the SC or would affect stock cars as well. anyway u guys with or without SC better be informed and carefully consider before doing the upgrade. needless to say i do not recommend them at any cost as the risk is just too big.

here's an interesting article to read about this topic:

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

 

[leforte]

ess530i
your car being supercharged/modded has nothing to do with the damages caused. your supercharger is just another accessory being driven by the main beltdrive and thats it. there are countless other similarly modded 530s around and non have reported any similar failures. since you mentioned to me your pulley is of a said particular brand, i sudgest you return it for a full refund and bill your damages to them as the manufacturer has a 100% warranty that it would not cause any damages from using it as clearly stated on their website.

IMO your case is a very clear indication or rather a ripple effect of vibration induced stress fatigue caused by the undampened pulley to the attached components. the crank pulley is the one and only component in your drivetrain that generates pulsating vibrations due to the combustion forces of each cylinder per engine cycle. the crank pulley/harmonic balancer is there to absorb/counteract/reduce this vibration pulses from being being transfered to other engine components and accessories by converting any excess vibrations to heat.

FYI since you are reinstalling the original bmw crank pulley, the unit is a major part of the factory balanced rotating assembly, do make sure your mechanic have it properly aligned with the markings indicated on the crankshaft/engine during installation or its just going to cause you another issue later on.

 

[ess530i]

ess530i
your car being supercharged/modded has nothing to do with the damages caused. your supercharger is just another accessory being driven by the main beltdrive and thats it. there are countless other similarly modded 530s around and non have reported any similar failures. since you mentioned to me your pulley is of a said particular brand, i sudgest you return it for a full refund and bill your damages to them as the manufacturer has a 100% warranty that it would not cause any damages from using it as clearly stated on their website.

IMO your case is a very clear indication or rather a ripple effect of vibration induced stress fatigue caused by the undampened pulley to the attached components. the crank pulley is the one and only component in your drivetrain that generates pulsating vibrations due to the combustion forces of each cylinder per engine cycle. the crank pulley/harmonic balancer is there to absorb/counteract/reduce this vibration pulses from being being transfered to other engine components and accessories by converting any excess vibrations to heat.

FYI since you are reinstalling the original bmw crank pulley, the unit is a major part of the factory balanced rotating assembly, do make sure your mechanic have it properly aligned with the markings indicated on the crankshaft/engine during installation or its just going to cause you another issue later on.

leforte thanks for enlightening me on this. yes i didn't think the sc should have anything to do with this as the crank pulley is driving the sc pulley not the other way round. but i was told that the stock belt & hoses cannot take the extra initial torque generated by the SC and should be upgraded if possible. then again, many cars have been supercharged to even higher HP without facing these issues. so now the finger points back at the pulley.

i will go for a refund for the pulley + install and would be very happy if i could get 50% of the damages. wont reveal the brand of pulley and where i bought them from yet as this would be quite damaging to its reputation.

anyone with SC + lightweight crankshaft pulleys or just lightweight pulleys in the house...care to share?? do mention if your pulley has the balancing ruber or not...

 

[ess530i]

http://www.youtube.com/watch?v=1cfI7nuTFRA

turn on your speakers and hear the sound at high RPM it seems as if high cams are installed but in fact it is the sound of severe vibration from the engine due to the missing rubber

 

[leforte]

leforte thanks for enlightening me on this. yes i didn't think the sc should have anything to do with this as the crank pulley is driving the sc pulley not the other way round. but i was told that the stock belt & hoses cannot take the extra initial torque generated by the SC and should be upgraded if possible. then again, many cars have been supercharged to even higher HP without facing these issues. so now the finger points back at the pulley.

i will go for a refund for the pulley + install and would be very happy if i could get 50% of the damages. wont reveal the brand of pulley and where i bought them from yet as this would be quite damaging to its reputation.

anyone with SC + lightweight crankshaft pulleys or just lightweight pulleys in the house...care to share?? do mention if your pulley has the balancing ruber or not...

hey bro,
installing any lightweight pulleys on the accessories is ok so long as they are not too underdriven that it impedes the tast its supposed to do. they do work with good performance felt. anyway most well made, professionally produce underdrive/lightweight pulleys (eg. like those sold by calvin tan@eurocarmotorsport) only has the power steering unit + a waterpump unit. they are properly engineered with properly calculated reduction in drive to give a good balance of performance and functional reliability. most will not mess with/change the alternator pulley as its a lifeline for any car electronics.

as for the crankpulley, there are indeed some in the market that has rubber dampers in them. some functional as designed, but most are just for show as its just a tiny piece of rubber inserted into a groove in the pulley ie those made by mytheological.. and Even for those that have the right designs, they may just cause other issues as they may not be the proper weight to balanced the engine as the original bmw unit. just imagine a wheel that is balanced without the proper lead weights, it will still vibrate at a certain degree.... so this is the reason why most tuner would not be bothered with a crankpulley as its already adequate for its tast.