Pulleys

[m3f_park828_94ead836d3]

ok damn.. now i want the JC pullies... look nicer i guess.. also those evo sport ones look good too.. i dont know if i want to risk it using crank pullies.. i probably should get uuc stage 2 lightweight flywheel /m5 clutch anyway.. oh ya by the way S50 manifold... dude... install was a biaaaach but so worth it.. dyno dyno dyno.. or should i wait for the shark? ahahha im having way too much fun

[m3f_1-bar]

The JC pulleys do look nice, but its a shame it does not include a crank pulley.

[m3f_00poop6x_6dca3456a4]

What is this risk people say there is about the crank pulley?

[m3f_1-bar]

the risk has been discussed in this thread, look on previous pages. There HAS NOT BEEN ONE FAILURE from a Crank Pulley. But there has been 3rd party dyno's showing 10whp.

[m3f_park828_94ead836d3]

is it ok to run crank and acc pullies... just wondering.. i know if i get the flywheel i can't run the crank pulley

[m3f_00poop6x_6dca3456a4]

So it's a stress controversy.....

[m3f_1-bar]

this was recent from bimmerfourms:



Quote:

Originally posted by Estoril4dr

Which one do you own now and which one made you faster in a straight line. I understand theres more to the flywheel than just straight line performance, but i would just really like to know which one is faster. Cost wise it wouldnt be too different in my situation. I already have to change out my clutch.. which leaves just the cost between the actual flywheel part and the crank pulley. With the URI at $238 plus belts.. that puts it up at around $270. Since I could get the flywheel at a small discount, the difference in amount between the two is at most $200. With that said, what im looking for is an increase in acceleration from 10-90mph. Im not looking for the increase in WOT situations but during normal-spirited driving situations. Does the flywheel only make me go faster if i rev it all the way up in the first two gears? I like the fact the crank pulley allows me to feel the increase right away and all through out the power band. Maybe if i got the ltwflywheel along with UUC acessory pullies i would be able to achieve this?





well, I'm not an engineer and I didn't do any time trials but I have enough seat time in my car with all it's various mods to give what I believe to be a very objective opinion.



my URI crank pulley was part of their 4 pulley set. the power difference was noticable immediatly and throughout the ENTIRE range of the motor. with a few auto-x's under my belt before and after the upgrade I can direclty relate to how fantastic of an upgrade it was. acceleration regardless of speed was instant and much more power was getting to the rear wheels then before. I would seriously compare it to a difference in displacement. these were installed on my 2.5L M52 motor.



now working with the flywheel - comparing back to back the flywheel is a good upgrade but it is NOT able to give you that kick in the pants that you get from the pulley set. acceleration is great for the first two gears but you begin to lose the sensation of a lighter flywheel almost immediatly where the crank pulley gave you more push regardless of speed. 10mph and it pulled - 50mph and it pulled - 110mph and it pulled...wow!



so what am I driving today? I'm using the flywheel, surprised? Well I plan on purchasing a supercharger for my car so I can't use an underdriven crank pulley since the blower won't turn at the proper speeds. The flywheel is the next best upgrade for those looking to do mods that the crank pulley doesn't support. So, I bought a flywheel, spring hub clutch and accessorie pulleys from a well known NJ based company (name withheld to protect the innocent ) and have been very happy with the results as I continue to work the car up into a true streetable monster.



I have since sold my URI pulley set along with the 2.5L motor and running the new hardware on a 3.2L motor.



-Ron

[m3f_park828_94ead836d3]

so...... if i dont get the lightweight flywheel... crank + ACC pullies are okay?!

[m3f_SG_M3_d1201712b5]

you can combine UUC pulleys and a URI crank pulley. But you can buy the full URI pulley set.

[m3f_Max M3]

so...... if i dont get the lightweight flywheel... crank + ACC pullies are okay?!



At the very least, yes.



If you follow what the guy from Unorthodox was saying in his quoted email, even with precision pulleys AND lightened flywheel, there's been no evidence of engine damage ever reported! I've used their products in the past and the workmanship is really second to none.



I've also run a lightened flywheel and underdrive crank and accessory pulleys on an Acura (Physics theorys are still the same) for 20k miles then completely taken the engine apart. There was NO damage or even excessive wear on any internal parts especially the main bearings, which is generally the part(s) that would show excessive wear from a non-harmonically balanced crank assembly. Granted that's not the smooth precision German i6, but then again, it DID rev to 9k!!!

[m3f_imports4ever858]

hey i found a great article on why the crank pulleys are dangerous, so far his explanation in it makes a lot of sense to me and i think after reading it, some of you guys will change your mind on getting one.. hope this helps http://www.dinancars.com/html/dange...wer_pulleys.htm

[m3f_SG_M3_d1201712b5]

OMG, not the Dinan papers again. Remeber Dinan also thought the best way to fit headers on a z8 was to cut the frame. Dinan also sells ltw flywheels. Read the responce from the owner of URI a couple of pages back, most dinan's are just pure BS.

[m3f_imports4ever858]

yeah i figured that too, but just wanted some feedback on the article, it just seemed that the scientific explanation made sense, but who knows, considering that dinan sells abs plastic intake for e46 m3 for $1,700, and an ugly exhaust system for e36 m3 for over a grand, they are just mind manipulators, and good advertisers, most newbies to the bmw world hear dinan the second they buy one, and that's all they have on their mind, by the time they realize that dinan is a bunch of rip off, and that there are other comps out there with cheaper and better products, they already spent a few grand here and there just with dinan.. although i do like their tranny chip, thats it.. i think that any company will bs you, whether its dinan, uri, etc.. the best way is to find out on your own or from your friend's or forums.. :beer:

[m3f_1-bar]

did you miss page 4 of this thread?