west

It appears that both the 545i and 550i share the same vibration damper/pulley (RealOEM Part # 11237568345). Nobody currently offers a underdrive damper/pulley for the 545i and 550i, so I'm thinking that if we get enough people (3 or more depending on how much people want to spend), we could have some pulleys made for us at a cost that isn't TOO terribly horrific. The price would definately not be low, and it would be higher than what most large production run pulleys cost (evosport, RPI, etc), but the unit price would be better than paying for a one-off custom damper/pulley.

I contacted these folks: http://www.bhjdynamics.com/. They make pulleys:


They said they build dampers/pulleys and said a one-off pulley might take roughly 6 months ETA and approx $2500.00 to build, if it is even possible. I'm sure that is a number that we can work on them with. Also, I'm fairly certain that an additional pulley will not cost another $2500.00, so we as a group could save on R&D costs the more pulleys people in the GB would want.

What I propose is this:

- We build a list of individuals interested in getting a pulley built for their 545/550 (doesn't have to be for sure buyers, just poeple interested at this point).
- We find somebody in the list to be our point of contact for the bhj dynamics guys, preferrably somebody good at bargaining.
- Work on pricing and actually figure out how much it will cost for R&D and each individual pulley.
- Figure out who is still interested once we've got solid numbers.
- Do some research on what percentage of underdrive would be appropriate for our engine.
- Send bhj dynamics our payments for how many people are still interested at this point
- Send bhj dynamics an OEM pulley and request it be re-built with a specific underdrive ratio.

What do you think? I know some engines respond better to pulley's than others, but take for instance the S85, which I think is an engine that responded rather well to an underdrive pulley. They were able to get 5.5% gains with the pulley bolt-on:



Anyways, comparing S85 to the N62 is like apples and oranges, but just wanted to show that pulleys can make a difference. We all know that 5% gains is probably the same as doing exhaust or intake or whatever, you probably won't feel it on the "butt dyno" for just the single modification, but the gains all add up and work together as a whole.

I'll add myself to the "I'm interested" list:

1) west (2007 550i)

rpav

i may be interested as well

west

Cool. Yeah, I mean, lets just see how many potentially interested people we can get, then contact the pulley guys and see what sort of quote they will get us based on the amount of interested people we have. At that point people may opt to fall out or move forward with the decision obviously. This GB is more of a feeler than a commitment at this point in time.

I'll add you to the 'interested' list as well:

1) west (2007 550i)
2) rpav (2004 545i)
3)
4)
5)

e6t.lab.rat

Glad you brought this up west. I replaced my waterpump a few months back and as soon as I pulled the crank pulley off, my immediate thought was "dang this is one rather large and heavy a$$ pulley." I wondered if there were any aftermarket ones available but, like you said there is none. This has certainly sparked my interest. Chalk me in as curious.... 2005 545.

west

This is a curious list anyways, so you are chalked in.

1) west (2007 550i)
2) rpav (2004 545i)
3) e6t.lab.rat (2005 545i)
4)
5)

Let's see if we can hit 5 interested individuals (20 would be even better!). The larger the amount of pulleys we can order, the more the engineering costs get diluted, hence a lower unit price.

e60oholic

I could be interested if the price doesn't end up being to ridiculous, and we get some good dyno results. So I guess put me in for curious.

west

Will do. Agreed, I don't think any of us want to pay ridiculous prices for a pulley.

1) west (2007 550i)
2) rpav (2004 545i)
3) e6t.lab.rat (2005 545i)
4) e60oholic (2004 545i)
5)

socale39

I may be interested...

Rizbel

1) west (2007 550i)
2) rpav (2004 545i)
3) e6t.lab.rat (2005 545i)
4) e60oholic (2004 545i)
5) socale39 (2004 545i)
6) Rizbel (2004 545i)

turboawd

have you guys thought about the drawbacks? less coolant flow, less power from alternator, less flow on ac, steering pump.