You are right, however, inline 6s should be very similar but all the new inline 6 forced induction BMW motors 2006+ come from the factory with harmonic balancers at the crank and as I've mentioned earlier there have been attempts at running solid one piece pulleys of which all reported/documented cases had motor failures directly related to the crank pulley. Everything I've read on the research and data gathering by Jamie and the people he worked with simply tells me it is a worthwhile investment to run ATI's harmonic balancer. We'll run it on our shop car's motor when the ERP and its single mass flywheel make it back in the car. I don't see any significant performance advantages out of a solid lightweight crank pulley and would much rather focus elsewhere for power/response gains.

 

if BMWs came with a harmonic damper from the factory and people replaced it with a regular pulley, that sounds like a mistake to me. the M96 and M97 engines do not come with one from the factory which is why a lot of guys are having success running the GT3RS pulley and the EvoMS pulley.

i'd give it a shot but to be honest i think $1000+ for a balancer pulley is a rip-off.

 

Well, the argument was the same as the one posed here, in theory inline 6s are internally balanced as well and they shouldn't need it. There really is no 'need' for external balancers on them. BMW couldn't have added them for balancing the crank and the info on reasons behind adding them in sits with their engine designers. Issues that were seen weren't crank related and were similar to what Jamie is describing.

My 2c, having a properly tuned balancer on the crank is something I'd personally choose for my motor any day over using a solid single piece for peace of mind and get my gains elsewhere.

There are many reasons why things get priced one way or another and a lot of it has to do with volume to make it worth making for a manufacturer. The same can be said for many other custom parts on higher end cars. Making 10 of something and 10,000 can change costs dramatically. ATI dampers for some other motors such as small black Chevys go for 350, sold by Jegs, but you can imagine the volumes being much different.

 

everyone is all about cost cutting. if the BMW you refer to did not need a harmonic balancer, BMW would not have put it on the car. going back to my point that if a car came with one, removing it is a mistake.

 

That's one way to look at it and I agree in the BMW case that it is/was a mistake and I spoke against it as soon as I saw it come to market back a few years ago.

However, in this case the issues Jamie is describing are different.

Funny enough, check out this story on M96/M97 dual mass flywheel removal. I know its on the extreme side of things but you mentioned them, not me

http://flat6innovations.com/index.php/broken-crank

Anyways, I've got my ATI damper on the way.

 

Balance and Harmonics are not the same. Really wish they weren't called harmonic balancers as it's confusing... And whomever called my word usage out, thanks for that...

Harmonics are the vibrations resulting from the uneven pulses from the firing of each cylinder. If you tap a bell at a regular interval it gets louder and louder. This is what is happening to your crankshaft, it's ringing, like a bell, at a certain point, the ringing has a significant amplitude and something has to give (like bolts backing out, oil pump gears breaking etc...). The ringing is in the torsional direction (in the direction of rotation), so it effects many things. Bolts coming loose, is one, but it also effects the valve train timing as the chain connecting the cams to the crankshaft is getting pulled back and forth, this causes valve timing changes and reduces horsepower.

What the damper is doing providing some counter force to the crank shafts harmonic oscillations and acting to dampen the oscillations before they grow in amplitude.

Crankshaft Balance is the balance in the rotating mass, so that it's not "lopsided"...

And an ERP clutch would be a single mass

 

You're welcome. As you are coming across as an authority on the subject, I think using the correct word would compliment your points.

Don't compare the flat 6 to an inline 6, not the same animal at all when it comes to balance/weight distro etc.

 

So has anyone had any ill effects from NOT running this ATI harmonic balancer thing?

 

Zero issues here running a 3.8 turbo Mezger with OEM LWFW and 996Cup light weight underdrive pulley. I am running an RSR crankshaft. Engine has 70+ track hours on it since last rebuild and is revved to 7500 pretty much on each shift.

 

https://www.dundonmotorsports.com/99...dampe?carid=37

Anyone ever use this on their car?

 

Hmmmm... Guess I'm not the only one looking into this.

 

ATI confirmed they only sell via Dundon motorsports for our platform.