Blocking Vanos

[techno550]

As a random example:

On an M50, as stock, vanos is advanced from just off idle to ~5k rpm. The movement is ~12 deg. The peaks are just under 4k and around 6k.
If we had a different cam, and we wanted a target operating range of only 4k to 7k, perhaps we'd want a peak at 5300 and again at 6500. We retime our cams for a peak at 6500, and then set our travel to ~3 deg and get our second peak at 5300.


On a dvanos motor you get to pick as many peaks as you want. You can optimize the cam position from idle to redline. On the S54, you get 60 deg of intake cam movement and 45 deg of exhaust cam movement. Its a very wonderful thing.

[Miasma]

On the S54, you get 60 deg of intake cam movement and 45 deg of exhaust cam movement. Its a very wonderful thing.

Impressive.

[rThor432]

This seems to indicate that you think it is good... and leads me to believe that you think this because someone did it.

No, I was just putting an example out there of a reputable company blocking the VANOS system because that is what the thread is about. I mentioned them because a backyard mechanic that blocks it because he cannot set it up correctly might be referred to as a hack. Bimmerworld is a great company and team, that is (of course) competent in working with BMW engines. So I mentioned them to back up the fact that people do it and they do have a reason for doing it other than the fact that it is too complex for them to handle. I also mentioned the reason, because I figured that someone might ask.

Dont assume too much. Good try, but you missed the mark.

[techno550]

No, I was just putting an example out there of a reputable company blocking the VANOS system because that is what the thread is about. I mentioned them because a backyard mechanic that blocks it because he cannot set it up correctly might be referred to as a hack. Bimmerworld is a great company and team, that is (of course) competent in working with BMW engines. So I mentioned them to back up the fact that people do it and they do have a reason for doing it other than the fact that it is too complex for them to handle. I also mentioned the reason, because I figured that someone might ask.

Dont assume too much. Good try, but you missed the mark.

How would the backyard mechanic not being able to "handle the complexity" make him a hack but someone else not being able to "handle the complexity" not make them hacks?

Not having the skill set to use something and thus not using it doesn't make that something "not useful".

The only time someone doesn't use it and it isn't because its too complex or outside their reach, in racing, is rules. If the rules don't allow it then deleting it is merely complying with the rules. That would be outside of this discussion though.

I'll go ahead and be the one to ask. ;) what is their reason for deleting it?

[rThor432]

Well, we arent seeing eye to eye and obviously you just want to argue. Everything that I wanted to say was said in my first post. Just a little contribution. You misinterpreted it, and you'll keep misinterpreting my posts in this thread for your entertainment, so I'm done.

You win, er, whatever it is you were trying to prove. Cheers. You are a special person.

[lennon]

Techno makes some good points but is off the mark saying bimmerworld is incapable of using and tuning vanos to their liking, if that's what they desired.

[M3 euro ltw]

I know for a fact that Bimmerworld locks the VANOS units because their race cars dont spend enough time in the lower RPM range to justify having the extra parts that are prone to failure.

Hmm, when I read this, I got two messages. One, an interesting data point, ie, on presumably some race cars from Bimmerworld they lock the cams. And then the conjecture from OP as to why they do it. Unless OP builds Bimmerworlds motors or tunes them personally, OP is not necessarily speaking for Bimmerworld when he gives the "reason" they do it. I think it is reasonable to assume that OP holds Bimmerworld in high esteem as a competitive race group...so, it is reasonable to interpret it along the lines of "Bimmerworld does it, so it must be good"..... but who really wants to be an internet warrier....I say drop that issue. One data point, not sure what set of rules or contraints motivated their choice to lock cams. Move on.

Not true at all. In a race engine the vanos can be more troublesome with regards to reliability then that are worth.

This logic only proves my point. You're admitting that VANOS is in fact worth something. After you admit that, its purely a matter of deciding where you spend your money. Many race teams with the budget to allow it would use that knowlege, ie that VANOS is worth something, and merely consider the vanos unit to be an item that is replaced in a timely fashion to avoid failure, like many other items on the race car.

Racing on an amatuer level or on a professional level is always, always strongly constrained by both budget and rules...

A winning race team is guaranteed to have made some budgetary decisions. If a team has to choose between retaining Dvanos, say spending $15,000 for motec and $2000 for dyno time, they may elect to instead choose a $2000 system, $1000 on the dyno, and lock the cams. They'll get great numbers, but be able to spend the residual $14,000 on the rest of the car for suspension upgrades, lightening the car or tracktime to tune the suspension.

The result in the latter choice might make it a "winning" BMW team that locked cams... but it was not necessarily the way to make the most power, just the fastest total package.

It is really unrealistic to argue that one cam profile is really optimal from 4500 to 8000 rpm on a common BMW race engine. (Techno simplified this discussion beautifully with that perspective)

If you believe this to be true, then obviously vanos is not needed.