Blocking Vanos

[MDryVur]

thought this was interesting.. i dont know if its a double post.

http://www.bimmerfest.com/forums/showthread.php?t=390088

[hoveringuy]

Why is VANOS blocked on racing engines? Is it a reliabilty issue or that the engine is constantly at high rpms where VANOS isn't effective, anyway?

[jahnaboi]

Why is VANOS blocked on racing engines? Is it a reliabilty issue or that the engine is constantly at high rpms where VANOS isn't effective, anyway?

Its that.

[techno550]

Vanos is always useful. It is deleted from some cars either by rules, or by people who don't know what they are doing.

[sharky]

I ran a 3.2 block w/ a non vanos head and Shricks that were advanced to make up for the vanos loss. Pretty cool setup but frankenstienish.

[zav3n]

Why!!!!!!!!!

[rThor432]

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.

[87e30]

Seems similar to vtec delete cams to me.

Use a cam that's effective in the upper range since that's all you need.

[techno550]

I ran a 3.2 block w/ a non vanos head and Shricks that were advanced to make up for the vanos loss. Pretty cool setup but frankenstienish.

That will move the RPM peak down, which will help the midrange, but not as much as vanos would... and you sacrifice top end to what leaving vanos intact would have done.

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.

Don't confuse "someone does it" with "it is good".

Seems similar to vtec delete cams to me.

Use a cam that's effective in the upper range since that's all you need.

Unless the engine is used at a constant RPM VANOS will be beneficial.

[M3 euro ltw]

As above...

The only "bad things" about vanos is that it does have some parasitic cost, it is more complex to program, it does add some weight to a car, and if you're running very, very, very wide duration cams, with huge compression pistons to match, it is possible that advancing and retarding the cams could cause overlap situations where you hit the valves.

However, the engines where those issues would be real, and make a difference are likely being rebuilt at least a few times a season, they're being run by drivers that are far more skilled that most of us and paid for their skills, and they're often in cars where gearboxes and diffs are carefully chosen in terms of ratios for each track the car races on. Those cars will be driven hard in a very, very narrow range of rpm, are geared as such, and will be driven by drivers that know this, and can keep the car in those rpms.

For the rest of the world, vanos makes sense and is a very real advantage to have if the tuner knows how to tune it.

Deleteing vanos is fine for narrow powerbands.... that is the basic message... if you want a broad area of power, you want vanos.

An example of what I'm talking about in terms of driving would be that E36 video with the sequential screaming gearbox in the Dutch supercar race. That is an S14 I believe, but they would have deleted vanos for such a car that was running such a narrow powerband, and shifting as often as it does. I'm sure someone can post a link... its pretty F-ing cool.

On my car, even with a six speed and 4.45.....think CR gearbox now, I prefer to have vanos active.

[rThor432]

Don't confuse "someone does it" with "it is good".

I dont remember making that connection at all.. Maybe you are confused?

[rneedham1979]

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

Vanos is always useful. It is deleted from some cars either by rules, or by people who don't know what they are doing.

[rneedham1979]

Again not exactly the most correct info... how do all the other manufactures succeed without vanos? If you look at any real racing teams running bmw engines they delete the vanos to ensure reliability and to reduce cam limits set by vanos. it is easier and much more beneficial to run a custom ground cam decreed into position instead of running a smaller vanos compatible camshaft.

In addition, on a race track how often are you below 4-5k? If the car is geared for the track the RPMs range will always be above the area in which vanos will help develop power/torque down low well unless your racing in the pits....

In addition Vanos does not give you more advance then if you remove the vanos. When you remove the vanos you time the cams to make power up top, you will only lose power down low.

The only "bad things" about vanos is that it does have some parasitic cost, it is more complex to program, it does add some weight to a car, and if you're running very, very, very wide duration cams, with huge compression pistons to match, it is possible that advancing and retarding the cams could cause overlap situations where you hit the valves.

However, the engines where those issues would be real, and make a difference are likely being rebuilt at least a few times a season, they're being run by drivers that are far more skilled that most of us and paid for their skills, and they're often in cars where gearboxes and diffs are carefully chosen in terms of ratios for each track the car races on. Those cars will be driven hard in a very, very narrow range of rpm, are geared as such, and will be driven by drivers that know this, and can keep the car in those rpms.

For the rest of the world, vanos makes sense and is a very real advantage to have if the tuner knows how to tune it.

Deleteing vanos is fine for narrow powerbands.... that is the basic message... if you want a broad area of power, you want vanos.

An example of what I'm talking about in terms of driving would be that E36 video with the sequential screaming gearbox in the Dutch supercar race. That is an S14 I believe, but they would have deleted vanos for such a car that was running such a narrow powerband, and shifting as often as it does. I'm sure someone can post a link... its pretty F-ing cool.

On my car, even with a six speed and 4.45.....think CR gearbox now, I prefer to have vanos active.

[techno550]

I dont remember making that connection at all.. Maybe you are confused?

I believe you said

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.

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

Perhaps I will rephrase. There is no "its only useful in the lower RPM range". Especially on a race car.

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

No, its very true. VANOS is an amazing tool. Very reliable too.

Again not exactly the most correct info... how do all the other manufactures succeed without vanos? If you look at any real racing teams running bmw engines they delete the vanos to ensure reliability and to reduce cam limits set by vanos. it is easier and much more beneficial to run a custom ground cam decreed into position instead of running a smaller vanos compatible camshaft.

You obviously aren't looking at real racing teams if this is the conclusion you are drawing. Even the club racers have figured out that if you want to go fast you cannot disable VANOS.
also, what is "VANOS compatible"? If you have a point where moving the cam that far causes issues, don't move the cam that far. That only limits you in one direction though, and chances are very good that you will see benefit from moving the cam in the other direction at some RPM range.

In addition, on a race track how often are you below 4-5k? If the car is geared for the track the RPMs range will always be above the area in which vanos will help develop power/torque down low well unless your racing in the pits....

VANOS does not have one RPM range where it is effective. VANOS is a tool. It lets you move the cam.

In addition Vanos does not give you more advance then if you remove the vanos. When you remove the vanos you time the cams to make power up top, you will only lose power down low.

advancing the cam makes power down low. Advancing the intake cam is also what is "dangerous" in terms of running in to pistons with the valves. When you delete vanos, its the same as unplugging it. or never activating it. it leaves the cam retarded and throws away everything you could be making in the midrange.
That is with single vanos at least. With DVANOS the gains are even greater with it active.



Lets change our perspective on this question.
Lets phrase it as "is there ONE cam timing that is best for all RPM ranges?"
the answer to that is obviously no.
Now lets look at VANOS. it is a tool that lets you alter the cam position on the fly.
Since we agree that there is no one cam position that is ideal for a wide range of engine speeds (nobody is going to argue this, right?) then we can also say that being able to pick more than one cam position would be beneficial. right?

[hoveringuy]

You bring up some interesting points. .

I have thougth of VANOS as being out of the picture by around 5400 rpm, but your point, I believe, is that it could just as easily be tuned to move the cam and be effective from 5000-7000 rpm.

If the intake cam were installed with static timing that is more retarded than normal, then VANOS would advance it to the "normal" position at 5000rpm and give you additional retard above that.

My VANOS has survived me playing with it endlessly. I've had an electronic "dial an advance" knob that was hard on it. Most people don't realize how often VANOS cycles in their cars. FOR YEARS. It's tough!