[M2BOT]

Originally Posted by M2siast

Precisely why it’s impossible for those to hit the oil cooler.

Impossible? A thrown rock can ricochet from the ground and bounce to hit the cooler. Impossible? It’s happened plenty already. Is everyone just lying?

[JABCAT]

Originally Posted by M2siast

I’d just have to see one to believe it. That’s why I said mythbusters could help us.

From a physics perspective, if a rock could bounce up and hit the oil cooler in the X3MC (my wife's has several damaged fins and evidence of rock hits), could it also not bounce up & hit the oil cooler on the M2?

[Tag]

Originally Posted by M2siast

It’s impossible for something to hit it “face-first”. We’re advocating a rock bounces just right to do a 45 angle bounce and hit it with enough force to kill it. That rock would’ve had to be thrown from a position higher than the cooler itself for it to conserve any energy to bounce up and hit the cooler, would it not? If a tire picks it up it’s not likely that height is the same.

Could it happen? How can we see it? Myth busters please!

Rocks are not perfect spheres and don't bounce like that. They're mostly irregularly shaped, some with sharp right angles and as they tumble at high velocity can take any number of trajectories including upward. A rock under a tire can also get kicked up into the oil cooler if happens to get pinched on the inner shoulder of the tire as the car runs over it.

[akumachu]

Originally Posted by Tag

Rocks are not perfect spheres and don't bounce like that. They're mostly irregularly shaped, some with sharp right angles and as they tumble at high velocity can take any number of trajectories including upward. A rock under a tire can also get kicked up into the oil cooler if happens to get pinched on the inner shoulder of the tire as the car runs over it.

Yup, the irregular shape was exactly the scenario I was describing above.

However, given the placement of our oil cooler underneath, I don't think our front wheels can turn enough to line up to to hit the cooler.

If I remember correctly the cooler sit further in front then the front axle, not behind.

[Tag]

Originally Posted by akumachu

Yup, the irregular shape was exactly the scenario I was describing above.

However, given the placement of our oil cooler underneath, I don't think our front wheels can turn enough to line up to to hit the cooler.

If I remember correctly the cooler sit further in front then the front axle, not behind.

Regarding the wheels, I meant a rock under the edge/shoulder of the tire can get pinched and kicked up, not getting slung from the rear of the tire. We also need to factor in that this car weighs nearly 4k lbs, so one corner is applying approximately ~1k lbs of force on a tire. I've seen rocks get pinched from the edge/shoulder of the tire and kicked up sideways on gravel roads as a car drives over them.

[Southtown]

Originally Posted by Kanrai

Same here. After the Dealer told me bmw always covers their mistakes. Hehe.

Just got an email that it’s back ordered 8-10 weeks…

[MineralGreyMetallic]

Rocks have been hitting radiators since they started being mounted to the front of cars over 100(?) years ago.

In fact, if I understand radiator design at all, that array of metal fins is protecting the tubing that carries the oil that's being cooled. The purpose of those fins is to be a heatsink. It's an efficient way to dissipate heat.

Something would have to completely penetrate that layer and then still have high enough velocity to then puncture the (metal) tubing carrying the oil.

I'm not trying to say anyone is right or wrong. Mostly I'm just trying to validate my understanding of radiators, so please correct me where I'm wrong.

Here's a good reference image where you can see the tubing that carries the liquid being cooled.

[Tag]

Originally Posted by MineralGreyMetallic

Rocks have been hitting radiators since they started being mounted to the front of cars over 100(?) years ago.

In fact, if I understand radiator design at all, that array of metal fins is protecting the tubing that carries the oil that's being cooled.

Something would have to completely penetrate that layer and then still have high enough velocity to then puncture the (metal) tubing carrying the oil.

I'm not trying to say anyone is right or wrong. Mostly I'm just trying to validate my understand of radiators, so please correct me where I'm wrong.

The fins are there to radiate the heat. Radiator guards are for protection.

[MineralGreyMetallic]

Originally Posted by Tag

The fins are there to radiate the heat. Radiator guards are for protection.

Yes, I forgot to be explicit about that in my post, but had edited after you responded.

[Kanrai]

Originally Posted by Southtown

Just got an email that it’s back ordered 8-10 weeks…

Same here, called them they said might be more by mid Feb, so might not be that long of a wait.

[akumachu]

Originally Posted by Tag

Regarding the wheels, I meant a rock under the edge/shoulder of the tire can get pinched and kicked up, not getting slung from the rear of the tire. We also need to factor in that this car weighs nearly 4k lbs, so one corner is applying approximately ~1k lbs of force on a tire. I've seen rocks get pinched from the edge/shoulder of the tire and kicked up sideways on gravel roads as a car drives over them.

It does not matter how fast and how heavy the force involve in the scenario is, if the trajectory can never get to the cooler, it does not matter. If your argument was drive backward, that would be valid.

I just saw there is a picture above and we could clearly see the front most edge of the tires are behind the cooler. So unless you are driving backward to shot the rock forward, the front tires driving forward can't shot anything forward.

I mean, we don't see rocks coming out in the front of the car when you drive forward regardless how fast or how you turn, right?

[Tag]

Originally Posted by akumachu

It does not matter how fast and how heavy the force involve in the scenario is, if the trajectory can never get to the cooler, it does not matter. If your argument was drive backward, that would be valid.

I just saw there is a picture above and we could clearly see the front most edge of the tires are behind the cooler. So unless you are driving backward to shot the rock forward, the front tires driving forward can't shot anything forward.

I mean, we don't see rocks coming out in the front of the car when you drive forward regardless how fast or how you turn, right?

If a rock is run over on the edge of a tire it can go in any number of directions depending on multiple variables such as the shape of the rock and where it gets pinched on the tire.

[Rx-7ames]

Originally Posted by FrankWhite!

Can’t take the risk and it’s cheaper than
1. An insurance claim
2. A new oil cooler
3. A new engine
4. Piece of mind

For the price of my deductible it was a no Brainer for me! I Installed mine the same time as my break-in service and was nervous the entire 1200 miles.

[akumachu]

Originally Posted by Tag

If a rock is run over on the edge of a tire it can go in any number of directions depending on multiple variables such as the shape of the rock and where it gets pinched on the tire.

Please don't forget that your tire is spinning and dragging rocks into the spinning direction.

So no, I don't believe that is possible because what you are trying to tell me that rock can shoot forward from under the car and so I should worry about the car behind shooting rocks at my bumper.

I think we have enough to worry about lol

It is one thing to have legit concern but it is a different thing to make up scenarios that not quite physically valid.

[Rx-7ames]

Originally Posted by M_Power Rob

*You missed a post (in a thread) from BMW CA wherein he stated he knows of two that came into his dealership.



Edit: *evidently I cannot find it now...

That was me. One drove too far into a curb. The other was driving down I5. Both had engine failures. Both were M3s.

[Tag]

Originally Posted by akumachu

Please don't forget that your tire is spinning and dragging rocks into the spinning direction.

So no, I don't believe that is possible because what you are trying to tell me that rock can shoot forward from under the car and so I should worry about the car behind shooting rocks at my bumper.

I think we have enough to worry about lol

It is one thing to have legit concern but it is a different thing to make up scenarios that not quite physically valid.

What you're doing is discounting all of the variables that are involved. Doesn't matter that a tire is spinning unless the tire grabs onto the rock and pulls it in the direction it's spinning. If, however, it rolls over the rock on its edge it will simply pinch it and shoot it off.

[Rx-7ames]

Originally Posted by MineralGreyMetallic

Also, why are more people rushing to install a grill under the car than to protect the one on the face of the car?

I would guess that someone who installs the skid plate will also likely install the front grill guards, but there is still rational in your question.

If you puncture your oil cooler under the car, you can blow your engine in .5miles or less. This is proven.

When I punctured my radiator I drove home for an unknown amount of time and got no warning. Then the next time I started my car I got a "low coolant" warning. I just topped off the coooent and drove 30 miles to work looking at the temp. It wasn't until I visually saw the coolant pooling that I realized there was something wrong.

In other words, a punctured radiator is much more forgiving, and therefore isn't as high a priority.

[KC87ZB]

Originally Posted by Rx-7ames

I would guess that someone who installs the skid plate will also likely install the front grill guards, but there is still rational in your question.

If you puncture your oil cooler under the car, you can blow your engine in .5miles or less. This is proven.

When I punctured my radiator I drove home for an unknown amount of time and got no warning. Then the next time I started my car I got a "low coolant" warning. I just topped off the coooent and drove 30 miles to work looking at the temp. It wasn't until I visually saw the coolant pooling that I realized there was something wrong.

In other words, a punctured radiator is much more forgiving, and therefore isn't as high a priority.

This is exactly the difference, the oil cooler is not at all forgiving, the cooling system will take a small puncture and you get plenty of warning - maybe

Picture a cold day and a broken radiator, you get low coolant way before high temp. What is the status of your engine? Keeping in mind that you may not get a timely high temp because the temperature sensor is normally submerged but now is not. How long for engine heat to soak the sensor?

[akumachu]

Originally Posted by Tag

What you're doing is discounting all of the variables that are involved. Doesn't matter that a tire is spinning unless the tire grabs onto the rock and pulls it in the direction it's spinning. If, however, it rolls over the rock on its edge it will simply pinch it and shoot it off.

For the rock to shot forward, something need to give it force in that direction.
Sure if the rock is shape like a triangle and then you drop the M2 on top of that, yeah, I can see that.

But a spinning tire that is on the ground? If what you said would happen, our factory assembly lines where convey belts and sorting wheels is going to have more problem than jamming.
Imagine all the stuff that could fling out in the reverse direction. lol

Keep in mind with Newton 3rd law is the reaction force. The ground goes backward in relative to the car going forward. Your rock is part of the ground, even though it is loose, but does not mean that wheel can send it forward.

[Tag]

Originally Posted by akumachu

For the rock to shot forward, something need to give it force in that direction.
Sure if the rock is shape like a triangle and then you drop the M2 on top of that, yeah, I can see that.

But a spinning tire that is on the ground? If what you said would happen, our factory assembly lines where convey belts and sorting wheels is going to have more problem than jamming.
Imagine all the stuff that could fling out in the reverse direction. lol

Keep in mind with Newton 3rd law is the reaction force. The ground goes backward in relative to the car going forward. Your rock is part of the ground, even though it is loose, but does not mean that wheel can send it forward.

I give up.

[akumachu]

Originally Posted by Tag

I give up.

haha, I worn you out !
much like what our cars doing to those brakes and tires.

[Tag]

Originally Posted by akumachu

haha, I worn you out !
much like what our cars doing to those brakes and tires.

It's Friday.