[madpistol]

Originally Posted by wtwo3

What does it say? The last paragraph says they didn't experience any power loss driving a civic type r up pikes peak. Why not?

This is what you said.

Originally Posted by wtwo3

This is true of naturally aspirated motors. However the m340i is a turbocharged motors. Turbos actually work more efficiently in lower air density, to the point you may even see a slight INCREASE in power output at the higher altitude.

Something else is going on. I'd visit the dealer to see if there's some issues with drivetrain.

Something else to consider is that the Civic Type-R uses a 2.0L 4-cyl, while the M340i uses a 3.0L inline-6. The M340i would need more air to operate at optimal levels. While the power loss might not be felt on the Civic Type-R, that doesn't mean it won't be felt on the B58 in the M340i. Also, the M340i is significantly heavier than the Type-R.

Air pressure is lower at higher altitude, so power is decreased, even on forced-induction motors. Just because one journalist says otherwise doesn't make it true.

They're also different cars, so they aren't directly comparable.

I have only ever heard that turbo motors lose less power than NA motors at altitude... but they still lose power.

[wtwo3]

Originally Posted by madpistol

This is what you said.



Something else to consider is that the Civic Type-R uses a 2.0L 4-cyl, while the M340i uses a 3.0L inline-6. The M340i would need more air to operate at optimal levels. While the power loss might not be felt on the Civic Type-R, that doesn't mean it won't be felt on the B58 in the M340i. Also, the M340i is significantly heavier than the Type-R.

They're also different cars, so they aren't directly comparable.

Yeah I wasn't trying to compare a civic type R to an m340i... I was just citing articles which stated in general turbochargers don't see performance drops from elevation.

My comment on potential increases in power was in reference to the table from one of the articles (below) showing elevation change impacts on power output (the example is from a 500 hp 3.5L single turbo engine). Not only did it not see a drop in performance at altitude, it actually saw a slight increase.




Like I said I'm willing to admit if I'm wrong but I'm just calling it like I see it. So let me know if I'm misinterpreting something.

[madpistol]

Originally Posted by wtwo3

Yeah I wasn't trying to compare a civic type R to an m340i... I was just citing articles which stated in general turbochargers don't see performance drops from elevation.

My comment on potential increases in power was in reference to the table from one of the articles (below) showing elevation change impacts on power output (the example is from a 500 hp 3.5L single turbo engine). Not only did it not see a drop in performance at altitude, it actually saw a slight increase.

Attachment 2840803


Like I said I'm willing to admit if I'm wrong but I'm just calling it like I see it. So let me know if I'm misinterpreting something.

It looks like the temperature at intake is also higher at higher elevation. Is it possible that could have something to do with it?

[wtwo3]

Originally Posted by madpistol

It looks like the temperature at intake is also higher at higher elevation. Is it possible that could have something to do with it?

Possibly... heat soaking? I know the standard m340i without the ZTK cooling package is susceptible to heat soak at consistent heavy load... but if OP is experiencing this drop in performance at all times, I'm not sure that's the issue.

[siegester]

Originally Posted by wtwo3

What does it say? The last paragraph says they didn't experience any power loss driving a civic type r up pikes peak. Why not?

It says those cars are tuned to not lose power for the race. This means adjusting boost pressure to compensate as altitude increases. Turbos are not more efficient at altitude, they just make compensating for it easier if there is enough overhead left in the stock turbos (to safely and reliably crank up boost)

[G30M]

Originally Posted by wtwo3

Yeah I wasn't trying to compare a civic type R to an m340i... I was just citing articles which stated in general turbochargers don't see performance drops from elevation.

My comment on potential increases in power was in reference to the table from one of the articles (below) showing elevation change impacts on power output (the example is from a 500 hp 3.5L single turbo engine). Not only did it not see a drop in performance at altitude, it actually saw a slight increase.

Attachment 2840803


Like I said I'm willing to admit if I'm wrong but I'm just calling it like I see it. So let me know if I'm misinterpreting something.

wow appreciate your post.

i should have qualified, assuming the turbo does not increase the boost psi to compensate, there will be less oxygen molecules to burn the fuel.

as you can see the ECU has been programmed to increase boost PSI.

do we know if the M340i is programmed to detect lower air barometric pressure and increase PSI to compensate?

maybe there's another detection method - i'm not a mechanical engineer. MAFS? O2 sensor? other sensor?

[G30M]

Originally Posted by wtwo3

My comment on potential increases in power was in reference to the table from one of the articles (below) showing elevation change impacts on power output (the example is from a 500 hp 3.5L single turbo engine). Not only did it not see a drop in performance at altitude, it actually saw a slight increase.

it's not that they saw an increase.

it's all in the boost. at sea level if you increase the boost you will have more power. at altitude if you did not increase the boost you will have less power.

we are observing the wrong cause-effect relationship. higher power is not caused by higher altitude. it's caused by the ECU.

[wtwo3]

Originally Posted by G80M4

do we know if the M340i is programmed to detect lower air barometric pressure and increase PSI to compensate?

Yeah I think that's a fair question, and I don't know the answer to that.

Someone in Denver should conduct a launch control to 60 and give us results... if it falls closer to 4.9 than 3.8 then perhaps bmw is limiting boost.

[wtwo3]

Originally Posted by G80M4

it's not that they saw an increase.

it's all in the boost. at sea level if you increase the boost you will have more power. at altitude if you did not increase the boost you will have less power.

we are observing the wrong cause-effect relationship. higher power is not caused by higher altitude. it's caused by the ECU.

True, but that's where the example of the civic type r was so surprising. Does the civic type r have variable boost pressure based on air density while the m340i is static?

I don't know enough about the tuning of each car to know for sure. And there's conflicting things I've read. Some places suggest that you shouldn't see a dip in performance as a blanket statement across all turbocharged motors.

[siegester]

Originally Posted by wtwo3

True, but that's where the example of the civic type r was so surprising. Does the civic type r have variable boost pressure based on air density while the m340i is static?

I don't know enough about the tuning of each car to know for sure. And there's conflicting things I've read. Some places suggest that you shouldn't see a dip in performance as a blanket statement across all turbocharged motors.

Was it bone stock, or did it have Hondata or other ECU tuning?

You will see a dip in performance (less than NA) at the same turbo loads given a higher altitude. To keep power the same the turbo must work harder and put more stress (psi) on the motor. The journalist hints at this by saying these cars were tuned for the altitude change

[G30M]

says similar power (only a little loss but not a lot)

[G30M]

says turbo charger compresses the air to sea level density up to a point. i love turbochargers! wow i learnt something today

[G30M]

i found the table that is posted above it's from garrett.

it specifically says the ECU compensates to adjust the boost to match the horses at sea level. (whether that statement is correct or not i don't know, someone said the boost should be the same ... ??? though in garrett's table the boost is definitely maxed out!)

so i still think it could be that Germans did not think about tuning the ECU to Bolivia's elevation?

i think the easiest thing for OP to do is to tell us the boost he's getting when he's launching maybe someone smart will figure out if that boost is normal or less than normal

i don't launch my baby so i can't help. i launch EVs

[wtwo3]

Originally Posted by G80M4

i found the table that is posted above it's from garrett.

it specifically says the ECU compensates to adjust the boost to match the horses at sea level. (whether that statement is correct or not i don't know, someone said the boost should be the same ... ??? though in garrett's table the boost is definitely maxed out!)

so i still think it could be that Germans did not think about tuning the ECU to Bolivia's elevation?

i think the easiest thing for OP to do is to tell us the boost he's getting when he's launching maybe someone smart will figure out if that boost is normal or less than normal

i don't launch my baby so i can't help. i launch EVs

I think your video above "decoding critical altitude" explains it best. Also if you take a look at the table, at the higher altitude, the heat at the turbocharger is also increasing (which makes sense). So it makes sense that there's a "critical altitude" beyond which the turbocharger won't spin faster - otherwise you risk blowing the turbo.

However - now if we're suggesting that OP's car has reached the point of critical altitude (let's say BMW limits boost pressure so critical altitude is reached sooner than other manufacturers, like with the civic type R), then shouldn't the car be throwing up an overboost code when he's launching it?

All this is why I still think there might be some other issues going on beyond elevation increase.

[oonowindoo]

That chart and Pike's peak examples are apple or orange comparison to what we are talking about here.

If you wanna know if altitude affects HP in turbo cars, you compare the same boost at sea level and at altitude.

You can't compare 10psi at sea level and 20 psi at elevation and claim that Turbos dont lose power.

[wtwo3]

Originally Posted by oonowindoo

That chart and Pike's peak examples are apple or orange comparison to what we are talking about here.

If you wanna know if altitude affects HP in turbo cars, you compare the same boost at sea level and at altitude.

You can't compare 10psi at sea level and 20 psi at elevation and claim that Turbos dont lose power.

Yeah there's conflicting information. Maybe I worded it wrong. Some sources say turbochargers effectively combat power loss from elevation increases without any mention of manual tune, whereas other examples (such as the pike's peak example) suggest that there is a manual tune in place to boost pressure and compensate.

In the below video if you skip to 2:14, he explains how a Ford Fusion sport will perform very similar at sea level as it does at altitude. So perhaps BMW turbo doesn't operate in a similar fashion and limits boost? That's the question then - what causes cars like a fusion sport or civic type r to not experience much performance loss, but an m340i does? Or maybe these guys are wrong.

[JITH]

I live in Mexico City, 2.2 km altitude and some highways out of the city (which is in a valley) can go up to 3.0 km or more. Altitude has always been an issue in the comments about hp in our cars, turbo or not.

With that in mind, I made around 4.2 in my 440i xDrive. My guess is that altitude, tires, even the kind of carpet the road has on it has a lot to do.

Regards,

JI

[oonowindoo]

Originally Posted by wtwo3

Yeah there's conflicting information. Maybe I worded it wrong. Some sources say turbochargers effectively combat power loss from elevation increases without any mention of manual tune, whereas other examples (such as the pike's peak example) suggest that there is a manual tune in place to boost pressure and compensate.

In the below video if you skip to 2:14, he explains how a Ford Fusion sport will perform very similar at sea level as it does at altitude. So perhaps BMW turbo doesn't operate in a similar fashion and limits boost? That's the question then - what causes cars like a fusion sport or civic type r to not experience much performance loss, but an m340i does? Or maybe these guys are wrong.

Yah... I personally dont know if certain cars have variable boost management build into any stock cars. Maybe they do. But that only means the ECU modifies/tunes the cars to the environment.

The fact that the ECU has to do that means altitude also affects turbo. It is just there are ways to compensate that loss with turbo (to a certain extend)and not much you can do with NA cars.

If the FI cars dont have variable boost capability, then it will lose power for sure.

Here are some examples.

https://www.reddit.com/r/FiestaST/co...is_ridiculous/

[wtwo3]

Originally Posted by JITH

I live in Mexico City, 2.2 km altitude and some highways out of the city (which is in a valley) can go up to 3.0 km or more. Altitude has always been an issue in the comments about hp in our cars, turbo or not.

With that in mind, I made around 4.2 in my 440i xDrive. My guess is that altitude, tires, even the kind of carpet the road has on it has a lot to do.

Regards,

JI

Thanks for the clarification. 4.2 is still relatively quick. OP's 4.9 is showing significant loss... wonder if loss is exponential after a certain altitude?

Still doesn't explain why some sources suggest loss would be minimal for certain turbo cars. I'd like to get to the bottom of that...

[oonowindoo]

Originally Posted by wtwo3

Thanks for the clarification. 4.2 is still relatively quick. OP's 4.9 is showing significant loss... wonder if loss is exponential after a certain altitude?

Still doesn't explain why some sources suggest loss would be minimal for certain turbo cars. I'd like to get to the bottom of that...

If your OCD is really that bad , Just take a road trip to a 10k peak and see if you could feel the difference yourself.

That is the most reliable way.

Everyone's 0-60 is gonna be different. From the way he described, he was not even using launch control. He was just torque braking.

But he also has DP, so who knows.. there is a chance that someone messed it up or his airfilter lid is open from his KN filter. All possible.

[wtwo3]

Originally Posted by oonowindoo

If your OCD is really that bad , Just take a road trip to a 10k peak and see if you could feel the difference yourself.

That is the most reliable way.

Everyone's 0-60 is gonna be different. From the way he described, he was not even using launch control. He was just torque braking.

But he also has DP, so who knows.. there is a chance that someone messed it up or his airfilter lid is open from his KN filter. All possible.

Ugh... I live in the shitty midwest. The highest elevation we get is goddamn speed bumps driving through the city. I'd have to take a REALLY far out road trip.

[kamaleon_m340]

Originally Posted by oonowindoo

If your OCD is really that bad , Just take a road trip to a 10k peak and see if you could feel the difference yourself.

That is the most reliable way.

Everyone's 0-60 is gonna be different. From the way he described, he was not even using launch control. He was just torque braking.

But he also has DP, so who knows.. there is a chance that someone messed it up or his airfilter lid is open from his KN filter. All possible.

If you refer to me, I used launch control.