[huma]

If you want a sports car, go for the STI/EVO. If you want a car that's classier and more comfortable, go for the M235.

[Vegetable]

Originally Posted by SmoWilly

Go to TFLcar.com...these guys liven Boulder, CO and perform 0-60 runs all the time. Yes, the NA cars and most other cars are significantly slower at our 6,000 feet ASL. I have run my convertible M235 (stock) at 0-60 in 5.0 secs and the quarter in 13.1. The coupe should be a little faster due to weight savings.

Did you really just recommend TFLcar.com? Grounds for permanent ban.. Sure they test at high alt.. but they suck.. worst group of reviewers (if you want to call them that) on earth.

[SmoWilly]

Just showing a fellow poster an option if they wanted to see some high altitude testing...I don't know of any other source and the magazines can't be believed.

I agree they do some weird things but for us at ASL it helps see what kind of real performance we'll achieve.

Most reviewers drain the tank, change tire pressures, empty vehicles of spare tires, run on a special track and are at sea level to get their 0-60 times...not a true test.

[nachob]

Originally Posted by opfreak

not true.

NA cars will lose far more power at elevation then cars with tubro.

absolutely true, NA cars will lose more power at altitude.

As air gets thinner, there is less resistance on the turbo impeller so I can spin faster and force almost as much air into the engine. That is why turbochargers were originally vital for aircraft flying at altitude.

A non X drive M235i at altitude will be faster as it is lighter than X version.

The M235i is very heavy already, I really wouldn't add AWD unless I really had to!
Just 2 cents.

[Zachman1750]

Originally Posted by nachob

absolutely true, NA cars will lose more power at altitude.

As air gets thinner, there is less resistance on the turbo impeller so I can spin faster and force almost as much air into the engine. That is why turbochargers were originally vital for aircraft flying at altitude.

A non X drive M235i at altitude will be faster as it is lighter than X version.

The M235i is very heavy already, I really wouldn't add AWD unless I really had to!
Just 2 cents.

Thanks for the input! Just curious as to why you would say that a non-xdrive m235i would be faster at altitude? An xdrive will generally pull a better 0-60 and quarter mile at sea level, so what would change that at altitude?

[opfreak]

Originally Posted by nachob

absolutely true, NA cars will lose more power at altitude.

As air gets thinner, there is less resistance on the turbo impeller so I can spin faster and force almost as much air into the engine. That is why turbochargers were originally vital for aircraft flying at altitude.

A non X drive M235i at altitude will be faster as it is lighter than X version.

The M235i is very heavy already, I really wouldn't add AWD unless I really had to!
Just 2 cents.

did you actually read what I wrote?

"NA cars will lose far more power at elevation then cars with tubro"


A car without a turbo will lose MORE power at elevation then a car with a turbo.

[Luminous]

Originally Posted by Zachman1750

Thanks for the input! Just curious as to why you would say that a non-xdrive m235i would be faster at altitude? An xdrive will generally pull a better 0-60 and quarter mile at sea level, so what would change that at altitude?

I think his logic being that the xdrive weighs more, it won't be as fast. I feel like the added traction of the xdrive would at least make up for the added weight.

[3.0L]

N

Originally Posted by nachob

As air gets thinner, there is less resistance on the turbo impeller so I can spin faster and force almost as much air into the engine. That is why turbochargers were originally vital for aircraft flying at altitude.

Generally, turbochargers have waste gates that allow variable amounts of exhaust gases to bypass the exhaust-side impeller. As altitude increases and the air becomes thinner, the waste gate gradually closes which spins the turbo faster. Increasing the RPM of the turbo compensates for thinner and thinner air.

As to the aircraft turbos, they are large enough to allow the engine to develope sea level rated HP to very high altitudes; sometimes over 20,000 feet. Obviously, that much turbo capacity is not needed on car engines. I imagine they seldom go above 10 or 12 thousand feet.

With our turbo cars, the necessary boost is controlled by the computer and a myriad of sensors, so it automatic. With most aircraft, the pilot must monitor a manifold pressure gauge and periodically increase the throttle as manifold pressure gradually decreases during climb. Gradually increasing throttle gradually closes the turbo waste gate. Once the waste gate is fully closed, the engine will then gradually lose HP as altitude continues to increase.

[nachob]

Originally Posted by opfreak

did you actually read what I wrote?

"NA cars will lose far more power at elevation then cars with tubro"


A car without a turbo will lose MORE power at elevation then a car with a turbo.

Yes, I agreed and added a couple more thoughts.

Did YOU read my post? Is basically agrees with you??

???

[nachob]

Originally Posted by Luminous

I think his logic being that the xdrive weighs more, it won't be as fast. I feel like the added traction of the xdrive would at least make up for the added weight.

X drive might have an advantage in some launching situations but in a rolling situation where 99 44/100 of the time, the extra weight will probably slow you down and the car is already too heavy. Adding weight will also take away some of the handling "feel."

So you are sacrificing fuel mileage, feel, performance and adding purchase and maintenance costs for just a little extra launching traction.

Unless you live in bad weather, I don't think it's worth the sacrifice.

[tke743]

Originally Posted by sstarrx3

Any car that is faster at sea level than the M235i will be faster at elevation...just a little slower overall. Wont be many at that price point...if any.

Obviously you failed High school physics. If not elementary studies. Seriously are you kidding?

[nachob]

Originally Posted by tke743

Obviously you failed High school physics. If not elementary studies. Seriously are you kidding?

Yes tke is correct. A normally aspirated car at sea level might be faster but a very high elevations you can have a significant power loss due to thinner air. The turbo car (m235) will have an advantage providing performance was close to start with. If you had two turbo cars at sea level then things would be equal at elevation. That would probably be true.

[its_paul]

Originally Posted by tones_balboa

A Golf R would be in the ballpark.

This x2. With a Stage 1 tune and it would destroy a lot of cars. I seriously considered it for a bit but prefer the 235's body styling.