| Author | Message | ||
| rob guess (Beast)
Member Username: Beast Post Number: 288 Registered: 5-2003 |
James; All of those tracks were about 3000' to 3600' in elevation. Tracks like Grants, Aztec were over 6500'. Then there was Alamosa Co. over 8000'. My favorite texas track had to be Lake Whitney, loved those ruts. 1985-1989 Kawasaki Team Green here. Rob | ||
| James Dunne (Audiguy)
Member Username: Audiguy Post Number: 267 Registered: 6-2003 |
Rob, I remember having to change the jets in my carb for each track. I never raced any further into NM than Hobbs and Roswell. Usually raced Texas, Louisiana, over to Florida and up to the Carolinas. Raced California a few times including Carlsbad and the LA Coliseum. Ran for Kawasaki Central Region. Texas Pro #85 in 1972-1974. | ||
| rob guess (Beast)
Member Username: Beast Post Number: 286 Registered: 5-2003 |
Matthew; I Agree that living at altitude stinks The modern ECU will adjust the amount of fuel being injected for you One thing to realise is that performance is reduced at altitude on a hot day also If you were to test compression in the winter then check it again on a hot day in the summer you will find a difference Same goes with compression at sea level and altitude The only bright side of this is the fact that you will use less gas at altitude I myself lived with the same problems in NM when i had to race at sea level it took a while to get used to the extra horsepower Rob | ||
| Robert Callahan (Rcallahan)
Member Username: Rcallahan Post Number: 343 Registered: 7-2002 |
Hey, FWIW, there is also less air resistance at altitude, therefore it takes less power to go a given speed! | ||
| James Dunne (Audiguy)
Member Username: Audiguy Post Number: 264 Registered: 6-2003 |
In a BMW it is the Lambda air flow sensor that adjusts everything for you. It reads air/fuel mixture, atmospheric pressure and a host of other things to make the microscopic adjustments needed to keep you engine running at its peak. Mike is right in that the dealership does nothing to change these settings for altitude. That went out with mechanical fuel injection and carburetors. | ||
| Mike B (Srt_mike)
Member Username: Srt_mike Post Number: 332 Registered: 12-2002 |
Nothing is done by either of them. They rate their engines at sea level - the physics which dictate the power loss at elevation (sorry if this sounds ride) "ain't their problem". People living at elevation have no "right" to the advertised horsepower, because the advertised horsepower is defined at sea level. It would be like saying "Sears sale on snowblowers in Massachusetts only!" and someone in Texas wants the same price  As for how it's compensated for, cars will either have a MAP sensor (manifold pressure) or work on a speed-density or mass-airflow which allows them to detect how much air (in terms of air molecules) are coming into the engine, and they adjust ignition timing and injector pulse width to accomodate. You can drive a modern car from Pikes Peak to Death Valley without adjusting anything - the computer will do the adjustments. | ||
| Matthew J Germane (Mjgermane)
Junior Member Username: Mjgermane Post Number: 114 Registered: 1-2003 |
Just curious because at the elevation I am at it is quite a difference in horse power compared to sea level. For example, I am in Salt Lake which is roughly 4500 ft about sea level. If you look at a BMW M5 with 394 horse power at sealevel, up here it has roughly 340 hp. That is quite a difference. The equation I am using is: elevation (in feet)/1000 * .03 * horse power I know that air pressure with elevation is not linear, but for this purpose this equation will suffice. Anyway, 340 hp from a 394 horse power engine is a big difference, so I am just wondering what, if anything, is done about this by the dealer and/or car manufacturer. |