Rocky Mtn driving-power loss?

"Joe J" wrote in news:hqnaih$ba5$ snipped-for-privacy@news.eternal-september.org:

You probably won't notice any changes at all to the engine's behavior.

Your Honda's engine-management system will compensate for changes in air density far better than the crude system used in the '84 Saab. That's what the Honda's air-pressure sensors are for!

Thank you, I was wondering about technology advancements.

What about the Subaru your taking on this trip? How are you going to drive two cars?

You will experience some power loss at higher altitudes, this is normal for all 'normally aspirated engines'. What is happening at higher altitude is the air pressure is lower. Contrary to what seems to be suction in an engine (and vacuum cleaners, or human lungs etc.), it's the ambient air pressure that PUSHES the air into the cylinder. At higher altitudes less air is pushed into the engine which means less oxygen and consequently less fuel can be allowed in (leaner fuel mixture). Since the advent of emission controls all engines employ a method of 'altitude compensation'. This is done by leaning the fuel mixture. On some carburetted cars (with emissions controls) a device would leak air into the intake manifold at high altitude to lean the mixture. This device functioned like a barometer. Some of them were a sealed metal (copper or brass) accordion-like bellows. At higher altitudes the bellows would expand and open an air leak into the manifold. Now its the fuel injectors that change the mixture (compelled by the computer etc.)

In the real old days people would have to re-jet (smaller jets) the carburettors if they drove a lot at high altitudes. I think most garages in the Rockies 50 plus years ago would have an inventory on hand of all kinds of jets for re-jetting carburettors. At 10,000/12,000 ft back then, some cars would blow black smoke like the choke was stuck on, if they were jetted for sea level.

If you lose speed at high altitudes, shift to a lower gear and floor it!

snipped-for-privacy@FreeNet.Carleton.CA (M.A. Stewart) wrote in news:hqnpto$cd9$ snipped-for-privacy@theodyn.ncf.ca:

yet my terribly underpowered 1964 Triumph Herald 1200cc sedan still made it to the top of Mt.Evans;14,260 ft altitude,with 3 passengers! [in 1971] I didn't see any black smoke,either.

it would only reach 70MPH tops on the interstate at ordinary altitudes,such as in the prairie states.

That would be my wife driving the second car.

snipped-for-privacy@FreeNet.Carleton.CA (M.A. Stewart) wrote in news:hqnpto$cd9$ snipped-for-privacy@theodyn.ncf.ca:

Vegas is 2,100 ft above sea level. Denver is over twice that. Wisconsin is

On second thought, I revise my assessment to concur with yours. OP will notice some power loss, but it's unlikely to have any material effect on his driving other than the need for more regular use of larger throttle openings. OP might be wise to turn OD off on long, steep inclines in order to prevent insanity from the constant upshift/downshift that's likely to occur.

The upside is that the car will get stronger as the OP travels downhill!

OK, what's OD?

Joe

"Joe J" wrote in news:hqo5c1$d41$ snipped-for-privacy@news.eternal- september.org:

Overdrive. Most 4-speed ATs have an OD ON/OFF button.

"Joe J" wrote in news:hqo5c1$d41$ snipped-for-privacy@news.eternal- september.org:

overdrive. or "economy" mode for the transmission. I didn't know that Accords had it. It gives better gas mileage on flat runs,but get into the mountains,and it sometimes drops out because the torque is too low for the incline,and worst case,it "hunts" back and forth.

Absolutely correct. I drove a Jeep Grand Cherokee across the Rocky Mountains National Park to what they called the highest road in the US (13,000 ft.) and knew enough to push the button to take it out of overdrive (because it did "hunt" on all inclines.) Now I own a Honda Pilot Touring, and live in the Sierra Nevada, and it does the exact same thing, and I have to push the button to take it out of overdrive. The Jeep is a straight six and the Honda a V-6, but it is almost uncanny how they are almost the same when it comes to grades. Almost always it is better to push the button and get the lower gear, with higher rpms. Also (not stated) is that, at the lower gear, with higher rpms, the pressure systems are more effective. That's hydraulics, air conditioner, etc. Y'all know this better than me. I never "lug" an engine on an incline. Always have the higher gear.

On Apr 21, 8:06=A0pm, Tegger wrote: snip

I suspect the OP may need to use 4th gear depending upon how much stuff he's able to cram into the car and what RPM he's able to maintain in compliance with speed limits and traffic.

OP might be wise to turn OD off on long, steep inclines in order

I'm guessing when the OP says '98 5 speed, he's talking manual trans.

Some pretty country up by Leadville. You might consider slowing down and having a look. In any case, Happy Motoring

Sorry, I've had manual trans since 1978.

ACAR wrote in news:e849e2ad-a0ac-4853-99b7- snipped-for-privacy@s7g2000vbk.googlegroups.com:

Heh. Yep. I read wrongly.

"Joe J" wrote in news:hqpmg8$9m1$ snipped-for-privacy@news.eternal-september.org:

I see that now. Most people these days have automatics, so I "automatically" assumed you had one too.

All but one of my cars have been manuals. The only time I owned an automatic was in 1986/87.