Rocky Mtn driving-power loss?

Going on cross country trip next week from Vegas to Wisconsin via I-70,
Denver, Rockies etc. I have a 98 Accord, Vtec, 4 cyl, 5 speed. The last
time I made this journey it was from East to West and in a 5-speed, fuel
injected, 84 Saab and it struggled up those inclines.
Anyone have experience with 4 cyl Hondas driving through the Rockies? I'm
not pulling a trailer but the car will be loaded with household boxes.
Well, as many as you can put in a coupe anyway.

Thanks,

 

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!

 

(M.A. Stewart) wrote in

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.

--
Jim Yanik
jyanik
at
localnet
dot com

 

That would be my wife driving the second car.

 

(M.A. Stewart) wrote in

Vegas is 2,100 ft above sea level. Denver is over twice that. Wisconsin is
1,000 ft or less.

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

 

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

 

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.


--
Jim Yanik
jyanik
at
localnet
dot com

 

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.

 

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.

 

Heh. Yep. I read wrongly.

 

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.