Big Cottonwood Canyon Photoshoot and Near Disaster

[ninjazombiemaster]

Hey Guys,

I met up with a fellow Z driver and drove up Big Cottonwood Canyon, a 15-mile run southeast of Salt Lake City with a total elevation change of over 4000 feet.

We were up for a good cruise, and trying to get some sweet photos. Here's what I managed with my phone.

We also took another drive through Butterfield Canyon, a low elevation canyon near the copper mines in the southwest region of the valley. I haven't gone through the photos there yet. It was raining, and made for quite an exciting drive through wet, narrow, tree lined roads that are not common in Salt Lake.

My buddies car is a 280z, NA. We purchased our cars about the same time last year. Its amazing how different they sound and drive. His engines tone is very different, much quieter, revving at a higher pitch, but idles at a lower drone. Mine is very loud, and sounds more like a gigantic lawn mower.

His suspension, chassis and clutch are much more rigid. My car is soft in comparison. Neither of us enjoyed driving the other's car. His actually felt slower to me! But who knows. We didn't drag race..

Anyway, back to the story. Once we reached our turning point in the canyon, my car made it about 10 feet down before my engine died. Must've been the elevation. I turned the key - and nothing. Here I am, rolling down the canyon with my engine totally dead. Now, its all downhill, pun intended from here. It didn't hit me immediately, but without my engine on, it has no vacuum; Without vacuum, brake boosters cannot function. Here begins a 4000 foot descent down a 15 mile canyon with no power braking. By far, one of the most frightening experiences I've ever had. While I could slow the car manually, not nearly as quickly as the driving conditions necessitate. Nevertheless, keeping my head calm got me safely to the base of the canyon, where my car started suddenly and continued with no further issue.

The entire experience was captured by a dash cam.. although it looks much slower in the video than it felt in person.

[guaro]

That was a ride , glad your OK.

[SteveJ]

I'm curious, is your car an automatic? If not, why didn't you let engine compression slow you down?

Also, for it to die while running and then restart later might indicate junk in the gas tank.

[ninjazombiemaster]

Its manual. I thought engine braking was reliant more on vacuum than the compression and was negligible in effect when the engine isn't running.

Fuel looks clean. My tank should be in good shape, filter is spotless. I'm blaming the carbs at this point. Next day off I have, I'm gonna re-tune them and see if I get any insight.

[SteveJ]

Engine braking uses the engine's compression stroke to slow you down. Try it some time on a much more gradual slope.

Are your fuel lines insulated well? You may have been experiencing some vapor lock, though it's funny that the car would start and then experience vapor lock.

If it was the altitude, tuning the carburetors wouldn't help. They would need to be re-jetted. Also, you would probably have experienced sluggish performance on the way up.

As far as checking your gas, some time when you get down to a gallon or two, drain the gas via the bottom plug and see what comes out. Unless you have had the tank boiled and sealed, you might be surprised at what you get out.

[ninjazombiemaster]

Performance on the way up wasn't great. But I'll give that a try and see what comes out.

I don't believe I've ever experienced vapor lock, surprisingly. My car always starts, no matter how hot. Even when my engine is over 200 degrees, and its 100 outside. Sure does make me want AC, though. On that note, though - is it normal for the Temp to sit roughly halfway? My gauge goes from 180-250. My friends 280z would only reach a quarter of the way up. I have the aluminum radiator upgrade, as you can see, and I'm all topped off as far as coolant goes.

[gogriz91]

Might be elevation and heat, I had what I thought to be vapor lock in the center part of Yellowstone whereas I didn't have a problem down at Jackson Lake Lodge and in the valley. Got a tow, put an electric pump on to augment the mechanical and no more problems.

[SteveJ]

Performance on the way up wasn't great. But I'll give that a try and see what comes out.

I don't believe I've ever experienced vapor lock, surprisingly. My car always starts, no matter how hot. Even when my engine is over 200 degrees, and its 100 outside. Sure does make me want AC, though. On that note, though - is it normal for the Temp to sit roughly halfway? My gauge goes from 180-250. My friends 280z would only reach a quarter of the way up. I have the aluminum radiator upgrade, as you can see, and I'm all topped off as far as coolant goes.

You might want to talk to the guys at Z Therapy about what can be done to improve high altitude performance.

What temperature thermostat are you running?

[Stanley]

Aren't you glad you don't have power steering? BTW, looked like you were going fast enough. Nice Canyon.

[ninjazombiemaster]

You might want to talk to the guys at Z Therapy about what can be done to improve high altitude performance.

What temperature thermostat are you running?

Good thinking. Bruce might have some ideas. Its just the normal 180 Nissan thermostat if I remember correctly. That'd put halfway at 215 degrees. I have a small crack in the exhaust manifold that may be party responsible. Isolating the exhaust would probably be effective.

Aren't you glad you don't have power steering? BTW, looked like you were going fast enough. Nice Canyon.

Haha, yeah. Only time I wish I had it is parallel parking, but I prefer not having it.

It really is a beautiful canyon though. I have a minute so I'll see if any of my other photos turned out. I am considering an electric fuel pump. Although I don't seem to have vapor lock problems, the added pressure won't hurt, and will make certain.

[FastWoman]

Driving steep roads like that, you REALLY need to understand engine braking. You don't WANT to use your brakes (much) on a road like that, because you'll overheat them possibly to the point of failure! You should have ridden it down in maybe 3rd gear. Your spinning engine would have given you vacuum for occasional power braking.

FAIW, if I were taking that hill downhill in my 280Z, with my foot off the pedal and the engine spinning way over the 2500 RPM (?) fuel cut limit, the system wouldn't have injected fuel anyway (and therefore wouldn't technically be "running").

I'm glad you're OK. Phew!

Edited August 20, 2013 by FastWoman

[ninjazombiemaster]

Here are my favorites from Butterfield.