High Altitude Driving

[Worker Not 0]

I am meeting up with a caravan in California and driving to Colorado for the smart Car Nationals in July. The planned route will be going up to an elevation of 12,000 feet thru one of the mountain passes. There is also a planned trip to the top of Pikes Peak - elevation over 14,000 feet.Somewhere I read that the smart diesel has a restriction for mountain driving. I thought I read it in the owners manual but I can't find it. I also tried to find the info in one of the forums but I had no luck. I would like some kind of clarification about this.Some of the solutions put forward to me are: 1. Purchase a new 2013 gasser 2. Put my 450 inside my 5th wheel trailer and take the interstates to Denver. This deprives me of the enjoyment of caravaning with a great bunch of dedicated smart car owners. Still can't make the trip up to the top of Pikes Peak. 3. Be a relief driver for a few drivers that are travelling solo.Thanks in advanceWorker Not ( Ron T)Here is the caravans itinerary: ( Subject to change) When SoCal Smarties put together a run they do it RIGHT!!!A more detailed EXAMPLE:Starting at Penny's Diner (Lunch). Dagget-Yermo Rd. and I-15. South side of road, west of Dagget-Yermo Rd. AM/PM for gas on corner (but is a cash only station - lowest price for gas from Barstow to Stateline (NV). This should be a gas stop for allNext stop - rest break at Mobil Gas Station. Just out side of Vegas on Speedway blvd. exit on right. Alamo Casino also there. 158 miles from Penny's diner - 2 hours 35 min. driveNext stop - Mesquite, NV. Turn left Falcon Ridge Parkway from I-15, Right on West Pioneer. Hotel will be on right. Many places to eat, but not many near hotel. No nearby gas stations either. At next evit off I-15 is East Pioneer (West Pioneer will run into it), there are gas stations and Casinos with Buffets. 67 miles from last rest area - just over an hour drive. Gas stop for all. 225 miles from last gas up at Penny's.Next morning leave for Loves Travel Center (Rest Stop). Right turn onto UT 130 South into Travel Center. 96 miles - 1 hour, 33 minute drive.Several 80 MPH test sections along I-15 coming up. Exit to I-70 east.Next stop - Wingers (Lunch) in Richfield, UT. Right turn on W 1300 South, then next two right turns. A gas station is nearby - everyone should fuel. 107 miles from Rest stop. 1 hour 40 minute drive. 203 miles since fill up in Mesquite, NV.Next stop - rest break - Devil's Canyon Rest area on right. Bathroom and great view of Devil's Canyon nearby. 78 miles - 1 hour, 13 minute drive.Between Salina, UT and Green River, UT is a section of I-70 with no services for 108 miles. Just warning you.Next stop - Grand Junction, CO. for overnight stop @ Holiday Inn Express. - Parachute, CO. Exit 75. Turn left onto road 215 (left turn at end of ramp). Turn left into rest area. Indian jewelry store nearby (No affiliation with said store - just noticed it nearby on Google Earth). 144 miles - 2 hour, 15 minute drive. (Grand Junction could be alternate rest stop - just easier freeway access at Parachute)Next stop - Lunch at Eagle Diner in Eagle, CO. Exit 147 and turn right. Turn right at first light and Diner is on the left. Two gas stations nearby. 73 miles from Parachute - 1 hour, 15 minute drive. 217 miles since Green River - all fuel here.Next stop - rest break - Silverthorne, CO. Exit 205 and turn right. First right turn and then left into Burger King parking lot. Just happens to be Outlet Center there also. 60 miles - 1 hour drive. (Silverthorne is just before the "tunnels")Alternate (or additional stop?) Silver Plume (exit 226 on right) is 20 miles past Silverthorne. Georgetown Loop train station Museum here - unknown if bathrooms available. Not much parking either.Next stop - Westin Westminister. I-70 to I-76. I suggest CO 287 north to CO 36 West. Exit W 104th Ave. and turn right. Very next left (Westminister Blvd W) and then right into hotel. 72 miles - 1 hour, 30 minute drive. 145 miles since last fill up.Alternate - FOR THE DRIVE - exit I-70 39 miles from Silverthorne onto Route 6. Route 6 is the original road through the Rockies that I-70 replaced. This is a two lane road mostly following a river and goes through several tunnels. Comes out into Golden, CO and goes back into I-70 - a possible side trip?

[Huronlad 186]

I would just make sure I had a full tank before heading up. The drive up will not be overly taxing on the cars, speed limit is something like 35 mph.

[Alex 21]

The high altitude restriction is because of the possibility of fuel boiling, with resultant high pressure pump damage. Listed as 2600 meters, about 8500 feet.I believe it can be somewhat exceeded except in the worst-case scenario. What is the worst case, you ask? Very high ambient temperature, almost empty fuel tank, slow speeds so less air flow over the fuel cooler, and extended full throttle operation.I have never heard of an actual problem occurring, however, so it may be more of a theoretical concern. You may well want to skip the Pikes Peak climb, and take it easy on the high passes, with a full tank to help dissipate the heat. Hope for a cool day as well.The fuel cooler is located under the passenger seat area (look for a vent in the belly pan) and a fan and/or a water spray could be added, which should greatly increase cooling capacity. But again I've never heard of a problem.

[bilgladstone 13]

Boiling fuel is the threat. Like Alex, I think it's more theoretical, but you never know. The fuel cooler grille has a simple little air dam in the middle that, by creating a high-pressure zone in front and low in back, pushes air up at the front half of the matrix and sucks it down at the back half. I wonder if you could add a small extension to the dam to increase air cooling?Yes, keep a full tank for dilution of the hot return fuel. And make sure you put in a clean, new air filter so the engine doesn't breathe so hard at high altitude. That makes a difference too.And take 'er easy so EGT doesn't go sky-high.Bil

[Worker Not 0]

The high altitude restriction is because of the possibility of fuel boiling, with resultant high pressure pump damage. Listed as 2600 meters, about 8500 feet.I believe it can be somewhat exceeded except in the worst-case scenario. What is the worst case, you ask? Very high ambient temperature, almost empty fuel tank, slow speeds so less air flow over the fuel cooler, and extended full throttle operation.I have never heard of an actual problem occurring, however, so it may be more of a theoretical concern. You may well want to skip the Pikes Peak climb, and take it easy on the high passes, with a full tank to help dissipate the heat. Hope for a cool day as well.The fuel cooler is located under the passenger seat area (look for a vent in the belly pan) and a fan and/or a water spray could be added, which should greatly increase cooling capacity. But again I've never heard of a problem.

Thanks for the quick reply Alex. I have taken off the "belly" pan a few times already. I replaced the fuel filter once and I never noticed the fuel cooler. I have driven from Los Angeles to Las Vegas a few times. At Baker California there is a 6 percent uphill grade that is about 12 miles long. I usually have to drop down into 4th gear near the top of the grade.( NEVER lug the engine and keep the revs up) Elevation is over 4000 feet at the top. I have driven this once with an outside temp. over 100 degrees F.The car water temp. got to 202 degrees F (scan guage reading) Temp "BLOBS" never exceeded THREE! Why does the higher altitude have this restriction? I know the air is thinner at higher altitudes but I thought that the turbos by forcing air into the engine compensated for this.By the way I should have included this : 2005 Passion Diesel with 60244 Kilometers.I will skip the Pikes Peak Run.

[Worker Not 0]

Boiling fuel is the threat. Like Alex, I think it's more theoretical, but you never know. The fuel cooler grille has a simple little air dam in the middle that, by creating a high-pressure zone in front and low in back, pushes air up at the front half of the matrix and sucks it down at the back half. I wonder if you could add a small extension to the dam to increase air cooling?Yes, keep a full tank for dilution of the hot return fuel. And make sure you put in a clean, new air filter so the engine doesn't breathe so hard at high altitude. That makes a difference too.And take 'er easy so EGT doesn't go sky-high.Bil

Hello again BillI few years ago you supplied me with instructions on how to force the A/C to stay on permanently so it wouldn't cycle on/off during acceleraton. Thanks again!I use a K/N reuseable filter. Is there a guage available to moniter the EGT (Exhaust Gas Temperature)?I will be looking into installing a small fan and some way to spray a mist with your suggestion of a dam extension.

[bilgladstone 13]

A related question: does cooler fuel yield better combustion, power, or fuel economy?

[Alex 21]

Why does the higher altitude have this restriction? I know the air is thinner at higher altitudes but I thought that the turbos by forcing air into the engine compensated for this.

Nothing to do with what happens in the cylinder, or anywhere except the low pressure fuel system, in the tank and the low pressure pump. Water boils at a lower temperature at altitude, same with fuel. The fuel system on a common rail diesel generates quite a bit of heat in the fuel, and under extreme conditions can lead to the fuel actually boiling in the tank. Boiling fuel will prevent the low pressure pump from feeding the high pressure pump, leading to a stalling car and a possibility of pump damage.I really think the precautions mentioned above will keep you from having trouble, as long as the day isn't a real scorcher and you skip Pikes Peak. A water spray onto the cooler is rather excessive, unless you really want to bag Pikes at full throttle. The theory is sound, but I wouldn't worry about it.

[Worker Not 0]

Thanks for the replys Bill and Alex. I still have a few months to ponder about what I am going to do about taking this trip. I will keep you posted.thanks again.Ron T