Ultimate One-Ton HD Challenge: Eisenhower Pass Exhaust Braking

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Our final exhaust brake test, this time on the Eisenhower Pass grade, was conducted down the same grade we had just climbed, and it proved to be an interesting competition. We kept many of the parameters of the test similar to what we did during our Davis Dam exhaust brake testing with just a few simple changes. We set all the trailer brake controllers to 7.0 again, knowing there could be some technical variation from one factory brake controller to another (without some type of verifiable certification, that's all we could do).

We targeted 50 mph for our tunnel-exit speed and allowed for a speed range between 40 and 60 mph, much larger than the 10 mph range with the earlier brake test. Since the Eisenhower grade is steeper and shorter, we opted to give each truck more room to work its grade-shifting and exhaust-brake controller software.

 

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Each truck had two passengers and a trailer weighing around 21,000 pounds. As in the Davis Dam brake test, the GMC Sierra 3500's more aggressive and sophisticated exhaust brake was designed to work best with the cruise control to keep the heavy loads in control. So this time we tested each truck with its cruise control on to see if it was smart enough to hold the truck and trailer at the designated speed. Only the GMC held that speed for the full run. Both the Ford F-350 and Ram 3500 just ran away until we touched the brake to slow down; at that point the cruise control was deactivated.

The GMC had the best brake-testing run down the Eisenhower grade with cruise control set at 50 mph in the tunnel; it never needed a touch of the brake or accelerator during the entire run to the Dillon exit. Top speed never exceeded 53 mph, and it never dipped below 49. Not bad, considering the GMC was running at 95 percent of its gross combined weight rating.

The Ford F-350 came in second, needing only one acceleration touch and one brake touch for the entire grade run, downshifting quickly during our only brake touch down to 3rd gear (at 3,400 rpm) which, in combination with the exhaust brake button lit, was plenty to get us down the hill comfortable, never exceeding 57 mph.

We tested the Ram 3500 in both Full and Auto settings and found, with this combined weight on this particular grade, it took five touches in both settings. Full required zero accelerations and five brake events, while Auto seemed more adaptable and in control, requiring one acceleration and four brake events.

We also took front disc brake temperatures of each truck at the bottom of the hill to determine which pickup had been working harder, and the results are as you might expect: The vehicle with the most brake touches (Ram) had the highest temperatures at 425 degrees; the Ford was next at 419 degrees; and the GMC had the lowest at 315 degrees.

Cars.com photos by Evan Sears

 

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Overview | Milan Dragway | Fuel Economy | Milford Hill Climb | Milford Braking | Davis Dam | Davis Braking | Eisenhower Pass | Eisenhower Braking | Results

Comments

I would have checked the brake controller settings by checking the voltage output with manual override applied on full braking or doing test stops using just the trailer brakes and manual override on the controller.

How can you set rules then allow everyone to break them. You said the parameters were between 40 mph and 60 MPH. Yet you allowed all of the trucks to exceed that limit with only the Ram even close.

The failure to meet your set goals makes the data useless and tends to make one believe the Ford/GMC were traveling at break away unsafe/ uncontrolled speed. Both beyond what could be considered human error. While the Ram may have just been human error depending on how long it exceeded 60 mph. Data that you did not include.

Clicking on the Eisenhower pass link brought me to this braking page. Please fix that.

The GMC held its own. Congrats to Ford on the pull for pulling as well as the tried a true bar setter, Duramax. The Duramax upgrade is sure to leave the competition in the dust in 2017. I would happily own any of the three but would only purchase a Duramax.

Rear brake temperature?

Same as comment above, I am not able to get to the Eisenhower Pass test, it just brings me to the braking test. Would love to be able to the read that! Thanks.

Seems like you got it write this time. :>)

Well, you got the headings right anyway.

I am not sure why you put the hill climb and braking data on the same page when you have different headings for both.

What are you talking about buddylam? If you're referring to top speeds for the pass, that's going up...not down. The speed restrictions were for braking coming DOWN the mountain. GM hit 53 and Ford hit 57. We're not told what Ram hit, so I'm curious what you're talking about.
Their graphics are a bit confusing though because it's combining the information from both tests.

In my life, I have never used the cruise control while towing. Nearly all of the towing I do is on roads where this is not possible (highways and country roads, not interstates).

Given the disparity between the performance of the GMC with and without cruise control at Davis Dam, I would have really liked to see that comparison here, too. I am a Ford guy, so part of this may be based on bias, but it seems like you intentionally altered the test protocol to favor the GMC.

Huge fail again as they still don't make the weights even for the trucks, in this one they only say the weights were around 21,000 pounds.

That tells us nothing and again I bet they had the Ram pulling the heaviest load.

@Ramadan little Horn 1500 - enough of the whining. You sound like a little girl who got mud on her dolly.

Your Ramistani idolatry means that any loss is massively confusing for you.

Again, the top of this hill has a sign reading "Trucks 35 mph". Please test the trucks within the scope of the speed limit and report how well they do then. Anyone blazing 60 mph down westbound I70 around there with a trailer is asking for it.

Set on 7 whatever that means?? Wtf really? How bout all on max and trailers that are the same weight for a START!... Anyway all are capable even with 500 extra pounds or so stacked on for some reason



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