141.99 MPH With A Trailer!

The Ultimate Tow Test!

The Diesel Power Staff
Feb 1, 2013
Photographers: The Diesel Power Staff
At one point or another, most diesel enthusiasts have towed something. Whether it’s a tractor towing a hay wagon at 5 mph, or screaming down the freeway at 80 mph with a fifth-wheel, having a trailer behind us is something we can all relate to. So we set out, nearly a year ago, to prove that diesels can tow better than anything else by breaking the current land speed record while pulling a travel trailer. Before we get into the attempt, a little history. In the ’90s, British automotive journalist Mark Walton drove a Dodge Viper pulling a travel trailer (also known as a caravan in other parts of the world) to 126.7 mph to establish a modern World Record speed. In 2002, a highly modified escort rally car bumped the record to 128.8 mph. In 2003, the record took a big jump, as the combination of a 2-mile-long South African runway, a 700hp twin-turbo Mercedes, and an aerodynamic caravan meant a 139.11-mph record.
Photo 2/21   |   1302dp 01 141
The record had stood at 139.11 mph since then, but not for a lack of trying. The British-based TV show Top Gear tried to break the record (then at 128.8 mph) with a modified Mitsubishi EVO, only to run 125 mph before blowing up the engine. More recently, an unnamed European company attempted to break the 139-mph record with a Porsche Cayenne S Turbo, only to have its aerodynamic trailer come off the ground at speed! In the last few decades, the record had moved around from Australia to Britain to South Africa, so it’s clearly an international record—and not an easy one to break!
The Plan
We needed a plan if we were going to tow faster than anyone else on the planet—and some crazy friends to help us along the way. We found those partners in Pacific Performance Engineering (PPE) and Carson Trailer, which builds a wide range of campers, car trailers, and toy haulers. For our haul truck, PPE would be bringing The Sleepermax out of retirement. The truck already had aftermarket connecting rods and pistons to make it survive at its 744-rwhp state, but for record-breaking speeds, additional horsepower had to be on the table. To that end, the GT4094 and GT45 turbochargers were swapped out for PPE’s big compounds—mammoth GT4202 and GT55 turbochargers—along with dual wastegates to keep boost in check. A set of Exergy Engineering injectors provided 100 percent more fuel capability than stock, while a Nitrous Express (NX) dual-stage nitrous system was on hand in case we needed the extra horsepower.
Photo 3/21   |   The engine that powered this ’06 GMC to the record was built by Pacific Performance Engineering (PPE) and featured a number of mild and wild parts. Things like coated pistons, billet main caps, and a performance cam were skipped, but the engine did receive connecting rods, PPE’s pistons, ported heads, Dual Fuelers, and PPE’s Race Twin turbo kit, featuring 75mm and 106mm Garrett ball-bearing turbochargers. Horsepower checks in at 1,004 rwhp on fuel, and an estimated 1,300 rwhp with nitrous.
For the trailer, we were understandably worried about aerodynamic stability, sway, and the trailer otherwise getting loose on us. To complicate matters further, we couldn’t use any type of sway control for the record attempt. In an effort to remain aerodynamically neutral (no lift or downforce), we chose the Carson Kalispell trailer. It was light, used a single axle (less rolling resistance), and was of 140-mph build quality. The Carson trailer was a perfect embodiment of a record-setting trailer in that it was compact (only 7½ feet wide and 10½ feet long), but it retained full amenities, including a bed, fullsize refrigerator, and kitchen appliances—all for about $10,000.
Choosing Tires
Our greatest fear during this attempt was crashing at 100-plus mph, so we spent a whole lot of time researching where the rubber meets the road. After speaking with many different manufacturers, some of which simply said “No way!” we finally settled on a set of 305/50R20 Toyo Proxes ST IIs mounted on 20x10 BMF wheels. The height of the tire would increase our overall gear ratio and give us plenty of rpm for 140-plus speeds, while the 20-inch wheel diameter would give us a smaller sidewall for more stability and a greater weight rating. Considering we’d be hustling a 7,000-pound truck along at triple-digit speeds while towing a trailer, all of these were very desirable traits. The final piece of the puzzle was speed rating, and since the Toyos are rated at 149 mph, we knew we’d be safe.
Photo 4/21   |   Wheels and tires were of utmost importance for this project, so we were very careful when it came to picking them. Four 305/50R20 Toyo Proxes ST tires were mounted on 20x10-inch BMF Novakane wheels finished in Death Metal Black. The larger-diameter wheel enabled us to pick tires that were load-rated to 3,086 pounds each, yet still had a speed rating of 149 mph.
The trailer tires also had to be specially ordered, as traditional trailer tires are built for strength rather than speed and are actually only rated for 65 mph. For the trailer, we selected tires originally meant for a heavyweight sports sedan—a set of Goodyear Gatorbacks. They were rated for the speed we wanted to go, and each could support 1,477 pounds of weight.
Doing the Math
With the truck and trailer prepped, we had to make sure we could actually break the existing record, and that’s where a fair amount of math came in. While we could have lowered the truck, put on racing tires, and made numerous aerodynamic modifications to make it look like a pure race vehicle, we decided to see if we could break the existing record just as one would normally drive down the road. After all, as former Editor David Kennedy said: “Race vehicles look like a race car driver could drive them…a normal vehicle looks like anyone could drive it.”
Photo 7/21   |   We were somewhat worried about how the Carson Kalispell trailer would hold together at more than 140 mph—especially with a front window—but the crew at Carson told us not to worry, they build a solid product.
So if we were going to eschew the aerodynamic modifications, we needed a way to figure out how much power we’d need to move our brick towing a brick through the air. For this, an online calculator (www.rbracing-rsr.com/aerohpcalc.html) proved very helpful. While we also used three or four other computer programs to back up the math we found on RBR’s website, the calculations said we’d need more than 1,000 rwhp to go 140 mph, based on a drag coefficient of .60 (which is bad) and a frontal area of 75 square feet (which is even worse). As it turned out, RBR’s calculator was almost dead-on.
140-mph Towing: How it Applies To You
When we first introduced the idea of high-speed towing months and months ago, we got a whole flood of letters supporting our attempt, but we also got a surprising amount of backlash. “I have no idea why you’re doing this, I just want better fuel economy,” one reader wrote. Another indicated he didn’t think anything we did would apply to him.
As it turns out, virtually everything we did to break this world record can be thought of in normal, over-the-road terms. Aerodynamic load and drag holds a direct correlation to fuel economy. Building an efficient engine is another key to both towing with power, and fuel efficiency. While our EGT limit was sufficiently higher than we’d ever recommend to anyone, there are similarities there, too. While you might not tow with nitrous, well-matched turbos (especially compounds) are very important to towing combinations. Load and speed rating of tires are a direct crossover, as is trailer tongue weight.
We didn’t just do this stuff because we could—we did it for all you readers, too. While you might not want to tow at 140 mph, everything it took to get the truck and trailer there can be directly applied to a normal, 55-mph towing effort.
Testing for the Record
Testing for the record was one of the hardest parts of the whole ordeal. The dragstrips wanted no part of us, and even a retired airstrip didn’t want us on their runway. “You need 3,000 hp to do it, plus, you’ll crash through our fence and die,” was their general opinion.
Photo 10/21   |   Before our first test pass, a last-minute check was made to ensure all the lug nuts were tight on both the truck and trailer, and the tires were all at maximum pressure (50 psi).
What we knew we could do, though, was test the truck and trailer independently, so that’s what we did. In testing the truck, we ran some 12-second passes at Fontana Speedway on the low-boost nitrous tune-up and also made some dyno pulls, hitting 634 rwhp at 38 psi, then 818 rwhp on one stage of spray. A final test run, with more fuel at 60 psi, yielded a wild, 1,004 rwhp at 60 psi— without nitrous!
As for the trailer, we mostly tested it behind our ’95 Dodge Ram known as Project Triple Threat. We found we could hit 100 mph pretty easy, and the trailer remained stable—even after emergency freeway lane changes. In talking with Carson Trailer’s David Endres, we were told the optimal hitch location was a few degrees below level, and our trailer tongue weight should be about 15 percent of the 2,700-pound total.
Finding a Venue
After months of building, testing, and math, we still had to find a place for the attempt. The existing 139.11-mph record had been set on a 2-mile-long South African runway. But before that attempt, the team had gone 120 mph on a mile-long runway. Since the Diesel Power magazine effort had a lot more horsepower but a lot more aerodynamic drag, we felt it would take about 1½ miles to reach our top speed, with another ½ mile to stop. So we set our sights on an arrow-straight road of 2 miles or more, which is actually pretty hard to find here in the Los Angeles area. Initially, we planned on running out at El Toro airfield, but they said they lacked the room. The El Mirage dry lakebed got dismissed because of drag and traction, and a 3-mile-long road up in Lancaster, California, was out because of the cost of shutting down a public road. So we arrived at the Mojave Air and Space port, a 2-mile runway located in the desert north of Los Angeles.
Photo 11/21   |   We noticed some oil on the ground, and with 2,000 degree EGT, we were very concerned we had blown something up. As it turns out, the Garrett ball-bearing turbos, as well as the rest of the engine, were still just fine.
As it turns out, our luck was doubly good, as MKM Racing Promotions was holding its annual event, The Mojave Mile, a standing 1-mile event that measures a vehicle’s exit speed. The event coordinator, Mike Borders, was surprisingly receptive to our crazy idea and said that given the proper tires and some safety equipment, we could at the very least make a few 120-mph test passes there. Then tragedy struck. At a private event before the Mojave Mile, an older gentleman had a heart attack and died at the wheel of his Ford GT, leaving the car to spin off track at more than 200 mph. The airport was understandably concerned and told Mike they would be enforcing the rules with an iron fist. “Well, there are a few journalists who want to try to go more than 120 mph while towing a trailer,” he admitted, and that was it…the day before our scheduled run, we were sunk.
Trailer Specifications
Price: $10,000
Size: 7 feet 6 inches x 10 feet 6 inches x 10 feet
Weight (empty): 2,670 pounds
Max weight (loaded): 5,200 pounds
Fully Self-Contained
Fullsize Refrigerator
6-gallon Water Heater
Insulated Walls and Ceiling
Quality RV/Marine Battery
18,000 B.T.U. Furnace
60-amp Converter with 12-volt Battery Charger
Air Conditioner Pre-Wiring
Heavy-Duty Axle with Electric Brakes
Great Ground Clearance for Traversing Backcountry Roads
During the months following our last-minute cancellation, we were busy with Diesel Power Challenge, and the magazine. Despite having most of our needs met, we still lacked a location, and the ambition. After all that effort, we had nothing to show for it. Perhaps the final piece of the puzzle came when David Kennedy mused to Associate Editor Jason Sands: “Well, we have a running truck and a trailer. If I made you do it next week or you’re fired, what would you do?”
After careful consideration, we knew the answer had to be El Mirage Dry Lake. It wasn’t perfect, being that it was a dirt surface, but it had the space we required and was affordable. It was then that everything came into focus, and we knew our attempt was to be made at El Mirage.
Truck Specifications
Price: $80,000 (est.)
Year/Make/Model: ’06 GMC 2500
Owner/Hometown: Joe Komaromi; Fullerton, California
Engine: 6.6L Duramax diesel; ARP head and main studs, ported heads, Carrillo rods, and PPE pistons
Air: PPE compound turbos; Garrett GT4202 and GT5533
Fuel: PPE dual fuelers and 100-percent-over injectors
Programmer: PPE Hot+2 E.T. Race and EFILive
Transmission: Prototype PPE Stage 6
Suspension: Cognito steering braces and tie-rod sleeves
Wheels and Tires: 20x10 BMF Novokane, 305/50R20 Toyo Proxes ST II
Performance (calculated without trailer)
0 to 60 mph: 2.5 seconds
Quarter-mile Time and Speed: 10.8 seconds at 136 mph
Top Speed: 206 mph
Final Testing
Before our official run, David from Carson Trailer and Corey Macha from PPE met up with us at El Mirage to do some testing. We unhooked everything and went 104 mph on a test pass. Then we hit 125 mph with the truck and trailer—matching Top Gear’s attempt—while keeping EGT less than 1,600 degrees, and without using nitrous. Our official run needed us to go 15 mph faster, and we knew those last 15 mph were going to be tough.
The Record Run: Break it, or Bust The Truck Trying
It all came down to one day. We’d hired a timing official to set up timing lights at El Mirage. We had the truck, trailer, and a crew of about 30 people giving support and help in any way they could—from photography to changing nitrous bottles. Associate Editor Jason Sands explained the day of the attempt from the driver seat:
Photo 12/21   |   Success! We’d blasted by the record. We brought the truck and trailer back around to our timing area for inspection.
A lot of people were asking me if I was nervous before the run, and I was, a little, but I got through most of the jitters the night before. At that moment, I was just aware of what it was I had to do. I knew I needed to manually shift the truck, hit both stages of nitrous, and keep an eye on the EGT gauge—all while keeping the truck between the cones. I had practiced on dirt before, so I knew the truck and trailer were going to wander a little at high speed. The wandering isn’t so much of a sway, but more of a quick darting motion from side to side. Overcorrect, and I could cause a spin. Undercorrect, and the truck would make its way off course. Steering motions are made in quick flicks of the wrist rather than big, sweeping gestures.
Photo 13/21   |   “I just need a little more!” Associate Editor Jason Sands can be seen saying to PPE’s Cory Macha. Between runs, Cory swapped out nitrous bottles to another full one to maintain proper bottle pressure for the second attempt.
With all of this in my head, I strapped in, put my fire jacket on, took a deep breath, and lowered the visor of my helmet. The timing official signaled that the course was clear, and I was off. The first run was mostly a test of the course, and I found that a little past a quarter-mile in was a pretty big bump that upset the truck and trailer. I lifted to about half-throttle (lifting all the way would’ve upset the vehicle even more) and then rolled back in it. I kept EGT at about 1,600, and then powered through the traps without activating the nitrous. It was pulling, but not much, and when the timer yelled out “120 mph!” I felt a sinking feeling. I wasn’t sure if we would have enough to beat the record, even with the 10 percent extra fuel that Joe Komaromi from PPE had put in the tune the night before.
There was nothing to do now but crack the bottle and see how far two 0.080 jets of nitrous could push us. This time, I waited until after the bump to nail it, but as the truck accelerated, the steering corrections I had to make multiplied, and by the last ½ mile of the course, I didn’t feel it was safe to take my hand off the wheel to grab the second stage of nitrous. I was movin’ as I went through the traps, but in the desert speed is hard to judge. If you would have told me I was going 130 mph or 150 mph, I would have believed either. I took a quick glance at the EGT gauge as I headed toward the last quarter-mile and saw it was buried at 2,000 degrees. All I could think about was not crashing and mentally preparing for the engine to let go. Surprisingly, neither one happened, and the truck blistered through the traps at full power. As I came back to the timing tower, the crowd was giving me the thumbs-up. “You beat it!” they yelled. The official speed was 139.33 mph. I had eeked past the record by a mere .2 mph.
Photo 14/21   |   Since most trucks don’t go 140 mph in four-wheel drive, we figured the front differential was having trouble with the extreme speeds. After our first run, we noticed a good bit of oil had been flung out of the vent tube on the front axle onto the ground and onto our BMF wheels. This worried us somewhat, but with the trailer spinning the tires at 80 mph in two-wheel drive, we knew we had no choice other than to run it in four-wheel drive for one more pass.
I left the truck running so it could gradually cool down and talked to the PPE crew about the attempt. I told them I had seen 2,000 degrees on the pyrometer and asked if they wanted me to make another run. Joe Komaromi shrugged and simply said, “If we’re going to blow it up, now’s the time. We still have the second stage left.” That sounded like a yes to me, so I suited up for the next pass.
Photo 15/21   |   The record setting crew from left to right: Timers Alan Rice and Mike Cook; David Endres from Carson Trailer; Driver Jason Sands; Joe Komaromi from PPE; Sean P. Holman, Editor of Diesel Power Magazine; David Kennedy, Publisher; and Dan Grant and Corey Macha from PPE.
On the third run, I waited even longer to make everything happen. I turned on the first stage of nitrous, shifted into Sixth Gear, grabbed the button for the second stage, and held the truck and trailer at about 110 to 115 mph. I waited for a full 15 seconds before nailing it and hitting the button for the second stage and powering through the traps for the last ½ mile. I could hear the engine working hard and was pushed back in the seat as the second stage hit. I felt the truck hit an aerodynamic wall rather quickly, but it just felt faster than the previous run. As I returned to the pits, everyone was cheering again. We’d broken the 140-mph barrier—and beaten the record by a full 3 mph, to the tune of 141.99 mph.
Photo 16/21   |   Since we were shooting for an official record, we had timers from the Southern California Timing Association come out and measure our exact speed, down to the third decimal place. We also had GPS on board, which backed up the official time with a 142-mph reading.
After the champagne celebration, you might be thinking we loaded everything up and went home, but that actually wasn’t the case. We took the PPE Duramax, loaded in the freeway-friendly tune, and went out to dinner: truck, trailer, and all the hardware. As we pulled into the parking lot of a burger joint and ordered our food, we looked back out at the dusty truck and trailer in the parking lot. It was then that it hit us that we had just gone faster than anyone else on earth with a trailer a few hours ago and were now taking the same four-door truck out to dinner. And it doesn’t get any cooler than that.
Photo 17/21   |   Editor-in-Chief Sean Holman captured this shot of the ’06 GMC and Carson trailer blasting across the desert at triple-digit speeds. Or more accurately, at 141.99 mph!
Top Speed Comparo
To put this accomplishment in a perspective of speed, we’ve included a few handy graphs. Our 141.998-mph trailer record nearly tripled California’s 55-mph speed limit, is close to double the 85-mph Texas speed limit, and beats a stock Duramax’s top speed by a good 40 mph. The trailer record is even within 30 mph of the current production-bodied diesel record, which we probably could have demolished if we had unhooked the trailer.
In fact, using the same aerodynamic calculator we used to predict our top speed with the trailer, along with an estimated 1,300 rwhp, puts a re-geared PPE/Diesel Power Duramax’s top speed at 206 mph—faster than the Audi R10 race car! Whether we would want to drive a 7,000-pound truck at that speed is another matter all together.
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Fullerton, CA 92831
Nitrous Express
Wichita Falls, TX 76310
BMF Wheels
Orange, CA 92867
Carson Trailer
Gardena, CA 90248
Toyo Tire
Cypress, CA 90630



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