Brian Kohlmann's 1931 Chrysler Coupe Blown 392 HEMI

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Brian Kohlmann's 1931 Chrysler Coupe Blown 392 HEMI

Postby scottm » Tue Sep 12, 2017 10:57 pm

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The “Fuel Coupe” is back for more action at Drag Week 2017
http://www.hotrod.com/articles/fuel-cou ... week-2017/

At Byron Dragway’s Melt Down Drags, Brian Kohlmann’s trailer/hot rod laboratory seems to be a pretty popular destination. Passersby are immediately drawn in by his ’31 Chrysler coupe’s brilliant green paint, radical stance, and chromed out, blown Hemi riding between the rails up front. When the sunlight hits the Chrysler’s panels just right, this uber hot rod’s Tractor Beam engages, and pulls unwitting onlookers in for a closer look

There is shock, awe, gasps of delight, and comments such as “stunning” from the dropped jaws of the newly obsessed observers. No doubt Brian went for that extreme Fuel Altered mid ‘60s look that so many of us just ogle over, but the amazing thing is that these typical spectators only know the half of it. They see the “sedate” part of this two-headed Hemi monster. It’s what lies below the surface that Brian’s real genius has taken over and cunningly created a Jekkyl/Hyde mannered marvel of engineering for the ages.

Yes my friends, underneath its gassed-up outer street car persona lies much more than you would expect. Sure the mighty supercharged 392 Hemi is the king of drag strip mills, and this particular one’s got that potent elephant sized punch up front. That would be enough for some guys, but we found out it’s not enough chemistry for a mad-scientist in training like Brian.

Roadkilled

A few years back, Brian built up this neat ’31 into a top performing street/strip car. Fabricated on its original frame and basted in a hot orange hue, the Hemi powered ride showed up at several top races, including 2015’s Roadkill Nights. After realizing that the potent hot rod needed some updating on several fronts, Brian took the time to reflect on the weak points of his ride while recovering from a pretty good blow to the noggin. Once the fog cleared, he knew exactly how this car was going to be reborn. He and good friend Roger “Radar” Lechtenberg had talked about doing a nitro car for the street for the past two years, and there was a partial plan in place. He just needed to put it into effect.

His idea was to first structurally bring this ride up to NHRA specs. Brian got to work immediately, and along with Chassis Service out of Waukegan, Illinois, they designed a chromoly double rail tube frame that would not only look the part of a ‘60’s Fuel Altered racecar (complete with all the necessary trimmings), but was also built to meet the NHRA’s strict safety requirements. Once the completely reengineered chassis was ready, the stage was set to do what has never been done before.

Fuel, Good Man!

Brian had raced at Hot Rod’s Drag Week in years prior, and wanted to bring something to the table that hadn’t been entered at the event previously. He knew if he could pull it off, the Chrysler would not only be a speedy spectacle out on the 1,320-foot warpath, but it would also give him an edge that the other racers didn’t have. And that edge he desired was the use of “fuel” out on the Drag Weeks selected dragstrips; nitromethane fuel that is.

Of course the main and most intimidating rule of Drag Week is the fact that race cars have to hit the road and make the trip between venues, racking up a thousand miles over the course of the week. This is what separates the streetable racers from the hordes of typical, trailered, “track only” cars (as seen on reality TV). That particular point is what makes this event one of the most competitive and awe inspiring weeks of the race season. So here was his dilemma; how do you build a nitro burnin’ Hemi that can hit low 1/4 e.t.s on the track, and then run several hundred miles on the open road to the next raceway?

Split Personality

Brian’s idea to make this work seemed pretty straightforward at first thought, though its simplicity was a mirage. Its intricate design and build had to be conquered by some major brainstorming; treading a path that perhaps no one in a flame retardant suit had traveled before. It was obvious to him that his Chrysler would have to be built to run gas on the street between events, while having the capacity to run nitro at the track. Brian decided a “dual-fuel” and “dual ignition” engine would be required.

There was no written text on the matter, no websites giving step-by-step instructions, and no YouTube “how to” videos showing the process of making a Hemi burn both gas and fuel with little turn around in the pits. Brian was going to have to blaze this trail himself.

Since he’d campaigned a blown nitro altered-wheelbase car prior to this undertaking, Brian had the experience under his belt of both building fuel based engines and driving them to victory on the track, but building an engine that could burn both nitro and gas, that’s a different story. Still, it’s a tale that Brian had the wherewithal to write. He just needed to sharpen his pencil and do his homework. He once again called on good friend and nitro expert Roger to help out. It was good to have another madman to bounce his crazy, unproven ideas off of.

Nitrosity

Nitromethane, or CH3NO2 to you chemistry buffs, is an interesting fuel to say the least. Just the whisper of its name implies danger and instability, and it has a long history of causing both havoc and destruction on an almost biblical scale. You have to be prepared for not only its best moments, but also its worst. Technically speaking it’s a liquid that is very stable on its own, but heat it or compress it and things can get pretty hairy.

With Drag Week 2016 a less than a year away, Brian forged ahead with his dual-fuel –plan, started with his original block, and added some interesting pieces. First he took an off-the-shelf, four-port, upright Hillborn EFI casting and modified it to run EFI for gas and mechanical injection for the nitro. The cam is set for optimal nitro performance, though the minimal compromise here is still suitable for the gas/street set up. Two unique ignition systems are used. The electronic distributor for gasoline/street use is in the original location at the rear of the Hemi, wired into an F.A.S.T XFi-2 control box. The magneto that provides the spark for the nitro sits on a dual drive system up front, which can be disengaged rather quickly when not in use.

The dual drive is a pretty neat device that is run directly off the cam. It also runs the fuel pump for the nitro, which gravity feeds to the pump via the Moon tank up front. The gas tank is in the trunk, along with the radiator and fan set up for cooling this beast. Relocating the cooling system cleaned up the front end and added to the look of a true 60’s Fuel Altered vehicle. An air shifted three-speed Lenco with a Bruno converter drive transfers the power to a Dana 60 rear packed with 3.73 gears. A torsion bar front suspension, built in the style of mid-60’s Fuel Altered and funny cars, adds to the period perfect look. Vintage polished ultra-rare American Racing magnesium wheels are straight out of the 60’s and capture the look to a tee.

Highway Star

Brian finished assembly, and immediately rushed his way to Drag Week 2016. After months of work, the Chrysler performed to his early expectations, figuring in the fact that there was zero time to test. The first time the Chrysler was under its own power was the day it was loaded up on the trailer for the event’s first stop in Columbus. By the end of the week, the combination came together and worked as he had planned, and Brian got it down the track like a nitro Hemi ride was intended to do.

“It was a huge milestone just to have the car drivable in a year”, states Brian. “Overall it was a huge success. There were several unproven ideas that we needed to see if they even worked. Switching from gas to Nitro and back, or even not knowing if the radiator in the trunk would keep the car cool,” he continued. It all worked, it just needed some refining after a baseline was established.

Since the end of Drag Week 2016 the hot rod has had some upgrades. Brian’s positive all the wrongs have been righted, and the Fuel Coupe is ready to take on the field at Drag Week 2017. After some more testing and more seat time for Brian, he is confident that this year, the Chrysler will hit its mark during Hot Rod’s signature event. “There are easier ways to build a fast race car, but we are determined to see this through. Running a 7.50 average for the week would be something that my co-pilot Mark Janack and I would be proud of…that’s faster than these cars ran back in the day”, says Brian. We have a feeling that this year’s Drag Week is going to be a memorable five days of racing. Stay tuned-in to the action at www.hotrod.com.


Awesome ride!

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