Thursday, May 20, 2010

Ultima GTR - Building the Street-Legal Race Car


Part one is building of the Ultima GTR. Part two will be a test ride review.

The Ultima GTR is very special vehicle. Essentially a tube-frame race car that happens to be street legal, it's a kit that must be assembled. However the end result is very impressive. Take a look at their website and see for yourself. In this case, Chris Julian, a brilliant medical device inventor with over 20 patents is making modifications and refinements during the over 3 year build process while running his company, Ridge Medical, Inc. And the good news it's almost done!

The car is available as a kit for $41,000 which includes free shipping via boat from the United Kingdom. A rolling chassis is $89,000 but still needs an engine. In this case, a 505 horsepower Corvette Z-06 motor was found, still in the crate on Ebay. An ideal powerplant due to it's light weight, power and dry sump lubrication system for a low center of gravity. The rebuilt transmission is from a 1980's era Porsche Turbo which will handle the power and package nicely in the rear of the car. At a target weight of 2,200 lbs, it's power to weight ratio is simply incredible when most exotics are over 3,000lbs.

The most noticeable, and beautiful of the custom modifications is the "bundle of snakes" exhaust headers designed by the owner. Check out the video, they make for a nice exotic sound you usually only hear at historic races. This fabrication was one of the biggest challenges. Check out the slidehow of the various enhancements.

There are other quite clever modifications as well. Knowing how lousy the roads are in Northern California, not to mention driveway curbs and the like, ground clearance would be an issue at a stock 3.5". Suspension mounting brackets with remotely activated hydraulic rams extend the ride height 2" to overcome obstacles. Low speed ride height adjustment is rare even among exotics.

A fuel surge tank was added to assure properly fuel pressure during high g-force loads. An integrated datalogger was added with multiple inputs and programmability. Currently set up for fuel and oil pressure, brake temperature, engine bay temperature and air pressure under the car all with alarms in case a pre-determined threshold is reached. Fire suppression is also on this car.

It will have air conditioning, a defroster and numerous revisions to the interior including a status display. The color is a gel coat which is embedded in the fiberglass body itself which makes rock chips less conspicuous. Another step in weight reduction would be a full carbon fiber body but unfortunately is no longer offered.

The Chris's description of the kit car market is "buyer beware" but was very impressed with the build quality of the Ultima. But like any small volume manufacturer or kit car, there will be challenges in building and maintaining. The suspension must be partially disassembled to change the battery. The side pods are not designed to be easily removed despite the tube frame design. Changing the belts near the bulkhead will also pose a challenge. Keep in mind this is meant for track days and weekends, not fifteen thousand miles per year as a daily driver.

Due to the tuning required, it is not equipped with anti-lock brakes nor traction control. Forget airbags. Not dissimilar to a race car. No driver's aids, no electronic interference. More of a pure track weapon than the Dodge Viper ACR. However, less expensive but more pride in terms of labor, assembly and personalization than the new Viper ACR-X, prior generation known as the Competition Coupe.

The Ultima represents something that no longer exists from a volume manufacturer: A lightweight street car. A tube frame chassis is also virtually non-existent, now carbon fiber at a much higher cost. Electronic nannies are taking over, stability control required in 2012. This is a race car, lightweight, powerful, and just happens to be street legal. It's the ultimate track day car.

Special Mentions:

Incredibly resourceful and clever, Chris sites his father and late uncle as influences starting with their drag racing history from the 50's and 60's.

The final frame welding and finishing before powder coat was done by Thomas Chilcote Fabrication- Tommy Jr. and the late Tom Sr. Beautiful work but unfortunately the company no longer exists.

Check out the interior photos of the quality leather work done by Bascom Upholstery with special mention to John and Randy.

Lawrence Farmer was also cited as a great inspiration and reported to be one of the best race fabricators in the business and knows pretty much every historic racer/owner in the business. Additionally he's built at least a half dozen GTR's including his "Miller Racing" Ultima. Lawrence can be contacted by anyone interested in building an Ultima at (408) 483-9085

Piston Heads UK automotive forum

Building and Fabrication:

"Solid Works" is the CADD software used to model the interior, suspension, headers, and many of the 100+ custom components on the car.

"Dimension" is the manufacturer of the fused deposition modeling system (FDM) that was used to mock up many of the interior pieces

A demo copy of software from "Advantage CFD" was used to study the ground effects.

HAAS CNC is the manufacturer of the automated machining center owned by the builder and used for many of the fabricated components.

Stay tuned for Part 2 when the build is complete and the Ultima GTR is on the road.

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