Chuck Johnson’s Bonneville Adventure – Part One

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Chuck Johnson's Bonneville Adventure
All racecars need to be nut and bolted, racers slang for inspecting every critical bolt in the entire car before every event, here Chuck checks the suspension bolts

The suspension was also pretty well suited for high speed running. Because of the lack of Aftermarket development for the B12 Sentra Chuck arrived at several ingenious solutions for his cars suspension. Nismo short body, 4-way adjustable dampers were used on all 4 corners. (At one time the B12 was a popular Group A racer in Japan so Nismo developed a damper for it, but Chuck bought the last suspension parts in existence so please don’t bother Nissan Motorsports looking for some of these parts).   They were converted over to coil over springs and adjustable ride height with hardware from Ground Control using Eibach ERS 2.5′ racing springs.  The stock gushy rubber bushings were replaced with modified Energy Suspension urethane bushings made for a B13 Sentra.  Thicker swaybars from a KN13 coupe were fitted. Ground Control Camber plates were used to eliminate gushy rubber, lower the car while maintaining wheel travel and of course to make the camber adjustable.

Chuck Johnson's Bonneville Adventure
The brake system get bled with fresh Motul 660

In the front, a Fastbrakes’ SE-R Cup 4-piston caliper big brake kit handled stopping duty.  In the rear Chuck machined custom adapter brackets to accept disc brakes from a B13 Sentra SE-R. A larger bore Stanza master cylinder keeps the mush out of the system as do braided steel brake lines.  Hawk Blue brake pads were used to help stop the car from anticipated high speeds.

It would be lame to travel 1000 miles to Utah and have an intercooler pipe blow off so every coupler gets double checked

Being a seasoned road racer with NASA and no stranger to the curse of Mr. Murphy, Chuck wisely started to do preparation work on this car, which is probably the world’s fastest B12 Sentra many months before the actual scheduled event.  As always in racing, despite steadily working until the AM hours on work days, delays in parts arrivals kept the car from being completed right up to the early morning before Chuck and his girlfriend Annie Sam were scheduled to leave for Utah. 

Chuck’s car was pretty stout to begin with even before its preparation for the salt. However, racing is not the same as having a fast sano street car and the car had to undergo further modification to assure reliability under extreme conditions. Additional work had to be done in order to prepare it for safe and reliable running for over 2 miles at 150 mph at full throttle.  This is much more rigorous than your typical ¼ mile blast or illegal freeway run. These types of power demand events last but a few seconds of high boost trauma.  Top speed running on the salt means that the car will see as much as 90 continuous seconds of full throttle, full load stress.  This is like 6-7 quarter miles passes with no time for a cool down between runs.

The SR20 engine although strong has a penchant for overheating when boosted.  To prevent this from being a worry, Chuck did several things to prepare the car.  First most obviously, he installed a huge aluminum Koyo Motorsports radiator of the type favored by SE-R Cup racers.  A higher pressure Nismo radiator cap raises the coolant’s boiling point. 

Chuck Johnson's Bonneville Adventure
All vacuum, fluid and oil lines were double checked

As SR20’s are also plagued by excessively high oil temperatures Chuck had Brian Kono of Afterhours Automotive build a new lower core support which offset the radiators mounting points to the left.  The new lower core support allowed room for a large Setrab 13 row oil cooler which was mounted side by side with the radiator. This would help keep the temperatures under control during Bonneville’s extended full throttle high speed conditions.  A large capacity remote oil filter reduces pressure drop of the system and makes oil changes a snap.  Kono also fabricated new 2.5” intercooler piping and an open 3” stainless exhaust system for the car.

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