STIFF PROPOSITION

THE process of making a killer street machine legal is shrouded in conjecture and mythology, so when Glenn Davies of Moits Motorcars invited us along to watch the process of putting a car through torsional twist testing, we jumped at it.

The Moits team were doing this as part of a 1968 Chevy Camaro they’re constructing for Customs 4 Cancer. While the charity previously raised a stack of money for the Cancer Council when they raffled Cooper Zahabi’s Rides By Kam-built 1970 Chevy Nova, they’ve progressed to commissioning Moits Motorcars to build them a killer Camaro featuring all the go-to pro touring gear, like Forgeline wheels, Tremec manual transmission and a full Roadster Shop Spec-series aftermarket chassis.

To avoid the huge expense and convoluted process involved in engineering a car to Individually Constructed Vehicle standards (see sidebar, p. 178), Moits is setting the C4C Camaro up as a Modified Production Vehicle, and the chassis tests are a key part of ensuring the aftermarket chassis is a-okay to use.

These tests were performed on a deadstock, cherry museum-piece ’67 Camaro to set a baseline of data. “We borrowed this car from a friend, and I am so nervous about using such a clean, stock, untouched car for these tests,” says Glenn, smiling through gritted teeth. “We’ve taken every precaution, but it’s still a little tense because you don’t see completely stock ’67 Camaros anymore. We were very lucky to be able to borrow this one from a good friend!”

Moits needs the information on how a stock Camaro performs so they can later compare it to the aftermarket Roadster Shop chassis. These tests are designed to compile data that show the non-oe chassis performs just as well or better.

“When you’re doing extensive modifications to a car, like what we’re doing on the Customs 4 Cancer Camaro, there are a few different procedures to follow to make sure everything is legal when it comes time to be engineered,” Glenn explains. “We need to be able to prove the modifications we’ve made improve the car’s safety on the road, and part of that is gathering data to show how an original car performs in these same tests, so we can compare the modified car once it is done.”

The day kicks off with a beam test, which involves bolting the rear of the car to the floor of the workshop, loading ballast into the cabin and measuring the sag in the chassis from front to back. To remove any variables affecting the results, the stock shock absorbers are removed, and fixed metal braces that the Moits crew have made previously are installed to lock the car at ride height.

“We need to ensure the car is completely locked down, so we have to remove the stock suspension so that once it is on the jig there is no movement or variations going through the dial gauges,” says Glenn.

Dial gauges are spaced evenly under the sills to measure the amount of sag in the stock chassis, and these numbers are recorded in a spreadsheet by the engineer, Peter Gillard, who can draw the figures out into a curve.

Once the data has been collected, the ballast is removed and the dial gauges reset ahead of the torsional twist test, which involves mounting the front of the car to a specially set up I-beam that’s fastened to a pivot point. A jack is placed at a specific point near the end of the beam, and 340kg (750lb) of twisting load is applied to the front of the car. Dial gauges under the sills read the amount of deflection per kilo of twisting force applied, and are noted down as degrees-per-newtonmetre.

“The 750lb is worked out through an equation put forward under the National Code about how much load needs to be applied based on wheelbase and the leverage of the arm,” explains Glenn. “We can’t test the C4C car until it is complete – engine in, chassis, brakes and suspension finalised. Then we test it the exact same way.”

With the figures noted down, the Moits crew were then right to put the stock ’67 back together so the owner could come and collect it, while they got back to working on the C4C build. The data was put into a spreadsheet to be referenced later on, while the engineer took a look at some other aspects of the build’s right-hand-drive conversion, which may need further testing.

“Because this car is going to be raffled after it is finished, we want to make sure it is properly engineered, handles well and is safe,” Glenn says. “We don’t know who is going to win it, so we want to make sure it is the best it can be and will drive like a late-model car.”