Video: Setting up Grimace's rear suspension for peak traction

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Project cars always throw up plenty of challenges, especially when they’re as heavily modified as the twin-turbo, Dart LS-powered VS Commodore ute we call Grimace.

We were hoping to have it singing on the dyno with Adam Rogash at MPW Performance & Race Fab in this episode of Carnage, but the ute decided to fight us at every turn.

Scotty first had to sort the radiator hoses, which turned into quite a faff. With all the intercooler piping in front of the motor, it required some intricate routing to get the cooling plumbed up properly.

Scotty also changed the wastegate springs in our TurboSmart ProGates wastegates. They came fitted with base pressure springs of 14psi, which is a bit too wild for a 427ci behemoth.

TurboSmart gives you a bunch of springs with wastegate kits, so Scotty switched them for much tamer 7psi springs. They’ll make it much more manageable on the street, and still allow us to run in the 20s for boost pressure with no problem.

Another major roadblocks to getting on the dyno was a trigger issue, which was eventually whittled down to the trigger sensor on the front of the engine being spaced too far out from the trigger point. It wasn’t reading correctly, causing rough running. Of course, you can’t dyno tune a car without a solid timing signal.

On top of that, the water pump also started leaking. The last thing you want to do is rush a car to the dyno half-done, so Scotty elected to pull the pin on the dyno session for this week so he can dial the car in right before it gets strapped down.

While the lack of dyno action was disappointing, Scotty and Adam decided to corner-weight the car to see how it sits now with all the go-fast gear in it.

They did the same when the car was still a V6; back then it came in at around 2910lb (1320kg). With its new engine, turbos, nine-inch, Powerglide and big rear tyres, she’s only ballooned to around 3214lbs (1457kg).

Adam was happy with the weight distribution for a ute, too. He also showed us how he sets up the rear end of a car like this using fancy software, as he does with all of his fast stuff.

For example, anti-squat calculations will compensate for separation of the VS’s radial tyre. In a nutshell, it’s all about optimising the rear end for peak traction and the best-possible ETs.