Yost Autosport #YAE92 M3: Part 1 – We Officially Void the Warranty


We chose a Sparco Pro-ADV seat as it fit both myself and Jordan well and was easy on the budget.  Don’t mind our wooden mock-up seat base.  We had a few ordering mix ups with Sparco USA.

With the car prepped, we trekked it down to Precision Chassis Works in Gilbert, Arizona and arrived to a shop full of high quality BMW race car builds.  Given that this was the first time the car had left our hands as well as our first time dealing with Precision Chassis Works we were admittedly nervous so we had a long list of requests for the poor guys.  Being that a roll cage is a pretty permanent thing we put a lot of thought into it.  We wanted it to be minimalistic in order to save as much weight and budget as possible, but it still had to be super safe.  We wanted it to be Grand-Am legal just in case we ever had the budget to enter a race or two with them, and we wanted a design that allowed easy ingress and egress for quick driver changes as well as maximum headroom. Precision Chassis Works did not disappoint.  What we got back (in a timely fashion may I add) was even better than expected. We went with a pretty standard 6-point roll cage but the craftsmanship and details are what make this truly a piece of art. The welds are perfection and the fabrication is absolutely top notch.  They even reinforced our rear sub-frame mounts tying them into the cage, a common weak point on BMWs.  The joints in the rear X-braces and main hoop are even positioned in such a way to give maximum visibility out of the rear view mirror.

In order to save weight and cost Precision Chassis Works decided to ditch the usual stamped gussets and make the main hoop such a tight clearance that you could actually weld it straight to the body in four different points.  Talk about fabrication skills.

Another example of the talent at Precision Chassis Works.  This is the notching that was done on the rear brace mounts pre-welding.

The Grand-Am mandated “NASCAR” style driver’s side door bar protrudes as far as possible into the gutted door skin to make it as easy as possible to do quick driver changes mid-race.

Some weld porn for all of you fabrication junkies out there courtesy of Precision Chassis Works.  This is the main junction area at the rear of the roof where the main hoop, roof braces, and rear brace connect.

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