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


While it was down at Precision Chassis Works we also had another piece made for the car by a gentleman who happened to also be located in the greater Phoenix area.  Given that our car came with a sunroof from the factory we had to plug the hole left from its removal.  We had originally planned on replacing the entire roof with a carbon fiber piece but fortunately we found someone who agreed to make us a carbon fiber plug for the hole saving us around $1,250.  While we may still eventually switch to the full carbon fiber roof, the money savings at this stage is more useful than the additional weight savings of a full carbon fiber roof.

A bespoke carbon fiber sunroof plug cost us less than 25% of what it would cost to do a full carbon fiber roof replacement.  While the gutted roof and carbon plug still probably weigh just a few pounds more than the factory carbon fiber roof, the cost savings were much more helpful for our self-funded build.

Once the car was back in our hands it was time to break out the Sawzall and get to shedding some more weight.  Armed with a copious amount of cutting tools we got to work.  Some of the “low hanging fruit” we cut out like the rear speaker deck lid and some of the larger brackets we were no longer going to use didn’t weigh as much as we had hoped, but in the end after cutting and cutting and cutting some more we ended up shedding over 50 pounds of bracketry and metal.

Now it was onto the hard part…gutting the factory wiring harness.  Because we’re gluttons for punishment and because stand-alone engine management systems are expensive we decided to trace un-necessary wires one by one back to their source and remove them.  This process took days and it was mind numbing work.  To make things harder on ourselves we decided not to cut any wires but instead remove them from the connectors just in case we screwed up and had to reconnect any of them.  In the end though, it was all worth it as we cut out over 35 more pounds of weight from the interior wiring harness alone.  For now we left the engine wiring harness alone and there are probably even more wires we can remove from the interior harness but we’ll wait until we hear from someone that knows what they’re doing to tell us it’s okay. Once we got everything out we knew for sure we didn’t need then it was time to plug what was left back into their rightful places and pray that the car started.  Fortunately for us, it fired up first try and seemed to run without a hitch.

The final step in this first major stage of the build was to paint the interior.  This not only adds an aesthetic benefit but also helps protect the raw metal from the elements.  We chose rattle-can black as a color, because it looks good, it’s cheap, and everyone else’s race cars are white inside.  Once painted we fabricated a few small plates and panels out of aluminum to cover the center console and driver’s side foot box so the surfaces the driver would be touching would all be smooth without anything to snag their driving suits or feet on. Last but not least we fabricated a dash panel out of that same aluminum that will house some gauges, switches, and other fun things at a later date.  A final cut and fit of the dash around the roll cage and this project was officially through its first major phase.

A quick paint job to protect the raw metal finishes off phase one of this build!  The Sparco Pro-ADV seat is in (with an actual seat bracket this time), and the dash has been re-fit after the cage.  An aluminum gauge panel finishes up the interior… for now at least.

Be sure to check back for the next phase of the project which will include the first round of go-fast goodies!


Yost Autosport

Precision Chassis Works


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