Pilot cars ...

[Keith Seymore]

Originally Posted by ssl78

If I remember right every model year the stopped the year prior assembly line to build the following year car to see if anything had to be altered.

Not quite.

Typically by the time you are ready for assembly plant involvement you have already been through a couple rounds of stationary builds ("prototypes").

Current production build would continue at the present line rate; the future model year pilot builds would be introduced one at a time, and perhaps with an empty carrier in front of and behind the special build, to provide a little cushion. The new model launch team (engineering, mostly, but also program management, and the other disciplines - purchasing, containerization, logistics, quality/reliability - would also be on site) would follow the build through the process making note of any issues or problems for resolution. There is, of course, cross pollenization and sharing of learnings between the various assembly plants as well, as the model year is rolled out.

Usually there would be a couple iterations of this, one earlier and then a second right before model changeover, typically for each affected assembly plant.

By way of background, the "prototype" and "pilot" designations have been replaced with the more descriptive terms below:

Mule - hand cobbled stationary engineering build; can be from the same platform or even a different platform. For example - M/L Van (Astro/Safari) mules were built from chopped down Suburbans.

Integration build - engineering activity using cobbled or fabricated design intent parts, in the experimental build facility (GMARC, or Truck Validation Center, or at the GM Tech Center). These will be the vehicles used for overall development (ride/handling, squeak and rattle, ergonomics, powertrain, etc) and full vehicle durability/validation.

Manufacturing build - Non Saleable: assembly plant activity using unvalidated design intent parts, built down the assembly line. Vehicles have experimental VINs and cannot be sold to the general public. These are primarily for assembly plant practice, but the vehicles will go on for continued development and validation work, as well as some show duty and maybe early Captured Test Fleet usage (allowing the program team members to get exposure and normal usage miles).

Manufacturing build - Saleable: assembly plant builds using fully validated design intent parts off production tools. Vehicles have production VINs and can be sold at the end of their internal usage even though they are pre-production units. More assembly plant practice, with final refinements, show usage, and Saleable Captured Test Fleet usage.

Start of Regular Production - the real deal.

I mention all this because there has been a move to introduce the assembly plant earlier and earlier in the design process, turning what had previously been a slow, methodical, learning event into a mass production activity. I spent the whole summer in Wentzville (St Louis) one year building Integration level van bodies down the assembly line. Prior to that it would have been unthinkable.

K