HI John,Phil tx for your insight ...... what exactly does the 150k and 90 percentile testing mean / entail ? Does Ford go over and above other mfgs in its vehicle test programs ? Tx John
I am happy you brought up this question as it has several aspects of which I will address a few.
Okay...a 90 percentile customer runs a mining company, a courtier service in Los Angeles stop and go traffic, servicing oil rigs in an oil field. In other words, beating the crap out of the truck way beyond what you would imagine. We instrument vehicles in these environments for loads, accelerations and stess/strains. From this we calculate cumulative fatigue damage and from this data we refine our durability to mirror 150,000 of the vehicles we see after the users turn them in to us. I suspect you do not beat the shit out of your vehicle every day like these users do. So 90 percentile means there are 10% worse customers that are above to which we strive to meet at 150,000 miles. This is why I am proud when 4G Rangers report 200 to 300, 000 miles in their Rangers before they sell them.
So...lets talk durability testing. This is not one truck that we test. It is program specific but encompasses quite a few vehicles. Each Prototype vehicle built goes through a sign off process.
Notice is sent to each design engineer for each vehicle to sign off their components. This is a pain for the engineers as it disrupts their day and many do not sign off the prototypes except for durability prototypes as a component failure or anomaly results in their devotion to the problem, So NVH vehicle...yeah...yada, yada...the NVH people will sort it out. Durability...not on your life will you get a pass if a problem is identified... So each prototype vehicle gets a Hoist review in the Experimental Garage. There is a documented process that each system is a go for Durability testing...maybe over time 12 to 15 vehicles depending...(numbers change per program) but not just one vehicle. Engineers visit, inspect and more importantly ensure that proper torque is applied to their attachment fasteners. Example is the rear axle suspension engineer. He/she will request a torque check on the build. Then the engineer signs off. So if there is a problem and the durability flags an issue, and there is no sign off recorded from the engineer, he will catch hell from his boss on up the chain. Durability signoffs are not take lightly or blown off for the most part.
Okay, I may have told this before...On the PN96 program, F Series redesign. I was in CAE at the time and alerted to a dash panel cracking around the brake booster. Almost impossible to see, but I recalled the Miserable Mustang II dash cracking on manual trans vehicles, I request a review of all durability vehicles...The test engineer in Arizona protested but in the end they developed a system to inspect the vehicles. Almost 95% of the test vehicles had cracks. So I marched over to the Body Engineering Supervisor...a good guy and delivered the results, which I backed up with CAE analysis. I could have taken arrows in the back but Matt had his act together, and between our CAE input and his direction to his engineers we strengthened the dash panel (I know...you call it a firewall). Today when I see a PN96 vintage vehicle on the road, I know it is a sound vehicle... PN 96 was job #1 1996, but the 96 has no bearing on model year, purely a coincidence.
Ranger Vehicle Engineering
Ford Motor Co. Retired