135 MPH driveshaft failure

MattW wrote: You can't have it both ways. It's either a performance vehicle or it's not. So with that in mind...

Can't have it both ways? I think that's the most unGRM thing I've heard!

Joey

MattW wrote: What's next? Brake rotors that explode off when you hit 140mph? It's a slippery slope we're going down.

They may not explode, but it is a real possibility that they will not perform properly if you are panic stopping from 140mph, or they will take that abuse once, but require repair or replacement after. Again, by using some math, a cartravelling at 140mph has 56% more kinetic energy than the same car at 112mph (E= 0.5 * mass * speed^2). That additional energy has to be turned into heat in order to stop your car. Yes, I am sure that Ford has ensured the brakes are designed for normal operation and prudent safety factors, but the reality is that when speed goes up, forces and energy increases very quickly.

One real world example of going over the design of the brakes is back home where I used to live, there are two cities separated by an 11km long mountain road and about 600 m of elevation (this is about 300ft/mi of vertical drop). The Ford P71 cop cars would occasionally have to make a quick trip down the hill and after just ONE hot trip down, they will be in the shop the next day for a complete set of calipers, pads and rotors. Most modern brakes will do a good job of slowing you down from any speed once, but to ask them to do it again may not be wise.

MattW wrote: You can't have it both ways. It's either a performance vehicle or it's not. So with that in mind... The car has a speed limiter, so have many cars over the years. I take a speed limiter as a gentlemans agreement, a way to keep the government content about OEM's making cars that are way faster than any sort of speed limit you could find on this side of the pond. Not as a way to curb design limitations on a vehicle. If the car isn't designed to go faster than 112MPH than don't give it a 300BHP engine. I mean it's a grocery getter after all? What's next? Brake rotors that explode off when you hit 140mph? It's a slippery slope we're going down.

Yeah you're sort of missing the point. For whatever reason, there was a speed limiter on the car. As an engineer you need to design around a set of criteria and add a safety factor (so you can sleep at night). The criteria for this car is Cost, Efficiency, Fun. As you now know Ford engineers have already determined that the aluminum driveshaft in the V6 isn't adequate for higher speeds than the 112mph limiter. That's why they designed a different shaft for the V8. The aluminum shaft helps get the 31mpg which to me in amazing. You can't build a car to do everything. Cheap, Fast, Reliable, pick two. And in this case (not something race cars typically consider) is gas mileage.

It is like others said, if you wanted to go faster you need to upgrade the weak links. If the guy wanted to be safe he should have investigated every part before he removed the speed limiter.

BTW I'd love to see a video from outside the car...I bet it was spectacular. Lucky he isn't dead...