135 MPH driveshaft failure

ReverendDexter wrote: Again though... single data point. Has anyone heard of any other issues with these driveshafts? I mean, with the MT82 shift issues, you at least knew somebody who knew somebody who was experiencing it... this is one jackass on youtube who thinks trying to do a max speed run on a public road is a good idea.

I didn't want to add this to my post as it was long enough already, but my main thoughts when I read this are: what if this was the one driveshaft that day that was balanced, but we right on the edge of acceptable (i.e. it is redone if it is 0.10oz out of balance, but this one was 0.09oz out), then the fact that this out of balance, with the overspeed, and you have multiple things adding up to equal one broken part.

Yeah it sucks that the drivers car broke, but I would not expect warranty, nor decry the manufacturer for this failure as it was brought about by purposefully exceeding the warrantied design. I work at an industrial plant, and if we did something like this to a piece of new equipment still under warranty (i.e. exceed design values by ANY amount), the vendor would take one look at it and tell us to get lost if we asked for warranty repair (then quote a replacement part with a 30% markup).

It certainly seems odd that all the forums posting the limiter over-ride do not mention this a weak point or list much in the way of warnings.

JThw8 wrote: Because everyone wants HP and economy, there are compromises that have to be made to achieve that. There is no need for a street driven car to need to exceed 112 mph but that aside, they designed the car for an intended purpose, it was just not the owners intended purpose. The car is not under designed or E36 M3ty engineering, it functions fine when operated within the specifications for which it was designed.

What's the highest speed limit in America, 75-80?

No need to have a car that goes faster than that then. No need to drive a car with navigation, or that doesn't use diesel, or doesn't get at least 94mpg, etc etc etc

FWIW, Japanese market cars are limited to 112 or 116 MPH by law. The US has no such law. There's no point in Ford mentioning the speed limiter since it's not a legal requirement.

Cadillac makes a big deal out of the CTS-V Black Diamond wagon being a regular production station wagon capable of 200 MPH. Obviously, it's in their best interests at the time of sale to have tires etc capable of living at those speeds. Ford makes no such claim in print but they did put a speed limiter on it. The guy chose to remove the speed limiter and by doing so took the responsibility for the results on himself. I know attorneys hate like hell to hear this, but at some point personal responsibility must rear its ugly head.

Otto Maddox wrote: Why are so many people defending E36 M3ty engineering? Honda makes hairdresser cars that don't explode. So do lots of companies. I guess really it is forced E36 M3ty engineering by management. I suspect the engineers are not proud of this.

   Exactly. I'm going to play devil's advocate here, but really, what did Ford think people were going to do? You're advertising a performance coupe with 300hp for crying out loud! 300hp was super car territory not too many years ago. People without the cash to buy a GT are going to buy them and race them, drag them, autox them, you name it. They had to know the first thing people were going to do was to remove that speed limiter, especially on the manual cars.
    Also, everyone is saying that the car failed after taking it out of it's specified parameters, which is absolutely true. But isn't that what we do everyday here? Last I checked, an early 944 came from the factory with a 150hp 4 and not 300hp american v8, and far as I know the don't fall apart after you take them beyond their original specs. Heck when I was young and stupid, me and my brothers built up a 1988 rx7 turbo 2. It came from the factory with all of 165hp. When we finished the car, it put 430hp at the wheels, we beat the hell out of that car. You name it and we did it. We ran the 1/4 a few times with it with slicks and it ran a best of 11.1 and we never had a single drive line failure (Apex seals are another story of course <img src="/media/img/icons/smilies/crazy-18.png" alt="" />).  People duplicate the power of their &quot;Hairdresser&quot; Honda products all the time.
  I like to follow races like the Silver State Classic, people there remove speed limiters all the time to jump classes with different average speeds. It's especially very common with all the German cars with the 135 and 155 limiters.

In reply to zpeed7:

I think the aforementioned RPM limiter analogy still stands. Zing it to 8 grand, the motor might pop - is this Fords fault? Could they have built it with overdesigned valves, springs, rods etc? Sure, but it doesn't make it a requirement for every system. If I put 80 psi of air in my tires, they may pop. If I zing it to 8 grand, it may pop, it I drive 20 mph over the speed limiter, it may pop. I can and have modified cars the way you mentioned, but I don't yell at Chevy when their 10 bolt sheds an axle and it comes walking out the tube during a pass, it was my fault for putting that much power down (never did that, but it's a good example).

Can we be honest. The car has a speed limiter for a reason. Perhaps Ford's engineers understand that there is a limitation on the vehicle and this placed the speed limiter. A previous poster mentioned the V6 has tires rated to 112 or 118. Why would Ford expose the company to a massive liability if the speed limiter was not in place. If the drive failed during the course of normal use, I would say Ford has a fault piece or possible faulty production or design, however the part failed due to use the product was not intended for. Its not a Roush/Shelby/SVO/GT ect. Its a V6 auto and doesn't have the letters M or AMG affixed to the engine, just saying.

zpeed7 wrote: But isn't that what we do everyday here? Last I checked, an early 944 came from the factory with a 150hp 4 and not 300hp american v8, and far as I know the don't fall apart after you take them beyond their original specs. Heck when I was young and stupid, me and my brothers built up a 1988 rx7 turbo 2. It came from the factory with all of 165hp. When we finished the car, it put 430hp at the wheels, we beat the hell out of that car.

But when they fail, we don't blame Porsche or Mazda...

The slippery slope:
The V6 has enough power to push the Mustang to 150MPH. Ford finds the current driveshaft can't handle it so they upgrade to the GT driveshaft and the V6 can go all day at 150MPH. Until the tires that were only rated for 120MPH start blowing so they have to add VR rated tires to fix that issue. Now they find that driving the Mustang all day at that speed overheats the diff, so they add a diff cooler. But driving the car at that speed makes the engine run hotter so the oil ages faster so they add an oil cooler to help that. Now they need a bigger radiator. Now someone points out that the V6s aerodynamics are slightly different from the GT and the V6's front end gets a little light around 140MPH so they'd better add the aero package from the Boss 302 Laguna Seca just to be safe. But at 150mph the GPS instructions that were designed to give you plenty of time to plan your lane changes at 60mph only give you 20 seconds of warning about your upcoming exit so they add a bunch of programming to the system to give you speed-sensitive instructions instead of just the standard "in 1 mile take exit 134". Suddenly your $24,000 entry level V6 is the same price as a GT with 100 hp less, all to please 5 people who bought the wrong version of the car for their needs (and thousands of internet pundits who will decry any failure on any vehicle as evidence of a car company going down the drain). Sure some of my examples are ridiculous, but I hope you get the idea. You have to draw a line somewhere. Ford knew the limit of the driveshaft and used a perfectly reasonable solution to keep the cars well away from that limit.

Like it or not, vehicle performance is just one aspect that is taken into account when designing a car. Profit is a major factor. Without a profit, there would be no Ford. It is the profit on the V6 that allows Ford to come out with products like the Boss 302 where they're probably barely making money or losing money on every car sold. The guy obviously had no problem spending money tuning his Mustang to remove the speed limiter so he should also have no problem spending the money to upgrade to the GT driveshaft and any other part to safely exceed the speed that Ford deemed appropriate from the factory. Why should Ford lose a lot of profit giving everyone the upgraded driveshaft when only these few people will use it?

The people who get screwed are the ones who are racing V6 Mustangs in a class that won't allow upgrading the driveshaft to the GT part or another suitable replacement. Of course, every race car is going to have it's limitations.

Bob

Y'all realize that the V6 Mustang isn't the only car with a factory speed limiter, right?

Let's see, google says...

• BMW - All, including ///M cars
• Mercedes - All, including AMG cars
• Porsche - Nearly all
• Lexus - All
• Mazda - Oh boy, that'll blow your mind...

Sheesh!

Hmph. My '71 914 had a 5800 RPM rev limiter rotor, the 907 Lotus in the Jensen had a 7200 RPM rev limiter rotor. I say 'had' because the only way the electronic ignition pickup assembly would clear was if it had a standard rotor. They obviously thought enough of the thing's necessity to spend whatever extra it took. But I took it out because I valued the electronic ignition.

So would it be Lotus' or Jensen's fault if I overrev it? Sheesh.

EDIT: Per, Tom etc I did not start this thread with the intention of it turning into this kind of E36 M3storm. Please lock or delete if you see fit.

Javelin wrote: Y'all realize that the V6 Mustang isn't the only car with a factory speed limiter, right? Let's see, google says... * BMW - All, including ///M cars * Mercedes - All, including AMG cars * Porsche - Nearly all * Lexus - All * Mazda - Oh boy, that'll blow your mind... Sheesh!

I think the krauts have an agreement to limit to 155 not because the cars can't handle more like the Mustang.

I don't get the tantrum about a failed driveshaft after a driver modifies a car to exceed it's designed parameters. Mod a car, expect some carnage. Some parts will not be up to the new task. Also, the car is the first to have 300hp and get 30+mpg. That's an incredible design feat and part of that is due to light weight materials used in design and manufacture. Also, it's affordable.

Mustang modifier said: "I modified my car and then broke it!"

Btw - the V6 'Stang is pretty awesome. A friend flogged one around VIR all day long for a BFG photo shoot. He loved it. It never broke. But then again he had the good sense to leave the speed limiter in place as Ford intended

In reply to Otto Maddox:

Show me any other Mustang that could go 118 MPH, had 305 HP and was rated for 31 MPG from the factory.

The vast majority of the people who buy these cars will probably never even go close to the top speed. The people who are exceeding that are enthusiasts who will keep pushing until something breaks. They will then fix and rectify the failure point (better driveshaft) and keep pushing until the next thing breaks. If nothing does, they'll supercharge it and turn up the boost until rods go flying. Then they'll get forged rods and go until something else cuts loose.

You get the idea.

Oh, BMWs? They are limited to 155 from the factory, too. Some of them have way more horsepower than this Mustang. I don't hear anyone squawking foul over that.

I can't count the amount of stuff I've broken from exceeding the design limits. My purpose in life is to find the design limits in every mechanical thing I own. The only person I've ever been pissed at is myself.

Sounds like a lot of American car company hate to me. Where is the hate for BMW over the cheap ass cooling systems I keep hearing about or the rear sub frames that rip out of the body.

Fundamentally, I don't think that a driveshaft failure at 135 mph on a car limited to 120 is a sign that Ford screwed up.

BUT, it does seem like a relatively slim margin considering how much abuse most production machines will take in many areas, and that concerns me as someone who tends not to leave machines alone, or just drive them to the grocery store.

If this is a new norm, it would mean retraining myself to worry more about a lot of bits of a car that I would normally not think about until I was making a bunch more power or something.

I guess, in some ways, it's a little odd that the machine is engineered to survive only its hamstrung capabilities, and not its actual capabilities. Not necessarily wrong, as that could introduce a lot of requirements as others have pointed out, but it means that one is skating on thinner ice than one might think.

I'm guessing, as fuel economy and weight become more of an issue, things will be getting flimsier. That's going to go for all manufacturers.

I have a 1.5 HP engine that was designed in the 1920s. It is 4 feet long, 2.5 feet wide and weighs in at around 300 pounds. It has been running for damn near 90 years.

I have a 3.5 hp engine on a lawnmower that is 12 inches square, and weighs about 30 pounds. It won't last 10 years.

Everything new is lighter and cheaper. Most of it is designed to be just good enough. Why, you ask, because that is what most consumers want. They didn't design that car for us. They designed it for the other 98% of people that buy it. For you, they will void the warranty .

I am just wondering if a nearly new one fails at 135 how will a 5 or 10 year old one hold up? I'm not blaming Ford it just seems like an awfully small margin to me. I think this particular one was faulty or damaged. If he had kept the speed limiter and it failed in ~5 years at a track day at 105 mph then who's fault is it?

I don't think 135+ is a "low" safety margin on a 112MPH part. If I have V-rated (or whatever letter it is tires) good for 113 and they don't blow until 2 letters up (it's ~10MPH per rating, no?) I'd call that pretty damn good.

As an aside, I have experienced a driveshaft failure before. Busted u-joint on the the old FB RX-7 (225K+ miles original, natch) on a 7000RPM clutch-drop on a 1/4 mile strip. It was like run #6 in a row, too. Pretty sure I exceeded Mazda's design specs on that one

this thread needs an ignore button. i'm shocked at the hate for the manufacturer of a part that did not break until experiencing forces 45% greater than the vehicle's design limit. that's a huge margin. huge.

Did Ford honor the warranty?

ransom wrote: Fundamentally, I don't think that a driveshaft failure at 135 mph on a car limited to 120 is a sign that Ford screwed up. BUT, it does seem like a relatively slim margin considering how much abuse most production machines will take in many areas, and that concerns me as someone who tends not to leave machines alone, or just drive them to the grocery store. If this is a new norm, it would mean retraining myself to worry more about a lot of bits of a car that I would normally not think about until I was making a bunch more power or something. I guess, in some ways, it's a little odd that the machine is engineered to survive only its hamstrung capabilities, and not its actual capabilities. Not necessarily wrong, as that could introduce a lot of requirements as others have pointed out, but it means that one is skating on thinner ice than one might think.

Didn't someone already do the math that the driveshaft was seeing 50% more load at 135 than 112? Doesn't seem like a "slim" margin to me.

Meh.

Stick a long, one-piece driveshaft made out of unobtanium in a BMW, and it will go kerflooey, too. Ford did not "skimp" or use sub-standard parts or design. They built it to a price point. Lighten up, Francis.

The OEM battery in my '96 F-150 only lasted 8 years, what a cheap P.O.S.

I'm gonna complain.

Add me to the list of those who do not get the hating on Ford. The car was designed to not be driven over 112MPH...PERIOD! The fact that the engine is capable of pulling at speeds over that doesn't mean it should.

People in the US love acceleration. In order to achieve the acceleration this market desires, a certain amount of power must be available. However, a car that accelerates quickly, doesn't mean the car has to be particularly FAST. The US market also doesn't want to give up power for MPG, yet they want good MPG. Enter the V6 mustang.

It has over 300 HP. So what? That's great for acceleration. People love the feeling from light to light, People love it for jumping on highways. That's what this car was designed for...not the people who expect to go 160MPH (I mean the speedometer does read up to 160, so it SHOULD be able to do that, right?)

Someone has already given the example of the pickup truck. Just because an F150 has the same-size bed as an F350, doesn't mean it has the same brakes, transmission, springs etc.

Buy the vehicle that fits your needs or don't complain when something breaks,

Ford's fault? Lack of engineering? Seriously!!?