Drive Shaft

[Peeker]

The drive shaft on my MKIV is obviously very short. With my eng/transmission configuration (4.6L DOHC/T45) it’s only about 13” long. The tube is 3”. I do need to have it lengthen so they need to put a new tube in. The driveshaft shop is using a 2 1/2” tube vice 3”. Does anyone see an issue with a 1/2” smaller tube?

[Avalanche325]

Personally, I wouldn't do it unless they could show me that what they are doing is just as strong as the one with the 3" tube. If they have some calculations that show that it exceeds what you are going to throw at it, with a safety margin, I would. It may be thicker walled or better metallurgy. Some dude saying "it'll be fine" wouldn't do it for me.

I would be worried that they are just using what they have on hand. If that is the case, run away.

[Sdonnel]

Another thing to confirm is that they use the same series u-joint in the new shaft. The smaller tube will allow for smaller end components, which may in turn, require smaller u-joints. I would recommend staying with the 3 inch tube.

Scott

[Peeker]

I ended up going with the 2 1/2 tube but they used the same U joints since they were brand new.

[Avalanche325]

Did they give you any numbers? I'm curious how the torque ratings compare.

[Peeker]

No, they didn’t give me any numbers but the U joints are still going to be the weak link. It’s not like I’m running a 427 with 600 HP. I’m running a 4.6 L and this is going to be a street driven car so I really don’t think it will be an issue. I spoke to someone who has done more than a dozen of these cars and he didn’t think it would be an issue. Only time (and torque) will tell.

[Sdonnel]

No matter which tube you ended up with, I strongly recommend the Metco Driveshaft Loop. Installs easy and is built for the FFR Cobra.

Scott

[swwebb]

No matter which tube you ended up with, I strongly recommend the Metco Driveshaft Loop. Installs easy and is built for the FFR Cobra.

Scott

Strongly agree!

[RBachman]

Mike Forte' also has a nice loop. Although his requires a little drilling and tapping. Not difficult, just takes time and attention. I have one on mine and ordered it when I purchased my engine/trans combo.

[Avalanche325]

I am also a fan of the Metco loop. Bolt-in. It takes more time to jack the car up than to install the loop.

[jrcuz]

I agree, very easy to install the Metco safety hoop.
JR

[Peeker]

So I just looked up a hoop on Matco. It asks which type car but obviously you can’t put FFR MKIV in the drop downs so which one would I use?

[JohnK]

https://www.metcomotorsports.com/proddetail.asp?prod=MDL2500

[GoDadGo]

The drive shaft on my MKIV is obviously very short. With my eng/transmission configuration (4.6L DOHC/T45) it’s only about 13” long. The tube is 3”. I do need to have it lengthen so they need to put a new tube in. The driveshaft shop is using a 2 1/2” tube vice 3”. Does anyone see an issue with a 1/2” smaller tube?

Why would you want to run a smaller diameter driveshaft is what is perplexing me?

You shouldn't have an interference issue with the frame with a 3.0" tube diameter.

If you need to get a driveshaft made, we have a shop in my home down that makes them.

Let me know if I can be of any assistance to you.