3 replies to this topic

[BEN99W]

I recently viewed a video of a guy who modified an RX8 propshaft for his seven type kit car. His reasoning being that its carbon fibre construction makes it much lighter than normal steel shafts with all the associated benefits that brings.

 

Here's the vid:  

 

https://youtu.be/JLFE7Iuk9uk

 

Has anyone ever tried this on a 5 (mk1 or 2)? Seems like a reasonably cheap /easy upgrade project, but I can find no reference to anyone having given it a go despite all the track and racing 5s.

 

Have we just been missing a trick? 

 

Ben

[noobie]

As said in that video, it all depends.. the carbon tube is somewhat lighter, but the press in ends needed to run the carbon are heavier than the weld-on stuff.

 

Stock MX5 and RX8 propshafts are within 500gr of each other, but the RX8 is 20cm longer. I think the RX8 and MX5 might share output spline configs, but not sure. Would be interesting to know the RX8s pinion flange bolt pattern. Guessing its larger then ours, so that would require welding and balancing.

 

I think in the end it will be some expense and work and you'll probably save 500grams or so but not much more. If they share pinion flange specs....then it becomes more interesting.

[BEN99W]

Indeed. This is what I was lazily pondering without going to the effort of pulling my car apart and laying my hands on an RX8 prop.

I dont think I'd trust a prop I'd welded but as you say, IF the end specs are the same...

[Zed.]

I'm a great example of over-thinking and over-complicating things but altering a cf propshaft is not something I'd bother with  

to me it's more to do with if the standard item fits & works

 

is that slight weight difference going to be worth the work?

at that diameter there'll be no noticable flywheel-inertia decrease?

also, this relies on re-joining after shortening...



Rich.