I wonder if anyone has ever hydro formed aluminium? Be nice to make a few expansion chambers, but might be difficult/impossible using aluminium rather than steel?
Must be possible using certain alloys of aluminium as quite a lot of modern mountain bike frames are shaped using hydroforming.
My opinion is that most alumnium grades will not be malleable enough to deform enough for what you want.
I dont beleive Aluminium will be able to withstand the temps an Expansion Chamber will endure. If it was all the race teams would be using it. Hence why they use Ti
Chevrolet do it as a matter of course for their Z06 and ZR1 Corvette chassis rails. Not sure if hydroforming is done on the Else too, or if it is just a load of extrusions bonded together.
Ally for tailpipes/silences on trailbikes. Never seen an ally header, expansion chmber or link pipe because the gases are hotter (900deg+) than the ally's melting point (660deg).
Sometime in the 90's Pro Circuit were producing aluminium front pipes for 2 stroke MX bikes. I don't think i ever saw anyone racing with one though and they only seemed to be available for a year or two.
From what i remember FMF might have made them too.
I'm sure they were stamped out and welded up at the seams.
Any particular alloy in mind? What sort of wall thickness were you thinking of? The only potential problem i can see with hydroforming is the HAZ behaving differently. Should be easy enough to fix that (if it is an issue) by annealing the entire thing before or after welding- gonna get annealed the first time the engine is run anyway!
As Pete and Shox i'm thinking it wouldn't last long... if some OE manufacturers are using ally exhaust pipes close to the exhaust valve i'm thinking (alright, guessing) there must be something else going on too like ceramic coatings Would the thermal conductivity of aluminium not mess with things from an exhaust design POV? i.e. effectively 'sucking' energy from the exhaust gases
Will give it a go...........material will be annealed before forming, and I guess its just a matter of trying it and seeing if its a feasible way to make pipes? As to heat a couple of people I know have used aluminium header pipes on 4T trials bikes with no problem, and while EGT on a road going machine may well be too high for alloy pipes, they have been used on trials bikes for many years without any issues.
I would imagine the biggest problem to overcome would be the issue of work hardening and fatigue strength when using aluminium, certainly for an expansion chamber. Make it out of ali thick enough to resist damage and everyday use, almost back to the weight of steel.
hahahaha I've dealt with the yanks for 20yrs in MX and MTB. They might come out with this sort of stuff, but from experience it never works, lasts, or does the job.
If they were any good, or stood up to the job every ****ing MX bike would have them on
Maybe Honda need some advice from the experts on here about aluminium exhausts not working? Heres a few Honda models which have them fitted TLM, RTL, 315R, 4RT.
At last. Why the hell did that take so long for you to furnish the info. It's been said to you before! Why the secrecy? It doesn't help you one bit. This is a forum to disseminate information, something your posts lack.
So more info please
How old are these bikes? 80s 90s
Supply a list of bikes produced within the last 5 yrs with Alloy headers?
Better still supply a list of 2 stroke bikes with Alloy exhausts? That last more than 1 race