Quoting from the book Gurneys Eagles the exciting story of the AAR Racing Cars, in the section on the "mag-ti" (so nicknamed for the used of the then novel materials) section on reducing the weight:
"A big challenge successfully surmounted was the crafting of the exhaust headers in titanium, reducing their weight to 16½ pounds from the 36½ pounds the steel headers scaled."
There are many pictures in the book that show them in painted white. I assume those are the steel ones used at first.
In all through the use of magnesium and titanium they shaved off 88 pounds to bring it down to 1,192 pounds from the original 1,280.
As an aside that was still 92 pounds over the 1100 pound minimum
Re: A shameless image thread for the enginephiles
Posted: 20 Aug 2018, 20:44
by e36jon
Hey gang
I feel like I started the header material debate and got us into an image-free conversation. So, as penance, here are the Ti headers (I believe.):
Let's all commit to getting our image on so the thread maintains it's awesomeness...
I think of the Eagle F1 crew being not unlike Penske in the CART days: No one was going to call them scruffy...
Roon: You would think with an engineering degree I could break down the factors of mandrel bending Inconel, but I can't. Ask me about draft angles for injection molded parts though... I'm working off of a vague memory that Inconel is much harder and less ductile than either stainless or other steels that might be used for headers, so cracking during forming is an issue. But then, how do they come to have mandrel bent sections to then cut up into pieces and re-weld into headers? I leave it to others to put this to bed.
Modern inconel exhausts use hydroformed sections welded together. I think before that they did mandrel bend them though ?
Fun fact: the exhaust primaries of the Merc V8 posted by roon on P78 used overlapping sections to act as a friction damper for the manifold.
Re: A shameless image thread for the enginephiles
Posted: 20 Aug 2018, 22:43
by e36jon
I looked around online and there are several motorsports centric places that will make Inconel u-bends for you. They all talked about the specificity of the internal support die (material, offset, etc.) and other aspects of 'doing it right'.
Id love to see a side- fired tji implemented into one, but with 4 valves, 2 on each side of the cylinder.
They look cool, but they would have to be the most inefficient head design possible!
But rock-hard reliability and an awesome and quite special sound does for me forgiving it. I have a single cylinder flathead with over forty years still running from time to time. And it always start at first try.
Ah, that's what that is. I saw one of those on a stand (with no information attached) at the Reno Air Races back in 2015 and had no idea what it was. It looked like someone had built it in a shed as a joke - it was so long and complicated!
