View Single Post
Old 02-28-2009, 09:35 AM   #23 (permalink)
MechEngVT
Mechanical Engineer
 
Join Date: Jun 2008
Location: Richmond, VA
Posts: 190

The Truck - '02 Dodge Ram 1500 SLT Sport
90 day: 15.15 mpg (US)

The Van 2 - '06 Honda Odyssey EX
90 day: 22.63 mpg (US)

GoKart - '14 Hyundai Elantra GT base 6MT
90 day: 31.2 mpg (US)
Thanks: 0
Thanked 7 Times in 6 Posts
Quote:
Originally Posted by davidgrey50 View Post
A stupid question: Why couldn't an exhaust system (at least the cooler downstream parts) be made of aluminum. Weight is the enemy, and all that...
Structural integrity of the pipe itself aside; cost. Exhaust is a component where the steel can be very thin because the shape of the product is structurally sound (section modulus relative to the direction of loading i.e. vertical vibration). Aluminum would have to be thicker because it is weaker and it is more difficult to bend although it can be done. Weight savings would be reduced by added thickness, plus aluminum costs quite a bit more per unit weight.

The C5 Corvette Z06 used titanium exhaust pipe which was even lighter than aluminum would be plus can handle the heat as well as steel. It was even more expensive. While weight is AN enemy, in almost all vehicle applications there is a cost/benefit tradeoff that is attached to weight reduction and "exotic" unseen parts typically cost high and benefit few.
__________________
  Reply With Quote