cast vs stainless exhaust manifold
 

cost aside, what are the pros and cons of cast vs stainless?

Easy. Cast steel is durable. Stainless doesn't rust. That's about it. If you use stainless, make sure that it's thick. It gets brittle with heat cycling unless you use aircraft stainless which is slightly softer and heat cycles much better. Most aftermarket stainless exhausts are NOT made from this though. The cast steel stuff is durable and won't warp as easily. Cast manifolds are heavier (not by much if you build the stainless strong) and last for a hell of a long time. They rust though. There are coatings now to prevent that though.

thanks traveler.

I guess what I really want to know is if one flows better than the other. For the price of stainless, I'd hope it'd flow better. Otherwise, I'd don't think "shiney" metal justifies the cost.


If you were going to make a stainless mani, would you use 321 or 340 or something else?

Why would stainless flow better? Stainless costs more because it is a more expensive material. Stainless Steel Exhaust systems cost up to double what aluminized steel exhaust systems cost, but don't perform any better. Performance is based more on matching tube diameter to the application, not material.

Flow also depends on shape. Usually manifolds that are tubular as opposed to the log style flow better.

thats not really true

monster pro5

Actually it is very true

im just saying that it depends on design, tube length, material
etc.
depending on the application and availability of space for a given vehicle
and is your definition of log style contain a 4in one set that is off to the side , ofcentered, etc
sometimes ( depending on the application ) you need that extra heat and velocity the log style utilizes for the proper heat diff. in the inlet side of the turbine and the outlet


later from monster pro5

thanks for the replies. good info

cast iron retains heat alot better, and u want ur heat in ur exhaust so it will flow faster....for manifolds, u cant go wrong with cast iron

now your talking!!