Just talking on another forum about it, ive been told by quite a few people that heat rapping mild steel manifolds and down pipes promotes cracking (ive seen mongoose downpipes crack because of this)

anyone know if thats 100% true, and if so why ?

cheers

JR

 

Do you mean cast manifolds? Tubular one's just about always crack wether lagged or not.

I think it'll be excess heat from a bad set up that will promte the cracking, or poor quality in the first place.


If you heat up and cool down metal enough times, then I'd be surprised if it doesn't crack eventually.

 

its the tubular ones i was mainly talking about, ive heard alot of them when lagged promte cracking, but im not sure why ???

 

Because the heat wrap keeps the heat in which ultimately stresses the steel more..

 

I’ve only heard it shouldn’t be used when the car isn’t driven daily, because it of holding moisture.

Cant see why it should promote cracking, although it will obviously get hotter inside the wrap with no surrounding air to cool