i want switch to close loop. using the flexpipe (from autozone) to connect from wastegate dumptube flange to 12" down the downpipe, is that acceptable? what's the pro/con of using a flexpipe? the shop recommended custom welding various J bends to fabricate a hard pipes, but is there any other obvious cons of using a flex pipe? thanks all.

 

non cons at all. you really should use some sort of slip joint or flex section because of the thermal expansion of the manifold/DP/dumptube in relation to eachother. The dump tue will stay cool until full boost then all of a sudden it will gain like 1000 degrees.

also try to make it go back in more than 12" down. something around 18-20 is good if there is room and make sure it enters at a low angle so it's a smooth transition. good luck

 

I know its old but has anybody found any cracking when not using a flex?

I do not think it is really needed when the welds are made right but i would like to here from someone who's had bad experiance running without a 1.5" flex.