OK, I need some input on this. My son works at at place that makes industrial hoses. They have some surplus 4" stainless flex pipe that I can get below cost. They use the same stuff for exhaust on some of the caterpillar driven ferries down here. I am wondering about coming off the turbo with a 4" 90, a short piece of pipe, another 90 and flex pipe from there back with a flange about at the back of the cab to make the connection. What do yall think?

 

Flex will work.

However even though it is stainless, it will not offer the service life of tubing. Most of the time it starts to leak at the band clamps or in the flex seams.

We use it on semi trucks (short runs of 2 to 3 feet to connect runs of tubing or to connect the turbo pipe to the main system) and get 1 to 2 years of service life. Keep in mind any leaks under the passenger compartment can range from a slight nuisance to deadly depending on your situation.

For a quick fix or to join stacks to your tubing I would go for it. But for a system I would avoid it.

 

Flex would probably work. You may have to put some extra hangers on it to keep it from sagging or rubbing on body or frame, You will have to keep your eye on it for leaks in the seams. Flex deteriorates faster than steel pipe, but if it's real cheap it may not matter to you. I preferr to not use it for more than a vibration cusion between the eng pipe and the frame mounted pipes. You will also have to use the band clamps to seal it to the pipes.

 

I use it between my downpipe and the rest of the exhaust... I find that it reduces resonance due to vibration of the system, and it makes servicing the truck much easier... with the band clamps, you can break down the exhaust pretty quickly and put it back together just as easily.

Forrest

 

Thanks for the input. The boy is checking on the price of some light-weight SS pipe also. I like the idea of putting the flex between engine and frame mounted pipe. Another question, are most turbo exhaust 2 1/2 inches?

 

i've been running 4" flex from the turbo back for over a year now with no problems. one of these days i'm going to build a hard pipe system so i can run an e-brake. so far, no problems though. i've got my downpipe rigged more like a 2nd gen too. i had to flip the mount on the tranny the other way, but it's a lot straighter now. i'd post a pic, but i'm not allowed for some reason. if you want, i can email some.