[mikek6]

Found out yesterday that previous owner put 3" pipe from cat back to rear axle /ubbthreads/images/graemlins/crazy.gif

What is best thing to do for replacing with 3 1/2"? Is it advisable to use clamps for replacement piece since i don't weld?

How has that smaller dia effected my performance?

Thanks,

Mike

 

[DBogo]

yea either bump it up to a 3 1/2 which came stock or a 4. the smaller diameter isnt flowing the amount of exhaust that it should and your EGT's are most likely higher, you could use clamps not a bad route to take, if you dont weld you could ask someone to help you who knows how to weld, i welded mine. but if you dont know anyone who welds clamps will work fine just make sure you get them good and tight

 

[helixhippie]

Yeah, it'll effect your flow some.
Does it have the stock downpipe? The 94-97 PSD vans had no cats. One option is to order what's called a van "starter" pipe that has the same shape front flange as the factory cat. They are 4" & you can continue back in 4". Eliminating the muffler will make it sound good, not too wild like a gasser.
Easiest thing is to order a complete 4" system from someone like Dale at Tymar Perf. & start at the turbo if you want increased power & economy.
Good clamps are ok if you don't weld. I used the stainless band style clamps that you can see in my pix.

 

[ratio411]

Re: PSD Vans

My 95 and 97 E350 Supers both had cats. The piping is all 3.5" as well. The down pipe is much larger and complete though, compared to my 95 F350.
Clarify what year 'starter pipe' is needed, I might like to put that in place of my so-so welding job to make a !cat pipe.
Dave

 

[bullridin_fool]

Re: PSD Vans

the 96 e-350 bus i have also has a cat on it /ubbthreads/images/graemlins/shrug.gif it did come stock with a full round 3" downpipe though /ubbthreads/images/graemlins/biggrin.gif