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I don't own a fister muffler, but if I were to weld this myself, I would have to use the curved piece if I wanted a larger diameter bypass pipe. If you notice in your first pic, that pipe barely fits, and I would be suspect of the weld between the pipe and the housing of the muffler. Using the curved pipe gives you room for a better rod angle and therefore a better weld. Additionally, you can get a tighter joint welding the pipe to the side. If you had a perfectly coped pipe, it wouldn't fit as shown in the first picture. All in all..one looks like it was welded by an amateur, and the other was professionally done.
As above , welding access is easier with the curved pipe, and cutting the holes in the existing pipe is easier at that angle. The first one looks like you have to cut one pipe off the muffler and weld straight pipe on to it, cut hole in other pipe, weld pipe with bypass back to muffler and then weld bypass to other muffler pipe. Curved pipe drill 2 holes, insert curved pipe, weld.
As above , welding access is easier with the curved pipe, and cutting the holes in the existing pipe is easier at that angle. The first one looks like you have to cut one pipe off the muffler and weld straight pipe on to it, cut hole in other pipe, weld pipe with bypass back to muffler and then weld bypass to other muffler pipe. Curved pipe drill 2 holes, insert curved pipe, weld.
Originally Posted by SKM
I believe Fister uses a 1.75" diameter bypass pipe and the curved pipe is probably easier to weld.
I beleive you are both right. This was my hunch, but just wanted to see if anyone knew for sure. Thank you.
It is not necessary to remove an inlet or outlet pipe to weld a straight pipe. A local shop installed 1.75" stainless with TIG welds and it came out quite well.
Apparently, the larger diameter the tube, the deeper and richer the exhaust note. Smaller = raspier. Can anyone attest to this?
That’s a tough one to figure out. Given how small these pipes are, I don’t see how it would make a difference on tone. I would think a larger pipe might be a little louder, though.
As a hobby welder, I feel like this is the smartest/cost effective option by having the pipes "outside" the bends. Did you have any rubbing or extra heat hitting the inside of your bumper? Do you have a sound clip somewhere or video showing it installed. I think I want to do 2" piping as well.
A smaller pipe makes it harder for gasses to pass through, thus forcing the majority of the gasses to flow into the baffled chamber. The other thing to realize is there is no standard for the size hole that is cut into each pipe to accommodate the bi-pass pipe. Thus, I've looked at a lot of photos of people doing this themselves and I've seen 3/4" holes cut with jagged edges left to be fitted with a 2" pipe. Conversely, I've seen very clean 1.5" holes to accommodate 1./75" pipes. I'd say the latter would be louder. Just my non-scientific reasoning.
As a hobby welder, I feel like this is the smartest/cost effective option by having the pipes "outside" the bends. Did you have any rubbing or extra heat hitting the inside of your bumper? Do you have a sound clip somewhere or video showing it installed. I think I want to do 2" piping as well.
There is about 1/4 inch between the tube and the heat shield. No rubbing. I've taken temp readings of the outside fender and have noticed no increase in heat compared to the stock configuration. I just sold my car on Friday so I don't have a sound clip unfortunately. Upgrading to a 996TT. The sound was awesome at WOT.
The bend allows the fish mouth of the crossover tube to nicely hit the tubes they are to be welded to.
If it was straight,, it would be harder to get a nice all around fit before welding. Just my 2 bits..
01-26-2020, 03:39 PM
Fister Hack Cross Pipe Configuration Question
