Yes happy, it's a good thing to do for both sound and heat. As for looks, they're hidden by the heat shield and air intake anyway, I wouldn't worry about that.
It is louder, but not by all that much. It is not the internal restrictioins that cause the heat, but the catalitic reaction that is exothermic.
Quite a while back I purchased a couple of y pipes. One from Bradan and one OEM from another F355 owner. The OEM pipe that I purchased was in fair shape. The outer shield had dents in it. I gutted the cats out of it, but decided I wasn’t going to take my OEM y pipe off because my original pipe was in great shape. Recently, I decided to take the shield off of it, have s/s pipes sectioned in where the the cats were, straighten the shields the best that I could, then have a shop fix and weld the flange. I removed the dents once the shield was taken apart. Sent the y pipe out to GP Headers who welded the new s/s pipes in and then to Enfield Auto Restoration who rebuilt the flange and welded the shields back together. I wanted to keep the OEM look.
Yes the pipe has heat insulation under the shield. The last two pictures shows the y pipe sitting on the white material, the white material is what is under the shield. Zack sent me a little extra just in case I needed it. The idea of replacing the cats with straight pipe came from one of your posts on how you thought that the straight pipes sounded better than when you just used gutted cats. It makes sense, as the exhaust flow doesn’t enter this cavernous area then hit the edge where it transitions back into the pipe as the exhaust exits. So the exhaust should flow smoothly through the pipe. Thanks for the inspiration.
They did a great job replacing and welding the pipe where the cats were and that was all they did on this project. I straightened the shield out myself. I cut the flange apart then took most of the dents out of the shield, which took me quite a bit of time. It was an experiment for me and I figured I couldn’t make the shield much worse than it already was and if it didn’t come out like I wanted, I wasn’t going to use it with the way I purchased it anyway. It was a no lose situation. However, using a cut off wheel to cut the spot welds on the flange, made a mess out of the flange in some areas. Since I don’t weld, I took the y pipe to Enfield Auto Restoration in CT, who have skilled metal fabricators who fixed the flange and reattached the shield. They did a great job with fixing the flange.
Yeah I have broken those spot welds myself on a factory header and it does make a bit of a mess of things. I think I might try as an experiment, but may be easier to just cut the flange at the perimeter, clamp together and tig weld the entire outside edge, sand/polish.
Here are a couple pictures of the shields after quite a few weekends worth of work on and off. It took me a lot of hammering to get the shield where I felt it looked decent and would consider putting it on my car. I wish I had your welding skills Jim or if you lived closer would have made the project easier.
I would have thought that trying to separate the flange would have been the best way to do it, but it turned out to be a big mess. If I had more metal working tools it might have been better, maybe? I think if I was going to do this again I would cut close to the flange on the underside of the shield and have it tig welded along the perimeter like you mentioned. Grind down any excess weld. Flange would be intact, and since it is on the bottom near the flange you could finish it to your desired level or leave it alone.
Cool stuff. I take it the only way to gut the cats on the 5.2 y-pipe is to remove the heat shields and cut windows? Give what's involved there it may be easier to buy aftermarket. What's the difference in sound? I imagine more of the F1 howl?
Not sure yet. His prices have always been reasonable. Will post as soon as he tells me, but he is my most trusted fabricator. For things he’s never done, he likes to go at it and then give me a price after he’s done. I trust him enough not to give me an outrageous price when it’s all said and done. 5.2 Y-pipe would involve more work I’d assume.
