Just some pics I ran across organizing some of my old computer pics. I took these when I took the stock DP off my 99 GTP (cut it up so I could send the cat in for $$$)

The main reason- the ubend (looks ridiculous off the car):



What it looks like from the exit end of the downpipe assembly:



Second reason- the upper part of the DP is nowhere near as large as it seem from the outside...

Crap in the inlet:



Down where the cat mounts- you can see its double wall all the way through (so its nowhere near the size of the outer pipe):




Sorry I don't have any measurements or anything, just thought these pics would be interesting for some to look at who have been considering upgrading their downpipe- or going with headers/DP.

 

I was going to make this thread after this weekend when I took my old DP off :P

maybe i'll just add to the imagery, and show what my new DP looks like before I install it

 

Here are pictures of a ZZP 2.5" 304 stainless steel bolt in downpipe with cat. To compare the old with the new

 

After seeing these pics I am definitely ordering a new downpipe and converter from ZZP. Quick question should I go with a 3" downpipe since I am supercharged?

 

its your call. i think if your gonna change your exhaust to 3" i would go with a 3" pipe. but remember, it'll just be a 3" pipe to a 2.5" outlet if you have stock exhaust. so now your disrupting flow going from 2.5" piping to 3" dp to 2.5" piping. gains will be nominal with the 3" over the 2.5". im running a 2.5" downpipe w/hi flow cat on my setup and it flows free as a bird + it sounds great.

IMO, as long as you change the downpipe you'll see results. you pick the road.

 

3" downpipe for s/c applications for sure. The 2.5" was made for the NA guys.

 

do you have any suggestions on exhaust? I've seen many people with Borla and they sound like an accord struggling. I would really like to have that deeper sound, like a v8.

 

No, not really- go on youtube and streetfire and watch videos of various 3800s to see what you like. No catback exhaust really adds any performance on 3800s, so its just up to what sounds good to you.

Personally, my impala has all stock catback, my gtp has stock mufflers w/ a res delete and cat delete, my monte is 3" w/ a single magnaflow- no cat, no res but with headers.

I don't really particularly love any of those setups. I'd say my favorite of what I have is probably the gtp, it has a very mild 'performance' sound without really being able to hear much of the engine's nastyness.