stock downpipe with custom 2.5" catback

[msfamilia]

***now with installed pictures***stock downpipe with custom 3" catback

I am planning to do the above but I am worry that if the stock downpipe (=midpipe, whatever you call the one with 2 stock cat on) flange would mate with a 2.5" piping perfectly without a leak?

 

[Swerny]

With the right flamges it will be fine.
Do away with the midpipe (cat section) if you are looking for a power increase.

 

[orng1]

I had my exhaust like this for a while. 3" cat back with a 2.5" flange connected to the stock mid pipe. I was happy with it until I replaced the mid pipe to a custom 3" mid no cats. I swear all the power came from that. Now I have the CS S and J pipe to go with it. Free flowing exhaust from the turbo back. If I were to do it again I'd go mid pipe first.

 

[msfamilia]

very interesting

looks like I have to invest on the apexR1 2.5" catless midpipe.

 

[ca_deal1]

very interesting

looks like I have to invest on the apexR1 2.5" catless midpipe.

With just the cat back you are only looking at 2-4whip. But if you get the downpipe and catback, you are looking at around 7-10whp.

 

[sweetlou69]

ya man get rid of the bad stock dp..the dp or midpipe technically is where u make most of the exhaust power..the stock setup sucks

 

[msfamilia]

I am going to bring my car into Weapon-R for a S-pipe back full SS DP+catback.

Should be similar to ApexR1 design.

Will report back when it's done.

 

[sweetlou69]

good move.. i got the turboback ghl and its an awesome setup

 

[speedprotegewi]

a good friend of mine runs a muffler shop in the area and we are pondering trying chopping the cats off and replacing with a high flow cat (in wisconsin need emmisions =/) and then goin custom from that.... will i lose much by not changing the actual dp or is the big power loss from the cats?

 

[msfamilia]

a good friend of mine runs a muffler shop in the area and we are pondering trying chopping the cats off and replacing with a high flow cat (in wisconsin need emmisions =/) and then goin custom from that.... will i lose much by not changing the actual dp or is the big power loss from the cats?

I would vote for the cats.....

lets put it this way, I think you will gain more from changing out the pipe that the cats "live in" in oppose to just changing the S pipe and J pipe.

 

[msfamilia]

Got the exhaust installed.

Custom 3" J pipe back with Apex'i N1 muffler.

Would have done S pipe back if we could find the J pipe triangle flange locally.
Well, we killed 2 cats.

Car spools so much faster now and gain an extra psi from 8 to 9......
at highway speed, the noise is way too loud for my taste....... Silencer going on soon.

 

[ca_deal1]

That looks really nice ...