Exhaust Experts Chime In Please

[1stChildhood]

Strictly for reasons of somewhat louder sound, and appearance sake, I am getting ready to order the new Borla cat-back split rear system. It grates on me in a way to spend this much for a basically non-HP increasing mod, but the above 2 factors are apparently important to me.

What I am wondering is this: Since the factory system has pretty good flow anyway, and some people in this forum are actually reporting a slight loss on the dyno with some aftermarket systems---

Is it actually likely (I guess it's theoretically possible, like with no exhaust headers at all, hence no scavenging) to have too much flow?

Regardless of that answer, do you think that generally a cat-back system alone will give a few more HP, fewer, or likely no significant change at all in the case of this LS1?? (I might go headers in the future. I know that would need a tune. That is a problem since there is no dyno in this whole state to my knowledge.)

[OrangeCrushM6]

Something you might consider is having one of your stock outlets rerouted to the other side giving you the look you want. Won't be louder, but you can remedy this by
deleting your resonators or changing out your mufflers. Much cheaper option. There have been several people up here get very little to actually losing hp with certain catback systems. PFYC is working on a cutout replacement part for split duals. Should be ready soon.

[Chevelleguy]

I'm in the same situation so I'm glad you posted this. I am going to look into having one of my factory manifold outlets rerouted to the other side and match the dual tips. I'll see how that goes before changing mufflers and removing resonators.

The cutout insert from PFYC would be nice.

Good luck with whatever you go with.....

[GoatFence]

I love the Borla Split rear. I looks great and sounds even better (a little louder with a little higher pitch). Someone here dynoed 10 RWHP, SOP felt like 15? The stock has the pipes crimped and flattened in out in two places, anything aftermarket should flow better than our stock systems.

[jfulcher]

The LS1 Fbodies seem to do better with their true dual systems w/ 2.5" piping than the Y-pipe design with a 3" IP. I'm sure you'll gain a little power. I haven't seen many people on here lose power by making things more free flowing. And a lot of the F-bodies run that true dual system with no cats, so it's damn free flowing.

[nick@kooks]

From our experience, we've seen the Magnaflow cat back pick up 7 more rear wheel hp over the stock set-up combined with our header system. I am not yet familiar with the Borla system. Nick "Kook's Headers"

[IndepGTO]

I just installed the Borla split dual exhaust last week and really like it. It's not much louder than stock but you can hear it. Cutting out the valance wasn't that big of a deal and you can't tell it whatsoever. Hopefully, I got close enough to the factory side that when PFYC comes out with the trim pieces they will fit. From what I've heard, however, you still may have to have a body shop install it as it may need to be filled and painted to match your car...if that's the case, I won't bother buying it.