I’ve been up down and side to side on this one. Read plenty of posts here and elsewhere both for and against. Just wondering if there’s any new info anyone knows of like an actual dyno run with vs without or anything else. I bought the Borla Y pipe and it comes with the delete, when I talked to them they told me the same thing they’ve told everyone, that they didn’t see any decrease in power, but they have nothing to back that up. I’ve read the Jeep engineers saw a 30 ft pound increase with vs without. But how true that is who knows. I don’t have a long arm and don’t plan on doing one, just trying to decide if I should go ahead and put it on or leave it off when I install it

 

I put the borla climber exhaust on my Jeep and it uses the loop delete. I didn’t notice any power difference, whether it’s a loss or gain. I understand why they designed it with the loop… keep flow even on both sides. I’ve been using my exhaust for about 8 months and haven’t had any side effects. I mainly deleted my loop since the original pipes were nasty and cemented with mud. The previous owner apparently never heard of pressure washing the underside of the Jeep. I’ve gone through a lot to clean it up and keep it clean. Otherwise I probably would have just left it there, I did however want a bolt on kit that raised the exhaust out of the way of the rocks since my stock resonator was smashed and the stock muffler was about smashed to bits as well.

 

I bought the aFe and Hooker headers Y pipes and was disappointed in the quality on both. Never knew the Borla Y existed until recently. Love that it’s 304 stainless. Probably would have bought it without the delete but they didn’t have that option. Now I’m torn on wether or not I should just use it lol. I did the Corsa dual cat back so I have an unequal Y at the end too, not sure what effect that might have negative or positive with the Y pipe being unequal too. Corsa is actually installing it all for me for free so I gotta decide between now and then lol

 

On my previous Wrangler 3.6L, I did a full manifold back exhaust, high flow cat and cold air intake (K&N, Magnaflow, etc). I ran the Jeep in the 1/4 mile on my GTech meter before and after, 3 runs each in the same location with about the same weather conditions. All of that cost, work and noise resulted in an average of maybe 0.1 - 0.15 seconds quicker and maybe even reduced low end torque. Lol, it was a colossal waste, and it sounded like the teenager's Civic up the street. I guess it turns out the stock systems aren't too shabby.

 

my stock exhaust is long gone. I need the Y pipe for driveshaft clearance, I have 6.5 inches of lift, even with a custom Adams driveshaft I still need the relocation. Currently I have the aFe rock basher cat back, but A it’s not loud enough and B I’m sick of the exhaust letting out underneath me. As far as power I have a aFe Momentum GT intake with a BBK 78mm throttle body, MSD blaster coils, and Superchips tuner, so that’s another good reason to let it breathe more. And I’m looking at possibly supercharging at some point. Which is why I went with the Corsa cat back this time because it’s the only exhaust for the JKs that is over 2.5 inch diameter. 2.75 the whole way into a dual outlet. Exhausts give you sound and lets the engine breathe better when you’re bringing in a lot more air

 

Update: come to find out the Borla Y pipe must be used with the loop delete. It won’t line up otherwise. So looks like the loop is going bye bye lol

 

The only thing that most exhausts and intakes do is gainpower because of weight reduction IE your wallet is lighter

 

It's not for emissions or cafe (corporate avg fuel economy) regulations -- And the factory spent money on it, so it probably has enough value to justify the cost. I'd bet that the effect on power is primarily at top end of the rpm / power range. Surprising that there isn't a with/without dyno run somewhere.

 

I did the delete and gained HUGE HP & Torque...(although it was attached to a Prodigy Turbo Charger)

 

not looking for a power gain, just need driveshaft clearance, delete came with the Y relocation. Didn’t want to do the delete if it lost power because there have been a lot of claims that you lose considerable power when you delete the loop. But this specific Y pipe has to be used with the delete so not much of a choice.