MY JBA exhaust setup, questions left, lessons

Discussion on fuel delivery & intake/exhaust tech & mods.
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Joined: Mon Jan 28, 2019 3:45 am

MY JBA exhaust setup, questions left, lessons

Post by Numbah1 » Sat Sep 28, 2019 6:19 am

Thought process:

I bought JBA SS headers and catted conn pipes. Told the shop i wanted an H pipe and later cutouts.

Solo said a full setup: kooks headers, solo catted conn pipes, balanced (or shorty) was 2205.
JBA headers, catted conn pipes were 1185.
Weld in 2.25 cutouts were on sale for 133, 267 for 2.

Install price was 540, good place to start why

•1st lesson/headers:
They spent a few days getting the headers on. I was going to ask if the kooks install was easier. They ruined the oil dip tube getting it off and with GM on strike... they had to get an after market pce, so i missed 2 races. Not that i care now, but id ask if Kooks are easier to get on.

•My visit / catted conn pipe:
I opted for catts b.c of back pressure, hp.
They had the headers on when i dropped the cutouts off. Fit REALLY good! They held the catted conn pipes up to the headers and it stopped just before the resonator. Im running DoD for as long as i can, so i skipped the H pipe and asked them to leave it. Later a friend in automotive engineering said the resonator was basically an H pipe and i wouldnt gain much by having it replaced for an H pipe, so it made the decision permanent to keep it.

I gave them the cutouts:
The mufflers are split! Looked like the kooks mid pipe bolts to our mufflers, so that was questioning. The facebook group seemed split on if these mufflers rob power too. 1 guys said, "could gain 2, could gain 20" by eliminating them Solo mufflers are like 480 and 2 cutouts are like 320 so it made it easy.
I told them i thought that 1 guy (Zeos from youtube) had cutouts in the ANGLE before it bends for the muffler flange. It seemed like the best spot, still get back pressure from cats, resonator acting like an h pipe, and had most room. B.c they were downward facing, clearance was a concern clarence, and he said it was a bad idea. So he gave the car back

If you read thru this wall of text and are using a cutout, reply with where and what please and thank you!!

•Mid pipe:
I read Camaro5 guys dont gain by swapping mid pipes. Theirs are also 2.25. Other guys have said that dont think by just going to 2.5 is going to gain hp on here too. So i dont think the 2.25 / 2.50 matters.

• Initial sound
Holy crap it was quiet!! I could hear the exhaust in the resonator in 8 & 4cyl mode was modes, but the windows down at 25, lol i could hear rocks under the tires! I swear it was quieter than when i bought it. 55 was tbe same. No highway test b.c my car runs wierd in 4cyl mode with my cai. It didnt sound good, or like a v8 till 5k. I work at night and most my drive is at night, so it was perfect for me then.

•No mufflers
I race tomorrow and have no interest in losing 2 or 20 hp thru the mufflers after having headers on it! Soo, i took the mufflers off lol sounds tough, not straight pipe 350 like thank god!!!! I can hear some drone in both cyl modes though. Its quiet enough to here i could roll with it, but i dont want it this way permanenty.

Ill post ET gains here and on my general info thread of my gains

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Joined: Thu Feb 07, 2019 5:49 am

Re: MY JBA exhaust setup, questions left, lessons

Post by Ilikemtb999 » Sat Sep 28, 2019 9:37 pm

5th gen camaro exhaust is 2.5” from the cats back to the mufflers, at least the ls3 catback is.

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Location: SE PA

Re: MY JBA exhaust setup, questions left, lessons

Post by xcidmigs » Sun Sep 29, 2019 12:52 am

I don't know where you got the info about the H pipe not being a restriction... It clearly is as it has the smallest ID pipes in the stock system, I find it hard to understand how you have headers with what 2.5" cat pipes? getting necked down to that somehow and don't think its a restriction. Pretty much everyone running headers on a G8 or newer SS sedan has been using the magnaflow X pipe muffler to replace the stock resonator and also not have their car super loud or raspy like you seem to be saying you want?
I have the 2.5" OEM camaro LS3 front cat pipes into one of those mufflers and then 2.5" straight pipe exiting there to the bends by the diff like you described where I put in 2x 2.5" cutouts before reattaching to my stock mufflers. closed its almost stock silent, open, well ITS NOT....

look here for some good pics on the suitcase muffler

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Joined: Mon Jan 28, 2019 3:45 am

Re: MY JBA exhaust setup, questions left, lessons

Post by Numbah1 » Mon Sep 30, 2019 10:15 am

I never said it wasnt a restriction lol i just said i had it left in there b.c im still using DoD. I later learned after that theres no separation of exhaust in the resonator, and is H pipe like. However, being able to hear the exhaust in the resonator was unexpected, and ill prolli have it removed for an actual H pipe.

I also didnt mean to say i wanted it loud. I just didnt want to lose HP by leaving mufflers on it. It could be silent just as long it makes more power

Ill throw out too that a county sheriff pulled up behind me at a stop too and turned off half a block later, so its not earthquake loud w/o mufflers

I had wheels & a otr cai
My old runs were
2.09 60ft, 5.85 330ft, 8.93 @ 80.8
2.09 60ft, 5.86 330ft, 8.94 @ 80.8
2.07 60ft, 5.83 330ft, 8.92 @ 80.9

The air was better, so these shouldve been ~.05 higher
2.05 60ft, 5.74 330ft, 8.75 @ 83.0 mph
2.05 60ft, 5.73 330ft, 8.75 @ 82.7 mph
2.06 60ft, 5.76 330ft, 8.77 @ 82.8 mph

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