Exhaust Mod's

rlcole321 · June 6, 2021

I have a 2018 rado L83 short bed, I'm looking to the forum for some feedback for exhaust mod's, mainly the do's and don'ts from what other people have done or tried but improving power(but not robbing from the bottom end just to give it to the top end).

Mainly from the cat back, but also trying short tube headers to connect to the stock cat configuration, and with and without the "Flapper" valve. Please give some feedback, thanks.

pokismoki · June 8, 2021

yeah, leave the stock manifolds on the truck, they are tuned to increase torque at lower rpm, headers are for high rpm power . if you want headers use 1- 3/4" on the 5.3 motor, dont get sucked into the 1-7/8" your gonna loose toque

i would remove the factory 3rd downstream cat, but keep the two upper cats, this shouldnt effect any CEL light, because i dont believe there in any o2 after the 3rd cat

cut out the flapper valve if you got one after the muffler on your model truck.

Edited June 8, 2021 by pokismoki

CamGTP · June 10, 2021

Shorty headers is like throwing money into a bonfire.

rlcole321 · June 10, 2021

Yeah, I knew about the 1 3/4" tubes to keep the low in torque, but you think there's no improvement under Nat. Asperated operation. What about other mod's, I'm considering the muffler replace w/ Open flow and no Res. or straight pipe leaving the Resonator. Any comments or have dome's. I may be going supercharge letter down the road for this truck.

M1ck3y · June 20, 2021

My truck never ran better (wot) then when it was all stock except for a corsa catback. That is until Gm's updated tune, which was supposed to fix transmission shifting harshness took the life out of it.

Since then its been tuned and has Kooks headers. These headers are great low-mid rpm, especially when it's running hot. They pull alright at high rpm/high speed too, but it low-mid where they shine.

imo if you want to be quick, get a blower and call it a day. If you want people to hear you, get full exhaust.

And if your made of money... stroked lt1/l86, twin turbo, upgraded driveline...

MikeBMW · June 20, 2021

1 hour ago, M1ck3y said:

My truck never ran better (wot) then when it was all stock except for a corsa catback. That is until Gm's updated tune, which was supposed to fix transmission shifting harshness took the life out of it.

Since then its been tuned and has Kooks headers. These headers are great low-mid rpm, especially when it's running hot. They pull alright at high rpm/high speed too, but it low-mid where they shine.

imo if you want to be quick, get a blower and call it a day. If you want people to hear you, get full exhaust.

And if your made of money... stroked lt1/l86, twin turbo, upgraded driveline...

Sure, but if you want your neighbors to not hate you, just get a Borla exhaust installed by the dealership.
Still sounds great and no one hates you, except for that person you pass as you kick down the accelerator.

BattleBorn iZ · June 20, 2021

I installed a Borla ATAK black tip dual side exhaust. Love it! Took me about and 1 and a half.

pokismoki · June 21, 2021

for a daily driver dont install headers... they do make power but at a reliability cost... there's still untapped power on the table just using and tuning with cheaper OEM parts

600-750 hp truck that cant stop or handle aint worth the money wasted on boost.. i havent seen any reliable tuning on the gen5 LS trucks that utilizes the torque tuning, all the boosted trucks are hacked tuned and may not be reliable

If you want to be quick I suggest a Camaoro SS, ZL1, or Sport bike

Edited June 21, 2021 by pokismoki

lucas287 · June 22, 2021

23 hours ago, pokismoki said:

i havent seen any reliable tuning on the gen5 LS trucks that utilizes the torque tuning, all the boosted trucks are hacked tuned and may not be reliable

Not a true statement. Sure some are hacks, but there are many fantastic Gen V calibrators that are far from hack jobs and unreliable. Is it as good as GM's multi-million dollar facility for building calibrations? No, but there are quite a few folks that have it figured out. Spend some time on HPTuners forum and you'll learn pretty quickly who knows what.

pokismoki · June 23, 2021

problem is getting free time to figure the stuff out, and find quality shops.. too many scammers in this hobby

lucas287 · June 23, 2021

1 hour ago, pokismoki said:

problem is getting free time to figure the stuff out, and find quality shops.. too many scammers in this hobby

Yup - unfortunately it requires an immense amount of time to figure it out on your own. You need a really solid understanding of how Gen 3, then Gen 4 operated to understand Gen 5 stuff.

However, if your basic bolt-on like me, basic changes in HP Tuners feel really good SOTP-wise. Is it any faster? doubtful