Sorry, another header question

everkain · February 7, 2019

Hey everyone,

I just bought a 2018 denali 5.3 back in december and have a few questions about headers. I'm thinking about getting some long tubes for the truck since i've run them on all of my cars over the past 25 years. However, i'm not too familiar with these new direct injection engines. Realistically, how much power would i gain running long tubes with a catted Y-pipe or custom X-pipe. I would also have this setup dyno tuned at ECS in jersey. I'm just trying to see if the power increase is worth the time and money. I remember picking up about 35rwhp on my 2002 z06 when i did long tubes with a tune and thought that was worth it, so i'm on the fence. If anyone has any videos, dyno plots or advice, i would greatly appreciate it.

KARNUT · February 7, 2019

Hey everyone,

I just bought a 2018 denali 5.3 back in december and have a few questions about headers. I'm thinking about getting some long tubes for the truck since i've run them on all of my cars over the past 25 years. However, i'm not too familiar with these new direct injection engines. Realistically, how much power would i gain running long tubes with a catted Y-pipe or custom X-pipe. I would also have this setup dyno tuned at ECS in jersey. I'm just trying to see if the power increase is worth the time and money. I remember picking up about 35rwhp on my 2002 z06 when i did long tubes with a tune and thought that was worth it, so i'm on the fence. If anyone has any videos, dyno plots or advice, i would greatly appreciate it.

I would check with a tuner to see if a tune would be required with headers. If so is it worth a warranty fight if the lifters start failing due to cylinder deactivation. I got rid of mine do to cylinder deactivate. I mess with an old truck. I can understand the I got to modify. I did it with all my trucks starting in the 70s. These new trucks run pretty good stock.

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DenaliX14 · February 8, 2019

Honestly with a 5.3L and some nice 1 7/8 long tube headers, high flow cats and CAI you're looking at about 25-40 depending on your tuner.

1 7/8 Headers with Catted Y.

https://www.texas-speed.com/p-4900-tsp-2014-chevygmc-53l-1-78-304-stainless-steel-long-tube-headers-53l-catted-y-pipe.aspx

CAI

https://afepower.com/afe-power-50-30028rh-momentum-xp-pro-5r-cold-air-intake-system

About $1,500 in parts and another $500+ for tuning at a shop. So let's say $2,000 installed.

If you want the MOST bang for your buck TUNE included. Get a Procharger HO kit. $6,000 over a weekend and maybe a case or your choice of beer. Puts you at about 500hp at the wheels. done...

I have gone down that rabbit hole and am now WAY into my build.

$3k on full exhaust

$3k on ported heads, cam shaft and upgraded valves, push rods and rocker arms.

$5k on LT4 supercharger

$1,200 on Torque converter

$2K on transmission rebuild.

when I could have just done the procharger lol. HOWEVER I love where my truck is going. #roadto1000hp

Edited February 8, 2019 by DenaliX14

everkain · February 8, 2019

9 hours ago, DenaliX14 said:

Honestly with a 5.3L and some nice 1 7/8 long tube headers, high flow cats and CAI you're looking at about 25-40 depending on your tuner.

1 7/8 Headers with Catted Y.

https://www.texas-speed.com/p-4900-tsp-2014-chevygmc-53l-1-78-304-stainless-steel-long-tube-headers-53l-catted-y-pipe.aspx

CAI

https://afepower.com/afe-power-50-30028rh-momentum-xp-pro-5r-cold-air-intake-system

About $1,500 in parts and another $500+ for tuning at a shop. So let's say $2,000 installed.

If you want the MOST bang for your buck TUNE included. Get a Procharger HO kit. $6,000 over a weekend and maybe a case or your choice of beer. Puts you at about 500hp at the wheels. done...

I have gone down that rabbit hole and am now WAY into my build.

$3k on full exhaust

$3k on ported heads, cam shaft and upgraded valves, push rods and rocker arms.

$5k on LT4 supercharger

$1,200 on Torque converter

$2K on transmission rebuild.

when I could have just done the procharger lol. HOWEVER I love where my truck is going. #roadto1000hp

yeah, that is kinda what i was weighing out. i wasn't sure how these new DI engines took to simple bolt ons, but it sounds like it's pretty much the same. How well do these new 5.3's handle boost anyways? What's "considered safe", 8-9 psi?

DenaliX14 · February 8, 2019

7 minutes ago, everkain said:

yeah, that is kinda what i was weighing out. i wasn't sure how these new DI engines took to simple bolt ons, but it sounds like it's pretty much the same. How well do these new 5.3's handle boost anyways? What's "considered safe", 8-9 psi?

I have the 6.2L (L86). However, the newer 2014 GM V8's are built with durability and strength in mind. Watch this video. Instead of me drumming on this guy can help explain why they new block designs can take quite the beating. Your engine will handle a good bit before you have to do upgrades like mine.

qwank · February 11, 2019

A tune is a must

TJay74 · February 13, 2019

On 2/7/2019 at 9:34 AM, KARNUT said:

I would check with a tuner to see if a tune would be required with headers. If so is it worth a warranty fight if the lifters start failing due to cylinder deactivation. I got rid of mine do to cylinder deactivate. I mess with an old truck. I can understand the I got to modify. I did it with all my trucks starting in the 70s. These new trucks run pretty good stock.

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Not sure why you would say you may not need a tune, you will ALWAYS need a tune with long tube headers, every time. If you dont you will be popping all sorts of rear O2 error codes and the WOT fueling will be off to the point you could damage the engine.

KARNUT · February 13, 2019

Not sure why you would say you may not need a tune, you will ALWAYS need a tune with long tube headers, every time. If you dont you will be popping all sorts of rear O2 error codes and the WOT fueling will be off to the point you could damage the engine.

I didn't say it didn't need a tune, I said check see if it needs a tune. I quit putting headers on when the HP hit 300. I used caned tunes on all my trucks headers or not. I didn't need to by just adding headers on the lower HP engines. Headers don't void the engine warranty a tune can, thus the statement. I'd be a little more cautious with all the cylinder deactivation nonsense. Hope that got your panties unbounded.

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TJay74 · February 15, 2019

No panties here unless they are the ones you left.

You said check with a tuner if a tune will be required with headers, and as I said you will always need a tune with long tube headers. Every time....

qwank · February 16, 2019

Long tube headers always need a tune

KARNUT · February 16, 2019

I’ve read articles saying not always required. It’s an easy google search. I would be in the tune category if I was doing lone tubes to get the full benefits of.

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00pooterSS · February 21, 2019

Headers are absolutely worth it.

I have way less than 1k in my entire exh setup. Speed engineering headers with y pipe and a 6.2 catback.

It picked up quite a bit.

The tune was absolutely necessary too. It didn't go any faster with the headers on it un tuned, after tuning there was a big difference.

Edited February 21, 2019 by 00pooterSS

auto_god · February 22, 2019

On 2/20/2019 at 10:58 PM, 00pooterSS said:

Headers are absolutely worth it.

I have way less than 1k in my entire exh setup. Speed engineering headers with y pipe and a 6.2 catback.

It picked up quite a bit.

The tune was absolutely necessary too. It didn't go any faster with the headers on it un tuned, after tuning there was a big difference.

Out of curiosity did you do the headers prior to the install of your catback or after?

Reason I ask is that my though process would lead me to believe the effectiveness of a given set of headers would be greatly diminished if the OE exhaust was still in place with the 6+ psi of backpressure that they've been measured to have. I'd be inclined to think that with these trucks a better flowing catback combined with headers and a tune would be the optimal combination.

00pooterSS · February 22, 2019

5 hours ago, auto_god said:

Out of curiosity did you do the headers prior to the install of your catback or after?

Reason I ask is that my though process would lead me to believe the effectiveness of a given set of headers would be greatly diminished if the OE exhaust was still in place with the 6+ psi of backpressure that they've been measured to have. I'd be inclined to think that with these trucks a better flowing catback combined with headers and a tune would be the optimal combination.

Well I had the flapper cut out about a year ago, I knew it was a huge restriction and I saw that back pressure post you're referring to a couple of days ago which confirmed just how bad that damn thing really is. But I had seen results from it already on my truck. I had also had a straight through magnaflow done in place of the factory muffler at the same time I had the flapper cutout.

Then I put headers on it in January this year, with the 5.3 catback still on it, but again, it already had no flap and had the magnaflow in place of the stock muffler (I left the stock resonator since it's a straight through)

Then a couple of weeks later I put a 6.2 catback on it but the flapper was cutout during install. And about a week after I had it tuned for the setup (I was already tuned for the previous)

Yes, if you're going to run headers you absolutely need to open up the catback to take advantage of them and tune it.

Edited February 22, 2019 by 00pooterSS