Exhaust Upgrade for 2019 Denali 6.2L

[kris shirley]

I am looking for advice on the best short tube headers and CAT back exhaust system that will bolt on. I am not looking for annoyingly loud, but something that will help pull my boat down the road, while still maintaining the luxury feel of the Denali. I do plan to do a tune once the upgrades are done. I have the K&N CAI for her already, but I am have seen so many options, I'm just looking for someone who had a similar engine and if they like the mods and would spend the money again! Thanks for your help!!!

[lucas287]

2 hours ago, kris shirley said:

I am looking for advice on the best short tube headers and CAT back exhaust system that will bolt on. I am not looking for annoyingly loud, but something that will help pull my boat down the road, while still maintaining the luxury feel of the Denali. I do plan to do a tune once the upgrades are done. I have the K&N CAI for her already, but I am have seen so many options, I'm just looking for someone who had a similar engine and if they like the mods and would spend the money again! Thanks for your help!!!

I'd recommend E85 and a good custom tune. That's the easiest, cheapest torque you can buy. For about what a catback costs you can pick up an honest-to-goodness 40-50 lb ft down under the torque peak. 

 

A catback might be 10-20 lb ft. Now if you're going for sound, that's a different story and just go for what YOU personally think sounds good. YouTube videos kind of suck though for that. I was at the dealer last week (for service warranty work) and was killing time on the new truck lot and noticed a pimped out '21 Silverado that had a lot of dealer add-ons. One of the upgrades was a Corsa Catback. I'd never heard Corsa in person (to my knowledge) on a Gen V truck motor. I coerced the salesman into starting it up for me and revving it a few times. Man did it sound awesome. I consider myself a bit of an aficionado when it comes to V8s so it takes a lot to impress me. This was a very good tone. Anyways - ad for Corsa over. 

[lucas287]

...oh yeah don't do short tubes either. You already have short tube cast iron manifolds. Are they perfect? Nope. But they're much better than the log style manifolds. I'd go long tubes and preferably 1.75" primaries which eliminates your bargain brands.

 

Even then it might be overkill for YOUR specific goal. The issue that NO ONE discusses is part throttle velocity. They look at a dyno curve and think "I gained torque down low" or "only lost a few ft lbs". Dyno runs are at 100% WOT. Who is at 100% throttle and 2,000, or even 2,500 RPM?? Exactly. It's a misnomer. With part throttle, port velocity becomes very important to have good tip in, throttle response, and torque production. Most long tubes available for our trucks increase volume FAR too much at part throttle. (postulation of mine - not proven) Volume increase will have an opposite impact on velocity. Think about this: you go from the "wimpy" little cast manifolds and 2.5" down pipes to headers with 1.75" primaries that are 28"+ each that dump into a 3" collector...the volume increase is enormous. Good for full throttle, bad for part throttle - which is important for towing. Anyone that wants to argue needs to study exhaust science. Don't try to argue with "butt dynos" and actual dyno graphs that only reference full throttle. 

 

[CamGTP]

Just remember that's it's $1,900 just to tune that truck without owning HP Tuners, if you need to buy HP Tuners add another $300. Then spend hours, months or longer trying to figure out how to tune those trucks. There is literally nothing out there as far as tuning manual's go and the logic behind the 2019+ trucks is different than before.

 

Fun stuff.

 

I'd probably throw the idea of tuning and E85 out the window. Add your intake, buy a cat-back system and call it a day. Short tube headers is just flushing money down the drain.

[lucas287]

Man that gets me every time. It's not the old days anymore lol

 

For $1900 I'd put that towards a blower and have some real torque. 

 

Yep opinion revised then. ^what Cam said. 

[M1ck3y]

4 hours ago, lucas287 said:

...oh yeah don't do short tubes either. You already have short tube cast iron manifolds. Are they perfect? Nope. But they're much better than the log style manifolds. I'd go long tubes and preferably 1.75" primaries which eliminates your bargain brands.

 

Even then it might be overkill for YOUR specific goal. The issue that NO ONE discusses is part throttle velocity. They look at a dyno curve and think "I gained torque down low" or "only lost a few ft lbs". Dyno runs are at 100% WOT. Who is at 100% throttle and 2,000, or even 2,500 RPM?? Exactly. It's a misnomer. With part throttle, port velocity becomes very important to have good tip in, throttle response, and torque production. Most long tubes available for our trucks increase volume FAR too much at part throttle. (postulation of mine - not proven) Volume increase will have an opposite impact on velocity. Think about this: you go from the "wimpy" little cast manifolds and 2.5" down pipes to headers with 1.75" primaries that are 28"+ each that dump into a 3" collector...the volume increase is enormous. Good for full throttle, bad for part throttle - which is important for towing. Anyone that wants to argue needs to study exhaust science. Don't try to argue with "butt dynos" and actual dyno graphs that only reference full throttle. 

 

Just my .2

 

I have longtubes and my truck is nuts at low rpm. It will make asphalt behave like ice if you want it to (minimal throttle), but the tune does contribute to that. Definitely substantial gains low-mid, top-end didnt get the kick that I thought it would.  

[lucas287]

3 minutes ago, M1ck3y said:

Just my .2

 

I have longtubes and my truck is nuts at low rpm. It will make asphalt behave like ice if you want it to (minimal throttle), but the tune does contribute to that. Definitely substantial gains low-mid, top-end didnt get the kick that I thought it would.  

And that's where theory collides with reality lol I think a lot of older engine theory, while still valid to an extent, is flawed with how much cylinder heads flow and direct injection, etc.. some older vizard material would argue the use 1.5 or 1.625 long tubes on a sub 400 inch torque focused engine. But that might not be the reality any longer. 

[gat0r]

as others have stated, dont mess w/ shorty headers.   either do long tubes (LT) or stick w/ OEM.

 

might be worth inquiring w/ @BlackBearPerf for tuning as well

 

 

LTs w/ catback & tune would definitely wake up your ride.

 

if you can budget for it... supercharger would give most bang  (whipple or magnuson)