What did you do to your NNBS GMT900 Tahoe/Yukon Today?

[HiHoeSilver]

Don’t think, do something dammit!

Maybe when I'm old like you, and my daughter doesn't require me to transport her everywhere and fund everything she does, I'll catch up. Lol....
There is a 6.0 in my stable now, too, don't forget, Mr. Beast. That wasn't free.

 

[kbuskill]

Don't remember seeing the numbers before, was that on an engine or chassis dyno?

Chassis dyno... all the info is in the article at the link I posted earlier... they dynoed a stock pickup and then the only thing done to the truck was the JBA Cat4ward headers and a bolt on muffler with dual outlets into dual tail pipes. This was apparently without a tune or anything.

Check out the link... here it is again so you don't have to go back and look for it...

JBA Headers and Exhaust System Give This 5.3L V8 a Power Upgrade
https://www.offroadxtreme.com/engin...ust-system-give-this-5-3l-v8-a-power-upgrade/

 

[Rocket Man]

Chassis dyno... all the info is in the article at the link I posted earlier... they dynoed a stock pickup and then the only thing done to the truck was the JBA Cat4ward headers and a bolt on muffler with dual outlets into dual tail pipes. This was apparently without a tune or anything.

Check out the link... here it is again so you don't have to go back and look for it...

JBA Headers and Exhaust System Give This 5.3L V8 a Power Upgrade
https://www.offroadxtreme.com/engin...ust-system-give-this-5-3l-v8-a-power-upgrade/

So that’s shorty headers plus a cat-back? Just wondering how much restriction the stock muffler and resonator contributed.

 

[kbuskill]

So that’s shorty headers plus a cat-back? Just wondering how much restriction the stock muffler and resonator contributed.

Correct... I'm not sure about the restrictions on the factory catback system but I doubt that the catback system did much more than facilitate a better sound.

 

[Ilikemtb999]

Well, we hear all the time that shorties are no better than factory manifolds but Ken sure noticed a difference and one of the makers of shorties, I forget which, posted dyno results showing that they do indeed increase power. In the early 1990s with the Fox bodied Mustangs, one of the first mods was to put shorty headers on them.

Your cam choice scares me though! Level 3 what? Do you have the specs? I'm just an armchair warrior in this respect, lots of guys though have put cams in their trucks. I always want to see the time slips to measure performance. @randeez @Justin Yeager @NathanS @davidzog @erichyukondoit @Chrismnj @Albert Meza @mrcajunjoker @BourbonNcigars @Ilikemtb999 @Lsnoob13 @sfc_jones @sumo @fullofdayas @buddyhotrod @blackjack

Albert Meza has a recent post with video posted so you can hear his setup.

Yea I wouldn’t do anything that aggressive for a dd. I have a stage 1 vvt cam from Texas speed and I’m nervous I’ll need a stall for it. I might buy one and see how it goes and if it doesn’t need it then toss it in my caprice instead. I haven’t actually gotten it in yet though. Probably within the next few weeks. Hard to do since it’s my wife’s daily instead of mine now.

 

[Rocket Man]

Correct... I'm not sure about the restrictions on the factory catback system but I doubt that the catback system did much more than facilitate a better sound.

Not so sure about that. Factory mufflers are there to make things quiet and they don’t care if it requires sacrificing power or torque. It’s usually a choke point. I would have liked to see just the headers swapped out so the results could be completely due to them and not other things like a cat back because any company that sells catbacks also claim hp and torque increases over the factory setup. As Blowmaster states: “Like all Flowmaster systems, the benefits include improved throttle response, power and mileage. “ Throttle response being torque I assume.

 

[Ilikemtb999]

Not so sure about that. Factory mufflers are there to make things quiet and they don’t care if it requires sacrificing power or torque. It’s usually a choke point. I would have liked to see just the headers swapped out so the results could be completely due to them and not other things like a cat back because any company that sells catbacks also claim hp and torque increases over the factory setup. As Blowmaster states: “Like all Flowmaster systems, the benefits include improved throttle response, power and mileage. “ Throttle response being torque I assume.

As far as I’ve seen it’s just the resonator that’s a “restriction” in the stock catback.

 

[wendal]

Yea I wouldn’t do anything that aggressive for a dd. I have a stage 1 vvt cam from Texas speed and I’m nervous I’ll need a stall for it. I might buy one and see how it goes and if it doesn’t need it then toss it in my caprice instead. I haven’t actually gotten it in yet though. Probably within the next few weeks. Hard to do since it’s my wife’s daily instead of mine now.

This brings me to another couple of questions, and please forgive my ignorance :

What is a stall converter and what does it do?

What is vvt?

I saw vvt on Texas Speed website as well, and had no clue... Thanks in advance...

Sent from my GM1917 using Tapatalk

 

[swathdiver]

This brings me to another couple of questions, and please forgive my ignorance :

What is a stall converter and what does it do?

What is vvt?

I saw vvt on Texas Speed website as well, and had no clue... Thanks in advance...

Sent from my GM1917 using Tapatalk

When you stomp on the gas, the rpms jump to a certain rpm, hang for a moment and then continue north. This is roughly your torque converter's stall speed. Folks raise the stall speed to compensate for high rpm, high powered camshafts where the powerband is moved up. Not so good for trucks, ok for race cars.

VVT = Variable Valve Timing. Your truck doesn't have it. Introduced in 2010 to flatten torque band and increase efficiency.

 

[Ilikemtb999]

This brings me to another couple of questions, and please forgive my ignorance :

What is a stall converter and what does it do?

What is vvt?

I saw vvt on Texas Speed website as well, and had no clue... Thanks in advance...

Sent from my GM1917 using Tapatalk

A higher stall torque converter will “grab” at a higher rpm to get the engine more in the power band. If you brake torque your Tahoe (foot on the brake and the throttle) that point in which you feel it want to lurch forward is the stall speed where it’s locking up to move the vehicle forward. With a large cam it’s going to want to do that much sooner so a higher stall will fix that. Large cam with a stock converter will be incredibly hard to stop, keep stopped and keep running at idle.

Vvt is variable valve timing. It can adjust the timing on the fly so it can add timing at low rpm to make more power and retard timing at high rpm to make more hp. Basically best of both worlds of a high hp cam and low end torque cam. Your 07 does not have it though (at least I don’t think the Tahoe got it)

 

[wendal]

A higher stall torque converter will “grab” at a higher rpm to get the engine more in the power band. If you brake torque your Tahoe (foot on the brake and the throttle) that point in which you feel it want to lurch forward is the stall speed where it’s locking up to move the vehicle forward. With a large cam it’s going to want to do that much sooner so a higher stall will fix that. Large cam with a stock converter will be incredibly hard to stop, keep stopped and keep running at idle.

Vvt is variable valve timing. It can adjust the timing on the fly so it can add timing at low rpm to make more power and retard timing at high rpm to make more hp. Basically best of both worlds of a high hp cam and low end torque cam. Your 07 does not have it though (at least I don’t think the Tahoe got it)

Thanks guys. This is why I love this forum. There has not been a question about my truck that I could not get the correct answer here. You guys are GREAT!

Sent from my GM1917 using Tapatalk

 

[MajorJakkov]

anyone interested buying my VLEDS micro LED headlights? H11 bulb, 5000K temp, about a year old..new about $150

 

[iamdub]

As far as I’ve seen it’s just the resonator that’s a “restriction” in the stock catback.

I don't see how. It's at the very end of the line and it's a straight-through design. It's practically a fancy exhaust tip. It's there for sound wave manipulation and has almost totally zero effect on air flow.

 

[kbuskill]

Not so sure about that. Factory mufflers are there to make things quiet and they don’t care if it requires sacrificing power or torque. It’s usually a choke point. I would have liked to see just the headers swapped out so the results could be completely due to them and not other things like a cat back because any company that sells catbacks also claim hp and torque increases over the factory setup. As Blowmaster states: “Like all Flowmaster systems, the benefits include improved throttle response, power and mileage. “ Throttle response being torque I assume.

I agree... It would have been better to see a dyno run of just the headers on the stock exhaust to get a more accurate idea of what part gives you more benefit.

In my case, I didn't really care what they did separately as I was planning on redoing the whole exhaust anyway so I just wanted to see the overall gains.

 

[07Burb]

I don't see how. It's at the very end of the line and it's a straight-through design. It's practically a fancy exhaust tip. It's there for sound wave manipulation and has almost totally zero effect on air flow.

i doubt it has a performance impact but the stock resonator at the end looks horrible so that's why I chopped mine off LOL

 

[iamdub]

i doubt it has a performance impact but the stock resonator at the end looks horrible so that's why I chopped mine off LOL

Agreed. Someone could polish their's so it'd look like a fart cannon from a Civic.

 

[kbuskill]

Agreed. Someone could polish thier's so it'd look like a fart cannon from a Civic.

Unfortunately, I had to put mine back on... there really wasn't enough room anywhere else to put it after adding a 3 foot muffler underneath so I had them run it straight out the back and I tried to camouflage it by painting it flat black and putting a 4" stainless tip behind it.

My truck is low enough that you don't really notice it anyway... lol

 

[Ilikemtb999]

I don't see how. It's at the very end of the line and it's a straight-through design. It's practically a fancy exhaust tip. It's there for sound wave manipulation and has almost totally zero effect on air flow.

There’s a giant muffler/res right in the middle. Not the very end bit.

 

[gooffeyguy]

Mine's not lowered and I don't notice the resonator unless I'm laying looking under the vehicle [emoji848]

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

 

[Ilikemtb999]

I feel like it sticks out like a sore thumb but don’t need the vehicle any louder.