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

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Doubeleive

Wes
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I installed the JBA "cat forward" shorty headers on my 5.3l. I believe the Gibson shorties are basically the same. Either way I found these had really good torque improvement with independent dyno testing. I am always skeptical of in house dyno numbers because they are trying to sell a product.

They are 1 5/8" primary tube and they make good torque, which is what I was after. It is very noticeable while cruising the interstate and going to pass someone, you have to be careful because you will blink and you are running 90+.

@Doubeleive just laughed and thought to himself 90? That is residential neighborhood territory... lol
meh, only in the ghetto
 

Scrappycrow

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I installed the JBA "cat forward" shorty headers on my 5.3l. I believe the Gibson shorties are basically the same. Either way I found these had really good torque improvement with independent dyno testing. I am always skeptical of in house dyno numbers because they are trying to sell a product.

They are 1 5/8" primary tube and they make good torque, which is what I was after. It is very noticeable while cruising the interstate and going to pass someone, you have to be careful because you will blink and you are running 90+.
I dunno how I missed both the JBA and the Gibson headers! o_O The Gibsons are 1.5", to boot! :cheers:

Did you need to do a tune afterwards?
 

Charlie207

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I dunno how I missed both the JBA and the Gibson headers! o_O The Gibsons are 1.5", to boot! :cheers:

Did you need to do a tune afterwards?

Dynos show maybe ~8hp for shorties, and that was with no accessories and an electric water pump. It's doubtful you'd feel any gains in a vehicle in the road. Switching between crappy 87 octane petrol to E85 will give a better performance boost.

This isn't to say that shorty headers are bad, they look cool and add some sound...maybe, but that the factory cast manifolds and their millions of dollars of R&D by scientists and engineers, are actually pretty good.
 

kbuskill

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Dynos show maybe ~8hp for shorties, and that was with no accessories and an electric water pump. It's doubtful you'd feel any gains in a vehicle in the road. Switching between crappy 87 octane petrol to E85 will give a better performance boost.

This isn't to say that shorty headers are bad, they look cool and add some sound...maybe, but that the factory cast manifolds and their millions of dollars of R&D by scientists and engineers, are actually pretty good.
I won't argue that long tubes show more gains.

I will only say that I was skeptical and did a lot of research on these before I decided to get them. As mentioned, I don't put a lot of stock in claimed power increases from the manufacturers, obviously they are trying to sell their products.

I found, and still have somewhere in the recesses of my phones storage, dyno tests from unaffiliated sources showing the torque increased something like 45lb/ft under 2500rpm or something to that affect. That is all I was interested in was low-end torque. In all reality I am driving a 6000 lb brick, why would I care to have more HP at 6000rpm? I spend more time below 3000rpm than I do anywhere else, and these definitely make a noticeable difference in that area.

I think I have posted the dyno info on here before, I will have to look and see if I can find it.

Either way, to each their own as they say.

***EDIT***

I found it, here is a link to the other thread I started...

It has links to some of the articles I was referring too.

The part I liked the best was...

"However, as with any truck application, we’re more interested in gains in the low- and mid-range. The dyno chart below reveals healthy gains in these areas as high as 45 lb-ft of torque at the critical 2,500 rpm point. A power gain such as this down low will substantially help the truck’s acceleration and improve performance during normal driving conditions."

I also understand they installed dual 3" cutbacks exhaust at the same time, so the argument can be made that the headers alone didn't equate to those power gains, but I think most of us here are probably running some sort of aftermarket exhaust already and dual.3" is extreme over kill for a N/A 5.3l, although it probably sounds really good.
 
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Charlie207

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I won't argue that long tubes show more gains.

I will only say that I was skeptical and did a lot of research on these before I decided to get them. As mentioned, I don't put a lot of stock in claimed power increases from the manufacturers, obviously they are trying to sell their products.

I found, and still have somewhere in the recesses of my phones storage, dyno tests from unaffiliated sources showing the torque increased something like 30lb/ft under 2500rpm or something to that affect. That is all I was interested in was low-end torque. In all reality I am driving a 6000 lb brick, why would I care to have more HP at 6000rpm? I spend more time below 3000rpm than I do anywhere else, and these definitely make a noticeable difference in that area.

I think I have posted the dyno info on here before, I will have to look and see if I can find it.

Either way, to each their own as they say.


Good dyno comparison:
 
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mikez71

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I'm joining the AXN club soon. 160k miles younger than the old one.
Hopefully the 3.42 gears are worth it...
I still need a front diff..
IMG_0410.jpeg
 
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kbuskill

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Good dyno comparison:

I would like to point out that neither of those were tested below 3000rpm which is where the biggest gains were measured.
Also, long tubes may out perform shorties everywhere in the RPM range but that doesn't mean that the JBA shorties don't make improvements over the factory log style manifolds.

This isn't a long tubes VS short tubes debate. It started because header primary tube diameter was mentioned, with smaller diameter being better for TQ VS larger being better for HP. That is why I mentioned the JBAs having a 1 5/8" primary as opposed to most others being 1 3/4"+.
 

Doubeleive

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meh, headers smedders
all I ever experienced was more pita exhaust leaking.....
I can only suggest, re-checking the bolt torque at least every couple weeks
enjoy!!
 

kbuskill

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meh, headers smedders
all I ever experienced was more pita exhaust leaking.....
I can only suggest, re-checking the bolt torque at least every couple weeks
enjoy!!
I installed the Stage 8 locking bolts when I put these on and haven't had a single issue in the 5 or 6 years they have been installed.
 

Geoffsfas10

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Well hopefully I can have as easy of a time doing these.

ACANII - For [Black Edition] 2007-2014 Chevy Suburban Tahoe Avalanche LED DRL Projector Headlights Headlamps Left+Right https://a.co/d/dzOZJBT
make sure you take some pictures of those lights open. id like to see how the existing projectors are mounted in there
 

Pandabird

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Having fun with this I hope?
Absolutely! Didn't expect too much from a machine that cost less than 10k brand new. But for what it's worth it's been a backsaver for sure. Been digging footings for a greenhouse, a fence that reaches two feet underground and poles for the new chicken coop outside area, as well as removing a few stubborn birch roots that kept sprouting up year after year.
1000003919.jpg

Anyways to avoid going too much offtopic, today I opened up those brakes to check why the parking brake isn't engaging.
1000004513.jpg
Wonder if I can free up the brake pads somehow, looks like they are wearing unevenly (discs and brake pads are pretty new despite the parking brake looking ancient)
 

Grady_Wilson

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Absolutely! Didn't expect too much from a machine that cost less than 10k brand new. But for what it's worth it's been a backsaver for sure. Been digging footings for a greenhouse, a fence that reaches two feet underground and poles for the new chicken coop outside area, as well as removing a few stubborn birch roots that kept sprouting up year after year.

Anyways to avoid going too much offtopic, today I opened up those brakes to check why the parking brake isn't engaging.
Wonder if I can free up the brake pads somehow, looks like they are wearing unevenly (discs and brake pads are pretty new despite the parking brake looking ancient)
Wow, those parking brake shoes are nasty.
Makes me want to open mine up just to have a look but my parking brake is working as it should.
 

Scrappycrow

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I found it, here is a link to the other thread I started...

It has links to some of the articles I was referring too.

The part I liked the best was...

"However, as with any truck application, we’re more interested in gains in the low- and mid-range. The dyno chart below reveals healthy gains in these areas as high as 45 lb-ft of torque at the critical 2,500 rpm point. A power gain such as this down low will substantially help the truck’s acceleration and improve performance during normal driving conditions."

I also understand they installed dual 3" cutbacks exhaust at the same time, so the argument can be made that the headers alone didn't equate to those power gains, but I think most of us here are probably running some sort of aftermarket exhaust already and dual.3" is extreme over kill for a N/A 5.3l, although it probably sounds really good.
A major problem with dyno results like these is that they're virtually always full-throttle, whether by necessity on an inertia dyno or due to habit on eddy-current dynos. So, the results don't tell you anything about results at part-throttle, where the overwhelming majority of driving is done.

I'd really like to see pulls made on an eddy-current dyno, simulating a part-throttle steady-state pull up a grade (or even better, a series of steady-state load sweeps), with and without headers, and stock vs. aftermarket aftermarket exhaust. That'd be an order of magnitude more meaningful to me and many others.
 

Pandabird

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Wow, those parking brake shoes are nasty.
Makes me want to open mine up just to have a look but my parking brake is working as it should.
It was surprisingly easy to open actually. Just jack up and remove the wheel and two bolts holding the caliper in place, once you pulled away the caliper (always have a ziptie or wire in your pocket when doing this, the brake line will *not* support the weight of a brake caliper) the disc is simply pulled off. Installs back just as easy. I was actually a bit weirded out it wasn't torqued down by anything.

As for the parking brake shoe, yup that's a goner. Ordered AcDelco gold and the mounting parts kit as well, dunno if good or not but at least it was twice as expensive. Will post a few pics of the assembly when it arrives.
 

Grady_Wilson

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It was surprisingly easy to open actually. Just jack up and remove the wheel and two bolts holding the caliper in place, once you pulled away the caliper (always have a ziptie or wire in your pocket when doing this, the brake line will *not* support the weight of a brake caliper) the disc is simply pulled off. Installs back just as easy. I was actually a bit weirded out it wasn't torqued down by anything.

As for the parking brake shoe, yup that's a goner. Ordered AcDelco gold and the mounting parts kit as well, dunno if good or not but at least it was twice as expensive. Will post a few pics of the assembly when it arrives.
I have a set of caliper hangers for doing brake work.
And if all else fails, i have some 12 gauge THHN copper wire I use to hold up the calipers.
 

Charlie207

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Replaced the four outer brake hoses, and was going to replace the two inner-rear hoses, but realized I only bought one. Dang.

Sll six of the hoses are still in serviceable shape, with no cracks, rot, or serious rust, but RockAuto had some super cheap on clearance, so I ordered them all (or so I thought).

The old fluid was yuck, as usual.

1000009367.jpg
 

89Suburban

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I got a fkn flat tire when I went to pick up dinner. I must have picked something up and it came back out. I saw the small hole and the fresh screw or nail head mark on the tread. It was fine on the way there and when I parked.

When I came out with my carry out and went to leave I saw the tire warning on the dash. I just replaced those TPMS this past weekend.

I was like wtf one failed already??? I went to back out and the old girl was resisting. SHEET.

I got out and the right front was on the damn rim. I limped it under some parking lot lights so I could see and started to install the spare.

I love the lowered life, UNTIL you need to get the damn jack under the truck. Holy shoot. That sucked!

If I didn’t have that push bar on the front I would have been in deep do do. I used that to get it up enough to block it up to get the jack under the LCA.

Seriously considering removing the running boards so I can get a fkn jack under the frame rails if this happens again.
Certainly was a rough learning experience. Got some homework to do for sho…
 

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