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

[wendal]

OK, so a friend of mine with an 07 Avalanche pointed me to this shop west of Dallas: LSXUNLIMITED.COM

They do a cam upgrade and complete AFM delete including all the upgraded lifters, etc. for around $3k. My question to you guys is this:

Am I going to realize the full potential of these upgrades without upgrading my headers? Or if I choose to do shorty headers? I want to keep my cats, for noise and legality purposes .

@kbuskill , I read your thread about the JBA headers, and I am considering shorties myself.

Which brings me to my second question: Has anyone here done Pacesetter headers? They have ceramic coated shorties in the $350 range on RockAuto. Pacesetter also appears to be the only headers that RockAuto sells for the 07 Yukon. Any problems with them?

And yes, I've read all of you guys comments about long tubes or none at all, but they require the removal of the cats, which as I stated, I do not wish to do.

So, what do you guys think? I don't want to spend the 3k and not reap the full bene's...

 

[swathdiver]

OK, so a friend of mine with an 07 Avalanche pointed me to this shop west of Dallas: LSXUNLIMITED.COM

They do a cam upgrade and complete AFM delete including all the upgraded lifters, etc. for around $3k. My question to you guys is this:

Am I going to realize the full potential of these upgrades without upgrading my headers? Or if I choose to do shorty headers? I want to keep my cats, for noise and legality purposes .

@kbuskill , I read your thread about the JBA headers, and I am considering shorties myself.

Which brings me to my second question: Has anyone here done Pacesetter headers? They have ceramic coated shorties in the $350 range on RockAuto. Pacesetter also appears to be the only headers that RockAuto sells for the 07 Yukon. Any problems with them?

And yes, I've read all of you guys comments about long tubes or none at all, but they require the removal of the cats, which as I stated, I do not wish to do.

So, what do you guys think? I don't want to spend the 3k and not reap the full bene's...

You can run long tubes with aftermarket cats, need a custom Y-pipe and several companies that make long tubes, also sell a catted Y-pipe to go with their headers.

To answer your question regarding performance, how big is the camshaft you've selected? If it's mild and you're not looking to wrest every horsepower out of it, keep the stock manifolds and cats.

 

[kbuskill]

OK, so a friend of mine with an 07 Avalanche pointed me to this shop west of Dallas: LSXUNLIMITED.COM

They do a cam upgrade and complete AFM delete including all the upgraded lifters, etc. for around $3k. My question to you guys is this:

Am I going to realize the full potential of these upgrades without upgrading my headers? Or if I choose to do shorty headers? I want to keep my cats, for noise and legality purposes .

@kbuskill , I read your thread about the JBA headers, and I am considering shorties myself.

Which brings me to my second question: Has anyone here done Pacesetter headers? They have ceramic coated shorties in the $350 range on RockAuto. Pacesetter also appears to be the only headers that RockAuto sells for the 07 Yukon. Any problems with them?

And yes, I've read all of you guys comments about long tubes or none at all, but they require the removal of the cats, which as I stated, I do not wish to do.

So, what do you guys think? I don't want to spend the 3k and not reap the full bene's...

In my opinion...

If you are looking to get every last bit of power out of your engine ABOVE 5000 RPM then long tubes are the way to go.

If you are looking for more power in the 2000-5000 RPM range, where it's more usable for daily street driving, then the JBA Cat4ward headers do a pretty good job. Several of the header companies make headers that all look alike. JBA, Gibson, BBK, Dougs.. etc.

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/

Whatever you go with make sure you get ceramic coated and I would also suggest getting a good set of locking header bolts. I went with the Stage 8 locking header bolts found here...

https://www.stage8.com/product/8900-chevrolet-ls1-ls2-ls6-header-bolt-kit/

I purchased mine on Ebay for like $20 though.

Also you need to be cautious when choosing a camshaft. You need to figure out how YOU drive and where YOU want more power.

Keep in mind that these are big heavy trucks and you don't want to sacrifice a bunch of low end torque for the high end horsepower or else it will feel sluggish in normal everyday driving.

Also if you choose too big of a cam you will need to install a different torque converter to really take advantage of the power band.

This is all just my opinion... I am certain others will chime in as well.

Just FYI you CAN get long tube headers with an aftermarket Y-pipe that has cats in them... but all of that will cost substantially more obviously.

 

[wendal]

You can run long tubes with aftermarket cats, need a custom Y-pipe and several companies that make long tubes, also sell a catted Y-pipe to go with their headers.

To answer your question regarding performance, how big is the camshaft you've selected? If it's mild and you're not looking to wrest every horsepower out of it, keep the stock manifolds and cats.

@swathdiver, I am looking at a level 3 cam, which should allow me to still tow when needed. I'm like @kbuskill, looking more at low end to midrange torque and power, not so much too end speed. Not trying to race vettes or anything. Definitely will do ceramics. So I am gathering, since neither of you mentioned factory, that even shorties are better than factory...

Thanks for the feedback.

Sent from my GM1917 using Tapatalk

 

[swathdiver]

@swathdiver, I am looking at a level 3 cam, which should allow me to still tow when needed. I'm like @kbuskill, looking more at low end to midrange torque and power, not so much too end speed. Not trying to race vettes or anything. Definitely will do ceramics. So I am gathering, since neither of you mentioned factory, that even shorties are better than factory...

Thanks for the feedback.

Sent from my GM1917 using Tapatalk

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.

 

[kbuskill]

@swathdiver, I am looking at a level 3 cam, which should allow me to still tow when needed. I'm like @kbuskill, looking more at low end to midrange torque and power, not so much too end speed. Not trying to race vettes or anything. Definitely will do ceramics. So I am gathering, since neither of you mentioned factory, that even shorties are better than factory...

Thanks for the feedback.

Sent from my GM1917 using Tapatalk

The factory manifolds found on these engines are not nearly as restrictive as some of the older small block manifolds were... they actually flow pretty well for what they are.

But in my opinion there is room for improvement as seen from the dyno results in the link above.

If the dyno results were from the company that builds the headers then I would be less inclined to believe the results but I have seen these headers tested by about 3 different places with 3 different dynos and all 3 put out very similar improvements in power.

The biggest seller for me on these was the 45 ft lbs of torque that you gain at 2500 RPM and another 35 ft lbs gained at about 4700 RPM... there are gains throughout the RPM range but the biggest ones are around there according to the dyno.

The torque peaks about 500 RPM sooner than with stock manifolds. Also, when you look at the dyno sheet, you will notice that the peak torque with stock manifolds doesn't occur until 5100 RPM... with the JBA shorties you hit the same torque number (250 ft lbs) at 2900-3000 RPM and from there on out you are pretty much above the stock peak torque all the way to 5500 RPM.



Lots of guys will tell you shorties are a waste of time and money but dynos don't lie and I would much rather have the low end torque to get this big ol girl up and moving than to have a ton of horsepower where I will never use it...

Horsepower sells cars... torque gets the job done... lol

 

[HiHoeSilver]

The factory manifolds found on these engines are not nearly as restrictive as some of the older small block manifolds were... they actually flow pretty well for what they are.

But in my opinion there is room for improvement as seen from the dyno results in the link above.

If the dyno results were from the company that builds the headers then I would be less inclined to believe the results but I have seen these headers tested by about 3 different places with 3 different dynos and all 3 put out very similar improvements in power.

The biggest seller for me on these was the 45 ft lbs of torque that you gain at 2500 RPM and another 35 ft lbs gained at about 4700 RPM... there are gains throughout the RPM range but the biggest ones are around there according to the dyno.

The torque peaks about 500 RPM sooner than with stock manifolds. Also, when you look at the dyno sheet, you will notice that the peak torque with stock manifolds doesn't occur until 5100 RPM... with the JBA shorties you hit the same torque number (250 ft lbs) at 2900-3000 RPM and from there on out you are pretty much above the stock peak torque all the way to 5500 RPM.

View attachment 225709

Lots of guys will tell you shorties are a waste of time and money but dynos don't lie and I would much rather have the low end torque to get this big ol girl up and moving than to have a ton of horsepower where I will never use it...

Horsepower sells cars... torque gets the job done... lol

Making an awfully strong case here, ken. I like it. I've got a couple of broken manifold bolts, and am starting to hear the leak when cold. Had written off long tubes this hoe and figured on the KRAL clamps, but you've gotten me thinking over the last little while. Dammit.

 

[iamdub]

Monkey wrench time!

Any info on tri-Ys?

 

[Rocket Man]

Making an awfully strong case here, ken. I like it. I've got a couple of broken manifold bolts, and am starting to hear the leak when cold. Had written off long tubes this hoe and figured on the KRAL clamps, but you've gotten me thinking over the last little while. Dammit.

Don’t think, do something dammit!

 

[swathdiver]

The biggest seller for me on these was the 45 ft lbs of torque that you gain at 2500 RPM and another 35 ft lbs gained at about 4700 RPM... there are gains throughout the RPM range but the biggest ones are around there according to the dyno.

The torque peaks about 500 RPM sooner than with stock manifolds. Also, when you look at the dyno sheet, you will notice that the peak torque with stock manifolds doesn't occur until 5100 RPM... with the JBA shorties you hit the same torque number (250 ft lbs) at 2900-3000 RPM and from there on out you are pretty much above the stock peak torque all the way to 5500 RPM.

View attachment 225709

Lots of guys will tell you shorties are a waste of time and money but dynos don't lie and I would much rather have the low end torque to get this big ol girl up and moving than to have a ton of horsepower where I will never use it...

Horsepower sells cars... torque gets the job done... lol

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