Feel like a kid on chrismas

[Biggshawn824]

Hey, I'm Shawn, new to the group, hoping to find some advice and guidance. My wife bought me a 03 Yukon Denali XL for Christmas (shes the greatest), and I want to take it from stock to around 550-600hp, while still being daily drivable. I've already had the basics done ( oil change, tune up, fluids flushed and refilled). I've already ordered the bigger 07 type brakes and a cold air intake, and that's where I get lost in next steps. I've done 1000 Google searches, and each one says go a different route and its getting a bit overwhelming.

What should i upgrade/swap? What should i leave alone?
What is the difference between cathedral and square port heads?
Should I rebuild my current 4l60E or swap for a stronger one, or swap to 4l80E?
I always see 2wd/4wd parts but i never see awd, so can i use any of those parts?
Can i ditch the air ride?

I have so many questions and no one to really ask. Didn't grow up with " car guys " and haven"t been able to find a local car community yet due to just relocating to the area ( southern Indiana), so my education/research has been all YouTube and Google.

Past changing a flat and adding oil (notice I said adding, not changing), I know nothing about working on cars so most work will be done in a shop. So, if recommendations could come with a ballpark price, it would be greatly appreciated.

thanks in advance for all your help.

 

[OR VietVet]

Welcome to the forum from Oregon.

 

[swathdiver]

Merry Christmas Shawn!

The path to 550-600 horsepower from 320 is forced induction and or more cubic inches. A supercharger and the required engine mods might just barely get you to the lower end of your goal. A turbocharger with the required mods can attain that goal at the expense of durability and reliability.

A 425 or so horsepower LQ4 would be a nice 14-second truck with 3.73 or 4.10 gears and the stock transmission. A naturally aspirated LQ4 in that power range will not be pleasant to drive everyday.

There are lots of posts on here with horsepower recipes and many of the guys that did them are still active on here, the search feature is your friend.

 

[Miami-Dade]

@Biggshawn824 Move you here from intro section for your answers.

Welcome from NYC&South Florida Shawn!

Merry Christmas!

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.

Start with the basics:

How many miles on the truck? - Long-term wear and tear on components will result in multiple failures, if they are not addressed first, before adding HP to the truck.

Are the motor, torque converter and transmission original? If not, how many miles on them? - These are very critical items in terms of adding HP, if these items are original with a lot of miles on them.

What is your budget for this adding HP project? This project will NOT be cheap, particularly where you won't be doing any of the work yourself. Simply adding forced induction, without making any other changes will be in the neighborhood of $15,000+, and that is without spending any money on replacing/upgrading bottom end or top end motor components.

We can certainly work with you on this project, and it is important that you are seeking input to achieve an understanding of the project's complexities and costs.

 

[Bigburb3500]

What a great present! Budget will be a big part of it.

I think I would do a supercharger + required fuel mods and a 10L80 swap from powertrainswap solutions. Swaybars and general suspension work would make it ride real nice too

 

[strutaeng]

Hey, I'm Shawn, new to the group, hoping to find some advice and guidance. My wife bought me a 03 Yukon Denali XL for Christmas (shes the greatest), and I want to take it from stock to around 550-600hp, while still being daily drivable. I've already had the basics done ( oil change, tune up, fluids flushed and refilled). I've already ordered the bigger 07 type brakes and a cold air intake, and that's where I get lost in next steps. I've done 1000 Google searches, and each one says go a different route and its getting a bit overwhelming.

What should i upgrade/swap? What should i leave alone? Need more info. See below.
What is the difference between cathedral and square port heads? Cathedral has a tiny bit more low-end torque, but square port offer better airflow(and thus more HP.) Not a huge amount to make a huge difference for daily driving, I don't think.
Should I rebuild my current 4l60E or swap for a stronger one, or swap to 4l80E? I'm a big fan of the 4L80e. It's a much smoother shifting automatic transmission. Plus, it's much stronger than a 4L60e in stock form. You have to spend an insane amount of money at a 4L60e with aftermarket expensive parts to get it to hold big power, and then a lot or most still fail in a larger, heavier truck like yours.
I always see 2wd/4wd parts but i never see awd, so can i use any of those parts? Yes, the NP149 has proven to actually hold up really well in drag racing, in spite of it not designed for it. It can be a challenge to mate it to a 4L80e, however if you go that route.
Can i ditch the air ride? Yes

I have so many questions and no one to really ask. Didn't grow up with " car guys " and haven"t been able to find a local car community yet due to just relocating to the area ( southern Indiana), so my education/research has been all YouTube and Google.

Past changing a flat and adding oil (notice I said adding, not changing), I know nothing about working on cars so most work will be done in a shop. So, if recommendations could come with a ballpark price, it would be greatly appreciated.

thanks in advance for all your help.

Welcome and Merry Christmas! See above for some responses in red.

That's one heck of Christmas present TBH.

Umm, that's a lot of general questions. Like mentioned, a budget for upgrades will first have to be established before guys here can offer meaningful advice.

One question I have is: why do you have to upgrade in the first place? How did you determine you want 500HP? I would get the truck serviced and drive it for a while first.

Engine upgrades is like opening up the "LS engine Pandora's Box." There are SOOO many options out there:

1. A simple "cam swap" with a tune.
2. Bore your 5.3 to 5.7 and turn it into an iron block LS1
3. A stroker kit to convert your 5.3 to an LS 383.
4. An LS 6.0 LQ4/LQ9 swap from tbe junkyard.
5. Some other larger displacement LS with a 408 or 427, etc.
6. Forced induction with a turbo or supercharger.
7. Nitrous
8. Any combination from the above.

As you can see, all you need is money! Another question is: who is doing the work? Do you have the tools and time and a shop or garage?

I hope this helps.

 

[S33k3r]

Welcome from Texas! And a hearty Merry Christmas, too. (It's 75 degrees F today!)

 

[Double J]

You had me at “My wife bought me a Denali”….does she have a sister?

 

[Mudsport96]

Easiest fastest way to that power is injectors, fuel pump, turbo, intercooler and tune for e85. Oh and a 4L80e swap. At 14 psi and you will be in the neighborhood of 550 flywheel. Then replace the exploded gov-loc with a good posi unit.

RHP turbo 5.3 tahoe

 

[Marky Dissod]

... wife bought me a 03 Yukon Denali XL for Christmas (shes the greatest), and I want to take it from stock to around 550-600hp, while still being daily drivable ...

Since it's AWD, can we assume it's a 6.0L (not a 5.3L)? If I'm wrong, you might want a 6.0L.
Next thing you want is better axle gearing: 3.73 if mostly or all highway and/or she complains about gas expenses, or
4.10 if mostly stop'n'go and no one cares about gas expenses, or if you plan on any towing.
Better axle gearing is the only hope of helping the transmission last longer, every other mod that releases or improves performance wears out the trans quicker.

Next thing you need is a pcm tune. Personally I recommend pcmperformance.com for GMT800s;
there are other very reputable tuners that can also tune your pcm, usually for more than pcmperformance.
That's the stuff EVERYONE (ELSE) SHOULD HAVE ALREADY DONE, including you.

What should i upgrade/swap? What should i leave alone?

Everyone says how much power they want, almost no one ever quotes any stopwatch times.
AWD helps, but I've been in very powerful (2WD) sedans & coupes cars that can't hook from a stop, so their 1/4mile times are weak.
Point is, pay attention to the tires / steering / suspension. If it can't handle the power, especially in curves and swerves, less smiles per gallon.

What is the difference between cathedral and square port heads?

If you're not going with forced induction, stick with your present cathedral heads if you want forced induction, or consider upgrading to 243/799 heads if you'll stay naturally aspirated.
You don't really need rectangle heads. (Square heads are LS7-specific heads.)

Should I rebuild my current 4L60E or swap for a stronger one, or swap to 4L80E?

Sooner or later you will very seriously consider selling this vehicle.
When you do, whether it has a 4L60E or 4L80E will affect who wants to buy it for what, and how much they'll pay for it.
Were I you I'd beef up the 4L60E to '4L70E' if not '4L75E' spec; you can have yours rebuilt (more downtime) or buy a stronger one to swap in (less downtime).

Oh, one other thing: if it's a Denali, it likely has 18" or bigger wheels, if so, upgrade to the 2015-2022 GMTK2UC 4 piston front brake kit.

 

[Scottydoggs]

cost me 15k to get to 600 whp in my camaro with a 6.2, cam headers injectors and a blower. you need a damn good built tranny and a toque converter with a higher stall and a triple disk clutch in side it, (1300 bucks right there) so 600 whp will cost you a easy 20k by the time the smoke clears. that 15k i spent was 5-6 years ago, prices have all gone up, parts and labor.

my tahoe is 100% stock and my daily, im not touching it. hell i paid more for the blower on the camaro then i did for the tahoe lol

 

[Biggshawn824]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.

Start with the basics:

How many miles on the truck? - Long-term wear and tear on components will result in multiple failures, if they are not addressed first, before adding HP to the truck.

Are the motor, torque converter and transmission original? If not, how many miles on them? - These are very critical items in terms of adding HP, if these items are original with a lot of miles on them.

What is your budget for this adding HP project? This project will NOT be cheap, particularly where you won't be doing any of the work yourself. Simply adding forced induction, without making any other changes will be in the neighborhood of $15,000+, and that is without spending any money on replacing/upgrading bottom end or top end motor components.

We can certainly work with you on this project, and it is important that you are seeking input to achieve an understanding of the project's complexities and costs.

Thanks for the response. I've posted in other forums and only received jokes and sarcasm, so this is refreshing.

My Yukon (still workshopping his name lol) has 229K miles, all on the original motor (6.0) and trans (4L60E). I feel safe in saying the torque converter is original too (what is a torque converter?) didn't ask cause i honestly just learned it was a part from your question. But I can. The truck has one owner, which is my brother-in-law, so anything idk i can just ask.

It has been well-maintained and drives great, aside from an air-ride leak, which will be fixed as soon as the parts arrive.

I have noticed the trans struggles a bit through 1st and 2nd, and at times kind of stutters accelerating from a stop. So I'm assuming trans work of some sort is in my future. Which leads me down another overwhelming rabbit hole, rebuild V swap, then swap new V reman. Im leaning towards swapping new but hit a wall at 4l60 V 4l80.

In reading this thread, I think I might have gotten starry-eyed with my HP number. 550-600 honestly might be overkill, So lets forget that for a second.

Let's just say I have a 15k budget for engine torque converter, trans, and suspension. I can say I don't want a super budget build, but it also doesn't have to be the most expensive parts I can find, just to say I spent a lot. I want to stay NA and reg pump gas. the only mods i for sure know i want are the trailblazer ss intake manifold ( purely cause i like the look) and a cam that provides a decent amount of chop.

What should I touch V leave alone?
What area should I focus on first?
What kind of power could that budget afford me?

I never plan to do any racing or towing and idc about mpg, I just want a solid truck that i can cruise around in, with enough power to get up and go when I want to.

Thanks again for your help.

PS. I'm down to learn to work on my own vehicle and honestly want to, so any resources in that area would also be appreciated.

 

[OR VietVet]

When I was in the shops, I had people approach about "go fast". I have always felt and said I would not do go fast till I first made sure the driveline, steering and suspension and brakes were addressed first. My biggest seat of the pants upgrade is Hellwig suspension and I have a slight Black Bear tune. I admire what you want to do and hope you do a build thread here.

 

[adventurenali92]

First off, @Biggshawn824 welcome from Southern California from another GMT800 Denali owner! What a great Christmas gift your wife got you! These trucks are so much fun to drive, and so incredibly comfortable! Some interesting information here that I may speculate on. OP Probably has an LQ4 6.0 since it’s a Denali. I’ve heard that some came with a 5.3, though I’ve never seen a 5.3 powered Denali in person. if it’s a Denali it’s AWD as that was the only drive train option available on a 2003 Denali. It also probably already has 3.73 gearing as that was the factory option for Denali trimmed Yukons.

Power upgrades aside since I’m not well versed in that though I wanna learn a did line to do some as well. No one has mentioned the 2005/2006 Efan upgrade. Lots of benefits there. Also I would highly recommend a transmission cooler upgrade. Many options available on that front. The trukool 40k unit I went with has been great. No complaints. I’ve heard the 4L80E swap isn’t a totally straight forward swap as the output shafts are different due to the 4x4 transfer case being different than the AWD transfer case in regards to where the trans and transfer case mate up. I know it’s been done but just be aware it’s not a simple plug and play swap, it will take some work. I believe there might be some threads on that maybe? In the 2006 engine and drivetrain sub forum?

In regards to your suspension question I’d highly recommend you search the suspension subforum under the 2000-2006 section as there are literally TONS of threads discussing the auto ride suspension topic and pros and cons of deleting versus keeping. All boils down to how you’re gonna use the rig and what suspension options are gonna best to fit those needs.

 

[Biggshawn824]

When I was in the shops, I had people approach about "go fast". I have always felt and said I would not do go fast till I first made sure the driveline, steering and suspension and brakes were addressed first. My biggest seat of the pants upgrade is Hellwig suspension and I have a slight Black Bear tune. I admire what you want to do and hope you do a build thread here.

I've adreased the brakes, upgraded to 07 style 2pistons ( just found out from thread there's a 4 piston option.)

When you say drive line and steering what specific parts does that cover?

Aside from the new air shocks and compressor I have on the way what other suspension components?

Thanks for all your help.

If you have brands or sites you recommend plz include.

 

[Joseph Garcia]

Thanks for the response. I've posted in other forums and only received jokes and sarcasm, so this is refreshing.

My Yukon (still workshopping his name lol) has 229K miles, all on the original motor (6.0) and trans (4L60E). I feel safe in saying the torque converter is original too (what is a torque converter?) didn't ask cause i honestly just learned it was a part from your question. But I can. The truck has one owner, which is my brother-in-law, so anything idk i can just ask.

It has been well-maintained and drives great, aside from an air-ride leak, which will be fixed as soon as the parts arrive.

I have noticed the trans struggles a bit through 1st and 2nd, and at times kind of stutters accelerating from a stop. So I'm assuming trans work of some sort is in my future. Which leads me down another overwhelming rabbit hole, rebuild V swap, then swap new V reman. Im leaning towards swapping new but hit a wall at 4l60 V 4l80.

In reading this thread, I think I might have gotten starry-eyed with my HP number. 550-600 honestly might be overkill, So lets forget that for a second.

Let's just say I have a 15k budget for engine torque converter, trans, and suspension. I can say I don't want a super budget build, but it also doesn't have to be the most expensive parts I can find, just to say I spent a lot. I want to stay NA and reg pump gas. the only mods i for sure know i want are the trailblazer ss intake manifold ( purely cause i like the look) and a cam that provides a decent amount of chop.

What should I touch V leave alone?
What area should I focus on first?
What kind of power could that budget afford me?

I never plan to do any racing or towing and idc about mpg, I just want a solid truck that i can cruise around in, with enough power to get up and go when I want to.

Thanks again for your help.

PS. I'm down to learn to work on my own vehicle and honestly want to, so any resources in that area would also be appreciated.

As you noted, we are different than many other Forums, and that is the way that we all like it here. Good perception from your viewpoint. We don't accept sniping at or insulting, or attempts to degrade other Members. We do joke with each other, but in a respectful way. Folks who don't think and act like we do in this Forum, we tell them to go back to Facebook and Instagram, and they are soon gone. That being said, you are already receiving clarifying questions and sage advice from the knowledgeable folks on this Forum.

As @OR VietVet stated above, if you want to move forward with mods, the first thing that you have to do is shore up and stabilize where your truck's condition is today. That is so true and so often neglected, and, I'm guilty of that, was well, over my wrenching years. Someone starts adding performance mods to an unstabilized truck, maintenance-wise, and then wonders why when he adds one performance mod, three other items on the truck break.

Let's start here. If you are noticing issues with your transmission/shifting, you would need to address that before you even think long about mods to increase performance. You stated some symptoms that would suggest an issue with either the torque converter (device that connects the motor to the transmission), or the transmission itself, or both. @NickTransmissions is our resident transmission expert, and he will chime in with his thoughts and perspectives.

 

[Marky Dissod]

4L60E. Converting to a 4L80E is NOT straightforward, will make your XL slower.

4.10 unless highway MpG matters 'too much' vs city MpG. If highway MpG doesn't matter much, 4.10. City MpG WILL improve, as will smiles per gallon.
You'll be pleasantly surprised how effective 4.10 is, it'll make your 4L60E more durable and last longer too.

FTI, Yank, Circle D, Ultimate, or Vigilante are reputable torque converter upgrades, other reputable sources exist besides the ones I cited, but I cited elders.
You'll never tow, but - compared to nearly every vehicle lighter than your 6,000lb XL, it ALWAYS hauls heavy, sometimes up to 2000lb more than that.
Long story short: avoid 'loose' converters, avoid stall speeds over 2400 (engine) RpM - do NOT sacrifice your XL's low-throttle response & normal drivability.
If you do not get 4.10, DO NOT increase your converter's stall speed, DO NOT get a 'looser' converter.
If you get 4.10, you should still keep your stall speed under 2400RpM; if the converter is too 'loose', you'll regret it.
It is possible to get a torque converter that is NOT 'looser' than GM OE, with a slightly higher than GM OE stall speed, costs a bit more, totally worth it.
Yes, definitely upgrade your ATF cooling somehow, whether with a 'better' cooler, or by adding an aux fan to yours, or both.

If you'll never tow, '05/'06 electrical fans are EXCELLENT. You don't need later/higher wattage fan motors (nice to have, requires more alternator & a higher idle).

Trailblazer SS intake manifold is actually available on ANY/EVERY Gen4 5.3L / 6.0L V8 post-2005, think of it as a GMT900 intake manifold to avoid confusion.
If you're willing to improve your intake manifold, 243/799 heads will noticeably improve throttle response and power from 2000RpM up, once it's tuned for.
You don't want rectangle heads - 243/799 heads are basically Gen4 5.3L heads, so they're about as easy to find as that intake manifold.
If you're willing to reconsider the 87 octane requirement, 91 octane CAN improve both MpGs AND power from 2000RpM up, once it's tuned for.

With what you've left, try to avoid a cam with too much 'chop', especially if you did not go 4.10, especially if your torque converter is 'looser' than GM OE.

In terms of suspension and steering, you want stiffer springs & swaybars, and tighter shock absorbers, plus heavier duty front steering links.
I'm still learning about this myself, but I'm hung up on not adding front coil springs. If you're willing to ADD front coil springs your options open considerably.

 

[Mudsport96]

Did not catch the awd.
Ok so all the same parts I listed in my last post apply. And you will be using a 6.0 so the power will come easier.
The vid I am posting now is an awd Yukon xl and he did not know it was awd so the front wheels are strapped. He had a complete STOCK fuel system in this video so he was limited to what it could flow. But he makes 349RWHP while slipping the awd case so probably would be significantly more than that on the correct dyno. A stock 6.0 tested with no accessory drag will make in the neighborhood of 400 FLYWHEEL hp. So add 14 psi of boost and that is 800ish. Even losing 300 of that in the drivetrain will get you your 500.


Uncle Rob turbo Yukon

 

[Mudsport96]

6.0 dyno

jump to like 12 minutes to get the 6.0 stock hp dyno