Exploring an upgrade path

Hello guys.  I just acquired a 2004 Avalanche in really good shape and got it for such a good price that I think I can justify doing some mods on it.

I'm 50 now and haven't torn an engine apart, with top performance in mind, since my high school days.  Back then, all we were worried about was how the engine would run at wide open throttle.

With the Avalanche, I'd like to increase driveability and the fun factor while not hitting the gas mileage too badly.  Consequently, my concerns are now, not only making power, but where in the rpm range its made.  To start, I have to keep in mind that this is my daily driver now and in the real world, it's gonna spend most of it's time between idle and 3500 rpms, so I'm looking for an upgrade path that will work more on the bottom than the top.

Based on my research and past experience, going with a CAI is a waste of money.  I'll likely just get something like the Airaid MIT to relieve the restriction in the intake air flow.  Getting the air in should be covered, so that leaves getting the air out.  I believe that this would mean headers to get any sort of substantial gain from exhaust modification.

The question then becomes, long or short.  My knee jerk was to go with long headers, but the research I've done seems to indicate that, although long headers do make more torque and horsepower, they do so at the upper end of the rpm range.  I think I've decided to go with shorty headers because the dyno results I've found on the net indicate that they give appreciable gains from idle to the 3500 rpm range.  Right now, I'm debating on Doug's vs JBA.

Whatever I get, I'll likely run the stock exhaust system for a bit and then start putting some thought into what I'm going to put behind the headers.  I don't want loud.  Full throttle growl is fine, but I really don' t want droning.  Any ideas?

To top it all off, I'll go with a handheld tuner from diablo so I can run canned tunes until I know I'm done messing with the truck and will order a custom tune.  I'm figuring that this route will increase driveability and add to the fun factor.

Any comments or advise getting this 3 ton pig moving will be appreciated.

You are definitely headed in the right direction.  Black Bear Performance did an intake test and the Air Raid Jr. was the best out there so I would suggest going that route.  Basically a tube that used the stock air box and an upgraded filter.

I personally went with shorty headers and noticed a huge improvement in throttle response.  After installing the headers I had Black Bear Performance do an in person custom tune.  The Diablo was my 2nd choice so seems like you are headed in the right direction there as well.  I just don't believe folks who say shorty headers don't give you much performance increase.  Due to emissions and lack of free time shorties were the way for me.  My Avy also tows my boat a lot better since I had them installed.

Custom tune is the way you will want to go eventually as you already stated.  It was the single best mod I have done so far.  Made my truck a 100x more enjoyable to drive.  It was $300 and worth every single penny and then some. 

Basically I think you have a great foundation planned out to make your truck a lot more fun to drive without sacrificing MPGs too much.  I personally have a gibson catback exhaust and it has a good tone under acceleration but has 0 drone on the highway.  I will say though that after adding the headers I do have some drone now but it is very mild and too me just sounds like a kick ass V8. 

Another great and fairly inexpensive mod you can do is add a corvette servo to your transmission.  It will really firm up your shift points.  They cost about $20 and takes a couple hours max to install.  No need to drop the transmission.  Pretty straight forward if you google it.

Congrats on your new to you AV and welcome to the club...

Your on the right track with the mods. IMO the CAI is not worth to much unless it's truly a CAI and has a actual cold air tube (see pic) coming from the out side, otherwise a good flowing filter is all you need.


Headers are definitely on the list for performance here's the HP/Torque numbers shorty vs. long tube. Either are going to give some performance you decide which you want, just make sure you get them with ceramic coating. It cost more but reduces under hood temps and that goes along way in helping performance and increasing the life of under hood components..

Welcome to AV ownership and this website.

You haven't mentioned budget for these mods so I will say the old adage about "How much performance can you afford?"

Not sure I would worry with headers if you aren't changing the exhaust at the same time sine the stock exhaust is so restrictive. My personal choice for exhaust would be Corsa Sport CAT back set-up, They have a lifetime warranty and is an easy install they are also known for NO DRONE.
http://corsaperf.com/viewpart.aspx?year=2004&make=Chevrolet&model=Avalanche&partnum=14250&cfg=282

And for me the best bang for the buck on usable performance increase without tearing apart a motor or destroying gas mileage would be a Magnacharger supercharger kit. Many members have installed this set-up for towing with great results.
http://www.magnacharger.com/p-51-escalade-suburban-avalanche-tahoe-yukon-xl-48l-53l-60l-2004-2006-radix-magnuson-supercharger.aspx

Flowmaster 70 series muffler lets people know you aren't stock but no drone.  The 50 series is also a good choice with pretty much the same sound level but different tone.  Both will flow much better than stock and are priced right.  I've had two 70s on my truck - the first one lasted 200K miles.  Shorty headers are an easy install and you will be able to feel the difference.  If you change the tranny servo note that the computer has a programmed shift time and the firm shift will go back to a stock-like shift without custom tuning.  Custom tuning can get the quicker shift without the servo - I wouldn't do the servo again without doing more serious power adders than what you are talking about here.

Thanks for the responses guys. 

Bruizza, I ran across a few mentioning that servo mod.  I'd imagine that it involves dropping the pan on the tranny.  I'm gonna hunt down a vid and see what's involved.  Getting more than a couple of hours free is difficult, unless i do it in the middle of the night.

Randy, no true CAI's for me.  I live in New Orleans and the water rises often.  Those numbers on the headers look promising.

Vaeagleav, that's a stiff MSRP, but the system sounds interesting.  A blower with a bypass system like a turbo.  Kinda like having a Mad Max switch only automatic.  I'm wondering what kind of MPG hit I'd take with something like that.  I'm only getting around 12 as it is, but bolting on 100+ horsepower that's there only when I need it is really appealing.

It's looking like I'm gonna have to pay more attention to the tranny than I anticipated too.

I'll throw my two cents in on good info.
- drop in filter and the Air Raid tube (and I have a really good CAI, just dont think theyre worth it)
- Long tubes will make more power
- the Vette servo is a must and I didnt see a Trans Cooler mentioned but it should be madatory
- Corsa, Corsa, Corsa. no welding or custom fitting, no wheel reinventing needed, they fit PERFECT, sound amazing, and make power Now models: a Sport is louder adn sounds great with out headers, I have a Touring and its perfect with my Long tubes. for a family vehicle the the Sport and long tubes together would be a bit much. Neither will Drone - This is a way bigger problem than people Imagine until the buy something else and end up with a new thread on here chassing a different solution; It seems like every non Corsa "I know better" experiment goes this way.
- If you must have a tuner I agree with Diablo (I loved mine) but my custom shop tune was only $300 and its better.

Kenner Avy owner here!

I haven't even been able to start "upgrading" yet.  Been spending all of my time just trying to get things right before I start changing stuff.  My Avy has low miles, but it's still an '04.  I'll update when I get things rolling.  If I get things rolling.  Lately I've been debating on whether to keep the Avy or trade it in on something else.