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2003 Avalanche 5.3L 1.85 rocker question

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Old Jun 4, 2008 | 08:01 AM
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Default 2003 Avalanche 5.3L 1.85 rocker question

Will replacing my 1.7 ratio with 1.85 ratio rockers give a noticable improvement in everyday driving or just WOT?

Does it have any impact on MPG during normal everyday driving under 2000rpms?

Just looking to make the everday drive more effecient for MPG and improve its ability to put my foot into it when needed.

So far I have changed to a K&N filter and trying to get a ported TB to work.

(REP) message and high idle with ported TB
Put back stock TB until I can get that figured out.
May need to have the MAF air table played with.

any other easy bolt ons that will accomplish my needs without breaking the bank?
I was holding off on a cat back system until I needed a new exhaust (maybe another year or two).
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Old Jun 4, 2008 | 08:57 AM
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Replacing just rockers will achieve close to nothing, either mileage or performance wise. Maybe 3-4 RWHP across the band. Not worth the effort. The best thing you can do for mileage is keep your RPMs down to 1600-1800....whatever speed gives you that mileage, drive that speed when you're cruising. You may find you need a taller tire to get there.
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Old Jun 4, 2008 | 09:49 AM
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I replaced the worn out stock 265/75R/17 with some new 285/75R17 Revo's to keep the RPMs below 2K on the highway.

The tires look and ride great but still looking for better breathing and efficiency from the motor.

If the rockers are a bust I guess I will have to wait for the exhaust to go and do a stainless cat back.

I do not like spending that kind of money unless I needed to spend something to begin with. Makes it easier to explain to the wife.

I suppose I can look into a good tuner.
Has anyone here compared a hand tuner to a preprogrammed PCM by Nelson Performance.

Again, looking for economy under 2K and power over 2K.

His site posts rave reviews but I doubt they would post anything less than stellar.
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Old Jun 4, 2008 | 11:50 AM
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Just get a tune to start with.
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Old Jun 4, 2008 | 05:48 PM
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I have been looking into handhelds and custom tunes but everyone claims theirs to the best.

When reading some posts from users, some favor Hyperchip, some favor Diablo, some favor superdhips, etc...etc...

For every good post about a handheld, I can find a bad post about the same hand held.

If I am going to spend $400 I want to make sure they offer all the controls I would need, and multiple preprogrammed tunes to try from thier database.

Again, has anyone here compared the hand tuners to a preprogrammed PCM by Nelson Performance.

Again, looking for economy under 2K and power over 2K.

Again, his site posts rave reviews but I doubt they would post anything less than stellar.
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Old Jun 4, 2008 | 06:20 PM
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Originally Posted by 1989k1500
Just get a tune to start with.
That and exhaust. These LSx motors really do wake up with a good exhaust system. I personally would have spent the money on long tube headers and a good exhaust than the 1.85 rockers. You're looking at worn out valve springs sooner than usual now.
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Old Jun 4, 2008 | 07:04 PM
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I have not changed the rockers, I was only asking as I can get some for under $200 from a friend.
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Old Jun 4, 2008 | 08:09 PM
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Originally Posted by Mack201
I have been looking into handhelds and custom tunes but everyone claims theirs to the best.

When reading some posts from users, some favor Hyperchip, some favor Diablo, some favor superdhips, etc...etc...

For every good post about a handheld, I can find a bad post about the same hand held.

If I am going to spend $400 I want to make sure they offer all the controls I would need, and multiple preprogrammed tunes to try from thier database.

Again, has anyone here compared the hand tuners to a preprogrammed PCM by Nelson Performance.

Again, looking for economy under 2K and power over 2K.

Again, his site posts rave reviews but I doubt they would post anything less than stellar.
If you don't do anything, don't get a hand held tuner. You can get a custom tuned PCM from one of the site sponsers on the right side of the page --> Wheatly, Nelson, etc. They cost less and easily give twice the benefits. If you need to take the truck in for warranty work put your factory PCM back in.
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Old Jun 4, 2008 | 09:10 PM
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wheatley tune is only $275 a good catback $300-$500 pacesetters $550 servo's $100(flt)
all thats less than 2k and you'll see major performance gain
oh btw ive got about $1300 in the mods in my sig minus the aeroforce

Last edited by andrew383; Jun 4, 2008 at 09:16 PM.
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Old Jun 5, 2008 | 08:03 AM
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I am getting pricing on a magnaflow today.

From reading the threads, the Flowmaster 70 seems to be popular but I do not like the aluminized steel.

Looking for something throaty but not to loud.
Definately do not want droning in the cab.
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