Alum Block 5.3 L

mw243 · January 9, 2005

I just finished putting 500 miles on my Aluminum Block 5.3 L to break it in and decided to take it out for a few full throttle starts to see what it could do. My expeience left me a little disapointed. This engine is suppose to be making 310 hp in stock configuration with a 9.95:1 compression ratio ( up from the 9.5:1 ratio of the 295 hp iron block) but still had trouble breaking the tires loose off the line. My truck has the 4.10:1 rearend with the G80 locking differential and 265/70R17 tires with 4 speed auto.

Off the line, the engine starts off fairly strong, but as soon as the tires begin breaking loose at around 2000 rpm, the engine just bogs. It feels like I'm backing off the gas even though the pedal is to the floor. After the truck gets rolling, the power comes back. The shift from 1st to 2nd feels OK, but the overall power does not feel as good as during the 2nd to 3rd upshift. I hope to correct this problem and have a much better throttle response along with better contorl over the engine. Could this be a result of Torque Management ( haven't heard of this before reading this forum).

My last truck was four cylinder and it would easily break 31's loose with a 5 speed manual. This truck is my first automatic trans and I'm wondering if this the way all auto behave.

Are there any tuning programs available for the Alum Block or is anyone running a chip or hand held programmer on their Alum Block that eliminated the Torque Managment and increased the response time / allows for quicker downshifts of the trans?

My overall impression of the engine is that its a powerhouse that doesn't seem to get the ponies to the rear wheels. I have a 350 crate motor that produce maybe 270 Hp in a project vehicle and it handles 33's through a 3.73 axle with ease through either first or second gear. I hoping to duplicate the feel of the 350 carb engine in the 5.3 liter.

100R1 · January 9, 2005

Torque management is kicking in.

do a search in previous post on this website there is a lot of discussion about it and other mods of your PCM.

Westers PCM replacement can be custom tuned to remove as much of the torque management as you want

budhayes3 · January 9, 2005

Sounds like the factory tune with good ole torque management is killing you. I'd give a call to Bryan at PCMforLess...there's a link to the left. He worked wonders for my truck after I did my cam swap, and has a tuned 03 SS himself...he really knows these trucks and could nail it for ya!

builderpaul · January 9, 2005

NO such thing as full throttle starts. The new trucks are "fly by wire" ie when you push the gas down the pcm decides how much to open the throttle. Your foot may be to the floor but the throttle isn't open all the way. Try power brakeing, you can't do it. PCM won't alow full throttle, your rpms will get to maybe 2500 than no more. This can be removed with tuning. Many posts serch westers, nelson or if you want to do it yourself hptuners.

I have said it before this is false advertizing to claim the power these trucks have and then not be able to use it.

kirkRHughes · January 9, 2005

I just think it sucks that Chevy only puts the 5.3 HO in the 4WD Extra Cab. Can you imagine it in a SCSB with the 4:10,,,MMMmmmmmm

budhayes3 · January 9, 2005

I just think it sucks that Chevy only puts the 5.3 HO in the 4WD Extra Cab.Can you imagine it in a SCSB with the 4:10,,,MMMmmmmmm

<{POST_SNAPBACK}>

Ohh yeaaa

mw243 · January 9, 2005

Well I'm glad to know it's probably just an issue with the PCM... will have to fix that. Eventually I would like to get a magnaflow exhaust along with airaid intake and throttle body spacer... possibly a thermostat if its necessary. First...gotta get the bed taken care of so i can use it. Just wondering if it's better to add the intake/exhaust first or get a PCM flash...Im leaning towards a PCM flash, but the handheld would allow for easier tunning as assecories are added.