I'am new here so first I will say hello to all, I have been reading on this forum for some time now. The other day I just picked up a 2005 Sierra ECSB with the L33 Aluminum 5.3. Have a Mangnaflow and K&N FIPK on order and now I need a good tune, what is out there for the L33? I tryed a search and did not find much.thanks..

 

CALL THUNDER RACING THEY CAN HOOK YOU UP 225-745-7332 TALK TO DAVE.GEOFF DOES THE TUNEING HE IS GREAT DO ALL OF YOUR UP GRADES THEN GET A TUNE SO YOU DO NOT HAVE TO UP GRADE THE TUNE LATER

 

... the L33 has a tad more compression and LS6 heads. I am yet to see a side by side spec and hardwhare comparison of the L33 to LM7 on paper.
I'll bet you can't find a mail order tune for it yet. I am waiting on Allen Nelson AKA nelsonperformance.com to be able to send me one.
These L33's really fall flat after a shift compared to how my 03 LM7 did.

 

Do any of the handheld tuners work for the L33?

 

While waiting for a Nelson tune I called Diablo Sports because they had a $100.00 core credit if you turned in an old one. I still have one from my 03 so I just thaught I'd call and see what was up.
"Oh sure we have a programmer for the 05 5.3 Silverado", the phone person said. I asked which part number was for the L33 5.3. He said "Huh?". I wound up informing them of the L33 in the trucks. He put me on hold and agreed the LM7 tune would not be applicable towards the L33, it may work but would not really be optimised for the application, and said they would call me when it was ready. Now I am a registered user and as far as they know I want to buy and I have not recieved a call yet.
I just checked their site and they still do list an 05 tuner but know mention if it will work for an L33 or not.
I think GM has done somthing different with the L33 pcm and the progerammers are having some difficulties.

I would wait for a Nelson. I have been waiting for a Nelson since I got the truck in October 04. I had the predator on my 03 then went to a Nelson Tune and it blew the predator away. I use the predator to log live diagnostics and read and reset trouble codes for friends.

 

If the L33 has LS6 heads they would be 243 casting # and have sodium filled valves.I would be interested to know if that was the case.

 

I would highly doubt that it has ls6 heads.

1. The ls6 chambers would be too big for the 4.8/5.3 bore.
2. Why would a 4.8/5.3 need such good flowing heads (they dont put them on the gto)
3. It is my opinion that that much flow for the 4.8/5.3 would actually hurt performance and kill the lowend that these trucks need.

Rock, what are the casting numbers on the heads?

 

... is 799.
In the brochure at the time of purchase I read it was a the H.O. had Higher Flowing Heads. Now they may be LS6 castings to start with but now word on how they finish up for the truck application.
This is why I want a side by side spread sheet comparison on the L33 and Lm7. With cumbustion chamber CC info would be nice too.

 

The L33 also has a different cam than the LM7, I found out the other day. I work in parts a dealer.

 

It sounds like the L33 is a completly different engine from the LM7, so there is no one that has tuning for it yet.