Ls1b l31 5.7l

I thought I'd share these 2 unusual tune files I have. Both are from Mexico market GMT800 (99-06 & 07 Classic) Silverado 3500’s that came with 5.7L L31 CPI engines and 5 speed manual transmissions. They are both LS1B 1mb, 4x low resolution crank reluctor, basically a V8 enabled version of the 4.3L of the same era. I’m sure a few people will find these handy for engine swaps. I’m working on 350ci SBC EFI conversion with a manual transmission and I think these are a better option than manual transmission segment swapping an 01-02 512kb van OS.

If anyone else has similar files I’d appreciate if they’d share them. I’d like to have one for every model year 

Thanks for sharing.
Al

Nice one, particularly for the 1Mb PCM.

Here is a 2004

Thanks! More to toy with :)

I know most just use the van OS, but here's an 01 L31 manual trans from a GMT-800 truck out of Mexico. I'm still on the hunt for an 02 to compare to the 02 van OS. I did see quite a bit of difference in the VE table when comparing this one to the 02 van tune file I have. I know the L31 in the GMT-800 trucks used the larger MAF sensor like the LS engines used, but I wouldn't think that would make that big of a flow difference, especially considering the MAF scaling is different in each tune to match the MAF sensor used. Or it could be the newer intake just flows that much more(in which case I'm going to put one in my TAHOE).

Attachment 22904

It'd be nice to have some people in Mexico reporting back VIN's. I've come across a few 2006 GMT400 C3500HD 8.1L Manual online but no VIN listed. Also, It seems that all the L31 GMT800's that I find are 2005 and 2007, makes me wonder if they only made them on odd number years.

thanks for posting those tunes, If I had the money I would set up a tune repository and start collecting tunes for others to access. I have found links to a couple of repository's but they always seem to be difficult to access or outdated. There was one on drop box, but now I cant find it.


well stupid me I dug through some old emails and found this

https://www.dropbox.com/sh/4ydh5wltk...s4SRJ9NGa?dl=0

I found a list online of a company auctioning off trucks and it had vin numbers listed. That was how I found the 01. From what I've found, 1500's were 4.3's, 2500's were still 6 lug, but had the 5.7l up to 02, 5.3l after 03, and the 3500's kept the 5.7l through 07 classic and all I've seen were 5 speed manuals. It took me weeks to find that list, but they were all 3500's and up. Still looking for an 02 2500 with a 5.7l auto to see what GM did differently for them. The only difference's I seen in the 01 was the maf scaling since the gmt-800 trucks use an 85mm maf vs the vans 75mm maf, and the VE table was a good bit higher all around(not sure if this was due to the different intake, larger maf, or that they're tuned to run on leaded or unleaded fuel).

I'll keep looking for some 2002 VIN's and post them up if I find any. I did manage to find the 2006 GMT400 C3500HD 8.1L Manual that I was looking for. I was expecting it to run a 1MB ECM but it is 512kb with OS 12216125.

Attachment 22913

The VE table in the last file I posted is a lot different when comparing it to a 2002 GMT400. I can confirm that the truck which that tune came from did not have a propane conversion.

Quote:

---

Originally Posted by koolky

I'll keep looking for some 2002 VIN's and post them up if I find any. I did manage to find the 2006 GMT400 C3500HD 8.1L Manual that I was looking for. I was expecting it to run a 1MB ECM but it is 512kb with OS 12216125.

Attachment 22913

---

Interesting, maybe GM just kept using this as a carryover from 02 for the Mexico trucks? That's the normal 8.1 OS from 02, interesting to hear there are changes compared to the 02 MY version.

I know GM/Holden did some things like that for certain Holden vehicles in the 02-04 range so this isnt a huge surprise.