5.7 vortec 0411 rinning different os ??s

Im back again with the stupid questions. I would like to run the 1bar map rtt os on my tahoe but i have no idea what im doing. I need some guidance on what swapinf the os does and how it benefits me aside from the obvious. I had my 0411 mail order tuned and it ran good but startup was horrible and the shifting sucked. I have most of that figured out now but i would lile to be able to use the rtt function. Is this even worth my time? Im running a lt4 hot cam with 1.6 rockers and heads have been milled with metal shim headgaskets and flat top pistons. Bore and stroke stock and intake is stock. I am completely new to tuning and any help and advise will be appreciated. One day ill get the 5.3 in. Tia.

What OS are you using? I think I had told you in another thread that it doesn't work well to write a different OS to your ecm with hptuners. I may not have been very clear, depends on what you are trying to accomplish (engine swap in this case) you may want to change the installed OS on your ecm. Hptuners just isn't the best option to do that, I beleive on some ecm's at least a write entire does not write everything neccessary to do an OS swap. A dealer can supposedly flash any os and vin thats compatible with your hardware (not a 2015 os on a 2001 ecm). In my experience you are usually better off buying a used ecm (ebay or junkyard) that already has the OS you are wanting to run, then all you have to do is plug it in and use credits to license it.

I have done an 0411 swap in a 1997 silverado and that was running the OS from an express van (It's been a few years, but I thought that was one of the only factory applications of the 0411 ecm with 5.7 sbc with distributor).

Now all that was just to make sure you are on the OS you want to be? The rtt would be on one of hptuners custom OS that you just apply to the factory OS of your choice. Should be under the OS tab of ecm editor.

As far as rtt being worth it, I was never able to make it work on my setup, so I don't have any input there. If its still as easy to apply a custom os as it was a few years back, you don't have much to lose if you want to try it :)


Hopefully I'm not confusing you here, feel free to ask questions!

I bought my 0411 conversion from lextech when i built this engine because i was going to swap a 5.3 in before i got a misfire issue figured out. Thats a bad feelin when you start building another engine to replace one with less than 1000 miles on it because of an electronics induced misfire. I finally got the misfire issue fixed and sent the 0411 to be mail order tuned. I have no idea what os was on it from the factory. It has something like a 2000200 or pretty close to that in it. I guess ill have to post a tune file. I wrote in a different os last night and i had to hold like 5% tps to make it idle but i think that was in the tune. I flashed back to the mail order tune i modified and copy and pasted all my tables and settings over from that file to the different os. The current os that i recieved the 0411 with does not support the rtt code but the other os does. Im prolly lucky i didnt brick my ecm if it does cause issue. The other os is an express van os so i dont know why it wouldnt work.

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I forgot, but I actually had bought an ecm from lextech also. it looks like he gave me OS 12212156, which I don't think I was able to get rtt to work on ever. With that said I did find an old tune that was set up for 1 bar maf with rtt if you want to compare it. You wanna take it with a large grain of salt though as I'm not sure how well it was dialed in at the time. Also I went to an aftermarket intake somewhere in that range of time so if the injector data looks different, it may be from different intake/injectors.

My setup at that time was actually very similar to what you are talking with the hotcam and 1.6 rr milled heads and shim gaskets, although I had dished pistons in. It figured out to about 10:1 iirc. I really enjoyed that combo.

I really appreciate it. Ill look into it. The mail order tune is good but can be made a lot better. I absolutely love the engine combo. Its nice and peppy in the 2 door tahoe. I still have some startup and after startup idle issues to work out and the torque converter slips in a pulse rythym when pulling a small hill at cruising speed but besides that and the rough fuel milage its pretty good. I figured i was somewhere around 10.25-10.5 compression since the heads were milled and the deck was cut.

Got a little update. The mail order os was 2020005. I flashed to 12212156 with the 1 bar maf rtt code. The rtt function actually works! I dont use it much but it really is nice to have when i use it. I have logged 2 events and have gotten all of my cruise range and some of the higher range in the ve table tuned down to about -7-0. I still have some tuning to do before i go back to the maf tune but i see why everybody likes the speed density tunes so much. This engine is just so snappy in speed density.