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LTX and LSXPutting LT1s, LS1s, and their variants into Third Gens is becoming more popular. This board is for those who are doing and have done the swaps so they can discuss all of their technical aspects including repairs, swap info, and performance upgrades.
The question is about tuning and how it is best handled. Can the stock PCM be re-programmed to better suit a heads, intake and cam upgrade or is an aftermarket stand alone system required? If the stock PCM is a good candidate, whose tuning software would you use? For the record this is aimed at a 500 HP build direction. NA.
These are some of the considerations I have as I contemplate my next move. Or the move after that.
500 HP out of a 325" motor though, without The Force of some form, is pretty much a pipe dream. HCIE won't cut it unless you're willing to give up EVERYTHING ELSE about it just to hit a "dyno number". As has been getting discussed on LS1tech.com, the ASA LS1 was something in the range of 430 - 460 HP for example; and you're starting out with 10% (about 45 HP) less motor than that.
500 HP out of a 325" motor though, without The Force of some form, is pretty much a pipe dream. HCIE won't cut it unless you're willing to give up EVERYTHING ELSE about it just to hit a "dyno number". As has been getting discussed on LS1tech.com, the ASA LS1 was something in the range of 430 - 460 HP for example; and you're starting out with 10% (about 45 HP) less motor than that.
I suppose I should have specified. The LM7 PCM. The tuning then would fall to something like HP Tuners I suppose?
As for the 500 HP, it's a bogie of sorts. It would mean a lot of RPM and like you say, something has to give for that to happen. But hey, I saw Holdener do it just this morning on YouTube!
Seriously though, I'm doing the pro/con cost analysis thing more than anything (seeing as any actual building won't come until the fall/winter). Contemplating my Gen 1, I've got cylinder heads that combined with 383 CID should get close to that 500 at reasonable RPMs. Probably closer to the 480-490 range with revs less 6000. And yes, really a glory run on the dyno but still it lets me compare. And also thinking about the LS I have in my reserve truck and what it takes for the same output. For the record, this will see hopefully see duty in some open road events so both shortblocks will go the fully forged route regardless of the reputation the LS has for it's stock bottom end.
What it takes to get the LS there though, beyond the obvious hard parts, is the tuning and how it's best to go about it. Thus, this thread.
That's a good question. I'll have to check. I actually have two LM7's. An 06 and an 03. I've read that 05 was they year the Gen IV came along but not sure if it splits this model down the middle or not.
The guy is straight out of the 1980's but the topic matter is definitely more recent.
Different OEM controllers run out of data at different points (fuel flow, RPMs, ect). You'll have to research what will work for you. But you can't just necessarily switch from a Gen III to Gen IV controller because the controllers are looking for certain hardware on the engine that doesn't exist.
I have a friend that takes his LS1 to 8000+ rpm. It was working with the stock 0411 engine controller but he went to Holley HP EFI for the the faster processing speed, wide-band O2, and range of tuning capability. Increased engine response and output at high RPM, but street drivability and idle quality suffered.
Yes its PCM is highly tunable by EFI Live, HP Tuners, etc. Pretty flexible unit actually. I think they were all pretty much the same 03 - 06. I have a 2004 Avalanche and a 2006 PQ9 to go into it whenever I find my Round Tuit or get another (yes I actually had one at one time but then lost it), and they're so close to the same externally that they might as well be identical. In fact I sent the 06 one off to Blackbear for tuning and that's what's in the truck now running the stock LM7.
The guy is straight out of the 1980's but the topic matter is definitely more recent.
Different OEM controllers run out of data at different points (fuel flow, RPMs, ect). You'll have to research what will work for you. But you can't just necessarily switch from a Gen III to Gen IV controller because the controllers are looking for certain hardware on the engine that doesn't exist.
I have a friend that takes his LS1 to 8000+ rpm. It was working with the stock 0411 engine controller but he went to Holley HP EFI for the the faster processing speed, wide-band O2, and range of tuning capability. Increased engine response and output at high RPM, but street drivability and idle quality suffered.
Very enlightening. Thanks. Interestingly both the 03 and 06 Tahoes have drive by wire.
Originally Posted by sofakingdom
Yup, LM7 is Gen 3 by definition.
Yes its PCM is highly tunable by EFI Live, HP Tuners, etc. Pretty flexible unit actually. I think they were all pretty much the same 03 - 06. I have a 2004 Avalanche and a 2006 PQ9 to go into it whenever I find my Round Tuit or get another (yes I actually had one at one time but then lost it), and they're so close to the same externally that they might as well be identical. In fact I sent the 06 one off to Blackbear for tuning and that's what's in the truck now running the stock LM7.
Also enlightening. Now as far as my pro and con columns go, the software adds another layer of expense but like they say, "If you want to play, you have to pay."
I'll have to get under the hood of both vehicles and see what model PCM is in there.
I'll have to get under the hood of both vehicles and see what model PCM is in there.
Speaking of which, I had quick look and the entire computer is shrouded in plastic (which as I recall is a PITA to remove). Nothing can seen of any sort of identification, Is it under there or is there an easier location to access the model of PCM I have?
Speaking of which, I had quick look and the entire computer is shrouded in plastic (which as I recall is a PITA to remove). Nothing can seen of any sort of identification, Is it under there or is there an easier location to access the model of PCM I have?
Picture? I've not seen ECM's shrouded in plastic. Other than a mounting bracket.
As for the 500 HP, it's a bogie of sorts. It would mean a lot of RPM and like you say, something has to give for that to happen. But hey, I saw Holdener do it just this morning on YouTube!
Fun video to watch. I had a different takeaway though. The 5.3L had aftermarket heads, cam, intake and still got absolutely CLOBBERED by a stock 6.0 with a small cam. Seemed like building an n/a 5.3L was a poor use of money.... ?
The shroud comes right off; just snaps on, something like the fuse box cover. It's there for cooling. In fact you can see one of the latches in the photo. Once you pop the shroud off you'll see the air duct. Not really "buried" at all. Underneath there the ECM looks just like any other.
There are ones with blue & red connectors, and ones with blue & green. AFAIK 03-06 trucks w DBW are all blue/green. DBC vehicles seem to use the blue/red.
It's seems the advantage of the LM7 is more it's price point and availability (and seeing as I can daily drive two of them and really only need one...). I think that more than anything, at least for me anyway, is that it can provide a means to access the LS platform in general. Once fitted into the car and running, the build direction can go just about anywhere. Like an LM7 stroker....!
As for the LM7 in general, I guess the small bore puts a limit on the NA potential. Not unlike the 305 perhaps? I understand that the turbo guys like them though.
On a different note, this Holdener guy appeared out of nowhere to me so his cred was somewhat suspect. I believe his videos have been described as "clickbaity"? Then, while thumbing through a 12 year old issue of Engine Masters, I see his name on the masthead with the likes of Vizard and Dulcich. Perhaps I've been a little sheltered. Then again, his specialty appears to be Gen III and IV and my interest in those is only recent. Pretty steep learning curve at first but I've got a good grasp on it now. If it weren't for an expensive pile of parts dedicated to the Gen 1 platform, I'd jump ship.
Last edited by skinny z; Jun 26, 2020 at 09:38 AM.
I had that computer out and on my bench when troubleshooting issues with that truck. I don't recall the shrouding but then again it was a while back. The truck eventually ended up in my GM mechanic's hands for diagnosis and repair. I was thinking it didn't have a cover before and this was his work. Guess not. It seems it's removal was a non-event and not worth remembering.
Anyway, thanks for the heads up on the connector colour scheme. Something to go on for PCM I.D.
Yeah I agree with you about Holdener's videos; he's obviously knowledgeable and mostly common-sensical, but leans a bit too far in the direction of high-RPM big HP numbers for my taste. Not that those are "bad", only that there's more to most satisfactory builds than just hitting the biggest possible numbers.
Also, with things like the 5.3 stroker, SURE, it's "possible"; SURE, it can make lots of power; BUTT, is that the CHEEEPEST BEST LOWEST RISK way to get to "lots of power"?? Kinda like, is putting a 4" crank in a 305, a "smart" approach to More Power? SURE, it's "possible"; SURE, it "works"; SURE, it uses a "free" 305 block; but why spend $3000 on something that you can get the same "power" if you just go to the junkyard and pick it up for $50, without having to jump through all those hoops? Today, in 2020, when you can find 6.2 truck motors EVERYWHERE, how is stroking a 5.3 ANYTHING REMOTELY LIKE A Good Idea? I think alot of that sort of thing is more an intellectual exercise in some sort of "theory" than any kind of a practical and desirable course of action for a typical hot-rodder.
Just because a thing is "possible" does not automatically make it A Good Idea, let alone The Right Thing To Do.
And THAT has got me to rethinking my proposed 383.
Depending on the condition of (primarily) the heads and valvetrain, it may be that I abandon the idea and either A) go with an aftermarket 4.120" bore block and re-purpose my 350's steel crank and rods or B) make the move to LS.
I would suggest starting off with a 6.0 liter LQ4 or LQ9 and LS3 heads. Easier to make 500 HP vs the 5.3 liter LM7. More airflow from the LS3 style heads (all 6.2 liter trucks up to 2014 or 2015 have these heads). And the 4 inch bore of the 6.0 will aid airflow by unshrouding the valves. It may cost a little extra for the 6.0 setup but its well worth it. No replacement for displacement except boost. Then use the P59 ECU out of your 06 Tahoe to run it.
If I were to go all in with an LS swap, I'd step right into the LS3. We have one in the 69 C10 and with the cam swap, it easily passes the 500 HP mark.
But that's a fantasy at this point in time because the budget isn't there for it. Hell, it's not there for a simple Gen 1 shortblock (thanks world economy).
But, to get my foot in the Gen III / IV door on the cheap, that's where the LM7 comes in. I've got it already and the supporting bits like headers, engine mounts, transmission adapter (to the 700R4, the crossmember for which I have), maybe an intake, tuning software, etc, just might come in at the same cost as the aforementioned shortblock. Then once the swap is complete and I've developed the competency to tune it, I can entertain the thoughts about phase 2. If not the LS3, then the souped up 6.0 liter as suggested.
But for now, it's all bench racing and asking questions like the title of this thread. At least I've learned that I can work with the PCM in hand which cuts out a significant chunk of change by not having to buy one.
From my experience, the 411 pcm was found on early ls dbc engines .i.e ls1, lm7,etc.... It supposes to have faster processor speed and better updating abilities and is recommended by tuners. That's what I'm using on the 4.8 and I have another one for when I get my other ls engine to go in the Camaro.
Lm7 are decent engines.. I wanted one but I came across the 4.8 for a good deal.. plus I just wanted to put something in it to drive it since it had been sitting for 13 years.. The whole idea was to get the 4.8 to fit and run correctly , then I would swap in a 6.0 with ls3 top end one day...
Whoever commented on the 6.0 ls3 top end deal... I'm with him... its obviously a much better setup especially to hit 500hp, and still be a daily driver depending on cam selection. I think its possible with the lm7, although it may not be a daily driver though..
Whoever commented on the 6.0 ls3 top end deal... I'm with him... its obviously a much better setup especially to hit 500hp, and still be a daily driver depending on cam selection. I think its possible with the lm7, although it may not be a daily driver though..
Exactly. But you would need ported factory or aftermarket heads and more cam to achieve it. That will require additional cash for the heads. You can get LS3 heads way cheaper. The LQ9 will cost a little bit more than the LM7 also.
From my experience, the 411 pcm was found on early ls dbc engines .i.e ls1, lm7,etc......
I still haven't determined which PCM I actually have. Although with a drive by wire, is this not likely to be the vaunted 411? No idea but I'll find once I move on to that project.
Interestingly, the 500 HP mark with the LM7, while achievable, it'd be like trying to do it with the Gen 1 heads I have now. Even at 383 CID, with 255 CFM of port flow, it's a bit of a stretch. At coincidentally, nosing around the net, it would appear the stock LM7 heads flow about the same. That says a lot about the potential. Which isn't great.
But still, getting the swap accomplished is more than half the battle. The rest is plain and simple hot rodding.
Last edited by skinny z; Jun 28, 2020 at 12:01 PM.
I still haven't determined which PCM I actually have. Although with a drive by wire, is this not likely to be the vaunted 411? No idea but I'll find once I move on to that project.
Interestingly, the 500 HP mark with the LM7, while achievable, it'd be like trying to do it with the Gen 1 heads I have now. Even at 383 CID, with 255 CFM of port flow, it's a bit of a stretch. At coincidentally, nosing around the net, it would appear the stock LM7 heads flow about the same. That says a lot about the potential. Which isn't great.
But still, getting the swap accomplished is more than half the battle. The rest is plain and simple hot rodding.
The 0411 is the P01. The 2006 ECM you have should be the P59. Better ECM in my opinion. May be DBC capable depending on the part numbers on the ECM. Do you have the part numbers available or can you take a pic of the label? The P59 is more E friendly and can go up to 3 bar. Depends on the part number though.
Exactly. But you would need ported factory or aftermarket heads and more cam to achieve it. That will require additional cash for the heads. You can get LS3 heads way cheaper. The LQ9 will cost a little bit more than the LM7 also.
I can crack the case on the PCM (both of them) and take some pics. Can't say when though. But it's reassuring to know that I have the capability to tune whatever I might find.
Trying to work on the '18 Cadillac with the turbo 4 banger was a different deal altogether and that's what got me to asking if this '06 stuff is viable. All the tuning on the Caddy was done remotely. The LS3 in the C10 has an aftermarket controller so that was different yet again.
Getting back to 500 HP potential of the 5.3, I've found, as you mentioned, that ported stock heads or aftermarket is the only way there in NA trim. It's interesting to see that companies like Texas Speed and similar will take my mail-in heads and do the job. I've zero interest in the job myself although I'm fully equipped to do so. Aside from having a flow bench that is.
Exactly. But you would need ported factory or aftermarket heads and more cam to achieve it. That will require additional cash for the heads. You can get LS3 heads way cheaper. The LQ9 will cost a little bit more than the LM7 also.
Originally Posted by skinny z
I still haven't determined which PCM I actually have. Although with a drive by wire, is this not likely to be the vaunted 411? No idea but I'll find once I move on to that project.
Interestingly, the 500 HP mark with the LM7, while achievable, it'd be like trying to do it with the Gen 1 heads I have now. Even at 383 CID, with 255 CFM of port flow, it's a bit of a stretch. At coincidentally, nosing around the net, it would appear the stock LM7 heads flow about the same. That says a lot about the potential. Which isn't great.
But still, getting the swap accomplished is more than half the battle. The rest is plain and simple hot rodding.
Just as JAYDUBB said, the lm7 will need ported, aftermarket heads at the very least, as well as a host of other mandatory costly upgrades to achieve 500hp and it wont be a daily driver..
Obviously, your ls3 idea is a great one too, but I dont know much about gen iv/gen v tuning
These are early days regarding the LS swap in general. Plan A is to have another go at the Gen 1 platform (how many is this I can't recall) but that's dependent on the condition of the heads. They're aftermarket Vortecs plus a stage 1 porting job (for lack of better description) and those are key to my build direction. If they're trash, and they shouldn't be, but if they are, I'll move on to the LS. Plenty of really good Gen 1 parts would be left on the shelf though.
I can crack the case on the PCM (both of them) and take some pics. Can't say when though. But it's reassuring to know that I have the capability to tune whatever I might find.
No need to crack the case. Just take pics of the labels on the ECM's and post them. I have the part numbers and can advise.
No need to crack the case. Just take pics of the labels on the ECM's and post them. I have the part numbers and can advise.
By case I meant the plastic shroud that kind of buries it down beside the rad and battery. I can't even SEE any cables or labels without opening that shroud.
I'm going to have another look. Hang on....
And I didn't see any distinctive colours on the connectors as they're buried a little further in. I had this unit in my hands at one time when I was troubleshooting an electrical glitch with the truck although I've no recollection what colours they were.
Not as it currently sits.
I've an 03 Tahoe as well with an LM7. I may dig into that one a little further as it's not my daily. Seems to me when I removed the other one for inspection (in the 06) it started a chain of events that was difficult to work through.
