Hello-

So I was looking at shbox dot com and lt1swap dot com, as well as ‘horsepower tube’s pinout changes, most of that makes sense. Not all of it, most of it. Haha

one question I have is regarding the fuel injector stuff between the 2 systems- if I’m not mistaken, the L31 runs at 4 bar at approx 58-62 psi, give or take with its poppet (or actual injectors if you do the upgrade) gives you 19.1 or 21.9 or 23.1lb/hr depending on where you look.

LT1 runs at 43.5, has the vac regulator so less at high vac and more FP at less vac, so its something like 38 or so at idle and the full 43 at WOT, and the stock LT1 injectors are 24 lb/hr.

So are people lowering the injector flow rate in the 0411 L31 express tune by twenty percent or so across the board to accomodate for the LT1’s lower fuel pressure? I’m just tryin to get everything straight before I convert to the 0411.

thanks
mike

 

Not really clear what your are doing here.

Are you doing a 24X conversion on your 1996? Or are you swapping in a completely different engine?

What is the reference to the "L31" engine - that's a Vortec truck engine based on the Gen 1 SBC. Did you mean "LS1"?

Fuel flow is proportional to the square root of the pressure ratio. The LT1 runs at 3 bar (3 x 14.5 = 43.5 PSI). The LS1 engines run at 4 bar (4 x 14.5 - 58.0 PSI).

43.5 / 58.0 = 0.75. Square root of 0.75 = 0.866. An injector flow rated at 58 PSI will 13.4% less when operating at 43.5 PSI.

What is the reference to a "poppet"?

 

Hey thanks for jumpin in-

yah, so on L31 5.7 Vortecs the oem injector assembly uses these poppet style valves in place of actual injectors, the upgraded l31 multec 2 injector harness assys with actual injectors are better ir whatever. I think the assembly is around 500 bucks.

About the 0411 install- I’m looking to pull the 96 pcm and install the 02 express-programmed 0411 PCM without the 24x reluctor, so I’ll be running in batch fire mode vs true mpfi, really isnt a big deal.

I think I have most of the wiring figured out through the resources available, I guess really the last thing I’m wondering about is why the 96 Vin K v6 car has a clutch position input to the pcm wheres the vin P cars dont? Help me understand that, GM?!?!

I’ll throw my tune file up tomorrow, if you guys can take a look and see if Im missing anything, please lemme know!

I use EFILive, works pretty well. The base tune is from a 2002 express 4L60e 4x4, with changes made to accomodate VE, spark, idle speed from a 95 LT1 M6 bin in Tunerpro, as well as a trans segment swap from an 02 m6 z28.
Changed some fan parameters, also the tach output params.
disabled all the codes I thought I would need to disable, i’m probably missing something, tho.

I copied over/interpolated the LT1 MAF Hz tables, also. I guess the L31 vortec truck engines and the 96 LT1 use the same MAF, but the values are a bit different when comparing calibrations, not really a big deal, just something I noticed. Totally different intake systems, so MAYBE that plays into it.

still need to adjust the gear ratio, also.
also disabled VATS and rear O2s, EGR, AIR.

thanks for squaring me away on the fuel pressure stuff, makes sense! Ya I was kinda just takin a stab at that. 2002 express van has 23.1 lb/hr for the injector flow rating, so I’ll be dropping that accordingly.!

The main goal of doing the PCM change is to make it actually cost effective on the DIY tuning side. According to solomon’s page over at lt1pcmtuning dot com I’ll need to buy a CATS OBD2 tuning cable (few hundred bucks for obd2, iirc), wester’s ecm pro software (few hundred bucks more) and some other software program (more $$$).

Or just do the 0411 swap and have 200 bucks all in for parts/efilive license.

 

Never heard of this conversion. Know even less about the 96 V6. Nothing I can contribute. The only people that even show up here regularly any more are maybe a 1/2-dozen LT1 owners. I'm surprised you found anything about a 411/L31 swap on the Shoebox site.

No LT1 content in the swap at all, other than the LT1 engine becoming a boat anchor. Definitely needs to be moved to a different forum. Not sure where this belongs.

 

Although not well documented, it is most definitely a LT1 Engine Tech related question. 96Z28/SS, I am doing the exact same thing to my 96, but I’ve put this project on the back burner for now. I got as far as you did. I’m using HPtuners and have horsepower tube’s adjustments made to the 2001 Express Van tune. I have it ready to go, but I haven’t tried firing it up yet. After wiring up the 0411, other projects got in the way, and I haven’t gotten back to it since about this time last year. I do think your question is important since I don’t remember horsepower tube going over the injector flow rate. In case you are wondering, I am attempting this conversion to the 0411 computer solely to eliminate the need for the optispark in its current role. After 4 bad optis, it was either this or the 24x. This 0411 Express Van tune is the most appealing for me since I had the tuner and the PCM already from other projects. For me, it’ll be a free mod. I’ll get around to finishing it soon. I hoped by now there would be lot more people doing it, sharing their tune files and such.

 

No worries-

Ya so I just finished up getting everything running, so I'll kinda go through what I've seen so far.

So I followed a pinout diagram that made sense to me after matching it up with the 96 camaro service manual and the 02 express service manual, everything pinned out just fine and I had a few leftover pins, of course; but for the time being, I'm ok with those remaining in OEM (96) PCM connectors. I did splice another 2 grounds into the system that are required by the 0411, this is clearly defined on the conversion spreadsheet and is no big deal.

Starting off, my car is a 1996 LT1 M6, that's what this tune file is built for, having a 4L60/80 shouldn't be too different, however, as everyone knows, the solenoid logic and stuff changes throughout the years for 60/80e, I'm not a expert on that, but there are differences, of course. Luckily, segment swaps are a big win, of course, as long as the OS matches between the two calibrations (your source and current).

My car has BBK shorty headers, air pump deleted (previous owner said it had the solomon tune, so the air pump code was deleted), everything else is supposedly stock and kinda acts like it. SLP exhaust, 3.42 rear end, 275/40/17 from SLP,nothing special, pretty much a vanilla SLP car.

Before the PCM swap, I was looking at LTFT and STFT data, see how the car was running and LTFTs were matching up within 3% and never really getting too far 0, maybe +/- 5 LTFT, which is fine in my opinion. Generally the car ran good. AC works, both fans work, coolant is around 194-198, looks normal.

In the tune, I changed a lot of stuff, a lot of it is interpolated/transferred from the 02 L31 express as well as the 2002 camaro LS1 M6.
I also downloaded Tunerpro to look at a 95 LT1's bin file, just for reference on VE and spark to get a baseline. I'm primarily looking at the LS1 M6 file for throttle cracking/following stuff, but that isn't a 1 for 1, right, so that's just ballpark stuff to get rid of any MAJOR throttle hanging issues/unwanted cruise control... I also, like I was saying, did the Trans segment swap for calibration and diagnostics from the M6 LS1 cal into the 02 Express file.

Verified trans DTC processing and MIL enables were off, basically everything to do with the auto trans except VSS. You can check it out if you want to, I'll try to attach all the files.

Over on the engine side of the house, disabled processing and DTCs/MILs for
-cam sensor stuff (LT1 doesn't have one)
-EGR stuff (don't want it, sorry greta) I know technically it actually benefits things, but I'm going long tubes soon and want the LT1 looking clean
-AIR stuff (previous owner deleted it)
-anything to do with auto trans anything
-CASE relearn codes ( i don't think you can even perform one, anyway... no cam sensor... but I may be wrong on that, happens all the time)
-anything related to EVAP VENT. don't delete the EVAP purge stuff. evidently the 96 F body doesn't have an evap VENT function controlled by the PCM, old or 0411.
-disable VATS
-disabled CARS/CAGS
-disabled all torque management/abuse mode/etc
-changed some fan settings

-adjusted Speedometer settings and verified on the road

Now. The things that require attention...

1-Tach. doesn't matter what setting you use, the closest I can get it to reading accurately is setting the Hi/Lo with 12v Pullup enabled to '1'. This will read exactly half the actual RPM... which EFILive sees correctly versus the tach reading 1/2 low, so that's good. SO essentially the tach reads half of what it should, but the computer knows the true RPM, which is good. lol. I believe 96 clusters are literally a bastard year or something, the internet says it could be looking for a 4cyl pulse, some say its a v8 cluster, some say swap in a 95 cluster, its obviously something with the cluster because the PCM sees the correct rpm. Not really a big deal, I'm just glad it works, right. better than no response at all on any hi/lo setting, I can work with half rpm for now.

2-knock sensor. I read somewhere that you have to adjust the sensitivity to actually get knock to register, so not really a big deal, I just need to read more on that. The part numbers are different, that's fine, I am curious though as to why I don't have any knock error codes, the computer should test the knock sensor after x time/temp to make sure its working. But then again, I have seen some tunes that don't have this on/knock is totally disabled/engine doesn't even have a knock sensor, so we'll see on that.

3- IAC. The 02 express tune has a much larger 'count' capability than the OBD1 file does, but then again I haven't actually seen an OBD2 LT1 file in any tuner platform, so there's that... I was thinking that since the OBD1 IAC can only go up to what, 200 counts, and the 02 Express calibration can go up to 410 or something that there may be a logic/part difference in how the IAC is controlled, which would changed throttle crack/follow/idle etc etc etc. Looks like you can limit EFILive/HPT with a 'max IAC count', which his great, but this stuff (IAC settings/TC/TF) isn't as granular in the OBD1 bin in Tunerpro when compared to the 0411 calibrations. The 96 LT1 and the 02 express do have different IAC part numbers, HOWEVER... the car idles at its commanded RPM for a given temp, does not dip or hang at speed or make you think its broken, so I'm going with 'if it ain't broke, don't fix it'.!!!


4-Fuel injector flow rate
For some reason, to get my LTFTs to read like they were reading before the 0411 swap, I need to tell the 0411 it has 30pph injectors. I do not understand this.
someone please help me understand this one... 0411 tune is on 4 bar, 23.9 pph stock for the vortec van. LT1 runs at 3 bar, vac regulated, so ya know, 38-43/44 psi dependent on vac but always 1 flow rate, 24 pph. Doesn't it make sense to tell the 0411 it has smaller pph injectors because the machine is running on a lower FP, therefore for a given fuel requirement the 4 bar OS needs to hold the 3 bar injector open longer to squirt the required fuel?? This is not the case on this thing. I don't know, case of beer to whoever helps me understand on that one... If I enter 19.1 pph into the flow rate, it will run rich as hell, LTFTs running minus 12-18% through the powerband. I mean it is definitely running rich unless I run the 30pph flow rate, then everything is back normal.

Obviously the 96 injectors (if they even are 96 or different, they look original, IDK) have different offsets and characteristics when compared to the 02 express stuff, totally different setup but the point is, its working fine enough for now. When I do long tubes and a cam/LE1 heads I'll use some GTP injectors that have actual good known data. And the whole EOIT timing, thats different and Imll look at that when the cam goes in. This is bare bones good enough stuff for the time being.!


Overall, very happy with this swap so far, the car runs great, fires right up hot or cold, doesn't buck/stall/hang with the clutch in/out at speed, throttle response seems normal, power is there just like before, pretty happy with this so far. LTFTs are right back to where they were prior to the swap, both at idle and steady state/light accel/hard-ish accel, not in PE.
Also I verified the AC and fans work with the EFI Live dynamic testing stuff, everything is working. No big deal on the Clutch pedal position stuff, backup lights work fine, shes good to go save the tach thing and the knock sensor fine tuning. I drove it pretty hard up to 50-55, works fine, pulls hard, idles fine, no big deal.!!

I'll try to attach my calibration, the 02 express OS 12212156, and the 02 LS1 M6 OS 12212156.


About the pinout PDF in the zip file... ignore the last two pages with the 0411 80 pin tables. use the first four pages. say again; ignore the last two pages, go off the first four with the 96 connector tables.

 

Some videos. Im not a ‘youtube expert’

 

https://youtube.com/shorts/B0QTQbh-KWE?feature=share

 

 

I’ll do a read with HPT here in a few days of the car and post it up. No worries. Beer 30, boys

 

AMAZING!! I’ll keep you updated when I get back into mine. Very thorough and helpful. A great guide to a bare bones 0411 tune. Can’t wait to see your future tunes with those mods!