LS1 computer conversion ...?

[86LT1]

I've been tossing around the idea of doing an LS1 ecm conversion, and the idea doesn't seem that difficult to do... but things are always easier in your head than when you attempt it haha.

Its just that, at least in my area, finding someone who can tune an LT1 motor is getting harder and harder compared to the amount of ppl who can tune an LS1 motor... for the same price or cheaper, and at a moments notice instead of making a appointment. And I also heard you could even get a few more HP out of doing the swap.

But anywase, just wondering if there is a thread on doing this already?? Or if anyone could offer their advice and what was the estimated cost of performing this. Was it worth it? and would you do it again?

[zmm95]

Im interested in this aswell. I know you can run the stock single coil ignition system with a vortech dizzy if you get the 411 pcm

[86LT1]

Yea, i was hoping to change as little as possible to do this (pcm & wiring harness) .. hopefully we get some feedback on this topic

[94Blackbird]

Yea, i was hoping to change as little as possible to do this (pcm & wiring harness) .. hopefully we get some feedback on this topic

The only effective LS1 swap on the market right now is the 24x system. Which basically requires a new wiring harness.

I had been in the process of putting together a swap based on the later vortec 350 (01-02 vans came with the appropriate pcm) but for the amount of work it would have took to make it work correctly, I'd wind up about two steps short of a 24x swap anyways (having the intake manifold drilled for the vortec style distributor, rewiring the cam/crank sensor inputs) that deep into the project, I may as well have gone ahead with a coil per cylinder anyways and wind up with the 24x system.

Unfortunately, you're looking a a pretty extensive rewiring anyway you look at it to get the LS1 pcm to run properly.

[94Blackbird]

Im interested in this aswell. I know you can run the stock single coil ignition system with a vortech dizzy if you get the 411 pcm


It's not quite that simple, as the optispark is the cam and crank sensor. You'd have to get an OBD2 timing cover with the crankshaft sensor in it. Then you'd have to strip down the harness that went to the opti to separate the cam and crank sensor wires, as the crank sensor would still be on the front and the camshaft sensor is now located at the rear of the motor. Plus you have to repin the entire harness. The LT1 pcm uses 4 32 pin connectors while the LS pcm uses 2 80 pin connectors.

The only tune you'd be able to start with would be the 01-02 van tune as that is the only vortec 350 application that ran with the 0411 pcm.

Also, as far as continuing to use the opti for signal, not possible due to the signal type put out by the opti. It's not supported by the van tune. The opti outputs a digital type signal, while the vortec distributor is a 180 degree hall effect magnetic type signal, if I remember correctly. I can't remember the exact technical definitions, but the short story is that the two signals are not compatible at all. If you want the LS pcm, you're either building a 24x style conversion (which uses a modified vortec distributor for the cam signal I believe, someone will correct me if I'm wrong lol) or essentially rebuilding the wiring harness to run the vortec style distributor, in which case you're really only a step or two away from the coil near plug system anyways.

[zmm95]

Well im on the lucky end of things as ive got a 97 so i have the appropriate timing cover and ive already got my single plane intake ready to go in which has the hole for the dizzy.
So all your saying i would need to do is repin the connectors for the ls pcm, and then route the signal wires from the new dizzy and the crank sensor to the appropriate locations and be done?

[94Blackbird]

Well im on the lucky end of things as ive got a 97 so i have the appropriate timing cover and ive already got my single plane intake ready to go in which has the hole for the dizzy.
So all your saying i would need to do is repin the connectors for the ls pcm, and then route the signal wires from the new dizzy and the crank sensor to the appropriate locations and be done?


That's the theory. I didn't make it that far, so I don't know for sure. You'd have to get ahold of the pin outs for the LT1 and the 0411 pcm off a van.

Also do a google search, there are a few other people out there who are doing this as well. I think there are a couple of cars who may be up and running with this setup as well.

[zmm95]

Ive done a quick search but didnt come out with much, ill dig deeper later today.. if i do this i will definaltly make a write up of it. Just to be sure, running the van programming isnt going to limit me at all, is it?

[BLK95-Z]

Its not that bad, just expensive.

The tuning issue in my area along with the price of the 24x influenced me to just stick with a stock-ish LTx.

[zmm95]

Whats so expensive about it?. You could get the pcm for around $100 and the dizzy for maybe $150, what else is there? I mean i want to go this route to.get rid of my opti and alot more people in my area can tune the ls platform pcm, havent found one shop with a dyno that said they can tune my lt

[94Blackbird]

Its not that bad, just expensive.

The tuning issue in my area along with the price of the 24x influenced me to just stick with a stock-ish LTx.

He's not wanting to use the 24x system, he's wanting to convert to a vortec style distributor and re work the stock harness to connect to the LS pcm.

@zmm95- one thing to check into is the compatability of any of the sensors/gauge cluster. I can't say for sure because i never made it that far into the swap, but I think some of the speedos may use different signals between the years and there may be other incompatabilities that I can't think of right now.

[zmm95]

[QUOTE=@zmm95- one thing to check into is the compatability of any of the sensors/gauge cluster. I can't say for sure because i never made it that far into the swap, but I think some of the speedos may use different signals between the years and there may be other incompatabilities that I can't think of right now.[/QUOTE]

Ahh you make a good point. That never even crossed my mind. But since im a 97 i have the updated interior which usues the same gauge cluster as 98+ ls models so i see no issue with that being compatable, when you say sensors do you mean like knock sensors ect or like low oil and coolant sensors?

[94Blackbird]

Ahh you make a good point. That never even crossed my mind. But since im a 97 i have the updated interior which usues the same gauge cluster as 98+ ls models so i see no issue with that being compatable, when you say sensors do you mean like knock sensors ect or like low oil and coolant sensors?


Basically anything extranious that the engine uses for signal. temp sensor comes to mind, but I don't know about compatibility with the later LT cars, mine's a 94 so that's where the bulk of my knowledge lies.

[gregrob]

There are no issues with the Gen III PCMs and LT1 dash.... You just have to program for the tach and speedo accordingly.

If you do the wiring yourself, and source the coils and all the other stuff you need used, then buy only the necessities from EFI Connections, you can do the LS PCM swap fairly reasonably.

[86LT1]

havent found one shop with a dyno that said they can tune my lt
aint that the truth...

You guys that are in the process of doing this swap please make a thread when you complete, post pictures and note all the problems you had to overcome... If its worth it i would really like to do this.

[zmm95]

Sadly that is the truth.. id like to see a build thread for this too. This summer while im doing my heads and intake swap i wouldnt mind doing thiss as well... im debating if i should start gathering parts for the swap or not..
@Gregrob: you seem pretty knoladgeable about this stuff, what are the things i would need to buy from efi connections? I am also wanting to do the single coil setup, not the coil on plug.

[zmm95]

Bumppp. Lets get these questions answered!

[86LT1]

Bumppp. Lets get these questions answered!

I would have thought someone would have done this setup by now. I would like to see how much it costs and how to properly do all the wiring changes.

[zmm95]

Same! Ive read about some people doing it but very little is written, seems like it would be more popular than it is..