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I've been reading up on LT- and LS1 controllers as well as a few aftermarket ones. The main thing that I've noticed is due to the MAF/MAP function of the LT1, the information transfer is not as fast as it is with the Newer LS1 configuration. My question is this, which engine management system is best suited as a reliable/preferred upgrade to the LT1 engine? I do plan to convert from the opti to the coil per cylinder ignition setup.
 

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Ls1 pcm is the way to go. Car computers have sped up, been given more memory, more control functions, just like home computers have progressed.

And if your going to coil pack ignition, ls1 pcm is also the choice to make.
 

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Ls1 pcm is the way to go. Car computers have sped up, been given more memory, more control functions, just like home computers have progressed.

And if your going to coil pack ignition, ls1 pcm is also the choice to make.
Is the ls1 computer a better option than f.a.s.t, or big stuff 3?
 

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It's a better option, not because it's that much better than the others you listed, but because it can be bought for much less than the others.

If your going to the 24X system, you can just buy the crankshaft suff , I believe for around $700. Then go out and find ls1 pcm, engine harness and coils used. Search craigslist everyday until you find a good deal on the items. Then repin the engine harness yourself.

That way you save quite a bit of $$$ from if you bought the whole 24X system.
 

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It's a better option, not because it's that much better than the others you listed, but because it can be bought for much less than the others.

If your going to the 24X system, you can just buy the crankshaft suff , I believe for around $700. Then go out and find ls1 pcm, engine harness and coils used. Search craigslist everyday until you find a good deal on the items. Then repin the engine harness yourself.

That way you save quite a bit of $$$ from if you bought the whole 24X system.
hey coco what why is it called the "24x"? if you just buy an ls wire harness and swap over all the conectors/plugs to the new harness use the ls pcm, is that considered 24x or is there something else you have to get, other then the timing cover block off's and coils?
 

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LS1's require a 24 tooth relucter thats on a ls1 crank. So they shrink it up and put it where the relucter wheel on a 96-97 LT1 is so it can read crank position and determine when to fire coils, injectors, etc

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For the engine harness, you will have to do like shownomercy ad do some rewiring and re pinning of wires because of the difference in lt1 sensors, actuators, and the 24X stuff on front of engine.
 

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Or just buy a brand new one done and save a load of time and headaches with possible wiring issues down the road I did just because in the time I'd spend doing it I could make 1.5x the money it cost plus its all BRAND NEW

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I agree that the 24x system is the way to go to upgrade (significantly) the capabilities of the LT1 fuel/ignition system. The basic parts for the conversion are not that expensive if you're willing to do a little leg work and sourcing of your own.

You will need to buy the cam sensor mounting plate, and the 1x and 24x reluctor wheels from EFI Connection, as they are custom fabricated for the conversion. The sensors and coils themselves are factory GM parts, as is the wiring for them. EFI Connection stocks all of the necessary GM components to complete the conversion, so it makes a lot of sense just to buy the majority of it from them.

I built my own harness, mainly because I made so many changes to the entire engine electrical system...
 

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personally, i'd build a megasquirt and use speed density; i'd use a single o2 sensor, but still make it sequential. but i like pain.

agree the LS1 pcm is a very nice one, with custom operating systems available, and tons more tuneability.

there's also way more knowledge about it, thats the BIG thing. the more i dig into it, not many people truly understand the LT1 pcm. there are some very weird behaviors you run into, and you're completely on your own.

i found a value way in the middle of the range for the iac keep-alive that makes the car die off idle. i've found that blm cells 16-18 are actuated by the canister purge system. i also can't get around the fact that i have one o2 sensor further downstream than the other, and the lt1 pcm HATES it. weird stuff. nobody studies them because 99% of the serious chev FI guys have gone to the LSx platform.

when it comes down to it, the lt1 pcm is lacking a lot of important variables that matter a lot in driving range once you start modifying it heavily, including transient fuel (pump shot), closed loop behavior (o2 delay times, etc), and lean cruise.

funny thing is, the LT1 has a transient fuel map, but nobody has figured out how to modify it yet. i can tell you how to turn it on or off, but not how to tune it.

it has some sort of weird o2 compensations in the LT1 pcm too, to deal with exhaust design.. the F-body runs a 425 millivolt o2 swing point, but the Y-body runs 381... makes sense? no, not really.. always wondered whats up with that

even the ability to run a highway lean cruise mode almost makes me want to swap pcms. that kind of shit is getting really important, for people daily driving big displacement cars with high gas prices. there's just no good way to do it with an LT1.

of course there's another big glaring limitation; you can cam the thing to make high end power all you want, but rpm is a 16 bit integer, and it wont rev out that high. it runs out of data.
 

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Very well stated. I couldn't agree more!
 

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I thought about switching to the 411 pcm when I did my 383. I just didnt see any big benefits that I wanted to take advantage of at the time.
 
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