LS1 with traditional 18436572 firing order?
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Gen2-LT4 (10-18-2022)
04-14-2012, 07:29 AM
#26
TECH Enthusiast
I love LS motors, but feel the Fords do sound better, than the original SBC. Most people will agree with that. Copying the Ford order was a good idea IMO. There are only so many ways fire a V8, it's not like there are limitless combinations. It would have been hard to change the order, and not have it match somone elses order. In reality there is one order that is most likely the best for harmonics and longevity, I think thats where we are at, and why all modern V8s are all headed towards it. The LS/ford order is the most popular by far, and for good reason.
04-14-2012, 05:14 PM
#28
As I recall, GM used the newer firing order because finite analysis had shown it greatly reduces the stresses on the crankshaft. A beneficial side effect of this is the engine runs a bit smoother.
When changing an old school small or big block to the newer firing order, you would only need to change the cam and swap around the ignition and (if sequentially fuel injected) fuel injector plugs.
Personally, I doubt the exhaust sound "quality" will really change that much.
The next time I build up a big block for my Monte (hopefully this summer), it's getting the newer firing order.
As a side note, the final production version of The Big Block, the L18 Vortec 8100 (496 CI) engine had the updated firing order.
When changing an old school small or big block to the newer firing order, you would only need to change the cam and swap around the ignition and (if sequentially fuel injected) fuel injector plugs.
Personally, I doubt the exhaust sound "quality" will really change that much.
The next time I build up a big block for my Monte (hopefully this summer), it's getting the newer firing order.
As a side note, the final production version of The Big Block, the L18 Vortec 8100 (496 CI) engine had the updated firing order.
04-14-2012, 10:32 PM
#29
didn't WJ play with a 180* crank ?it sounded different.all of the reasons listed above are soooo correct .the top fuelers did the 4/7 swap.I should do a 4/7 cam for my dual plane 427 sbc.
04-17-2012, 03:04 PM
#32
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If it does anything it will net you a loss of power. I dont know if it will change the exhaust sounds.. Maybe what you are looking for is a lopey cam?
04-21-2012, 11:37 PM
#33
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04-22-2012, 08:14 AM
#34
All you really need to do is swap the 4/7 and 2/3 injector wires at the PCM, and coil wires at the PCM (1 wire per coil and 1 wire per injector), then go into the injector bank select table and swap the correct holes to 0 or 1 to assign them to the left or right side oxygen sensors, and it will run fine. If you really want the OBD2 misfire detection to also function, then there is one more table that tells the PCM what the firing order is so it knows which hole to assign a miss to when it see's a blip in cam/crank signal...probably take me 20 minutes to do, including swapping the wires at the PCM, reading the tune out of the car, making the changes, and flashing it back in...unless it's in a car where it's hard to get to the PCM, like a C5...then it'll take longer because you've gotta get inside the inner fender area.
After that, get a custom grind cam, slide it in, and have a newer style engine, with one of its technological refinements that made it better removed, so that it isn't as nice as it used to be...and a lighter wallet from the custom cam.
04-22-2012, 03:58 PM
#37
It's actually not much programming at all. GM used the 0411 PCM to run both LS1's and the regular Vortech 350 (L31 I think) in 2002 vans.
All you really need to do is swap the 4/7 and 2/3 injector wires at the PCM, and coil wires at the PCM (1 wire per coil and 1 wire per injector), then go into the injector bank select table and swap the correct holes to 0 or 1 to assign them to the left or right side oxygen sensors, and it will run fine. If you really want the OBD2 misfire detection to also function, then there is one more table that tells the PCM what the firing order is so it knows which hole to assign a miss to when it see's a blip in cam/crank signal...probably take me 20 minutes to do, including swapping the wires at the PCM, reading the tune out of the car, making the changes, and flashing it back in...unless it's in a car where it's hard to get to the PCM, like a C5...then it'll take longer because you've gotta get inside the inner fender area.
After that, get a custom grind cam, slide it in, and have a newer style engine, with one of its technological refinements that made it better removed, so that it isn't as nice as it used to be...and a lighter wallet from the custom cam.
All you really need to do is swap the 4/7 and 2/3 injector wires at the PCM, and coil wires at the PCM (1 wire per coil and 1 wire per injector), then go into the injector bank select table and swap the correct holes to 0 or 1 to assign them to the left or right side oxygen sensors, and it will run fine. If you really want the OBD2 misfire detection to also function, then there is one more table that tells the PCM what the firing order is so it knows which hole to assign a miss to when it see's a blip in cam/crank signal...probably take me 20 minutes to do, including swapping the wires at the PCM, reading the tune out of the car, making the changes, and flashing it back in...unless it's in a car where it's hard to get to the PCM, like a C5...then it'll take longer because you've gotta get inside the inner fender area.
After that, get a custom grind cam, slide it in, and have a newer style engine, with one of its technological refinements that made it better removed, so that it isn't as nice as it used to be...and a lighter wallet from the custom cam.
04-23-2012, 03:37 PM
#40
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I was wondering if anyone has done this firing order change on a LS1. I honestly hate the sound of LS1's and wish GM stuck with the traditional Chevrolet firing order and didn't copy off Ford. So has anyone ever seen an LS1 with the old school firing order or any threads on this?
18436572 > 18726543
18436572 > 18726543
