98-02 ls1
02-17-2017, 07:30 AM
#21
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I just did a build in a 98. We both wish he had a 99+.
He pulled the 98 LS1 due to a cracked sleeve (this was an issue with the older cars) and swapped in a cammed 6.0.
It kept taking out the 4L60e so he decided he was going to do a 4L80e swap and possibly a turbo later on. I had to pitch the 98 PCM because it won't control a 4L80e, and you can't flash a 3 bar OS onto it. This meant I had to re-pin the harness for the 99+ PCM.
Also, the later years came with an LS6 intake so you scored a few free HP.
He pulled the 98 LS1 due to a cracked sleeve (this was an issue with the older cars) and swapped in a cammed 6.0.
It kept taking out the 4L60e so he decided he was going to do a 4L80e swap and possibly a turbo later on. I had to pitch the 98 PCM because it won't control a 4L80e, and you can't flash a 3 bar OS onto it. This meant I had to re-pin the harness for the 99+ PCM.
Also, the later years came with an LS6 intake so you scored a few free HP.
02-17-2017, 01:08 PM
#23
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4L80Es came out long before the '98 or '99+ PCM....1992 I think? They don't need either of these PCMs to operate, they can be installed with other means of control (same way they are used in older muscle cars, etc.) But I do agree that the PCM swap has some benefits for a large scale forced induction build. It's just not a requirement if all that was planned was the trans swap, as there are other ways to control the trans.
02-17-2017, 01:35 PM
#24
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4L80Es came out long before the '98 or '99+ PCM....1992 I think? They don't need either of these PCMs to operate, they can be installed with other means of control (same way they are used in older muscle cars, etc.) But I do agree that the PCM swap has some benefits for a large scale forced induction build. It's just not a requirement if all that was planned was the trans swap, as there are other ways to control the trans.
The problem with the 98 PCM is that you can't do a 4L80e segment swap onto the PCM. The easiest way to get it to work is by using the 4L60e tune with a series of relays to control the shift solenoids correctly. You still need to load an 80e tune and copy over as many of the tables as you can for correct operation. It will work on a 60e stock tune but efficiency and wear are debatable.
My problem was only compounded by the lack of a 3 bar OS available for the 98 PCM. At that point, it just makes more sense to repin the PCM connector and run a new one.
02-17-2017, 02:38 PM
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No, I meant that 4L80Es were originally controlled by computers far more preventative than either the '98 or '99+ PCM, therefore a modern PCM is not required for proper operation of the unit. People swap these (4L80Es) into older muscle cars all the time with separate controllers, so a PCM swap would not be needed (just a controller) if trans operation was the only concern. But, again, for a major FI build I understand the advantages of the swap.