Computers/ LT1 vs LT4
Thread Starter
Team Owner
Joined: Feb 2006
Posts: 23,147
Likes: 117
From: San Antonio Texas
Computers/ LT1 vs LT4
I know the LT4 has a plug-in chip that is for different (LT4) knock sensors, and it has the rpm limit raised to about 6300rpm. My question is, are the computers really different or is it just a programming procedure that you can apply to any LTx computer? Should I pick up an LT1 computer as a spare, or would it not be compatible with my LT4?
Thread Starter
Team Owner
Joined: Feb 2006
Posts: 23,147
Likes: 117
From: San Antonio Texas
Thanks. Good to know. There's an LT1 computer near here for cheap, so I'll check out the year. Did the 97 Camaro & Firebird that had LTx engines have the same computer as the Vette?
Le Mans Master
Joined: Jan 2006
Posts: 5,621
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From: Orlando FL
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
'94/'95 OBD I computer will run an LT4 just fine. Simply needs to have the flash file updated. Frankly, an otherwise stock LT4 will run fine on the LT1 tune albeit down a tiny bit on power since the timing and PE tables are a little different. You'll probably see an EGR code or two as well since the LT4 doesn't have the EGR system.
There are two things that will not work if you use an OBD I PCM in a '96...the gas mileage info and the ability to pass an emissions test by plugging in. You'd have to have a sniffer test instead. Otherwise...plugs right in.
There are two things that will not work if you use an OBD I PCM in a '96...the gas mileage info and the ability to pass an emissions test by plugging in. You'd have to have a sniffer test instead. Otherwise...plugs right in.
Burning Brakes
Joined: May 2006
Posts: 985
Likes: 17
From: St. Louis Missouri
I've heard there are communication problems with the CCM using an F-Body PCM in a Corvette in the year ranges we are discussing. That may be why some functions are inoperative, as GS says. I do not know if this is a fact. I would check and see if the part numbers are different between common engine configurations.
Thread Starter
Team Owner
Joined: Feb 2006
Posts: 23,147
Likes: 117
From: San Antonio Texas
Well, mine seems to do everything just fine so far. But an LT4 is already 13 years old, and being a one year exclusive model, I'm starting to look for spare parts, just in case.
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