I read on another thread

"If you could find a L-69 chip, they are best for performance and could actually increase the fuel mileage some"

I was wondering if there is any truth to that and what kind of performance increase and how hard is it to do?

 

The timing tables in the L-69 chip are ALOT hotter than the LG4 chip. It would be of benifit.

 

However the L69 chip requires a knock sensor and an external knock module. You have to add these and pin the ECU out accordingly when using the L69 module or it is going to go into a failsafe mode and pull timing. So it is not going to be just plug and play. The 305 knock module from an L69 is the same part # that the 305 MAF TPI cars use. 350 MAF TPI cars use a different part # knock module though that is calibrated to that block.

 

His LG4 is a 1987 by his profile. 1985 and up LG4s had knock sensors and flattop pistons from GM.

 

Oh woops. My head is stuck in 83-84 LG4/L69 range, when the LG4s did not use the knock sensor or module.

 

Delete

 

anyone?

 

Just the chip. The benefits would be the more aggressive timing table.

 

Delete

 

Where could someone get an l69 chip?

 

The spark advance curves programmed into the L69 chip are more aggressive- most spark advance sooner, more in total. Benefits power and especially low/midrange torque. That's the primary advantage.

You could just keep using your LG4 chip and jack up the initial timing (I've done it myself lots of time) but guys who have tried it back-to-back vs. the L69 chip say that the hotter chip is still more beneficial to performance than the LG4 chip with the initial timing bumped up.

 

ok that makes more sense now.


you could fin one at a junkyard most likely

 

Any benefits to swapping the Ecm along with the chip? I just got the Ecm and chip from an 84 L69. Wondering if I should just swap the L69 chip into my 83 Z or install the 84 Ecm and chip into my car.

 

83/84 LG4 and L69 are totally different part # ECU's, as far as I know. You can't swap the chips. Also you need the knock sensor module and wiring added to use the 84 L69 ECU. I got it wrong the first time but for 83/84 for sure, you can not just plug and play, or you are going to throw codes for having the knock sensor circuitry missing. I would leave it alone. On a stock LG4, your camshaft is a much bigger restriction than your timing table.

 

Thanks for the info Was hoping I would be able to use it. My car has some mods, a CompCam XE262, Edelbrock Q-jet RPM intake manifold, full exhaust, and some other little things.

 

You can use it, but you will need to find a 305 knock sensor, knock filter module, and pin the ECU out accordingly. The knock module and sensor MUST be from a 305. The sensors and modules are calibrated to be block-specific. A 305 TPI car will use the same sensor and module as the L69.

 

Do you have a picture of the chip? Im not sure what it looks like or where it actually goes in the ecm, is there any numbers on it or anything so when I go to the junkyard I know its the right one.

Also if you decide not to do those mods u could aways sell me your chip : )

 

I currently am looking at a ECM that came out of an 83 T/A H.O. with part# 1226025 stamped on it. I was going to use it on mine but it sounds like that is almost impossible unless adding wires and sensors. I would be better off getting an aftermarket chip I guess for my 83 T/A with the LG-4.

 

Were there both auto and manual L69s? Because the chips will be different for the auto and manual cars, keep that in mind

 

In 1984 only the L69 was available with manual and auto. In '83 and '85-86 you could only get a manual.