I saw this thread https://ls1tech.com/forums/showthrea...ery+relocation & got some good ideas for wiring everything. I decided to go with the Painless relay shown in post #10 thinking it would eliminate a #2 wire from the alternator to the battery (lots of weight). Here's the instructions from painless:

I don't understand any material difference in the wiring scheme from this:

I'm also concerned that the supplied wire from the alternator thru the relay & on to the battery is only #8. I thought the relay would go between the alternator & the original + battery cable up front. Can someone shed some light on this?

 

It's also a good idea to make the ground as big as the main positive wire, it's a very small length of cable so weight isn't an issue.

 

Thanks, anyone else?

 

Sorry for the late responce, yes sir you need the solenoid in there to shut down the alternator once the disconnect switch is thrown, or it will keep feeding the battery and will not shut off.

 

The problem I've found with all the ways to wire in a disconect and make it legal, is that you remove power from the computer which resets it. This causes you to lose it's memory,affecting drivabilty till it relearns. Any help on this?

 

open loop tune, gets rid of that for the most part.

 

I need to reread that section in the rulebook...but I don't think using a relay is technically legal in the battery cutoff.

 

Im with 1LEJOhn! Sucks when that makes the computer reset

 

you only have to shut it off in emergency.

 

1lejohn is correct about the computer loosing power and memory with a mechanical disconnect. Painless offers a remote disconnect that has a by-pass wire for the ECM that will prevent this, but Fireball is also correct the NHRA rule book does not allow a solenoid operate disconnect switch to be legal. It has to be mechanical, there are some trcks you could go to and they will let through tech with them but i wouldn't count on it. The only thing i can see by the Mark98SS drawing is that you might be able to run the constant hot to the ECM to the battery and alternator side of the shut off switch and see if that will still shut the car down. If it does then the ECM memory would still remain powered.

 

I tried running a hot wire to the ECM and it keeps the car running with the mech. sw. turned off. You can even drive the car like this but the current needed for the electrical system at higher rpms causes the car to miss fire. The open loop tune may be the way to go. The disconnect has to be manually actuated, but you can use a relay to shut down the alt. output.
Yea I know that you only use it in emergences, but if they test it at tech. then cars that are driven to the track are screwed.

 

so is this legal or not

 

The solenoid is not legal.

It does not matter if the pcm is using speed density (MAP) or the MAF, or both to measure airflow, if the tune is spot on, pulling the power to the pcm should not make that significant of a difference.

 

I ended up not using the Painless solenoid, did a terminal block at the old battery location to connect the original starter, + post from the left near the fuse block & the new main battery wire from the rear. The alternator wire now runs seperate to the battery side of the switch. Turns the car off.

 

I have mine wired the same way a the diagram on the first post (lower diagram) and I never turn my cut-off switch off and I still loose my memory any help with this??????