1996 LT-4 Vette
Have an old NOS fogger plate, max 150hp. Sent it to Induction Solutions for blue print and flow. Need to figure out if there is a good solution for pulling timing only when on the bottle. I can tune the timing map to accommodate, worse case scenario, but then I have to drive around daily with that. It has a brand new Opti but otherwise stock ignition.

 

Everyone I know who ran N20 on a LT1 used a MSD box to pull timing.

 

Can the MSD box be ran alone?

 

Not sure I understand your question. I have never ran one and have no experience with them. Sorry.

 

I've found listings with their package of all 3 (coil, box and distributer) but I know their distributers are junk...

I'll call their tech, thanks!

 

Relay on the IAT is what I used on my L31.

 

Please elaborate!

 

MSD digital 6 plus and an adapter harness for your coil. Plug it in and wire it up. 12 volt hot triggered off of the nitrous wiring will trigger the box to pull the timing from base. I have always ran my nitrous kits this way on LTX cars over the years. The ignition box also helps with spark energy. Make sure to gap the plugs to ~.030 non projected tip ~8 heat range. I would pull 8-10 degrees from stock assuming you are running 36 degrees total if on pump fuel. Remember excess timing and fuel kills engines on the nitrous.

 

You wire a 5 pin relay into the IAT sensor. IAT goes to the normally closed pin. Signal wire to the PCM on the switched pin. IAT fixed resistor to the normally open pin. The other end of the resistor ties into the other IAT wire. When the nitrous arming switch is energized it substitutes a fixed resistance for the IAT. I generally use a very high ohm resistor. This tells the PCM that the intake air is extremely cold ~ -20°F. Then program the intake air temperature timing compensation tables to give the desired timing retard. You can lookup the IAT temperature sensor temperature. You can datalog and test to make sure the correct amount of timing is being removed before spraying.

 

F'kn GENIUS!

 

That is how I felt when I first saw it done. Works for the 24x LS stuff too.

I was running a 125 wet shot on my L31 at 6° retarded from the normal 28° of WOT timing.

 

I converted over to FAST EFI and didn't have this issue when I had my LT1 pulling large amounts of timing. However prior to that YES it was all done with an MSD Digital 7 box jumpered in between coil, and opti. I believe I used the Trans brake as the signal for changing limiters (launch rpm vs total rpm). Timing was all pulled the second the first kit came on....

The FAST made it much simpler with a crank trigger.....and a true distributor like what we all ran..