IAT resistor Pull timing for multiple Nitrous shots E38

Hi
i have a 2 stage plate system to go on my ls3 maloo and i also have a fogger which i am going to install
i was thinking of running first shot 50hp from around 2300rpm- 2500
then the 2nd 50hp at around 3000 - 3500 and bring the 3rd 50 in at 4000rpm

this will give me a softer hit, and the choice of how much gas i can use at any one time

i was thinking of wiring different ohm resistors up into the iat so it alters the reading down to say ,-10*c ,-20*c ,-30*c and pull timing that way individually for each shot.
i can also adjust injector flow based on iat to fine tune the mixtures

Can any one see any major reasons not to do it like this?
i dont want the custom os for the e38 as it will only let me pull timing at once for the 150 shot
thanks

While your idea seems OK from a ver y high level, I doubt it's going to work.

IAT has more of an impact than just spark timing. It also impacts VVE, predicted airflow, charge temp blending to name a few.

If you are set on this method of staged NOS release, then I'd probably look at using the E85 tables in the OS and feed the ECU with a changing Ethanol % signal. Set up the Flex fule tables to suit your engine and have the ECU pull timing depending on the simulated E85% signal being fed into it.

To be really honest though, I'd probably go with a dedicated NOS controller that will manage the timing separate from the ECU.

Simon

would engine coolant temp be any different? would i just wire up a resistor to ground for the ethanol from the correct pin would i need the custom os to do this?

ECT would be worse than IAT.....

You need to set up an ethanol sensor emulator to use the E85 tables. It is not a simple pull up /pull down signal. Search the forums, it's been discussed.

sweet, just looked around and found that what u are saying is by far the best option,
any way to get a rpm switched output from our e38? ie shift light?
or is it exclusively through can bus