Tom Porter

I am looking for an adjustable retard controller that I can install that will retard my timing 4-5 degrees only when my NOS 150hp shot is activated. Is there a controller out there that you guys would suggest?

newberd

I used a Box by RAMCHARGERS. It plugs into the crank sensor and has DIP switches inside to program how much timings to pull and it is also a window switch which you program at what RPM ranges you want your Nitrous to turn on and off. I just removed it from my 98 C5 because I' m installing one of Andy's SC kits. If your interested in it let me know.

0euro@EFIAlchemy.com

If you were to swap to the 99-03 PCM, EFI Live could do this for you, without having to purchase any other hardware

Tony @ MPH

Beer99C5 is running the EFILive custom OS on his car for this very purpose. The custom OS is actually really trick and supports a lot of different things, including valet mode (to limit RPM and/or speed when a toggle switch is activated) as well as booooost.

The cheaper/easier solution is to trick your IAT sensor. IAT is just a resistor that responds to heat. The PCM measures its resistance. Either get a rheostat with good adjustability and the ability to be stuck or potted into place when you're done, or get a bunch of small resistors. Set a toggle switch up so that you have one path through the IAT sensor for normal operation, and one path through the resistor alone or through the resistor and then the IAT sensor. It's up to you. You just want to fool the computer into thinking that the car's IAT is hotter than it actually is. The computer will naturally pull timing based on this. It helps to have someone who has tuning software and can tell you what IAT the computer is picking up as well as what timing retard that corresponds to.

Tom Porter

Is this a stand alone unit or is this piggy backed with something else?

newberd

Stand alone.

XSPOWER

Timing twister by MSD