stand alone engine management

if you have a stand alone engine management system do you still need your stock ecu to be tuned to accept the new program, or even to work around some of the original parameters, or will the stand alone setup take care of all of that...

for example, if you put a new cam in your car you need to get the ecu tuned to work with that cam.

if i put alot of work into my car and am going to be using a stand alone setup, do i need to get the ecu tuned first to accept the (new parts) and then use the stand alone setup to cover the rest of the parts...
or does it all matter what im using for the stand alone setup

just a strange question i was thinking of, kind of going over my projected expenses and was thinking it would cost a few hundred more to get the thing tuned right first before i go to the dyno and get it tuned correctly with the other computer.

i tried searching but i couldnt figure out what to search for to get the answere i needed

Depends which stand alone system you use, and what you use it for. Logically, as a minimum the aftermarket ECU will take care of fuel and ignition. There would be no need to "program" the stock PCM for anything related to either of those.... e.g. a new cam is "tuned" in the aftermarket ECU. There is no need to do anything to the stock PCM.

But.... how will you control your speedometer? Can the aftermarket ECU control it? In my case, I run a MoTeC M48Pro for engine management, but I use the stock PCM for the speedometer, the IAC motor (my older MoTeC can only run a PWM IAC, not the stepper-type IAC used in the 4th Gen). In order to allow the stock PCM to control the speedo, I still need to program it with the correct rear axle ratio and the correct tire diameter. In order for the IAC to work, the PCM needs input for things like coolant temp, etc., so you need parallel sensors in the case of 2-wire resistance sensors (CLT. IAT), or parallel wiring in the case of 3-wire sensors (MAP, TPS).

I also let the stock PCM run the fuel pump, so the Opti optical signals are paralled to both the ECU and the PCM. As crazy as it sounds... the stock PCM still activates the "Skip Shift" light on the dash, even though the car is running a TH400 with a manual valve body.

White Racing in Warren Michigan offers Plug-N-Play aftermarket fuel injection systems by FAST XFI, DFI and the new BigStuff 3 at http://www.whiteracing.com

These systems have interface harness(s) that adapt the origional cars wiring to the aftermaket programmable system. They all come with WBO2 (Wide Band O2 control) which is a built in Air/Fuel Meter that keeps the Air Fuel at the programmed ratio. There is a link there explaining what WBO2 can do for you at http://www.whiteracing.com/ClosedLoopAdvantages.html

The origional PCM is replaced with the new programmable ECM and there is usually very little installation time. The is an example of a typical installation on the home page. With the Plug-N-Play adapter, most of the OEM features are retained like Fuel Pump, Fan and A/C Control.

Below is a picture of the Interface Adapter for a 1990 Camaro to the FAST system for example which is one of the parts in the kit. Typically they start at $2000 for a complete kit.
http://www.whiteracing.com/images/90fbody.jpg

Contact dan@whiteracing.com for additional information.

They also have a Chassis Dyno and Online Tuning over the Internet.

well i am pretty sure i am getting the fast xfi system.
i am turboing the car.
ive pretty much changed every metal piece in the engine.
yes i have different tire size and i am chaging the rear end
i was just wondering if i needed to have them setup the ecu for everything i have changed inside the engine as well as have the xfi system run.....

What would you like to "setup" in the stock PCM for engine internals? I tried to explain.... fuel and ignition will be taken care of by the FAST. What you need top program in the stock PCM depends on what part of the stock PCM you are using. I kept my emissions running on the stock PCM.... but it didn't take any "programming" or setup.

I still don't understand what you feel you have to tell the stock PCM about "every piece of metal in the engine"????

the heads cam displacement all kinds of porting

all the metal

i dont know anything about computers thats why im asking all the questions
i am changing the rear end the tire sizes
so i thought i could work around that with the stand alone setup but from what you guys are telling me i need to get that programmed in and then the stand alone will change everything else

thats all man... i just dont know exactly how it all works. i had an idea and now i know more... and i thank everyone for there time

You need to program your FAST with the correct displacement. You do not have to tell your stock PCM the new displacement.

You can't tell either computer about the cam specs, how the heads are ported, what the heads flow, how big the combustion chambers are..... the computers do not need to know that. The person who tunes the FAST needs to know that so he can set up the timing and fuel tables correctly.

I'm running a 381ci setup, with a solid roller camshaft and some pretty decent LT4 heads. Then I spray a dry 300-shot on top of that. My stock PCM is still programmed for a STOCK LT1. It still operates the speedo and the IAC motor, turns the fans on and off, and activates the fuel pump. When I still had EGR, EVAP and AIR, it still managed to operate those systems, without knowing anything about my new engine, except the desired idle speed.... which I kept at 800RPM just like the stock PCM.

I also swapped from an M6 to an automatic tranny. The PCM needed to be reflashed to the stock A4 tables so the speedometer would read correctly (different number of VSS pulses per mile in the automatic vs. the M6).

I can't think of anything else, other than the tire diameter and the rear axle ratio. If you have and are keeping the 4L60E (unlikely with the turbo???) you will need to alter the shift tables.... but none of this involves telling the PCM anything about the engine specifications, heads, cam, etc.

hey thanks alot for braking it down even further...

i really appreciate you guys help