I was just curuous as to how the 402a engine compensates for the added boost without upgrading the ecu. Im still pretty new to this stuff but it seems like with all the added air/fuel, there should be a chip upgrade or something like that. I know it works obviously the way it is but if someone could explain this to me it would be greatly appreciated. Also, I was wondering if the chip is soldered in like on a Toyota or if you can easily swap them out like a GM. Thanks fellas!

Matt
95 GS

>I was just curuous as to how the 402a engine compensates for the added boost without upgrading the ecu. Im still pretty new to this stuff but it seems like with all the added air/fuel, there should be a chip upgrade or something like that. I know it works obviously the way it is but if someone could explain
>this to me it would be greatly appreciated. Also, I was wondering if the chip is soldered in like on a Toyota or if you can easily swap them out like a GM.
Thanks fellas!

Matt
95 GS

Well, let me see if I can answer you without confusing my self.

The way we compensate for boost starts with the fact our car uses a Manifold Absolute Pressure (MAP) sensor to determine how much air is being fed to the engine and will use this reading to adjust fuel. Our ECU is only programmed to read a certain amount of manifold pressure, or else it hits what is called fuel cut. To prevent this, you must install a device that effectively fools the ecu to see no more manifold pressure than it would at WOT. This is accomplished with check valves (unreliable, but inexpensive) or a Fuel Cut Defenser (also known as a VC1 from SplitSec).

Now that is just part of the whole. Now to address the fuel issue to coincide with more air being forced into the cylinder, you must effectively go with bigger injectors. If all you did was add bigger injectors to your car, then your car would run like crap at idle and regular around town driving, plus there is no guarantee that the ecu would recognise and operate a bigger injector properly. So to maintain idle and light throttle driveability, we use a bigger fuel pump and a fuel management unit (FMU fixed at a 12:1 fuel to boost ratio) to allow more fuel to be forced thru the squirter when there is boost. This effectively causes your injectors to act normal with regular and very light boost situations, but makes these same injectors seem much bigger when you have positive manifold pressure (read... BOOST!!!). This method is how Star accomplished the fuel enrichment, but Hahn is using a different setup.

Our ECU is not easily reprogrammed, nor have I heard of anyone who has successfully accomplished this task. Jet Performance claims they can reprogram our ECU, but as all the Turbo'd here can attest, why would we need it?

Also, from what I understand the "chip" is soldering in, i.e. not EPROM. In addition, I believe our ECU is actually filled with a gel-like substance to prevent vibration induced failure, but I am not positive, someone else told me that last part.

I hope I have not confused you, nor mixed up my information.

DoN

p.s. I am at work at don't know my password, so I created a new account...