Retarding timing while under boost
 

Hi all,
ive been doing some research on turbo charging my '90 for awhile now. My goal is to save money where I can and make a super budget build. Saving money where I can by custom fabricating. I plan to use a home made boost controller, build a water meth set up, rather than intercooling, and make a home made O2 signal cutout switch.
now before I get 100 different lectures on just using megasquirt instead, i want to make clear my intentions. I WILL BE USING MEGASQUIRT DOWN THE ROAD. But at this time for this build I want to see how much power I can make for as cheap a build as possible. My goal is less than $700. And i plan to push only 4-6 psi boost at the most with this setup. Now we are getting to my real question.

ive been trying to find a way to make a home made "bipes acu" of sorts. Ive read many different forum posts, and the general consensus seems to say the all the bipes is doing is adding resistance in line with the AFM and ECU when the unit sees boost. I also know the bipes unit uses other inputs like AIT and RPM. But what im wanting to know is, would adding an air pressure switch connected to a small resistor inline with the AFM to the ECU, which is activated by seeing +3 PSI cause the ecu to retard timing even more? Im hoping to be able to maintain the stock 10* advanced and when 3psi is reached retard back to 8-6*. Also im wanting to know if adding this resistor inline under 3psi boost would cause any issues elsewhere?

if(budget == nothing)
{lots of research required}

else
{not going to end well}

I don't see what could possibly go wrong.

You will still be slower than a Toyota Sienna at that boost level, btw.

There's significant likelihood you can't afford to repair your engine once it is damaged.

Good luck.

But you want to start with bandaids?

Theres a reason people start with ECU and wideband first.

if you dont have $300-500 to pick up a used MS2 then maybe you shouldnt be turboing your car...

Sometimes today's children will call you a hater for simply stating the obvious. I've seen it.

The problem with your theory is that the factory ECU has no way of knowing if there is any boost, no less how much. Even your idea of a pressure switch would be far from ideal because it cannot determine how much boost is present to retard the appropriate amount. The amount of timing retard required for 3psi is less than what is required for 6psi. Even if your theory of simply adding a resistor would work, it would only potentially be *correct* for one particular moment or circumstance, while it would be dangerous and possibly catastrophic for all the other circumstances.. Then there's the fueling which needs to be calibrated just as precisely to avoid damage.......

If it were as easy as adding a resistor, that's all everyone would do.

MSPNP Pro and TSE EFR setup or don't bother.