Here in the next month or two, my engine will be rebuilt/street ported and i'll be running a bigger turbo (i'm feeling the Borg Warner s362) with a Neukin T4 turbo manifold.

Anyways, I was reading aaroncake's walk through on installing it. I noticed that he kept the BAC to control the idle, but I would prefer if it was gone... (I did notice that his car wasn't fully built at that point) However, if it needs to be there, then so be it!

Basically, if I'm not running the BAC, then what will be controlling the idle?

Next question...
I want to run a parallel fuel system (probably 1600 sec, 850 prim.) Aaron wrote in his write up with the stock fuel system you enter "2" for the number of injectors (at least I'm pretty sure I read that). How does this work with a parallel fuel system?

That's all I can think of right now, I'm sure I'll think of more.
Thanks!

 

The car I used in the Megasquirt writeup was a friend's car, not mine.

Why would you want the BAC gone? Without it, the ECU cannot control the idle. Thus the idle will change based on load, weather, mood, alignment of the stars, etc. With the BAC you not only get the benefit of the ECU keeping the engine at a steady idle, but also the cold high idle which makes cold starts a hell of a lot easier and the car better to drive when cold.

If you really don't want the BAC (I don't see any valid reason for not using it), then just use a blockoff plate and skip the BAC mod on the 'Squirt.

Now, as for a parallel fuel system, it doesn't effect how the 'Squirt is configured at all. You still need to enter "2" injectors, connect the primaries to bank 1, and the secondaries to bank 2.

 

Keep the bac, you can however, get it idle W/O issues with a/c on with out it, but it is a real pain in the butt and it somewhat depends on the condition of the motor itself!
My worn 2 hell s4na motor would die some time's coming to a stop,i have to use a on/off solenoid to kick up the idle to get the a/c to work . My s5t2 idles at 900-1000 w/o the bac, it idles on the rich side and i use <idle advance settings> to compensate for no bac (advance's the timing if it drops below 700 rpm's) i can use a/c (w/o a solenoid) with out any problems i do have to let it warm up a tad and i do not have the TB thermo wax, it will warm up W/O touching the gas (lowest out side temp 40)!

If i was to do it all over i would use the bac, u can idle leaner and lower it will compensate for and drag from the P/S, A/C extra!You will make up any added expense from reduced fuel cost

 

thanks, aaron.

there was really no reason for wanting to get rid of the bac, mainly just wanted it gone to keep the engine looking clean

 

I use the BAC with closed-loop idle speed control.

Catches load increases and even turning the steering wheel with minimal change in RPM.

Ken

 

even for power steering rpm drop can the closed-loop idle speed control compensate?

 

RPM fluctuates but the engine doesn't stall, and you can watch it compensating by opening the valve more.

Ken