Extra injector before TBI - How can I control it?

[Ricardo_Penteado]

I don't know if this will work, so don't blame me if it blows up.

Set up each bank to run two of your main injectors.

Wire the extra injector to one of the two banks through a pressure switch that activates when the boost rises to the right level. As boost comes on, the extra injector starts pulsing.

Tune the VE table normally. When you tune the high MAP parts of the VE table, you'll be adjusting to compensate for the extra injector coming on.

Your table will look kind of wierd, but I think it'll work.

Fred

Thanks Fred, I also think that this should work, but I´d like to use a "cleaner" solution, without pressure switches. I am still thinking about using two VE tables, setting 0 value to the boosted part of the table, but I´m not sure if this will work...

[Ricardo_Penteado]

just out of intrest, do you position that extra injectors before or after turbo ?

I'm asking cos there's this theory that before turbo gives you better results in terms of lowet charge temp and better fuel atomization, but can damage the turbo....

Well, in my car, the extra injector is positioned after the turbo. Take a look:



But it is also quite common here in Brasil to use the extra injector before the turbo, most cases in drag racing cars. In street cars I believe that I´ve never seen it.

But about the charge temp, I think that after the turbo is the best solution, because here we use alcohol, not gasoline. Just to have an idea, after riding under boost for a certain period, if I pop the hood and place my hand over inlet manifold, it is possible to notice that it is quite cold!

[Ricardo_Penteado]

Sounds like Roger's staging algorithm in the Extra code is exactly what you want. Wire the four tpis to one bank, the tbi to the other and start tuning.

Eric

Eric, can I use this algorithm in MSIIV3.0? Where can I find it?