Turbo and Efi relations....

[Jim Sturcbecher]

>> Subject: Turbo and Efi relations....
>> 
>> 
>> One of the companies I contacted in comparing roots and turbo
>> superchargers sugested a system he said they use,,,
>> 
>> They add a circuit that clamps the map output at 1 inch of mercury
>> whenever the boost is in positive pressure, they then increase
>> the fuel pressure proportionately to boost with some basic
>> analog circuit. 

I think you mean 31 inches mercury so that the ECM sees full load.
(see below)

>> 
>> How does this sound?? 
>> 
>> It seems too simple but the company does seem to produce some
>> good stuff.....
>
>
>That is what Carroll Supercharging does. Good but $$$.
>
>frank
>
>
Yep, the Carroll unit is about US$1000 but is very sophisticated. I beleive
it is an electronically controlled unit that you can map a 10 point curve
across the rpm/load range.

I am just fitting a Vortech SFMU (Supercharger Fuel Management Unit)(US$300)
which is basically a mechanical regulator. It has four different internal
'plates' to define the pressure rise rate with boost, plus external
adjustments for idle pressure, and boost pressure limit. These types of units
take over where the ECM is limited due to having only a 1bar MAP sensor. It
actually has the effect of widening the dynamic range of the fuelling system.
This way you can fit an aftermarket supercharger and not need to get into
the ECM code to get correct fuelling under boost.

Later,

Jim Sturcbecher
jsturs at bart.nl