computer controlled turbo technology

[Ameer Antar]

Most aftermarket boost controllers do what your talking about...different 
boost levels, precise control. Apexi AVC is nice, but expensive, and isn't 
a complete package for the 5kt's. You use the supplied valve on the 
wastegate, but you also need something to control the boost going to the 
ECU to stop fuel shutdown.

Also, you don't want to have more boost at low rpm's, b/c at low rpm, the 
volumetric efficiency of the engine is high [means engine takes actually 
takes in 95%+ of spec 2.266L. This extra efficiency makes the effective 
compression very high...risking detonation. Volumetric efficiency goes down 
at high rpm...maybe 75-80% at 5 grand. It's ok to add more boost in that 
range. If you even look at the boost map on the stock 5kT ECU's, the boost 
is set lower at 1k rpm at about 1.04bar. At 5 grand, it's up to 1.42bar. 
This is right from SJM. Not only that, it's really hard to get full boost 
at 1500 rpm...

-ameer

At 01:05 PM 1/23/2001 , you wrote:
>Hey all,
>
>Why is it that the new 1.8t ECU has so much control over the
>boost?  If MC motors also have the WGFV and such, what is the
>difference that allows so much more control on the new 1.8t?
>
>Is it just the resolution and processing power of the newer ECU?
>
>I wonder if someone could make up an interface that controls the
>stock MC parameters that the ECU does, but allow for more
>control, like an overboost function or higher boost at lower rpms
>like the 1.8t.  Maybe something running off a laptop or something.
>
>Then you could add on other things that came about later one, like
>an elevation sensor (or ambient air pressure sensor).
>
>I guess for the trouble, one would go for a stand alone ignition
>system.  But even those don't control boost, do they?
>
>Does Eric's EFI'ed Max Q retain the stock computer to control
>boost?  What controls boost when one goes to EFI?
>
>Thanks,
>
>Ken