[Supras] No use of electronics with 550cc-Lex upgrade

[Dan Gyoba]

On 22 Aug 2007 at 18:18, berniek at technicaldevelop.com wrote:

> Dear Jeff:
> 
>     We have discussed the fact that you were able to get by without
> additional electronics with the 550cc-Lex upgrade.  I'm wondering if I
> boxed myself into a corner in that regard by upgrading my turbo to 57
> trim.  Did you do anything in that regard?

I certainly hope that this is not the case, since I intend to run my engine with the Lex/550 
upgrade and an upgraded turbo on the stock electronics.

To my thinking, this should be workable.  The ECU should learn to compensate well.

The Lex/550 upgrade does 2 things.  The AFM lies to the ECU about how much air passes through 
it, and the injectors deliver more fuel than the ECU thinks that it does.  This is only 2 axis 
of a 3 part equation, however.

Load, or, effectively boost remains the same, so the ECU really thinks that the engine is 
running with a poor turbo.  Upgrading the turbo should actually bring things into closer 
alignment, since now the load component is brought back into alignment with the AFM and 
injectors, so the ECU *should* start to see the engine running closer to the parameters that it 
expects.  It all depends on how much of an upgrade the turbo really has of course, but that's 
my thinking on the subject.

>From what I gather, most people are using add-on fuel control to keep the engine from running 
quite as rich in the top end.  Toyota did like to dump a lot of fuel in there.  It's safer to 
run rich, so that's what they did.

Dan Gyoba
'89 NA 451,732 kms, Turbo swap COMPLETE
http://www.abstractconsulting.com/~dan