[Subscribe to Daily Digest] |
The following applies to the T5 ECUs.
That is not a good idea for the trionc. After the output signal gets to the point where the zener passes current, the ECU does not see further boost increases. So increase of boost beyond this zener boost point will simply lead to lean condtions at high loads. A definate error.
With the trionic, if the map sensor is off spec. It will calibrate its operation using that sensor via the O2 sensor feedback. This works well as long as the map sensor output has a linear relationship with the air pressure. The only limit is the fuel pressure. The map sensor's output wire has a series resistor put in line. This forms a voltage divider with the 1K ohm resistor to ground inside the ECU. For small reisitance values, the ECU handles things very well. For larger resistance values, the fuel pressure is not enough to support the ECU's intentions. The fuel rail pressure needs to be increased.
It is possible to leave the BPC valve in control and use a large resistance, and you need to increase the fuel pressure, to get boost levels which compare to a modified ECU. Or a small resistance valve can be used to get a small increase in the ECU's boost settings, with the objective if moving the fuel cut pressure. This can be used to provide fuel cut head room when using a MBC which will always have some pressure overshoots. This solution can also allow for the MBC to take pressure from the throttle body or the manifold which will eliminate much of the boost taper that is created when using the turbo compressor housing hose barb. The objective with the MBCs and small resistor mods is not to increase the boost beyond around 15 PSI, but to simply make a MBC work a bit better at these pressures, especially in cold weather where pressure overshoots become greater.
Nether one of these can be considered a main stream solution for the masses at this point. More of the black arts. I am working on something that others might want to emulate. After there is a running history of others doing these things, then it might be considered safe.
posted by 65.68.10...
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.
 |
 |
 |
 |
 |
