Re: Project B7 420-R - 4.2 V8 40V BiTurbo Content
Posted: Fri May 24, 2019 4:15 pm
One of the issues encountered by C5 RS6 owners converting their cars to manual, is coding.
By this, I mean coding the ECU to have the characteristics of a manual. This allows the idle to be lower, prevents “rev hang” when clutching down for gearshifts, and generally makes drivability smooth. It also permits cruise control to function.
As the C5 RS6 had no manual option, the ECU has no option to be soft coded to control the engine as a manual. It will also trigger the ABS and ESP warnings, they will be non functional as a result. As the ECU will be looking for the absent TCU in the original Tiptronic car, a CEL will be triggered, putting the ECU in limp mode.
I am avoiding this, by running 2 x B6 1.8T 190 (BEX) ECU’s. And a custom wiring harness, based loosely on 2 B6 1.8T items. The B6 ECU’s of course will be 100% compatible with the B6 ABS module, and more importantly, the B7 RS4 instrument cluster can be modified to work. The C5 RS6 ECU would be less compatible here.
By this, I mean coding the ECU to have the characteristics of a manual. This allows the idle to be lower, prevents “rev hang” when clutching down for gearshifts, and generally makes drivability smooth. It also permits cruise control to function.
As the C5 RS6 had no manual option, the ECU has no option to be soft coded to control the engine as a manual. It will also trigger the ABS and ESP warnings, they will be non functional as a result. As the ECU will be looking for the absent TCU in the original Tiptronic car, a CEL will be triggered, putting the ECU in limp mode.
I am avoiding this, by running 2 x B6 1.8T 190 (BEX) ECU’s. And a custom wiring harness, based loosely on 2 B6 1.8T items. The B6 ECU’s of course will be 100% compatible with the B6 ABS module, and more importantly, the B7 RS4 instrument cluster can be modified to work. The C5 RS6 ECU would be less compatible here.
