PCM Options for Supercharged 454 / 4L80E

[dave w]

I'm open to ideas to upgrade from a $85 to something / anything that can operate a Supercharged 454 / 4L80E!

dave w

[93V8S10]

ELB running engine with piggybacked 7427 (or equivalent) running $0D modified for 4L80-E; or $0E/$31; or one of the trans only masks, controlling the transmission.

[dave w]

I did not know EBL would operate 2 Bar / 3 Bar MAP. That is good to know!

dave w

[Six_Shooter]

Or a 1227730/1227749 running $58/$59, with the aforementioned 16197427, or a stand alone tranny controller.

[dave w]

The vehicle is a 93 Chevy C3500 Dually, which has a 16147060 PCM ($85), so the current PCM can be reused.

dave w

[1project2many]

Dave,

Although it's typical to think "boost compatible calibration" when adding a turbo or supercharger, the requirements are different for the two forms of forced induction. While a turbo is a load dependent device needing a more complex tune, a supercharger's boost is a simpler function of rpm and throttle position. Knowing at what minimum RPM the S/C is able to provide boost allows very sufficient tuning using PE mode values. Once minimum RPM is exceeded, the minimum TPS at which boost occurs increases as RPM increases. This continues to maximum compressor flow or maximum engine rpm, whichever occurs first. PE mode enable rpm should be lower than or equal to minimum boost rpm, and tps values should not be higher than minimum boost tps. Spark can also be scaled by rpm although if using a 1 BAR cal with 1 BAR sensor you may feel lost without load based adjustment. In this case look for a TPS based PE spark table and use negative values if possible to decrease spark as throttle angle increases in PE mode. If the PE spark tables are limited to 8 bits, a simple change in code from ADD to SUB solves the problem. A C3500 dually is a heavy vehicle and you should expect it to spend large amounts of time under high load. Use a conservative spark table and make sure the knock retard is programmed to pull more spark out quickly and to add it back in very slowly just in case there's a problem. If you have a way to monitor an external 5V signal you can use a 2 BAR MAP and data logging to plot a graph of boost by RPM and TPS for use in future fine tuning this vehicle. Alternatively you can switch to a 2 BAR MAP and re-scale the MAP based calibration values appropriately using the voltage - pressure curve for your sensor. Since the ecm / pcm is not responsible for controlling boost, there is no advantage to using a calibration with extra functions built in to limit boost. Since MAP can be plotted as a function of RPM and TPS, you will provide acceptable performance mapping out boost fuel and spark tables using an alpha-N strategy. And since this is a heavy vehicle which will not subject to the same herky-jerky reactions as a lightweight car with a high power engine, you won't have to worry about the need for high resolution tables and overlapping functions to smooth any transitions in driver input. Bottom line for me would be to use the same mask unless I didn't have access to enough tuning data in which case I'd choose $0D.