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Speed Density Options and Configurations

One question we keep getting goes something like “how much is SD” or “what do I need to run SD”.

First, pricing information is listed on our website. So that one's easy once you've decided which items to order.

But to figure out what to order, you have to consider a number of different configuration options. This page attempts to list these out in a “walk-through” type layout.

IAT Sensor or Not

The simplest choice to make is whether you want to run an IAT sensor or not. Here are a few reasons you might want to run speed density without an IAT sensor.

  • You don't want to install the IAT bung on the throttle body elbow or you just run temporarily without an IAT sensor and then install one later.
  • You want to use the IAT input to log something else.
  • You want to use the MAF for a while as you dial in the SD table using our MAF/SD VE Table Tool.
  • You want to use the Mitsu-style MAP sensor bolted to your intake manifold and don't want to wire in an IAT sensor separately.

Obviously you lose the compensation you would normally get at full throttle with an IAT, but that usually just results in a richer mixture as air temps increase anyway. So it's not always a bad thing. You just have to remember that this compensation isn't taking place and expect to see lower (richer) A/F ratios at the end of a hard road course session than you were seeing at the start, for example.

Click on the following links to continue.

RUN SD WITH NO IAT SENSOR

RUN SD WITH IAT SENSOR

Other considerations not covered

There are so many different ways to setup SD that it's a little crazy sometimes.

For example, you could already have a MAP sensor and just want to install the IAT sensor. In this case, you might want to hard wire it or use the SD Cable anyway and just leave the MAP connector end of the SD cable unused (or cut off and wired to log something else).

Or you might already have a GM MAF cable and just want to use the break out points already provided with that. And, again, this could be with or without an IAT sensor too.

Or you might want to retain your factory MAF sensor temporarily while dialing in the SD VE table with the MAP (either temporarily or permanently) connected to an input other than the baro so that you can retain MAF operation.

So it's crazy to try to document and support every single possible combination that comes up. At some point, you have to step back, learn and take in all the options and put together your specific plan of attack.

sdoptions.txt · Last modified: 2017/08/13 10:56 by twdorris