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I analyzed, using EFILive, the differences between the Magnacharger tune for an 04 SSR equipped with the supercharger but otherwise stock, versus the factory tune for an 04 SSR. Interesting indeed.

Parameter B0701, catalytic converter protection against high temperature, is disabled in the Magnacharger tune. This is presumably because the exhaust is hotter enough to trigger undesirable protective measures by the PCM if not disabled.

The fuel cutoff rpm limits and the electronic throttle control limits, are both set at 6300 rpm, even though WOT shifting is set at 5500 from 1st to 2nd (actually 100 rpm lower than factory), and 5500 2nd to 3rd (same as factory).

B3618 Power Enrichment modifier based on rpm, which richens the mixture upon application of full throttle, ranges from 1.09 to 1.15 on the magnacharger tune, versus 1.15 to 1.30 on the factory tune. This seems contradiuctory until you remember that the Magnacharger directed A/F ratio is richer to begin with, so needs a smaller multiplier.

The maximum PE enrichment is likewise only 1.25 versus the factory maximum of 1.40, for the same reason.

The PE delay is however wiped out entirely, by setting it to disabled at any rpm over 100 rpm! Most tuners reduce or wipe it out with any performance tune, even on naturally aspirated engines.

The spark hi-octane table is used by the PCM to set spark advance under good conditions (hi octane fuel, low temperatures, etc). Here, the Magnacharger tune allows up to 23 degrees advance in the 4000 to 6000 rpm range with high incoming air flow, while the factory tune allows only 11.4 degrees. BIG difference.

The spark low-octane table is used with low octane fuel or high temperatures cause knock, and the PCM "blends" the allowefd values of the hi-octane and low-octane tables dynamically, always wanting to return to hi-octane values if no knock is encountered. The Magnacharger tune allows up to 20 degrees advance here, while the factory tune allows only 8 degrees.

The Magnacharger tune retards timing up to 6 degrees when the engine gets hot, and up to 9 degrees if incoming air into the air intake gets hot! This is why both naturally aspirated and supercharged SSRs run ****ty at elevated coolant and incoming air temperatures. You CANNOT undo this retard without frying the engine! So, let's work on getting both our engine coolant temperature AND our incoming air temperature DOWN!!

The limit on spark retard is 10 degrees in the worst case, for both Magnacharger and factory tunes. The limit on spark retard due to detected knock is 5 degrees on the Magnacharger tune, but 8 degrees on the factory tune.

The Magnacharger tune limits the duration of traction control torque reduction to 2 seconds (unless quickly re-activated again by another loss of traction event), while the factory tune limits duration to 5 seconds.

The torque limit reducton on the electronic throttle control is wildly different on the Magnacharger versus the factory tune, but I'm not smart enough to understand its effect, because the wording in EFILive is so bad as to be incomprehensible. As near as I can figure, the two tunes are reducing engine torque by very different percentages when loss of traction or a gear shift demands it.

The base transmission line pressure used while shifting under hard acceleration is wildly greater in the Magnacharger tune - up to 96 psi versus 66 psi for the factory tune, at the comparable applied torque. This is why I found it so objectionable when I had the Magnacharger tune installed briefly.

Likewise,Magnacharger reduces the engine torque much LESS during shifts - only 5% reduction at 440 ft lb for example, versus 23% reduction for the factory tune. This makes life for the automatic transmission and rear axle much more difficult, but gives you a cheap thrill when the tires break loose.

The Magnacharger tune also turns the engine colling fan on much earlier - 205 degrees versus 226 for the factory tune. Of course, any of us that have studied the thermodynamics of the SSR know this is NEEDED. In fact, my fan turns on at 190.

Thought you guys and gals might find these differences interesting.

Note that these are NOT all the differences - obviously the air/fuel and spark tables are quite different, but the differences above are the changes that you might not have thought of. To an informed eye, they are significant.

Jim G
 
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