SMT6 Rocks!
06-08-2005, 07:56 PM
#1
Burning Brakes
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SMT6 Rocks!
Just finished fine tuning the Vitesse Stage 2 kit with the SMT6. What an intelligent and elegant design perfect power has put together. As for John's kit I believe it's top notch and I'm impressed with how close his chips were out of the box to dialing in my car.
The wiring was straightforward utilizing John's adequate instructions to splice the SMT6 into the DME wire bundle specific for the 951. There's a test (bypass) circuit included that allows you to make sure you've hooked everything up correctly before plugging in the SMT6 module. This also allows for problem solving in the event that something is amiss with the engine by removing the SMT6 as a potential culprit.
I loaded a custom map based on extensive dyno tuning by John into the SMT6 via a simple laplink cable to my computer as a baseline and then worked from there. Of course none of our cars would be expected to fit the same mold with all of the various mods and engine wear so the ability to fine tune offers a lot. I was surprised how easy the tuning was - the goal being an AFR ratio around 12.5 in open loop. I found that the more effective parameter to watch was the actual Oxygen sensor voltage which at optimal output for 951 power is around 0.88 volts. After setting the AFPR at around 45 PSI it took only about 6-8 full throttle runs beginning at 2000 RPM in 3rd gear to close in on a steady AFR. I ended up with good steady power from about 2500 RPM to redline with full boost by about 3500 RPM (I'm at 6000 feet). I was initially having some hesitation problems off idle but with a little bump up in the fuel in the low RPM/ early MAF Deflection region of the map grid the throttle response is now perfect. Next up is utilizing the map switching capability to store a totally different tune for sea level.
Now time to get her on the Dyno. Curious about other experiences...
The wiring was straightforward utilizing John's adequate instructions to splice the SMT6 into the DME wire bundle specific for the 951. There's a test (bypass) circuit included that allows you to make sure you've hooked everything up correctly before plugging in the SMT6 module. This also allows for problem solving in the event that something is amiss with the engine by removing the SMT6 as a potential culprit.
I loaded a custom map based on extensive dyno tuning by John into the SMT6 via a simple laplink cable to my computer as a baseline and then worked from there. Of course none of our cars would be expected to fit the same mold with all of the various mods and engine wear so the ability to fine tune offers a lot. I was surprised how easy the tuning was - the goal being an AFR ratio around 12.5 in open loop. I found that the more effective parameter to watch was the actual Oxygen sensor voltage which at optimal output for 951 power is around 0.88 volts. After setting the AFPR at around 45 PSI it took only about 6-8 full throttle runs beginning at 2000 RPM in 3rd gear to close in on a steady AFR. I ended up with good steady power from about 2500 RPM to redline with full boost by about 3500 RPM (I'm at 6000 feet). I was initially having some hesitation problems off idle but with a little bump up in the fuel in the low RPM/ early MAF Deflection region of the map grid the throttle response is now perfect. Next up is utilizing the map switching capability to store a totally different tune for sea level.
Now time to get her on the Dyno. Curious about other experiences...
06-09-2005, 12:33 AM
#4
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Hi Michael nice tuning,
with the altitude v sea level thing, i was under the impression with a MAF and MAF chips that you wouldn't lose your tune with changes in altitude, temp, pressure etc. Be interesting to hear how much difference you find.
with the altitude v sea level thing, i was under the impression with a MAF and MAF chips that you wouldn't lose your tune with changes in altitude, temp, pressure etc. Be interesting to hear how much difference you find.
06-09-2005, 12:35 AM
#5
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Altitude might affect the spoolup characteristics, which "might" indirectly affect the tune. I don't think there will be much of a difference if any.
