RPR Posted June 28, 2016 Share Posted June 28, 2016 My SIII runs a 3.5 block with a 3.9 top end and Lucas "Hot Wire" 14CUX ECU. The EPROM is currently set to the "Saudi" (yellow) setting. It runs a bit rich at sea level. Having moved to Boulder, CO, day to day driving is above 5,000 ft and wheeling takes place up to 10,000 ft. Consequently, compression and power decline and it runs quite rich. Trying to figure out ways to improve tune at high altitude. Supercharging is not on the cards Questions: Does anyone know whether one of the other fuel maps will lean it out a bit ? "Australia and RWO" and "North America Non-cat" both seem options but I don't know anything about the fuel mapping characteristics of each. As you will recall, 14CUS only manages fuel, not timing. Timing is controlled by the distributor. In view of the altitude and greatly diminished risk of pre-detonation (pinging), would it make much sense to advance timing "a bit"? Any clever but simple/realistic ideas for improving compression? Any other tips for tuning to high elevation? Thanks very much. RPR Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted June 28, 2016 Share Posted June 28, 2016 Strictly speaking, as Hotwire is based on an air-mass meter, it shouldn't get any richer at altitude, as it will compensate for the reduction in density. Quote Link to comment Share on other sites More sharing options...
RPR Posted June 28, 2016 Author Share Posted June 28, 2016 Bowie, Thanks for the speedy reply. I take your point that it should adjust to altitude, so I will go with "my perception is that it seems to run rich". Having said that, I guess the question remains whether anyone knows what the fuel mapping characteristics of the five settings are and whether any of them might be better at high altitude than the Saudi setting. Still would like views on advancing timing Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted June 28, 2016 Share Posted June 28, 2016 You can tune the AFM with an allen key -if you fit a wideband O2 sensor, you can tune it yourself as you drive around Unsure on the other fuel maps, except the cat-equipped one, which would be richer to allow the cats to work effectively. Quote Link to comment Share on other sites More sharing options...
RPR Posted July 5, 2016 Author Share Posted July 5, 2016 Advanced timing 6 degrees and definitely felt improved low end performance, especially noticeable this weekend when up above 10,000ft for a good amount of time. Altitude creates several challenges, @ 35% less oxygen than at seal level, lower compression and about 35 - 40 less HP, which I can barely spare with my little 3.5 V8. Shoehorned into an SIII, that aluminium block makes a LOT of heat and at 10,000 ft, the boiling point for coolant is headed towards 200F and heat exchange is much less efficient. I have a heavy duty, high speed marine extractor fan installed in the right side of the engine bay that is extremely helpful and on long slow climbs will put the heart on full, which is uncomfortable but effective. I was able to run at 180F or less most of the weekend. Got up almost to the snowline at one point. The attached picture is of one of Colorado's 14,000ft plus peaks and I met some folks on the trail who had hiked up it to ski early in the morning. Quote Link to comment Share on other sites More sharing options...
hangover Posted July 7, 2016 Share Posted July 7, 2016 Nice looking shorty, are they MOG portals or Volvo C303 ? Quote Link to comment Share on other sites More sharing options...
RPR Posted July 7, 2016 Author Share Posted July 7, 2016 C303 5.99:1 Quote Link to comment Share on other sites More sharing options...
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