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Discussion Starter · #1 ·
I cannot stand cold weather, wishing it was spring already.

But my Twin Turbo's LOVE the cold weather and they go
screeming down the road.....


Happy Holidays to one and all.
 

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Sure. I've run them all year for years. I do take it easy when it's really cold.
Have you had forced induction tuned cars before? You can run after market tunes on NA cars all year round fine but not FI cars. FI cars MUST run rich. Part of the knock prevention is running the motor richer than an NA motor. This is done because temperature swings can have a much more dramatic effect on total air volume on a FI car than an NA car. Things like moisture and temperature in colder climates will cause FI engines to run significantly leaner in the winter time than the summer time. When you get a motor tuned in the summer time, the tuner will run the tune to the edge of what AF ratio will cause knock, this is great for summer time and max performance, but it means in the winter time your engine is running lean, more than likely leaner than what the tuner would have put on the car in the summer. The lean condition will cause high EGTs that can burn up valves, turbos, catalytic converters and any thing else being exposed to higher than normal temperatures.
 

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Have you had forced induction tuned cars before? You can run after market tunes on NA cars all year round fine but not FI cars. FI cars MUST run rich. Part of the knock prevention is running the motor richer than an NA motor. This is done because temperature swings can have a much more dramatic effect on total air volume on a FI car than an NA car. Things like moisture and temperature in colder climates will cause FI engines to run significantly leaner in the winter time than the summer time. When you get a motor tuned in the summer time, the tuner will run the tune to the edge of what AF ratio will cause knock, this is great for summer time and max performance, but it means in the winter time your engine is running lean, more than likely leaner than what the tuner would have put on the car in the summer. The lean condition will cause high EGTs that can burn up valves, turbos, catalytic converters and any thing else being exposed to higher than normal temperatures.
That's not how tuning forced induction vehicles or basic fuel injection works at all. I don't feel like typing a wall of text but please don't spread misinformation.
 

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I always thought the knock prevention on Direct Injection engines was more about delivering the fuel/air mixture directly to the cylinder in a much more direct and controlled fashion, than about running rich. I would've thought the "must run rich" stuff would've been for earlier, less precise engine designs. But someone who knows more about engines than I do (and I know there are at least a few on here who know way more about engines than I do) can probably explain what's going on here.

Stated more clearly, it's tough to trigger detonation when you only deliver the fuel exactly when it's needed, directly to the burn site. You could still get detonation by advancing the timing too much, but as long as you're not overly-lean I don't see the problem. Of course this assumes the tuner leaves enough safety margin for variable conditions. They have to get that performance from somewhere.
 
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