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Motor Vehicle Maintenance & Repair

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  • And also be aware that in many countries moving to a performance exhaust which is louder than the stock exhaust can bring legal problems, eg in the UK you may be fined, so best take that possible cost into account too! Commented Aug 7, 2012 at 10:41
  • I disagree with the MPG argument. Assuming normal driving, MORE throttle producing a given amount of output power tends to result in better MPG as pumping losses are reduced. Less throttle results in higher losses at low output levels. Remember, you're not going to get any more fuel than is needed for the air making it into the system, so there's no impact on fuel economy from that side of the equation. The only impact is on the other side... Commented Aug 7, 2012 at 13:07
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    @BrianKnoblauch, I think your comment conflates a few points: it sounds like you're arguing that a car will have highest MPG at full-throttle. The actual MPG number is going to depend on many more variables than just the throttle position (e.g., current speed => drag). Commented Aug 11, 2012 at 22:45
  • What I mean is more throttle for the same output power at the same RPMs, as long as you don't enter open loop, is the most efficient. Commented Aug 13, 2012 at 12:41