Torque & RPM at Shifts: Explained

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Discussion Overview

The discussion revolves around the relationship between torque and RPM during gear shifts in vehicles, specifically focusing on how these factors affect acceleration. Participants explore concepts related to engine torque versus wheel torque, peak power, and the implications of gear selection on performance.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant questions whether torque at the drive wheels increases or decreases when shifting from lower to higher gears.
  • Another participant asserts that torque decreases as higher gears are engaged, suggesting a trade-off between torque and RPM.
  • There is a claim that a car accelerates fastest at peak power, but others argue that maximum acceleration occurs at peak torque in any given gear.
  • A participant emphasizes that maximum acceleration can be achieved in first gear, but acknowledges that in practical scenarios, it may occur in higher gears depending on the vehicle's configuration.
  • Discussion includes the idea that while higher gears yield higher RPM, they provide less torque for acceleration compared to lower gears, but this torque can persist over a longer range.
  • One participant introduces a dyno graph to illustrate the relationship between torque and horsepower, suggesting that proper gearing can optimize acceleration across the RPM range.
  • Another participant presents a drag strip performance example, leading to a debate about the interpretation of acceleration data and its implications for vehicle performance.
  • Some participants express confusion regarding the relationship between torque and acceleration, particularly in the context of fixed gear ratios and vehicle speed.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between torque, RPM, and acceleration, with no consensus reached on the implications of gear selection or the significance of peak torque versus peak power.

Contextual Notes

Participants discuss various assumptions regarding vehicle performance, including the effects of tire slippage, gear ratios, and the specific configurations of different vehicles, which may influence the outcomes of their arguments.

  • #31
i whole heartedly agree with you.. the HIGHEST Rate of acceleration occurs from a dead stop
 
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  • #32
In fact, if you do the math, at 0 mph your acceleration could be infinity. Although, that's not the case due to obvious real-world limitations...
 

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