Modding Help Help with Tech Lua?

I'm trying to change the behavior of a booster I made, a rocket booster. What I'm trying to do is that it doubles speed upon activation (pressing F) and pressing the primary fire (left mouse button). What happens though is that it actually loses speed mid flight.

Here's the lua so far (the tech.parameter("doubleboostSpeed") is 180, by the way):
Pastebin link: http://pastebin.com/PiCETUps

Code:

function init()
  data.lastJump = false
  data.lastBoost = nil
  data.ranOut = false
  data.active = false
end

function input(args)
  local currentJump = args.moves["jump"]
  local currentBoost = nil

  if not tech.onGround() then
    if not tech.canJump() and currentJump and not data.lastJump then
      if args.moves["right"] and args.moves["up"] then
        currentBoost = "boostRightUp"
      elseif args.moves["right"] and args.moves["down"] then
        currentBoost = "boostRightDown"
      elseif args.moves["left"] and args.moves["up"] then
        currentBoost = "boostLeftUp"
      elseif args.moves["left"] and args.moves["down"] then
        currentBoost = "boostLeftDown"
      elseif args.moves["right"] then
        currentBoost = "boostRight"
      elseif args.moves["down"] then
        currentBoost = "boostDown"
      elseif args.moves["left"] then
        currentBoost = "boostLeft"
      elseif args.moves["up"] then
        currentBoost = "boostUp"
    end
    elseif currentJump and data.lastBoost then
      currentBoost = data.lastBoost
    end
  end
 
    if args.moves["special"] == 1 then
        if not data.active then
            return "activate"
        else
            return "deactivate"
        end
    end
   
    if args.moves["primaryFire"] then
        return "doubleboost"
    end

  data.lastJump = currentJump
  data.lastBoost = currentBoost

  return currentBoost
end

function update(args)
  local boostControlForce = tech.parameter("boostControlForce")
  local boostSpeed = tech.parameter("boostSpeed")
  local energyUsagePerSecond = tech.parameter("energyUsagePerSecond")
  local energyUsage = energyUsagePerSecond * args.dt
 
    if not data.active and args.actions["activate"] then
        world.logInfo("activate")
        tech.setToolUsageSuppressed(true)
        data.active = true
    elseif data.active and args.actions["deactivate"] then
        world.logInfo("deactivate")
        tech.setToolUsageSuppressed(false)
        data.active = false
    end
   
    if data.active and args.actions["doubleboost"] then
        boostSpeed = tech.parameter("doubleboostSpeed")
    end

  if args.availableEnergy < energyUsage then
    data.ranOut = true
  elseif tech.onGround() or tech.inLiquid() then
    data.ranOut = false
  end
 
  if not data.active and args.actions["activate"] then
    world.logInfo("activate")
    tech.setToolUsageSuppressed(true)
    data.active = true
  elseif data.active and args.actions["deactivate"] then
    world.logInfo("deactivate")
    tech.setToolUsageSuppressed(false)
    data.active = false
  end

  local boosting = false
  local diag = 1 / math.sqrt(2)

  if not data.ranOut then
    boosting = true
    if args.actions["boostRightUp"] then
      tech.control({boostSpeed * diag, boostSpeed * diag}, boostControlForce, true, true)
    elseif args.actions["boostRightDown"] then
      tech.control({boostSpeed * diag, -boostSpeed * diag}, boostControlForce, true, true)
    elseif args.actions["boostLeftUp"] then
      tech.control({-boostSpeed * diag, boostSpeed * diag}, boostControlForce, true, true)
    elseif args.actions["boostLeftDown"] then
      tech.control({-boostSpeed * diag, -boostSpeed * diag}, boostControlForce, true, true)
    elseif args.actions["boostRight"] then
      tech.control({boostSpeed, 0}, boostControlForce, true, true)
    elseif args.actions["boostDown"] then
      tech.control({0, -boostSpeed}, boostControlForce, true, true)
    elseif args.actions["boostLeft"] then
      tech.control({-boostSpeed, 0}, boostControlForce, true, true)
    elseif args.actions["boostUp"] then
      tech.control({0, boostSpeed}, boostControlForce, true, true)
    else
      boosting = false
    end
  end

  if boosting then
    tech.setAnimationState("boosting", "on")
    tech.setParticleEmitterActive("boostParticles", true)
    return energyUsage
  else
    tech.setAnimationState("boosting", "off")
    tech.setParticleEmitterActive("boostParticles", false)
    return 0
  end
end

 

I already tried:

boostSpeed = boostSpeed + 100

boostSpeed = boostSpeed * 2

boostSpeed = tech.parameter("boostSpeed") * 2

And so forth. All they do is make the boost slow down and/or stop.

 

try making diag = 3 / math.sqrt(2)