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notorquemiata-2

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Slow Boring No Torque Miata (Spring <del>22</del>23)

Plan

Block

  • Mazda BP6D Block with 10.0:1 Pistons
  • Oliver Conrods
  • ARP Main Studs
  • ARP Head Studs
  • Boundary Stage 2 Oil Pump
  • Hastings Rings | 30 Euro
  • ACL Main Bearings | 100 Euro
  • ACL Rod Bearings | 60 Euro
  • Head Gasket
  • Mazda BP6D VVT Head
  • Manley Back-Cut Intake Valves

Long Story

In the current state, the car has around 230250whp and is, at least to this point, reliable even under heavy use. Octane requirement is 95102 RON / 9195 AKI, this seems reasonable for 9.5:1 and 0.60.82 bar (912 psi). The intake air temperature is only 10 K above ambient temperature which leads to the conclusion that the current setup is somewhat efficient.

The goal for the next stage should be a significant gain in power while maintaining reliability and practicability.

Related:

Power Goal

As one can see, the airflow of the supercharger at reasonable efficiency (~0.65) is around 0.36kg/s.

In theory, this should lead to at least 360whp. Previous archivements were 302whp @ 6.74krpm by bigb5031, 93krpm @ supercharger. Supportive mods were I/H/E and mild head work, stock 9.5:1 compression, 98 RON / 93 AKI.

315whp @ 7.317krpm by trackdogracing, 100krpm @ supercharger, I/H/E, E85.

324whp @ ~7.3krpm by kraftwerks, 100krpm @ supercharger, mods unknown.

Constraints and Limitations

  • Torque output should be under 250lb/ft / 340nm (at the wheels)
  • Octane requirement must be ordinary 98 RON or lower. 100 / 102 / E85 is not an option. fuck it
  • Engine should not be knock limited, even under harsh conditions (45 C ambient / track use)

Decisions

  • Target RPM
    • 105mm sc: 8500
    • 100mm sc: 8100 - 161 mph / 259 kmh ←- current state
    • 95mm sc: 7700 (101 Euro + S&H) - 153 mph / 246 kmh
    • 90mm sc: 7300 (81 Euro + S&H)

95mm would be “optimal” but would limit rpm to 7700.

Smaller pulley would lead to more belt slip probability.

Engine Block (draft)

  • Pistons: Wiseco K590M84 84mm 10.0:1 OR Mazda NB2 83mm 10.0:1 used with new hastings (2C4651) rings - cost: 30 Euro
  • Conrods: Oliver A-Beam

  • Head Studs: ARP
  • Main Studs: ARP
  • Rod Bearings: ACL Race
  • Main Bearings: ACL Race
  • Thrust Bearing: Mazda
  • Oil Pump: Boundary Stage 2

Head (draft)

  • VVT
  • Manley Intake Valves (Back-Cut)
  • CatCams followers
  • CatCams Springs
  • 6mm Lash Caps
  • Tomei Cams, why?

notorquemiata-2.1693531937.txt.gz · Last modified: 2023/09/01 03:32 by imakeyoufast