Port timing calculators

Exhaust Duration Calculator
Stroke:  mm
Conod Length:  mm
Piston Crown to Top of Barrel at TDC:  mm
Height over Port, Top of port to top of barrel:  mm
 
Exhause Duration (degrees):
Auto Fill Other Fields
Once you have filled in your Stroke, rod length and Crown to top of barrel above. Click Auto Fill Button.
Auto Fill to clear the fields press
Clear
Transfer Duration Calculator
Stroke:  mm
Conod Length:  mm
Piston Crown to Top of Barrel at TDC:  mm
Height over Port:, Top of port to top of barrel  mm
 
Transfer Duration (degrees):
Once you have calculated your exhaust and transfer timing click this to give;

Blowdown
 
Blowdown degrees:
Inlet Duration Calculator for piston port motors
Stroke:  mm
Conrod Length:  mm
Piston Crown to Top of Barrel at TDC:  mm
Piston height inlet side:  mm
Inlet Floor Depth, Top Barrel to Bottom Port:  mm
 
Inlet Duration (degrees):
Ignition Timing in mm Before TDC Calculator
Timing Degress A:
Conrod Length:  mm
Stroke:  mm
 
mm before TDC:  mm

CC Calculator
Bore:  mm
Stroke:  mm
 
CC =
Corrected and uncorrected compression ratios calculator
Bore:  mm
Stroke:  mm
Height over exhaust port, top of port to top of barrel  mm
head volume (head cc)  cc
 
uncorrected  :1
corrected  :1
Two stoke oil mix calculator for %
oil %, enter your chosen oil %:  %
litres of fuel:  Litres
 
ml of oil required  ml
Two stoke oil mix calculator for ratio
oil ratio , enter your chosen oil ratio (eg. for 25:1 enter 25):  :1
litres of fuel:  Litres
 
ml of oil required  ml
Calculate BMEP using Torque
Torque (lbs ft)
CC
 
BMEP
Calculate BMEP using BHP
HP
CC
RPM
 
BMEP

13 Replies to “Port timing calculators”

  2. I have been using this calc for years. Absolutely love it. I have two suggestions. It would be neat if port open times were shown. I’d love it if I could have a printable page that I could label and save.

    Reply

    1. Thanks 🙂
      There used to be a printable version on the old site, I will have a look at adding what you have requested.

      Reply

  5. This is extremely useful thank you. One suggestion for improvement is a sketch, with a key, showing all the requisite measurements.

    Reply

  6. If I want to achieve 82 degrees exhaust open ATDC when hot what will I need to set it at cold is it 80 or 84 degrees many thanks

    Reply

    1. Its what ever you want your static timing to be. Say you are aiming for 17 degrees before TDC, you enter 17 in that field and then it will tell you how many MM that is before TDC so you can use a dial gauge to set your timing.

      Reply

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