1.3 carb on a 1.6? it can be done
Posted: Tue Nov 22, 2011 4:59 pm
With a bit of re-jetting, Info found on Auszookers, posted by Nisvit
Use a 1.05mm jet in the primary and then a 1.42mm jet in the secondary.
With a carb clean and these jet sizes we acheived a lambda ratio of approx 1 at idle, and 0.93 at 2800.. The reference books books I was using (bosch handbook) reckons that max torque is acheived at .9 lambda exhaust mixture so I was happy with the 0.93.
As this was effectively a no-load test we didn't get to test the secondary circuit reading but will see how this goes for now. The 1.42mm jetted secondary now allows you to feel the car accelerate at 80k when you open the second throat, which it didn't want to do before.
So in short form - if you are running a 1.6 bottom end with 1.3 carb, and it feels a bit doughy, try a 1.05mm jet in the primary and you will have the primary throat mixture about right.
the 1.42 was actually a primary jet from a TB42 carb gq patrol
Most jap cars seem to use jets with the same size threads, I have a heap of old corolla carbs ( the k series engines 12-1500). they used various jets from about 106-112 in primaries, and 119,130,145 & as large as 162 in the secondaries.
I have number drills to make exactly the size I want, and you can solder the jets closed if it is too big, and then re-drill them.
Use a 1.05mm jet in the primary and then a 1.42mm jet in the secondary.
With a carb clean and these jet sizes we acheived a lambda ratio of approx 1 at idle, and 0.93 at 2800.. The reference books books I was using (bosch handbook) reckons that max torque is acheived at .9 lambda exhaust mixture so I was happy with the 0.93.
As this was effectively a no-load test we didn't get to test the secondary circuit reading but will see how this goes for now. The 1.42mm jetted secondary now allows you to feel the car accelerate at 80k when you open the second throat, which it didn't want to do before.
So in short form - if you are running a 1.6 bottom end with 1.3 carb, and it feels a bit doughy, try a 1.05mm jet in the primary and you will have the primary throat mixture about right.
the 1.42 was actually a primary jet from a TB42 carb gq patrol
Most jap cars seem to use jets with the same size threads, I have a heap of old corolla carbs ( the k series engines 12-1500). they used various jets from about 106-112 in primaries, and 119,130,145 & as large as 162 in the secondaries.
I have number drills to make exactly the size I want, and you can solder the jets closed if it is too big, and then re-drill them.
