[Brake Bias]

I am wondering if anyone else has this problem. Car info is:

'73 240z, 280zxt motor

toyota front brake upgrade

280zx rear upgrade

 

The passenger side front tire is the first to lock up causing very uneven braking. Is this due to a poor weight distribution in the front of the car. The intake, exhaust, turbo, driver are all on the same side which seems like it would be much heavier than the passenger side and to be causing me this problem.

-jeremy-

[fooling the stock ecu]

I saw the 42% duty cycle firsthand. I did not believe it either, so I double checked it on a friends car. He has a haltech and pulled up his duty cycles on the laptop. My meter was right on with the readings the haltech was showing. I have even verified this 42% on a running vehicle, 6500rpm, 12 lbs boost.

-jeremy-

[fooling the stock ecu]

I do not think that you would get anything useful out of adding a resistor to the afm circuit. The ecu will only trigger the injectors up to 42% duty cycle, and adding more resistance will not increase the maximum output of the injectors. Leaving the system as it is will provide correct fuel input up to the maximum of 42%. If you want to tweak your afm, you need bigger injectors and tighten the afm.

 

-jeremy-

[fooling the stock ecu]

I put up a post asking about injector firing sequences, but didn't get many replies. The reason I wanted to know the firing sequence of stock injectors is because I had an idea to increase fuel flow with smaller injectors. Yes, I did say smaller. I hooked up my meter to measure duty cycle for the injectors and the duty cycle maxes out at 42% I found this to be quite weak, but that is with a good AFM wide open. I thought that if the injectors fire in two batches, to rewire them so that when a signal is sent out to fire the injectors, that it fires all six instead of only three. This would double the fuel input, since it would be firing twice as often. The stock injectors are 2.2 ohm and higher inpedence injectors would be needed to account for running six injectors on the driver instead of three. For 19# injectors have a much higher impedance and would not overload the driver.

I did not find a schematic of the L-jetronic for the turbo 280zx ('83), but every other schematic I found showed that the injectors are fired in groups of two. This could still work with wiring the driver to fire four injectors instead of 2, but diodes would be needed..

 

Has anyone else thought of this, or tried this?

-jeremy-

[batch fire injector sequence]

The reason I wanted to know the firing sequence of stock injectors is because I had an idea to increase fuel flow with smaller injectors. Yes, I did say smaller. I hooked up my meter to measure duty cycle for the injectors and the duty cycle maxes out at 42% I found this to be quite weak, but that is with a good AFM wide open. I thought that if the injectors fire in two batches, to rewire them so that when a signal is sent out to fire the injectors, that it fires all six instead of only three. This would double the fuel input, since it would be firing twice as often. The stock injectors are 2.2 ohm and higher inpedence injectors would be needed to account for running six injectors on the driver instead of three. For 19# injectors have a much higher impedance and would not overload the driver.

I did not find a schematic of the L-jetronic for the turbo 280zx ('83), but every other schematic I found showed that the injectors are fired in groups of two. This could still work with wiring the driver to fire four injectors instead of 2, but diodes would be needed..

 

Has anyone else thought of this, or tried this?

-jeremy-

[batch fire injector sequence]

Just some ideas running through my head... I remember reading that the fuel injector for the bosch L-jetronic system uses a batch fire sequence. ('83 turbo ecu) I do not remember if the injectors are fired all at once, or if there is two groups. I don't have access to my oscilliscope right now, so I can't test it to check. If anyone knows if it is one or two groups, let me know.

-jeremy-