High Primary Duty Cycle

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TRRAPLN
Posts: 23
Joined: Thu Jul 18, 2013 3:02 am

High Primary Duty Cycle

Postby TRRAPLN » Tue Jan 28, 2014 5:39 am

Now that my Asus win8.1 tablet is loaded with my Haltech program I decided to verify my primary injector duty cycle that I had suspected was high.

RX-7 rotary
550 OEM primarys
2000 ID secondaries
Sequental/Primary hold mode
Staging load is 2.2psi

In the screen shot of my fuel base map, you can see the secondaries are staged at 2.2psi. I always considered this high based on that the OEM staging point was at 0psi.

I get 92% duty cycle at 6800RPM! See Data Log Viewer screen shot.

Why is this so high if I'm set at primary hold? I thought the primary's hold the duty cycle after the secondaries kick in. Please explain why the primaries continue to rise.

In order to correct this, I was going to change the map and stage the secondaries at 0.0psi. This should save me 10-15% duty cycle.

I assume I would need to raise the secondary map to compensate for the primary injector duty reduction.
Attachments
Data log 2.2 stage.JPG
Fuel Base Stage.JPG

LMS_689
Posts: 1397
Joined: Thu Oct 18, 2007 6:30 am
Location: Floyds Knobs, IN USA
Contact:

Re: High Primary Duty Cycle

Postby LMS_689 » Tue Jan 28, 2014 6:57 am

Primary hold holds the pulse width of the last pre-secondary cell. Not duty cycle. So, for a given pulse width, as the revs rise, so does the duty cycle. You're map also has the pulse width rising with revs. So that adds to your issue.
Haltech Parts and Accessories
Custom Harness Construction
http://www.lms-efi.com
[email protected]
502-515-7482

TRRAPLN
Posts: 23
Joined: Thu Jul 18, 2013 3:02 am

Re: High Primary Duty Cycle

Postby TRRAPLN » Tue Jan 28, 2014 8:46 am

Thanks for the clarification.

So if I change my stage point to 0 then my last hold cell will be reduced along with the duty cycle.

LMS_689
Posts: 1397
Joined: Thu Oct 18, 2007 6:30 am
Location: Floyds Knobs, IN USA
Contact:

Re: High Primary Duty Cycle

Postby LMS_689 » Tue Jan 28, 2014 8:07 pm

Yes. Bigger injectors are a better idea.
Haltech Parts and Accessories
Custom Harness Construction
http://www.lms-efi.com
[email protected]
502-515-7482


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