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How do you know your injectors are maxed out??

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Old Sep 8, 2002 | 11:09 AM
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MY99TAWS6's Avatar
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Default How do you know your injectors are maxed out??

I see pulsewidths on my autotap or scanmaster but not duty cycle..I understand you can run at 100% for short periods..few seconds but better to be around 80% I think right.Anyway my pulsewidths read 19.60 or so didn't see them hit 20 yet..
I have a few mods..lid,holley filter,asp pulley,
b1 cam,gms maf,ported tb,ls6 intake,tts ,cats and cutout..my car is 99 so have the smaller injectors..I am power limited by the injectors yet? Would get some 30svo as plan on heads next season but might get dry nos and then figure I would need 38 or 42s probably.Anyone pick up power from going to bigger injectors with mods like mine.I am also having some top end mph issues...but still playing with shift points,tuning etc so can't say for sure if the injectors are holding my back.car doesnt go super lean up top..
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Old Sep 8, 2002 | 11:30 AM
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Default Re: How do you know your injectors are maxed out??

If your injector PW was 19.6 @ 6000 rpms you'd be at a 98% duty cycle which would be pushing your injectors to the limit. You can figure-out your duty cycle with this formula:

PW x RPMs/1200 = Duty Cycle
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Old Sep 9, 2002 | 10:05 PM
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Default Re: How do you know your injectors are maxed out??

Well since this looks true then how the hell can all these guys with similar mods to me and heads too run these little injectors..I don't think injectors will run over 100% will they...so I would think I need at least 30 pounders for now.
Why wouldn't my scanmaster or autotap show big leaning out at the top end..?? Or am I ok as I am still at 98%??? And what happens at 6500 rpm or you don't think the pulsewidths would go up higher with more rpm.have to check I guess..maybe when I thought I was hitting the limiter a few times my injectors were hitting the 100% mark..
I also am hearing conficting things on svo injectors..on corvette site I think I read that the svo are same spray pattern and work good on our cars and someone else was saying someone told him they are totally wrong for our cars and that we should run bosch injectors...more confused now.
What are the symptoms of running out of injector in an na car..??
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Old Sep 10, 2002 | 08:04 AM
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Default Re: How do you know your injectors are maxed out??

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by MY99TAWS6:
<strong>
What are the symptoms of running out of injector in an na car..??</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Running lean in the high rpms and a jagged dyno curve are symptons. A wideband dyno is a good way to test.

FWIW, some people have posted ATAP data showing duty cycle in excess of 100%.

If you are going to add a dry shot, go with the bigger injectors and be prepared to add a better fuel pump too.
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