stock injectors
01-15-2009, 09:40 PM
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stock injectors My tuner said my stock injectors are at like 80-90% DC, I can't remember witch, with just the mods in my sig. I was under the impression they could handle alot more power then that. Does this sound right? My fuel pressure is fine the entire time so thats not it. I'm planing a cam install and was wondering what size injectors I should go with if this is normal. I was thinking something around ~36 would be big enough. Thanks.
01-15-2009, 10:03 PM
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I do find that strange. I put down 400RWHP on stock injectors. I know that some model years had 26lb/hr injectors, and that might include 99, but '02 only had 28lb/hr, so that's not too terribly different.
01-15-2009, 10:39 PM
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Depending on what your plans are in the future, some Bosch Design III 30 lb/hr @ 3 bar would be a good safe upgrade at this point. If you have big plans in the future, go with the Bosch Design III 36 lb/hr @ 3 bar.
The richer the AFR, the higher the duty cycle will be respective to the modifications. If your IDC's are 80%, you are at the best practice maximum. You can continue to run at this point with no detrimental affects to the engine. 90% is over the best practice maximum, but still not detrimental. I wouldn't recommend further modifications to increase horsepower while using the stock injectors.
Take a look over at FICINJECTORS <sponsor> for great prices on Bosch Design III injectors.
The richer the AFR, the higher the duty cycle will be respective to the modifications. If your IDC's are 80%, you are at the best practice maximum. You can continue to run at this point with no detrimental affects to the engine. 90% is over the best practice maximum, but still not detrimental. I wouldn't recommend further modifications to increase horsepower while using the stock injectors.
Take a look over at FICINJECTORS <sponsor> for great prices on Bosch Design III injectors.
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01-16-2009, 12:13 AM
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i thought 98-99 were 28.6lbs/hr
2000 are 26lbs/hr
2001-2002 are 28lbs.hr
that being said i have a moderate cam and long tubes i have a 2000 and my injectors are 105% duty cycle... yeah i know time to change them i'm going to tell you what my tuner told me only buy fuel injectors once, to meat your goals now and any others you might want to get into later on i bought 65lbs either way they run like $4xx new and $2xx-$3xx used so take that into consideration if your going to buy some
2000 are 26lbs/hr
2001-2002 are 28lbs.hr
that being said i have a moderate cam and long tubes i have a 2000 and my injectors are 105% duty cycle... yeah i know time to change them i'm going to tell you what my tuner told me only buy fuel injectors once, to meat your goals now and any others you might want to get into later on i bought 65lbs either way they run like $4xx new and $2xx-$3xx used so take that into consideration if your going to buy some
01-16-2009, 04:03 PM
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i thought 98-99 were 28.6lbs/hr
2000 are 26lbs/hr
2001-2002 are 28lbs.hr
that being said i have a moderate cam and long tubes i have a 2000 and my injectors are 105% duty cycle... yeah i know time to change them i'm going to tell you what my tuner told me only buy fuel injectors once, to meat your goals now and any others you might want to get into later on i bought 65lbs either way they run like $4xx new and $2xx-$3xx used so take that into consideration if your going to buy some
2000 are 26lbs/hr
2001-2002 are 28lbs.hr
that being said i have a moderate cam and long tubes i have a 2000 and my injectors are 105% duty cycle... yeah i know time to change them i'm going to tell you what my tuner told me only buy fuel injectors once, to meat your goals now and any others you might want to get into later on i bought 65lbs either way they run like $4xx new and $2xx-$3xx used so take that into consideration if your going to buy some
01-16-2009, 04:09 PM
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98 were 28.8 and so are the 01-02's. they are differant part #'s but flow the same. 99 and 2000 were 26.4's. but unless your way rich you wont run out of injector at this point. if you lean them out enough you can push 28.8's all the way to about 450 rear wheel. i like to change them at about 430 rw to leave a little wiggle room. the stock injectors are very acurate and can be maxed out without issue. dependant on your cam/head combo and projected horsepower you could pick up some 98 or 01-02 injectors for cheap and be good with a good tune. just my .02..... alot of people dont like to go past 85%DC and say its not safe and what not, and recomend or require you to get bigger ones after that. but like i said the stock injectors are very stable all the way up so no need of it really. now if it was boosted or a turbo four banger cranking 9500rpm's then your margin of error multiplies much faster in the upper rpms thus the need for that cushin above 85% for cold wheather and differant times when more fuel is needed
01-16-2009, 05:14 PM
#13
98 were 28.8 and so are the 01-02's. they are differant part #'s but flow the same. 99 and 2000 were 26.4's. but unless your way rich you wont run out of injector at this point. if you lean them out enough you can push 28.8's all the way to about 450 rear wheel. i like to change them at about 430 rw to leave a little wiggle room. the stock injectors are very acurate and can be maxed out without issue. dependant on your cam/head combo and projected horsepower you could pick up some 98 or 01-02 injectors for cheap and be good with a good tune. just my .02..... alot of people dont like to go past 85%DC and say its not safe and what not, and recomend or require you to get bigger ones after that. but like i said the stock injectors are very stable all the way up so no need of it really. now if it was boosted or a turbo four banger cranking 9500rpm's then your margin of error multiplies much faster in the upper rpms thus the need for that cushin above 85% for cold wheather and differant times when more fuel is needed
The Bosch Design III is a great injector, but like all other injectors they have their limits. The best practice 80% maximum duty cycle should be followed regardless of the brand, size, application, RPM, or power output of the engine. One can push an injector past the limit, but as you go over 80% the injectors ability to accurately meter fuel starts the erode. It will also cause an injector to overheat which produces inaccurate fueling.
If you haven't read this, it's great information on this subject:
http://www.yawpower.com/injectordynamics.html
01-17-2009, 09:52 AM
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like i said not all or even most will agree on this. but i have run and seen many, many stock injectors run at 95% without issue for many years. if the fuel is stable in the logs and on a 2500 dollar wideband on the dyno and have been in there for more than three years im sold that it is fine. but like i said thats just me