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Old 11-01-2010, 05:28 PM   #1
87_325is
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Default Injector upgrade?

I have a stock m20 and my injectors are loud. Is there any other injectors I could put in that would drop right in? I have read that older Ford 4.9 or 5.0HO injectors will work but I'm still kind of confused. Is it okay to put in different injectors if everything else is stock? A little more power, gas mileage, and silent injectors is what I'm aiming for.
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Old 11-01-2010, 07:17 PM   #2
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Quote:
Originally Posted by 87_325is View Post
I have a stock m20 and my injectors are loud. Is there any other injectors I could put in that would drop right in? I have read that older Ford 4.9 or 5.0HO injectors will work but I'm still kind of confused. Is it okay to put in different injectors if everything else is stock? A little more power, gas mileage, and silent injectors is what I'm aiming for.
Most Injectors are made by Denso or at least share the same design; so they are interchangable with many makes and models, but when running different injectors (in your case bigger) it is good to have some kind of Tuning device to avoid from running too rich, and you should only do so if you are running lean (lack of fuel or too much air) and
the injectors max out. aka 100% DC

You have done nothing to be at a 100% DC with your stock ones (100% Duty cycle (DC) meaning your injectors are maxed out because they can only put out XXX cc\min or Lbs\hr and being at 100% duty cycle means the injectors will never quite fully close, on most n\a Cars it is hard to achieve this with out other serious modifcations being done that requires more fuel, otherwise you'll just be running pig rich.

Your computer doesn't register that you put bigger injectors in, and the amount of fuel being dispensed is based on the amount of air being metered, and throttle position read by the TPS Sensor, once the computer gets these readings it sends a signal via electricy to the injectors to how much they should open\how long to allow XXX amount of fuel to flow through. bigger injectors the computer will still submit the same signal but that same signal will allow more gas to flow through given the higher output of the injectors, causing you to run rich which will cause you to loose some power, and destroy MPG.

so in short note. your answere is no your would probably lose hp + Fuel Economy. and the noise you are hearing is the Injector Pulse (injector dispensing fuel\opening and closing) if you could find some "Silent" injectors, they probably wouldn't work at all. or would have some sort of sound absorbing material around them.

if your looking for more power and better MPG i would recommend a chip.

try

turnermotorsports.com

anyone correct me if I'm wrong about any of this

Last edited by Boot92 : 11-01-2010 at 07:19 PM.
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Old 11-02-2010, 03:53 PM   #3
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I disagree to a point. When larger injectors are put in, it runs rich, and the o2 sensor detects this and the ECU adjusts fuel flow/timing/duty cycles accordingly. The real question here is whether or not the computer can learn/compensate for this. 17# injectors are fine, I think IE has them. 19# injectors are a little much, though there are chips out there written specifically for 19# injectors that change the mapping more drastically to compensate.

ALso the 14# injectors, at this point, are probably a source of lost power. At best they were barely able to keep up with the M20 and some people argue that in their native state they still robbed some high end power. 20+ year old injectors with thousands of miles on them are probably gummed up and robbing efficiency.

And yeah, mustang 5.0 injectors work. They're cheeeaappp, though I'd spend the extra cash and get some brand new ones from IE or some other place. Use the search function on the forum, with any effort you will find a bazillion results telling you what part #'s to use.

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Old 11-02-2010, 06:44 PM   #4
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Thanks for the info! I think for now i might just get a fresh set of 14# injectors until I do an m50 swap..Also I read about some guys using an m30 AFM with Ford 19# injectors and chipping the ecu. Anybody have any input on this?
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Old 11-02-2010, 07:02 PM   #5
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I'd just get the Miller MAF and 19# injectors to go along with it. That'd put you in the same area as a stock m50 and you wont have to swap anything out, also aloooottt cheaper. Some exhaust work and maybe a WAR chip and you'll be in business.

Mark D has a 19# injector chip I believe, but its not in production so you gotta hunt around for it.

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Old 11-03-2010, 07:32 AM   #6
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you can pop in m50 17.5lb green top injectors. they're 4 pintle and dont run like crap in an m20 like 19lb'ers do without a 19lb chip.
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Old 11-03-2010, 07:43 AM   #7
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The miller MAF and war chip are awesome, im running them in my turbo build and its probably one of the most cost efficient and user friendly setups ive seen and the guys at miller are really good to work with and they will help you if you have any issues with it
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Old 11-03-2010, 07:29 PM   #8
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Quote:
Originally Posted by livetheride514 View Post
you can pop in m50 17.5lb green top injectors. they're 4 pintle and dont run like crap in an m20 like 19lb'ers do without a 19lb chip.
0280150415's? they are 18.1lb @ the M50's 3.5 bar fuel pressure. at the M20's 3 bar pressure they are about 16lb. im running a set of them, also had M30 19lb single pintle injectors in there before that.

@ the OP, tuning (ie- a chip) for the injector size u plan to run is a good idea..
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Old 11-03-2010, 11:55 PM   #9
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I've had sets of injectors cleaned and flowbenched. One set came in at 15.2#, and the other set came in at 16.8#.

As for putting in bigger injectors giving you more room up top, I disagree. If you do nothing but let the O2 sensor compensate, it won't use a wider pulsewidth unless the WOT map tells it to. Throwing in bigger injectors without proper mapping seems pointless.
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Old 11-04-2010, 10:01 AM   #10
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could well be.. i cant speak for the function of the O2 sensor on these cars because all the cars ive worked with here in the UK dont have O2 sensors so the ECU cant try to adjust the mixture.
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