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Discussion Starter · #3 ·
I might go with 24 lb-hr injectors, but I'm not sure if the computer will be able to handle it. Does anybody know if the computer can handle different size injectors? I thought they were programmed for a certain size injector, or maybe thats just speed density computers??? The computer is a Ford Racing mass air conversion computer. I guess I need to give FR a call. According to my Ford Windsor Small-Block Performance book, Engine HP = injector flow rate x number of injectors x 0.8/BSFC. BSFC is Brake Specific Fuel Consumption which 0.5 is the median value. So my calcualations show that 19 lb-hr injectors will support 243 HP and 24 lb-hr will support 307 HP. Also, according to Ford Windsor Small-Block Performance, 45 cubic inches will only add 19 HP and 40 lb-ft, but I need to factor in my RV cam. I believe a stock 302 puts out 195 HP, so I believe the 19 lb-hr injectors should be sufficient, but 24 lb-hr injectors would be nice to have knowing that the injectors aren't limiting my engine.
 

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The mass air meter that with your kit is calibrated to 19# stock injectors.So is the computer.Unless you are going with bigger heads the 19's will work.

Billy
 
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Hey shovel, I would talk with some mustang guys before you decide on what injectors to use. I know you can pick up a recalibration kit for the mass air for the 24# injectors but I dont think you would have to mess with the computer much. I have a few friends that are into stangs. Ill talk with them to find out if you havent gotten any info from FR.

late
 

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I heard it's better to clean the injectors while the engine runs

K-mart, Wallymart,etc can do this for you real cheap. A buddy of mine just did his RAM and his mileage went up 4-5mpg immediately. With a guzzler like his, that ought to pay off the $65.00 CDN in minutes!

Can you get yours into a shop ?

Sixlitre
 

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The PCM has a fuel map in it.When you are idling or at part throttle in closed loop mode it adjusts the injector firing based on 02 sensor voltage and mass air reading..With larger injectors you will be getting more fuel per injector pulse.You can buy an adjustable Fuel pressure regulator to tweak on this.Also when you go WOT the pcm does'nt use feedback control it can't react fast enough.At wot the pcm relies on it's programed fuel map.Again you can tweak this by using a adjustable FPR.It's best to have your MAF meter calibrated to your injectors and a chip in your computer to account for all the mods.If you stay with the 19's that will eliminate most of your problems.19's were also stock on the 351 and should be good for 300HP.Again an AFPR can help get more flow out of the 19's by jacking up the fuel pressure.Most mustangs guys use them.

Billy
 

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Ford Motorsport 19lb fuel injectors (8 injectors)
Price: $239.99
Brand: Ford Motorsport
Part Num: FMM9593C302

These are direct swap Ford motorsport injectors.
Available in 19lb,24lb,30lb.
Must use with correctly calibrated mass air meter when upgrading to larger injectors, or your car will not run correctly !
For example: 24lb injectors must be used with a mass air meter calibrated for 24lb injectors.
 

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Discussion Starter · #10 ·
Thanks for all the info fellas. I think I'm gonna stick with 19 lb-hr injectors just because of the simple fact that I just spent 620 bones on a mass air conversion kit designed for 19 lb-hr injectors and more importantly I'm broke and can't afford anything else. Later done the road I may look into a bigger mass air meter calibrated for 24 lb-hr injectors. bronocbilly69, so as long as the mass air meter is calibrated for the injectors the computer can handle it??? I thought I remembered reading that somewhere.

I would like to clean my fuel injectors without using the fuel rail method, because I've completely disassembled my lower and upper intake for cleaning and while I got everything off I'd like to clean them. If there isn't any other way to clean the injectors, I guess I'll just wait until everything is put back together and then use fuel injector cleaner the fuel rail way.
 

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I don't think that going from 19-24's would mean you would need a custom chip.However,the reason most guys go to bigger injectors is because of engine mods like bigger cams,heads etc.Now one thing I would recomend you get is an adjustable fuel pressure regulator.Heres why.You have just added 45 cubes to your motor.Your wot fuel map is based on 302ci.It's possible that at wot your engine will run lean.This is not good.With the AFPR you can set it to a higher pressure(with the vacuum line off).That way when you stick your foot in it(low vacuum) you will be getting more fuel.Under normal driving conditions the pcm feedback control should be able to correct the A/F ratio.I would consider it cheap insurance.As for cleaning the injectors I would clean and inspect the pintle caps(they are cheap to replace),O rings and the screens.That's really about all you can do unless you send them out and have them cleaned.

Billy



 

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Kirban and aeromotive are two popular brands.Check out some of the mustang sites.The regulator for the 89-93 mustang is the same as for the truck I believe.You can also get alot of usefeull info from those guys.Alot of those guys are running 347's.The corral.net is probaly the best board.

Billy
 

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Re: FP

ok, good. i have another one for ya. i was looking at your tank pic and i see the filler hole, send and return lines, and then this white 2-port thing with a hose on it. what is that?
 

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Re: White thing with a hose

Ah, i forgot about that thing... i see that line going down the rail all the time and have to remind myself what it is. I vaguely recall somebody mentioning that some vent gets clogged and will make gas filling slow... is that the one? Mine has always filled slow, and i'm sure whatever end is on that hose is encased in a nice thick shell of mud
 

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Re: White thing with a hose

No, it doesn't do anything when the cap's off - on your truck, the filler neck IS its own vent, with the real filler being a slightly smaller hard tube inside it. (Earlier ones were reversed - fuel flowed in the large hose & vent air came back up a smaller one inside.) On both, it's easy to kink the inner hose & make filling slow.
 
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