Bigger injectors on stock engine?
 

Would 30# injectors be really, really bad for my 95 GT?

(modifications in sig)

Well, first you would have to get the tube that goes along with the injectors for the Mass Air meter, which will be costly and without heavy mods or at least 350 horsepower you really don't need that big of an upgrade. Your computer would most likely adjust anyway to keep the right fuel/air mixture and you would not see any benifit from the 30's. They are good supporters of horsepower and make room , but they are not producers, kind of like pulleys. if you plan on spraying or boosting then I would say go for it. they would be needed to support such an application.:D

19# injectors will handle up to about 300hp. You could put the 30# injectors on your car or throw the money out the window and get about the same result with a stock motor. Put the $200 into pulleys, exhaust or suspension and you'll get more bang for the buck. You won't need bigger injectors unless you put on new heads, cam and intake, or put on a blower, a turbo or run a butt load of nitrous.

hey 95mustanggt,
I hate to change your subject but I was curious how your exhaust sounds with the off road and the dynomax. and what kind of dynomax you have. I was thinking about going with the mac off road h and the super turbo cat back system but I was told that the dynomax aren't that loud. I'll check this thread later but if you could send me a private message, that would be great. Its scottlt79.

thanks

I'm not trying to get any performance out of the 30#'s. I already have a set of pulley's in my trunk :).

I think my injectors are shot and I don't want to put another set of 19#'s on because eventually I want to go with TFS Heads, TFS Intake and TFS #1 cam. It will just be a while before I can afford to do this much to the car, so that's why I was wondering if I could run 30's without damage to the car.


SCOTTLT79 check your PM :)

go with 24's!

I agree, 24lbs/hr will work great with heads/cam. Naturally apirated those will support 400 hp, and will work on your stock engine. You will just need to get a matching MAF sensor.

I've heard bad things about 24# injectors.

Although I probably could run 24# injectors with no problem on the stock set up. I just don't want to go with 24#ers and after I install my heads/intake/cam set up have someone tell me I need 30's. I have to recalibrate my MAF, which I don't want to be doing more than once.

Another option would be to buy someone's old 19's (like mine for instance:D ) for like $20 and saving the $200 for later. Or you could check the ones you have to be sure you even have a problem. I also agree that the 24's are a much better choice for the combo your leaning toward.

I'll keep that in mind :)

I THINK that I have an injector problem. I have to perform a test on the fuel system first. My shraeder valve broke on me and Ford has been taking a couple days to get the part. It should be in this afternoon and hopefully I'll get the test competed.

Seriously, I may have to talk to you about your old injectors, if I need them.

Yeah, lots of poeple find it hard to tune the 24's and MAF perfectly. The Cobra computer and MAF is the ideal components to use from Ford when using the 24's for the best tune. But then again that's more money. I use the 24's with a C&L 73mm with no problems and excellent idle. I guess I got lucky. Most don't have many problems at all but there are a few that have stumpers. Good luck!:D

USMC302, what injectors do you use for your SC 95 GT?

19's but I wouldn't advise it for anyone else. I have the Vortech 155lph external pump and of course the vortech FMU, but the power seems to die away right at 4500rpm's. Don't know if it's fuel or not. Timing is good, but fuel would be my first guess.

I would guess fuel too. 19# with a Vortech. You should upgrade.

DON'T go with bigger injectors.

I learned this myself. I had a 70mm Mass Air, and 24lb injectors a little while ago. With my combo and those parts I COULD NOT spin the tires at the track on 245/45/17 street tires. I removed the injectors and mass air, and gained tons of low end torque, enough to need drag radials. The stock parts will last till at least 300hp. If you upgrade you will gain on the top end but lose torque down low.

Don't go with them just yet in my opinion!

True and I will, but 19lb injectors support up to 300hp, and with a stock motor and a 5lb blower, I don't think I am at that yet. But i will be doing the upgrade anyway.

With a blower I would recommend it, even if you don't have 300hp but without one, a stock or mild motor doesn't need 24lb injectors.

I have a ???????
 

95Mustang,I have a rather simple question for you? Do you have an adjustable regulator?

Years ago and I mean years ago back when FFW was nothing but a puppy,guy used to race Street 5.0 named Lee Rutter,he made 390hp with 19 pounders,but his fuel pressure was cranked up to 52psi.

Now I know you are not making that much hp but if you have an adjustable regulator you can fine tune the pressure to where you need it.

If your combo is tuned correctly you will be surprised what the stock equipment can support,remember these guys used to run big numbers with a lot of stock equipment until A4 blocks,R302 blocks and GT40 intakes came along.

Also with Motorsport equipment it is all a roll of dice with anything you buy.

Good luck with your combo.

i ran 11.7s with old combo with 19# injectors annd a dry shot..so they will go fast

Absolutely agreed, 19lb squirter will handle much with tuning. Don't forget a chip will help the fuel curve also, a lot of times the computer will take over regardless if you have 50lb injectors on a stock app. or not. It will read the mixture and utilize what you need.

HORSEMANS RACING, I just came from Camp pendleton, I know a lot of mustang junkies there, who are you with over there? You know they even have a mustang club there on base.:cool:

I don't have an adjustable fuel pressure reg. yet, but I'm trying to think a little further down the road. I know that I will have to upgrade my fuel system when I get my car where I want it to be, but I don't wan't to have to buy a bunch of "in between" parts.

For some reason I have heard bad things about 24# injectors and MAF's so I was thinking about the 30#'s. I know it may be more fuel than I need, but If I were to add a low pressure blower or power adder after my combo I would probably still be ok.

Thanks for all the responses guys.

Not a Bad Start
 

95Mustang,
that would not be a bad ideal really to get the fuel system first,that way it will keep your spending in check. For example with what I plan on doing is going 255 in-tank fuel pump,that way unless I am making some serious animalistic power I will never need another fuel pump.

Really to be honest the fuel system is probably cheaper to upgrade than any other high performance part out there.

95Mustang I would just tailor the fuel system to how much hp you want to make.

That is pretty much the only advice I can give you,avoid the bigger is better,and you should be alright.

I do not understand how a 24 pound injector with a calibrated MAF sensor can be bad??? I think someone might be thinking that the stock MAF sensor will compensate.

near stock engine: 19 pounders better

Near stock engine spraying 125 dry shot: 24 pounders better with AFR, 190+pump, and recalibrated MAF sensor

if you really want to find out what you need here's some math to help you out...
first estimate horsepower: 300 your shooting for?
next (BSFC) brake specific fuel consumption: .45 is lean, .55 rich (use .5 as an average)
then duty cycle of each injector. keep in mind that they are rated at 100% duty cycle (DC) in regards to output, but greater than 80% (.80) will kill the life of the injector.
NC (# cylinders): 8
here it is: [(HP x BSFC)/NC]/DC= injector size
[(300 x .5)/8]/ .80
=23.44 lbs-hr or 24# injectors.
thats assuming you have the pump and regulator to max out the injectors. cranking up PSI can only spit out as much fuel as the injector can flow. i maxed out my 24# injectors at 392 hp on the dyno before putting a hole in a piston. up to that point 24s are a safe bet. especially since jumping to the next size is about 200$ more expensive then the 24s. stock injectors will get you safely to about 250 hp. i learned my lesson the hard way, you dont want to max out your fuel supply unless your fiance doesnt mind not getting an engagement ring cause you spent the money fixing your motor.

What happened to your shraeder valve? Is it that same one that my 92 came with? If it is mine is just sitting in my tool box after a Fuel Pressure gauge install. Your more than welcome to it if it helps.

Chip

Thanks chipdog. I got another one from Ford for only $5. Installed it and it and found my FPR is shot. I think I'll get an Aeromotive Adjustable one.

As for my injectors I'll leve them for now I guess.

Where??????
 

I have a question since 30 pound injectors are the next size up,where is this ad that says 30 pound injectors cost 400 dollars? The most I have seen 30 pound injectors is $299.

Fancy math is cool and all that,but at least get the price of the injectors right.

It seems like Mustang owners more than any other hobbyist group loooooove to pump more fuel into their engines :D

Although my knowledge of engines is pretty elementary, I always assumed you increase the injector size corresponding to increases in air flow (intake, heads, etc) Am I wrong? Because I don't see where enough flow in your setup would even come close to requiring 30#, even 24#. I dont have heads yet, but with my setup I'm fine with 19#

Belle, I would be doing this only to avoid buying a set of 19# injectors and then turning around and spending $$$ to buy a set of 24 or 30# injectors. But like I said the problem is more in my FPR than injectors (so far), but I like to think ahead to avoid spending carelessly.

"Fancy math is cool and all that,but at least get the price of the injectors right."

carl, at least you got the point, thanks for posting something usefull