Any harm running a WAY bigger than needed fuel injector if tuned right?

I plan on building a low compression stroker motor that will see 14+ psi ...

BUT, in the mean time I wanted to run around 7 psi, on my stock bottom end. Until I have all the money to do everything right on the motor.

So say I was to get 72lbs injectors, could I get the PCM set for them, stock pressure, to run on 7 psi, just fine with no drivability issues, that way later on down the road I can use the same injectors and wont have to buy them twice?

Otherwise, I would probably find myself a set of 42#'s for now. Sell them off, and go bigger later.

Pro's/Con's ? Opinions?

go with the 42s and buy the bigger injectors later. easier to tune. less money

The largest high impedance injectors that are readily available are in the 50# range. You could run those, not a problem. The stock PCM will not run low impedance injectors - the drivers will overheat.

Rich

Thanks guys ...

I dont know why, I had it stuck in my mind someone had a 72# high but Owell ... Ok thanks.

Is there any problem with running injectors that large though? Assuming you got either an impedence converter or aftermarket pcm.

I'll be running 72lb injectors on a car that needs ~65lb. I'll be using them to there full capacity later, but until then...:shrug:

Edit: I think there are some 72lb high impedence injectors, i'll see if I can't find them.

So if I did buy the injectors now, which brands would you guys be looking at?

I can get Lucas ones at a good price. But if the SVO's show an advantage, I dont have a problem chipping out the cash for them.

O and I would be looking at 42#'s I guess then since I would have to upgrade later anyways. Thats more then enough for a bolt on, 7PSI blower car on stock heads and cam.

http://www.usrallyteam.com/injectors.html

Down the page there are some 750cc injectors (72lb/hr) that are high impedance. They're made for VW's and such but i'm sure you could get them to work:D

Hah actually, I think those are the ones I remember seeing in a GM Hi-Tech Mag. ....

It jsut seems like switching to low impedence is going to be overly complicated/expensive so maybe I will wait until later to do it all.

And Ill get myself some SVO or Lucas 42#'s ...

Later when you upgrade, you may want to look a little bit before committing yourself to 72# injectors. Personally I am running Mototron 60# injectors and spinning just underneath 16#'s of boost (15.7 to be exact). I have been told that they will support over 18#'s of boost effeciantly if needed.

Remember, you want the injector size that is best for the application you will be running. Anything outside of the size that would best fit your setup and you will not be running as efficiantly and may loose HP.

i built my engine low compression and running 60lb motron injectors. pcmforless tuned my pcm to run with these injectors with no super charger on their until i get the money to by it. i donot fluid engine at all and not running rich.

Well, the 72's were just a estimate really, I basically just want something that can support in the 600-700RWHP range, and hopefully I can do so on the stock PCM but its gonna be tough getting a set of high impedence injectors that will cut it ...

Those 60# mototrons, their high impedience, Any problems with them on the stocm PCM? What fuel pressure are you running? I could always run them, with an AFPR to keep from having to use a impedence converter or aftermarket pcm.

From first hand experience on friends cars the 75lb injectors purr like a kitten and 96lb (1000cc) run fine as well. If you plan on needing bigger in the near future just get the bigger ones now. I just installed 160lb injectors on my car and hope for the best!

Rodrigues, those are low impedience though correct?

the 75lb injectors are high impedance made by RC Engineering.
My 160lb injectors are low and would required a peak and hold driver.

Rodrigues, those are low impedience though correct?

Again, IMO you can certainly run a higher than needed injector size, but it certainly won't be efficiant, and you will loose potential HP.

My fuel pressure once my 2nd fuel pump kicks in at 4#'s of boost shoots up to 60. As you can see in my sig, I am still running the stock PCM with pump gas and no problems. My setup could probably be pefected if I swapped out my ported AFR 180's with some 220's. On a better day temperature wise and re-dyno'd on a dynojet I could have easily seen 650 at the wheels. I am sure swapping out for the better heads I could have gained an additional 50 RWHP if not more. (So yes 700 RWHP is attainable with the stock PCM, but it is expensive and not easy to accomplish) Here's a link to my dyno video;

http://thumbs.vidiac.com/5d911306-59a8-4540-8b66-982b00ebf51d.jpg

http://videos.camaroz28.com/video/5d911306-59a8-4540-8b66-982b00ebf51d.htm

Motron 60's would be a good choice for ya.

You think I could get 60's to provide enough fuel later on down the road when it is regularly going to see high boost on a 383 ? The heads will likely be LE3's ... I want to see how far I can go with the stock castings.

But ya never know, I may decide to throw some more $$$ at it and get AFR's ?

How can you loose potential horse power? If you are keeping a good spray pattern, the only thing different is going to be that it will have a shorter pulse width ( For now ) ... I dont understand what makes you loose potential horsepower by going "too big" with the injectors?

You think I could get 60's to provide enough fuel later on down the road when it is regularly going to see high boost on a 383 ? The heads will likely be LE3's ... I want to see how far I can go with the stock castings.

I have seen the 60's support 700rwhp on LS1's (though they run higher fuel presure 60-65psi base). This means if you have enough pump and a good regulator you could take the 60's to 700rwhp as well.

Hmmm ...

Alright thanks guys ...

I guess I have a little more research to do on this still, but you awnsered alot of my ?'s ...