Hey guys just wondering what sizes are available.So far all I have seen is the 42#. Also, do the stock fuel rails handle them well? Thanks!

 

I think 19, 24, 30 and 42 are the most common sizes. Im not sure, but I think the stock fuel rails should be good for 450 horse or so, but I could be wrong.

 

You could probably find 36s and 38s depending on brand.

What HP do you want to support?

 

most people go to the 42s. They will support all the power you need, and there is no downside of going to big.

-steve

 

Since I live in the SF Bay Area and we may soon be subjected to the dynamometer smog test, I do not want to inadvertently go overboard on any of my add-ons.

What I would like to do, my current thinking, is to go with an ATI, 10psi pulley, 90mm MAF and large enough injectors to allow me to dump the FMU.

Does this combination automatically dictate 42# injectors or would 30# or something in between be adequate or, will it not make any difference with regard to the smog test as long as my chip is properly burned to give me the correct A/F ratio.

I know that when I have to go in for my first test, I will be sent to the state operated station due to the supercharger setup and they are likely to be super critical. As I am sure many of you know, one test failure can open up Pandoras Box and it can be a real B@#$% to get the lid back on.

 

Unless I am mistaken larger injectors dont mean you will get more fuel and hence screw your smog test. With stock inujectors you need high preasure and a long duration to get the proper amount of fuel. If you go with #42 you wont be using more fuel than is needed. The injector, since it can flow more due to a larger apature, simply uses a shorter burst of fuel but the end result is still the same, its computer controled. The big difference comes at high R's where stock cant deliver enough fuel the #42's will be able to keep good air/fuel numbers.

 

Zyg,

Your response confirms my understanding of how the system functions however, there has to be a point where the injector becomes too large and either the pressure needs to drop below that neccessary for proper atomization or the pulse needs to be too short for proper control.

I would have to assume that the 42# size is sufficiently below that critical size, whatever it is, (as evidenced by their being standard on L's) that it will not enter into the equation.

 

Check out this link for some various recomendations by ProM

http://pro-flow.com/tech%20info/sizing.htm

 

Based on that information, any time we install 42# injectors, shouldn't we should also upgrade to 1/2" rails?

 

Yea, I noticed that as well. One thing I think most of us agree on though is that #42's are overkill for most of us. However they are basically the same price as smaller ones and getting them will ensure you wont have to change them out at a later date.

Maybe Crash! or Skidmark will chime in and give us better clarification.

 

Never thought about the rail size. what is the stock diameter?

 

based on the pro-flow chart I would have to guess they are 1/4" or 5/16".