What tune do you currently have?

 

if 420s are small and 630s are large, get some 550cc. On my Talon (4 cyl of course) I supported 325whp with 550cc and 425whp on 660cc. So with 6 injectors at 550cc you should be able to support into 400whp depending on your tune. Even supras with 660cc can support well into 550whp, so I would say a 60lb injector (630) would be quite a large injector for you.

Remember the larger the injector the worse your idle will be and will also make it difficult to pass emissions. The injector at idle only opens for a split second, so if you double your injector size then obviously at idle it must open for half the time it did before. What happens when you do this is you are spraying the same amount of fuel for half the duration you were before, so it's not a fine mist over a longer duration. This short burst makes the idle more erratic and also far less efficient. If you have emissions testing in your area you will find a point where no matter what you do, you can not pass emissions with a particular sized injector.

On a 4cyl the limit in Ontario was bout a 550cc (Talon 4G63) where I could pass emissions. When I had 800cc injectors (on AEM EMS fully tuned) I coulnd't pass to save my life. I just swapped in my 550cc and re-set my injector size in the ems and passed with no problems on a HFC.

Keep that in mind when you are picking your injector size, because larger is not better. Get one sized just large enough for the power you are making. You don't typically want to exceed 90% Injector PW..

Hope that helps a bit.

Regards,

 

just get the 60lb siemens, every tuner has a file for them and you will never max them out on your setup.

 

Unless he runs e85. At that point his IDC's will be near 100 percent. But I've seen cars running a 110-115 percent IDC.