I want to make sure I have this correct before I hit my next tuning session.
Stock ITR fuel pressure is about 42-45psi I believe. Now Im running larger injectors, 370cc, and wonder if I should be running the same fuel pressure, or maybe a little more or less? Is there an equation I could use to determine the proper pressure? Currently Im running about 32psi and it just seems a little low. What would be optimal pressure for 370cc and would compression ratio have an effect on how much pressure you should run? Basically what Im aiming for is the optimal fuel spray for proper atomization because thats key for making power. Thanks

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RTW DC2 &raquo;</TD></TR><TR><TD CLASS="quote">I want to make sure I have this correct before I hit my next tuning session.
Stock ITR fuel pressure is about 42-45psi I believe. Now Im running larger injectors, 370cc, and wonder if I should be running the same fuel pressure, or maybe a little more or less? Is there an equation I could use to determine the proper pressure? Currently Im running about 32psi and it just seems a little low. What would be optimal pressure for 370cc and would compression ratio have an effect on how much pressure you should run? Basically what Im aiming for is the optimal fuel spray for proper atomization because thats key for making power. Thanks</TD></TR></TABLE>

you don't run hondata by any chance? - that way you could measure duty cycle..
you want it to be high enough so your injectors don't overwork..

 

Thanks, Ill check out the RC site. Im running AEM EMS but dont know how to check the duty cycle. Ill have to look into it.

 

if the AEM is anything like Hondata or PowerFC there should be settings where you can adjust for size of injector. With this method you leave the fuel pressure the same as stock.

This usually means entering a figure to adjust for the new size i.e. from 240cc upto 310cc you would enter 240/310 = 0.77 or 77% so the injectors will be held for only 77% of the time indicated on the map to make the bigger injectors flow the same as the old smaller injectors (by reducing the time they are open).

 

RICHJ, So are you saying that even though Im using a larger injector, my map is probably set to recognize the larger injector so that Im getting the same flow rate as I would if they were stock injectors? That sounds like it would make sense, but since they are a larger injector, wouldnt that hurt the spray pattern of the fuel, kinda like its just dripping out of the injectors as opposed to spraying out?

 

The map would only be set up for your 310cc injectors if you have gone in the software to set it up, I'm not familiar with the AEM software so not sure where you would find the settings, but it should be a simple matter of changing 1 or 4 numbers (PowerFC does each injector individually, but others use the same figure for all injectors)

downloading demo software how: I will look and see if it's easy to find

 

Thanks RICHJ, I dont have my laptop with me right now, and Im not too concerned with where to find it in the software, Im more worried about the flow rates. Wouldnt having the same flow rate on these injectors(370cc) as compared to the stock injectors mean the fuel isnt spraying out properly? Maybe Im extra confused, but I would think that a bigger injector would need more pressure to get the proper spray pattern? Ugh. Told you I was confused lol

 

I have looked through the software and can't find the injector adjustment, maybe the AEM just doesn't have this feature (or it isn't in the demo configs)

Personally I would set the fuel pressure to standard and then set the ECU to account for the larger injectors, no problem with spray patterns then.

EDIT: Scrap that the AEM forum seems to confim that there is somewhere to change injector size (old and new values and it works out the % fuel to use) same with fuel pressure, cant find it on the demo though.


Modified by RICHJ at 6:17 PM 9/5/2003


Modified by RICHJ at 6:21 PM 9/5/2003