Quote:
Originally Posted by bcfromfl
The problem I'm having now is that apparently the recommendation is not to upgrade the fuel system for a basic A2A system...but Topz says to upgrade the pump. Then, apparently there is a recommended adjustment (?) to the tophat (?). And finally, an idea is being floated to upgrade injectors with no other upgrades, if I am understanding correctly. Can a larger injector manage the same spray pattern as a lower-flowing stock injector at the same pressure? Could a larger injector cause driveability issues at lower RPMs? Will a stock injector deliver enough fuel at 6-7k and 9psi?
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I can see where it can get a little confusing... I'll try to address it in pieces (at least the pieces I can help you with!).
Fuel system - CJM's answer to cupcakez was in reference to converting to a return fuel system. For his build he was only saying a return fuel system was not completely necessary. This is separate from upgrading the pump and injectors.
Pump and Injectors - you absolutely need to upgrade these when going FI. I am running a Walbro 255 and 600cc injectors, and I am pretty well maxed out. Wish I had gone a little bit bigger. If you want E85, you definitely need to go bigger.
Top Hat - the flimsy top hat on the stock fuel pump assembly tends to break where the rods are held in place. CJM makes an aluminum top hat to replace it.
idea is being floated to upgrade injectors with no other upgrades, if I am understanding correctly - you are not understanding correctly. You definitely need a pump and injector upgrade at a minimum.. for a modest 500whp build that is probably all you need. I think people are referring to upgrading injectors on top of the 255lph pump that Stillen provides with their kit.
spray pattern/driveability at low rpm - I do not know enough about the technical aspects of fuel injectors to talk about spray patterns.. but in the past this used to be a bigger problem (and by past, I mean like 1997). The stock ECU + Ecutek/Uprev is a powerful, highly granular tuning solution these days and high quality injectors and a good tuner should get you straight unless you are running gigantic injectors.
Will a stock injector deliver enough fuel at 6-7k and 9psi? - absolutely not. Upgrade the pump and injectors. I would recommend an Aeromotive 340 (as it is easier to install than a Walbro 450 because of the physical dimensions of the unit) and 750cc+ injectors... if you ever THINK you might go E85 you may as well just jump up to the ID1050x and Walbro 450. The price difference between difference sizes is not that much... I think the Walbro is actually cheaper than the Aeromotive in the pump department. Should you decide to go E85 later, you can reuse those components and upgrade to a return fuel system.
Does that help?