If you were at the limit of your fuel system...

This is more of a curiousity question. What is the actual flow limit on the OEM legacy gt fuel system(should be same or similar on 04+ STI's). Is the limit the injectors, with the fp able to out flow the 4 550cc injectors at 100% idc's? In other words, if you were to pick up a slightly large injector, the fp would probably struggle to keep up, but you still should see an increase of fuel flow?


Again, just curious(discussion with co worker).

 

I don't think the stock fuel pump could keep up with anything bigger than 550's. A Walbro is usually required at the minimum with any upgrade of injector. So I think the limit is first with the fuel pump and not necessarily with the injector.

 

So the pump is the limit and not the injectors?

 

I'm not 100% sure on that cause they are usually upgraded together so maybe it's both?

 

Correct, both are typically upgraded together. I figured if the OEM fuel pump could support the stock injectors to 100+% IDC's, then the pump is theoretically able to outflow the injectors. I dont know that to be fact though.

 

why would you skimp out on a pump? They are like $60

 

Thats not the question eddie.

Ill present in a different manner, if you change out to a wally on the stock injectors do you have more fuel potentional then you would with bigger injectors on the stock pump.

The basis of this question is simple, what can flow more at the limit. The stock fuel pump or 4 550cc injectors at 100% IDC's

 

so pushing stock injectors at 100% makes sense?

 

I would say it depends on fuel pressure but if you just let the pump have full control...I would think the injectors are going to max out first.

But I don't see the point of the question...you would be running extremely above the efficiency range of either making it worse.

 

theoretical question, do you know the answer?

Edit: fuck this is like pulling teeth.

Ok ill research on my own to see if i can get some intelligent conversation brewing.
550cc's=.55 liters

.55x4 injectors=2.2 liters per minute.

2.2lpm x 60m= 132 lph

OEM LGT and STI fuel pump is 145lph.

Injectors capable of 132lph<Fuel Pump capable of 145lph.

FYI for those in the future, your injectors are the limit before your fp is. Theoretically(tough concept to understand i know), OEM 04+STI and 05+ LGT fp can support ~600cc injectors. If there is something wrong in my math or if this theory doesnt play out in the real world let me know.

Otherwise here is the answer.^