When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
One thing to note- while I recommended upping the fuel pressure, you should plot the curves for your injectors and your fuel pump. Injectors flow more with more pressure. Fuel pumps flow less. At some point, they cross over. If they're closely matched, then at low fuel pressure you will be injector limited and at high pressure, you will be fuel pump limited. If you find the sweet spot, you could get 10, 20, even 30% more flow than with an un-optimized fuel pressure. To really get this right, it would be best to have a fuel pressure measurement at the fuel pump itself, but this can be inferred via line pressure drop calculations or estimates. There can be 10 psi or more line pressure drop between the pump and the injectors depending on your layout.
The earlier suggestions of a boost-a-pump help prevent fuel flow from dropping with increased fuel pressure and will increase the overall capacity of the system by allowing higher pressure + higher flow through your injectors and fuel pump.
My suggestion- these curves are all on the internet. Spend a few minutes plotting them out, doing unit conversions, and determining your limiting factor. If you're lucky, you can fix it for free by turning the FPR up. Here's an example I did for a LS engine with a Walbro 450, Walbro 525, ID 850, and ID 1050x injectors. With my existing injectors and fuel pump, ~38 psi fuel rail dP maximizes possible fuel flow (where the dark blue and dark green lines cross). With a BAP, that could increase to ~ 57 psi dP without an injector or fuel pump change.
Tim
Agreed. Sometimes, base pressure is not the answer until you get a bigger pump.
Originally Posted by hatrickstu
Not true. The idle and drivability is great on the 2600's, the dual slope matching makes a really big difference in this regard.
ID2000's have been discontinued in favor of the ID2600's, they are vastly superior.
Yep, the 2600's will be a little worse than the 2600's, but still very acceptable.
OP, this honestly doesn't sound far off. Your base is only 43.5 and the ID1700's only flow 6,900cc/min at that pressure. Increase the base another 20-25psi and you should have enough for 725-750whp.
Exactly! I'm not sure if I ever tuned ID2000's on gas, but I've had no problem with making them run smooth on E85. Same with ID2600's, on C85.
Originally Posted by F1TwoThousand
Classic tuner cop out. Blame fuel flow without raising fuel pressure. This is why i learned how to do everything myself.
Such a cop out that he didn't blow up the car and left the fueling safe? Was he tuning for a number or making a good tune with what he was presented? He may have very well had his reasons... That's not to say I haven't seen tuners recommend injectors when the fuel system needs upgraded, but there may be more going through that tuner's mind than what you realize, considering we sometimes have cars that have mechanical issues we find on the dyno and if we had not taken the time to test, they would have blown up. In many of those cases it likely wouldn't have actually been the tuners fault... That doesn't mean we won't take the blame. Back to fueling recommendations, I regularly see the Subaru community recommend injectors because they're showing 90% IDC, however, in the calculation used, 100% isn't static and I've run them as high as 137%. I did tell the customer that he should probably upgrade his injectors at some point, but he knew what to pay attention to.
Originally Posted by F1TwoThousand
Also love tuners that like to 'tune on the safe side' and so they stop at say 85% injector duty cycle. Its either optimized or its not.
IDC has nothing to do with "optimized". Additionally, "tune on the safe side" generally has to do with timing, boost levels, and AFR mixture. Tuning is completely based on reputation and results. It goes deeper than that, but that is the gist of the tuner 'business model'.
