rotarypower101

iTrader: (1)

Where do we stand with these injectors and how do they compare with the Injector Dynamics?

Are there any other sources for high impedance injectors to consider?

http://www.fiveomotorsport.com/produ...?p=055IMP1000X

http://www.fiveomotorsport.com/produ...p=0426IMP2000X

part numbers:

0426IMP2000X
055IMP1000X


Can anyone comment on how people should* be sizing their injectors, by flow rate proportionally Primary VS Secondary, assuming there is a fairly solidified consensus answer to this? Did the 550/850 combination have any significance on the stock system?

If a person knows their desired power range and has reached a point where changes to a system are minimized, are there advantages to selecting components that meet the requirements (with a reasonable SF of course) of a engine and power level?

Are smaller injectors really the way to go to be able to attain good/optimal precession control in the idle range? Is there typically a duty cycle/range that should be maintained to supply the best spray patterns and control of the injector?

What is the ideology we are trying to accomplish rather than just bigger is better when it comes to injectors and hopeful taking into account a specific system and power level?

Hypothetically if you knew your HP goal was 400 hp and you knew the supporting equipment would not change and was without issue of capability to support the requirements needed to drive injectors, what would be the optimal injector sizing that one would choose knowing the primary goal was drivability and no further power needs were to be desired?


Is there any sense to size injectors to power needs rather than just throwing common flowrates at a system and then dealing with the issues?


TIA

arghx

iTrader: (3)

They're all rebadged Bosch EV14 injectors adapted to various fitment requirements. EV14 injectors use a ball valve and multi-hole orifice plate. The Rx-8's use a similar architecture in their factory injectors.


I suspect it was a matter of atomization under low loads more than anything else. The 550cc injectors were better for that. For emissions purposes the statistical distribution of the droplet size is important.



I'm not sure I'm completely following you here but sizing in these applications is more about cost and fitment than anything else. The atomization on the current generation of injectors (EV14 style) is good enough for a modified car that doesn't have to meet stringent emissions standards.

It depends. Injectors have a range of non-linearity to them:



cost (in terms of dollars spent and tuning time required) is the biggest thing to consider besides fitment. There are all sorts of aspects to fuel injector design and control that really don't matter much in these applications. You don't need to know the statistical distribution of the droplet size for example, and you don't need to analyze the fuel film effects on the intake ports so that you can reduce HC emissions. You don't have to tune "start of injection" and "end of injection" maps which determine the injection timing.

In this situation, one of the best answers is: the injectors everybody else is using successfully.

Don't reinvent the wheel when there's no need to. The reason why I say that in this situation is that the biggest obstacles are figuring out injector latency/deadtime settings and staging settings that work. If you pick something that everybody else has tried before, you have a starting point to minimize that hassle.

the reason why people do the "throw flow rates at the system" method is because it's quick and easy. The constraints here are time, money, and fitment. Atomization and driveability on the new generation injectors are not nearly the issue it is with say a set of 850cc sidefeeds in the primary position, or low impedence 1000cc top feeds in the primary position. Those two injectors were definitely the hardest to tune on certain engine management systems and applications, especially when the owner decided to cap off the injector atomization port on the intake manifold.

Most of the "real science" behind fuel injector sizing and control has to do with emissions and that is not much of an issue in this application... the strictest California tailpipe tests are nowhere near as tough as what is required for EPA certification of a vehicle.