Thread: topfeed vs. sidefeed injectors

Whats the positives and negatives of each style injector?
Also what about low impedance vs high impedance? is there a difference in performance overall?

I have some decisions and changes to make on my nx rebuild,so any input on this would be greatly appreciated

I could be out in left field on this, but this is what I've gathered throughout the years.


Top-feed pros:
Better availability, especially as flow-rates increase
Cost (cheaper)

Side-feed pros:
Our fuel rail already uses them, no need to get a new one.
Their individual clamped-to-rail design makes mounting and sealing them easier, servicing one at a time possible, field testing possible, and other little nice things



Low impedance pros:
Better control (faster opening and closing speeds)

High impedance pros:
Much cheaper to control (no need for resistor boxes or special ECUs)





I would highly recommend high-impedance injectors to save you all sorts of electrical and control hassle. You will never notice the decreased performance due to the slower opening and closing times on 1990's generation gasoline engines. I like side-feeds for their simplicity on our cars, but there is nothing wrong with a good top-feed setup if you have to go that route to find the flow you need or meet a price point.

Thanks Ben.Thats a good start and the type of info I am looking for
My dliemma is as follows...
-I currently have Low impedance 1000cc topfeeds .It is what was on my Lowport DE+T in the nx that recently shit the bed.Everything was running and working good with no issues.
-I am having a hard time finding a low mile replacement lowport DE to put back in(would actually like a 10:1 lowport) ...so I may be forced to go VE instead.I am ok with that but a DE would just be plug and play,whereas the VE will require some changes to the manifold,piping,injectors/rail,and of course the tune.
-I am trying to decide whether to just sell the injector/rail setup I have and just get some STi or Nismo sidefeeds on the VE for simplicity sake....or to try to mod my topfeeds and rail to work on the VE.

Its a matter of trying to use what I already have vs. selling off and going a different route.

One big difference between top feed vs sidefeeds is the increased ability to control latency for bigger flow rates on the top feed vs sidefeed. Essentially, the sidefeeds are much slower to react (solenoid) to ECU signals and depending on the range of the ECU, the higher flow rate sidefeeds (about 850cc seems to be the transition point), become difficult to maintain proper latency at lower flow rate (idle) conditions.

Once you start getting into E85 fuel, anything over 350WHP and you will more than likely be needing top feeds as sidefeeds begin to lose resolution.

Also, the top feeds are just a new technology.

This is all in addition to what Ben said above.

This is great! keep the info flowing. This could be added to the manifesto if it keeps filling up with useful info like this

You can pull a resistor box out of almost any Honda at the junkyard to work w/low impedance injectors on the SR ECU.

modify the rail to work with the top feeds its cheaper , easier and you already have it .

any links to this? never heard of this

theres no links just some common sense and some basic fab tools to make new mounting tabs to go to the ve intake manifold instead of de