Piggyback

[JMo60]

ok, so after a little research i have been under the impression that you can not add fuel with an AFC or similar fuel controller? You use larger injectors, so the engine runs overly rich then use the AFC to cut fuel back until its where you want it?... or am i wrong here? i used to think for some reason that you could increase fueling a little bit with the stock injectors. Just wondering if my finds were accurate or not..

[timg]

You can add fuel with a mini-AFC, MAFT+, ICCU, or Split Second FTC1. I think Haltech and Perfect Power also have piggybacks that will work.
Larger injectors are a bad idea on the stock engine.
I am using 42.5 lb/hr injectors on mine with tuning provided by the Split Second FTC1. That is the absolute limit of a piggyback's ability to compensate for fueling without some sort of computer tuning.

Tim

[JMo60]

i have a computer/injectors for a stock 3100. i have a cam/header/3400 that needs a little more fuel... but how can an intercepted map signal read any higher than 100% at WOT? the map can only read maximum, and nothing over that correct?

[JMo60]

so, can i increase fueling using an apexi afc without getting larger injectors?

[timg]

If it's MAF based, everything I mentioned would work. If it's MAP based, you're on your own. You will either need larger injectors, PCM tuning, or possibly an adjustable FPR.

Tim

[JMo60]

its MAP based, so im not sure really what to do

[timg]

Adjustable FPR (very little help here)
Computer tuning on the stock ECU and injectors
or Larger injectors + computer tuning (piggyback, standalone, or chip burning on the stock ECM)

Tim

[JMo60]

well i have obd 1.5, so programing the computer and chip burning is out of the question. I think i will start with an afpr for now, then actually do some real tuning when i decide to get larger injectors..