Two big differences in the way one can perceive this...
(1) How big can you go with stock FI
(2) How big can you go SAFELY with stock FI..
4-5 years ago when I was really ramping up development for the 914 crowd (what a waste of time that was
) I took a TON of time to play with the stock EFI and get more power. Time and again I simply saw that too many variables are created with the stock EFI and that too many times the engine was having to be tuned and designed AROUND the induction system- far from an optimum way of handling a true development.
My answer to each of these is pretty short and pretty biased due to my lack of positive experience with the stock EFI...
To answer perception #1 - The engine can be made as big as you can afford- If you replace the stock electronics you can either stick with a stock or slightly larger injector and while retaining all the stock runners and plenums still easily get 130-145 HP. After that the stock plenum volume starts to limit things. Keeping this combo of induction not only takes a different ECU (like the ones I have been playing with for the past 5 months solid) but also takes an engine specifically set up for the other constants in the FI system that you probably don't want to change.
You can experiment with combos for this until the day you die and never find the answer- I tried it for several months and finally said to hell with it and went back to my "non guesswork" combo.
For #2.....
I can answer this easily..... Its a 2056 with no more than 8.3:1 CR and the web 73 cam with only slight port work. I generally do no port work with the combo because iit leads to other mods that sometimes add guesswork.
Here is a link to a kit that I made up just for the stock FI with "safe" power
2056 kitSo whats the best thing to do??
well now you gotta understand that this is coming from the man that don't care very much for the stock FI at all..
-remove the stock ECU
- smash it with the biggest hammer you can find
- replace it with an SDS unit or equivelant
- commence to have unrestrained fun.
Hell, I'll pay the shipping if you'll send your brain to me to be destroyed- so far a 12 gauge with 00 Buck Shot has been my weapon of choice for the job