Your car would run extremely rich at WOT if you put in higher flowing injectors, not to mention at idle and part load it would have a very tough time adapting to the extra fuel.

With these cars you pretty much have to run the injectors specified by the tune.

Not quite sure what you mean by "further modify the comp" because generally speaking ECU flashes are safe when performed by an authorized dealer. Having the ECU flashed for a specific purpose is also one of the easiest ways to gain more power (when you upgrade components).

 

true, but also the injectors that im lookin at arent that much bigger than stock, so the O2 would adjust for it automatically, it would only run rich when cold, i could see if i went to like 550cc but i only want the 315cc injectors. but if im gonna get another reflash ill wait and see if/when i cold afford a ko4 and do it all at once.
what i mean by further modify, is that im already happy it has a reflash and i dont have to spend money to get one, and to change it anyways would seem wasteful to me in a way. being as that i am just being power greedy lol

 

You're right, they don't flow a ridiculous amount more (especially if you drop down to a 3bar FPR), but your assumption that the O2 sensor can account for them isn't totally accurate.

During idle and part load conditions the ECU goes into closed-loop control using the MAF and primary O2 sensors to keep the AFR in check. Ideally in these conditions the AFR should be about stoichiometric (~14.7:1). Your 1997 uses a narrowband primary O2 sensor which can only read AFR in the range of about 14.2-15.0:1. So your O2 sensor can adjust for extra fuel flow in these conditions.

When you get into a full throttle situation, the ECU drops the closed-loop control so the MAF sensor is the only thing controlling how much fuel is injected. At full throttle your AFR will become more rich to maximize power, somewhere around 12-13:1 AFR (a range in which your narrowband O2 sensor is useless). This is the critical part why you can't just throw in higher flowing injectors... the ECU expects the injectors to be a certain size and running at a certain fuel pressure so it can inject the right amount of fuel based on airflow readings from the MAF.

So you might wonder why running extra rich at full throttle is bad... well, there is excessive fuel consumption, your catalytic converter loses efficiency and its life will be shortened, your O2 sensor's life will be shortened, etc.

 

it is an absolute terrible idea to run bigger injecors without the ecu knowing it. you MIGHT have a chance with me7 and an adjustable fpr, but it sill wouldnt work well. your ecu needs to know how much fuel it can add. if you could just throw in injectors without a tune then why would anyone get a tune?

 

that helps alot, i was unaware that the 97 ecu went into closed loop at WOT so that makes sense, i didnt think it was new enough to support that feature. but that a new reflash would be about 300$ again rite? and i would have to let them know of the upgrades i have. and would i need to upgrade my fuel pressure regulator? or is that just another ecs tunning advertisement thing? also what can the stock fuel pump handle as far as bigger injectors?

 

The cost of having a new flash performed will depend on which company and tune you choose to go with and who performs the flash.

Nobody really makes a 315cc tune for your car unless you go K04 and get the GIAC PC-16 tune ($300 + shop fee). I suppose you could contact one of the tuning companies about a custom tune, but you're likely to pay more to choose which injectors you want.

Honestly, I don't think you should even consider changing anything on your setup unless you plan to upgrade the turbo. Your biggest limitation right now is the turbo, so adding bigger injectors, FMIC, etc won't do a whole lot. If you do full exhaust AND FMIC you'll gain some power, but it's best to make sure you do these things while keeping in mind future power goals (I.E. don't get too small exhaust piping or a FMIC with a small core).

 

i dont plan on getting any big power adders in the future. mostly brakes lights and coilovers etc. but if i do get a custom exhaust or something. i will go 2.5" for sure. what is FMIC?

 

feount mount intercooler. you could just get a apikol side mount to replace the side one but you seem like the kind of person who would want one in the front

 

yes maybe, if i had 1k$ to blow maybe i would do that, but id start with other things first. all these little abbreviations are gonna make my brain explode lol