so i grabbed a set of primary injectors off a 87' SE rx7 at the junk yard. now what size are those, and what would happen if i replaced my stock secondarys on my 88' SE with the bigger primarys?

i just have a intake, header and exhaust.

 

I'm pretty sure your stock ECU won't know that they're bigger and so you'll run rich.

edit: that's for the bigger injectors. check the FSM for specs on the injectors on both models and whichever ones are the same you should be fine swapping those

 

well the car i got the injectors from is the same as my car, im just wondering what would happen if i was running primary injector size all around.

 

your ECU expects a certain allowable flowrate from the injectors, and if they're of a different size you'll get less or more fuel than the ECU intends to deliver, which is pretty much never a good thing. you'll get less than it expects if they're smaller than stock and in doing so you risk detonation because you'll run lean, you'll get more than it expects if they're bigger than stock and then you'll literally waste fuel and most likely be able to smell gas from the exhaust, as well as possibly messing up your cats or mufflers.

 

You have 460cc primaries and secondaries. If you change injectors with the same car there will be no difference. But, you need to verify that the new injectors are of the same impedance. Easy way to find out is if the plugs are on-center, then they are low impedance, if the plugs are off-center, they are high impedance.

Also, if you dont run on boost or a street ported engine, you dont need bigger injectors, your car runs slready very rich as it is.