4AGE Injectors

[cbjaust]

Car - AE86

motor - 4AGE

use - Daily

problem - no problem, just a question...

occurs/started when - N/A

I have a bigport 4AGE with stock cams and intake/exhaust and I'm pretty sure that it's using the grey 185cc/min injectors. I have a set of pink 200cc/min injectors so what would the outcome be if I installed the 200cc/min injectors.

Benefits/downsides would be?

Cheers

[ke70dave]

benifit - none

downside - your car will run rich.

----

bigger injectors no good unless you have the ecu to tune them.

not sure on how knowledge on how an injector works, but an injector is just an electrically opperated tap. the ecu sends a pulse of electricity (well..it grounds it) to the injector (in milliseconds, so at idle the pulse may be 10ms, and at full steam it may be 90ms, dont quote those numbers). and when the injector gets the pulse the solenoid opens up the little tap and lets some fuel into your engine.

now if you go ahead and put in a bigger tap (ie bigger injector) then when the injector opens for said 10ms or 90ms, the only difference is gonna be more fuel going in....

pluss its only an extra 15cc, hardly worth it anyway. from what i understand stocko injectors are pretty much on the limit for 4age, but they are fine for a standard engine. if you were going to get a set of camshafts, and inprove your intake (porting, quads etc) then a bigger set of injectors would be needed to supply the fuel to burn with all the extra air you can use, but you would need an aftermarket ecu to control them anyway.

if the engine is running well now, dont touch it!

ps. your signature pic is cool!

[cbjaust]

benifit - none

downside - your car will run rich.

----

bigger injectors no good unless you have the ecu to tune them.

not sure on how knowledge on how an injector works, but an injector is just an electrically opperated tap. the ecu sends a pulse of electricity (well..it grounds it) to the injector (in milliseconds, so at idle the pulse may be 10ms, and at full steam it may be 90ms, dont quote those numbers). and when the injector gets the pulse the solenoid opens up the little tap and lets some fuel into your engine.

now if you go ahead and put in a bigger tap (ie bigger injector) then when the injector opens for said 10ms or 90ms, the only difference is gonna be more fuel going in....

pluss its only an extra 15cc, hardly worth it anyway. from what i understand stocko injectors are pretty much on the limit for 4age, but they are fine for a standard engine. if you were going to get a set of camshafts, and inprove your intake (porting, quads etc) then a bigger set of injectors would be needed to supply the fuel to burn with all the extra air you can use, but you would need an aftermarket ecu to control them anyway.

if the engine is running well now, dont touch it!

ps. your signature pic is cool!

Thanks for that and re: the injectors, I though as much. Further to this if the head porting was improved with no other changes ie: stock cams and ECU would the enginge then flow better enough for the slightly higher flow injectors? Incidentally I found that the Pink Injectors on ToyoDIY (based on the part no on them) and at least one application for them was on an 87 MR2.

Cheers

[ke70dave]

Thanks for that and re: the injectors, I though as much. Further to this if the head porting was improved with no other changes ie: stock cams and ECU would the enginge then flow better enough for the slightly higher flow injectors?
Cheers

its to hard to say really unless you get out the wideband and measure the air fuel ratio.

the engine will be sucking more air with any improvements to the volumetric efficiency (VE), but as to how much air, and especailly how much fuel is required for this air, can only be done by measuring AFR's.

technically you can work out the VE of the engine and work back to how much fuel you need, but in general its only really used as a guide to buy the appropriatly sized injectors and set them up for initial start up, from there you work with your wideband to get the AFR's in order. also its usally the maximum VE that is calcualted, so as to make sure that the injectors are not maxed out, or too big for that matter.

as for the 87 MR2 thing, i thought pink injectors were for small ports? in which case they make a few extra killawasps and use the extra CC's they have a different ecu as well.

also there is a discussion on rollaclub atm about a possible factory "high compression bigport" engine. dunno much about that. but i do know that its not as clear cut as "bigport" and "smallport".

hope this helps.