bigger injector thread

[bastianshaw]

im just running a jc chip, will upgrade to PSIK at some point...should I get 19lb or 24?
im thinkun 19 mustang injectors but they are so expensive new....thoughts? whats the best way to go if im staying NA

[Pedaaa]

19lbs is more than enough for a stock b25

[Kershaw]

17lbs is more than enough on a stock cam.

[Jaxx_]

17lbs is more than enough on a stock cam.

this.

or do you just want bigger injectors for shitty idle? there's no point to adding injectors unless you NEED more fuel.

[MR 325]

17lb ftw.

[jlevie]

14lb injectors are more than sufficient for a stock M20B25 engine. To justify larger injectors you'd have to do serious (read expensive) internal work to the engine/head to increase the mass flow through the engine.

[bastianshaw]

14lb injectors are more than sufficient for a stock M20B25 engine. To justify larger injectors you'd have to do serious (read expensive) internal work to the engine/head to increase the mass flow through the engine.

what about w a miller psik and cam?

[Jaxx_]

what about w a miller psik and cam?

how high you wanna rev?

[bastianshaw]

how high you wanna rev?

8,500

[bastianshaw]

this.

or do you just want bigger injectors for shitty idle? there's no point to adding injectors unless you NEED more fuel.

Are you saying they will make my idle shitty or fix my already shitty idle?

[sweet6e30]

It always amazes me that people are more than willing to piss money away on useless mods and "makes no sense" altercations than to actually spend money get their motor running right as it should.
if you want better idle , tps, idle air control valve , clean throttle body, check vaccum lines, compression, ignition system, SERVICE the injectors- ie: ultra sonic and flow test/match them, check fuel pressure regulator , fuel fiter. FOR FUCK SAKES service and maintain your motor to SPEC get it running properly then tinker with it. Your better off doing mods once you have a solid and good platform with what to work from making diag easier and trouble free running

oh yeah , there is a plastic trottle cable clip that mounts the accelerator cable to the trottle body- that clip sometimes bends out of shape making for erratic high idle( syptoms of throttle body sticking open) check that clip !

........... just take your injectors out and have them services/cleaned/and flow tested. you'll be amazed at how much that will do for performance and everyday stable driving and economy
vent IS OVER !:hitler::hitler::hitler:

[nando]

8,500

24 hours. :p

[Ceeker]

It always amazes me that people are more than willing to piss money away on useless mods and "makes no sense" altercations than to actually spend money get their motor running right as it should.
if you want better idle , tps, idle air control valve , clean throttle body, check vaccum lines, compression, ignition system, SERVICE the injectors- ie: ultra sonic and flow test/match them, check fuel pressure regulator , fuel fiter. FOR FUCK SAKES service and maintain your motor to SPEC get it running properly then tinker with it. Your better off doing mods once you have a solid and good platform with what to work from making diag easier and trouble free running

oh yeah , there is a plastic trottle cable clip that mounts the accelerator cable to the trottle body- that clip sometimes bends out of shape making for erratic high idle( syptoms of throttle body sticking open) check that clip !

........... just take your injectors out and have them services/cleaned/and flow tested. you'll be amazed at how much that will do for performance and everyday stable driving and economy
vent IS OVER !:hitler::hitler::hitler:

+1 like he said...

if you decide to go 17lb the one advantage of this is 4 pintle spray pattern. it may give you slightly better fuel economy and have the option of throwing a chip in later.

[Jaxx_]

Are you saying they will make my idle shitty or fix my already shitty idle?

too big of injectors will become harder to control because the pulse time at idle will become less and less, but the opening and closing time stays constant. What that translates to is a smaller and smaller amount of time that the ECU can control to maintain a steady idle.



and again... on volvospeed we used to call it stage 0, which is before you do any mods you start with a good base and replace any issues you already have. So I'm starting it now... STAGE FUCKING ZERO.

[nando]

too big of injectors will become harder to control because the pulse time at idle will become less and less, but the opening and closing time stays constant. What that translates to is a smaller and smaller amount of time that the ECU can control to maintain a steady idle.
STAGE FUCKING ZERO.

that is true but you'd have to go way, way bigger than 19# for it to affect anything with tstock ECU. the dead time of a 19# injector is around 1.2ms, but the idle PW at stoich is going to be about 5ms. you won't run into problems until you get down to around 1.5-1.7ms at idle. even a 42# injector won't have too small of a PW at idle to control properly (I'm NOT saying you can use 42# on motronic!).

however if the dead time of your new injectors is different than the stock ones (likely), it will affect the linear relationship between commanded injector PW and expected fuel delivery rate. (the computer expects it to be linear, but with a different dead time, it will not be).