660cc or 720cc

[MadStylez707]

how much extra HP gains are we talking here from 660cc to 720cc injectors?...and which size should i use to be safe? given that mods are the same...reason being, i'm planning on upgrading injectors but trying to find out what injectors will work the best for my mods i'm planning to install soon...

mods: full 3" TB w/ hi-flow cat, walbro fuel pump, 264/272 cams, ARP head studs, and MBC.

any input would help. :wink:

[JanSolo]

Adding injectors to all that will probably add 0 hp. You need to figure out a tune before adding a fuel pump and injectors since the stock tune doesn't necessitate adding those.

For a tune, are you going SAFC2, reflash, stand alone, piggy back or MR badges?

[evo_dadi]

660cc should be fine with those mods :D it doesnt give you horsepower but it supports how your evo is gonna be tuned.

[chris]

what marcel said. im going in the same direction. but 272 cams and tuned with an safcII.

[Absinthe]

not a damn HP, you need to figure how you are going to tune FIRST, if you are going the AFC route then injectors will help, but with you mild mods if you are going with a flash or utec/xede you dont need the injectors just the pump.

[earlyapex]

If you are going SAFC route the 720's will give you more timing advance headroom.

[ob4]

afc does not alter timing.

[earlyapex]

afc does not alter timing.

I didn't say it did.

[EvolvedDSM]

afc does not alter timing.

Actually, it does, but indirectly. When you lie to the ECU about the airflow, it thinks it's seeing a lower load and, therefore, uses a more aggressive timing map. Yet another reason you need to know what you're doing before you go a play with one. Otherwise, you may be in for a nasty surprise.

[MadStylez707]

hmm..i see..so larger injectors itself do not add HP, but help contribute to a better tune(i.e. AFC, piggyback, standalone), than stock ones..

[MadStylez707]

For a tune, are you going SAFC2, reflash, stand alone, piggy back or MR badges?

i'm either going with a flash or AFC..., but then again i've heard you can use both for a better tune...

[EvoVIII]

how much extra HP gains are we talking here from 660cc to 720cc injectors?...and which size should i use to be safe? given that mods are the same...reason being, i'm planning on upgrading injectors but trying to find out what injectors will work the best for my mods i'm planning to install soon...

mods: full 3" TB w/ hi-flow cat, walbro fuel pump, 264/272 cams, ARP head studs, and MBC.

any input would help. :wink:
with those mods, no injector is needed, stock injectors will do the job just fine so save urself a 5-600 hundred buck and invest into something else instead

[Widebandphillip]

i'd go 720cc just for the hell of it. 680cc will do the job. Stockers are at dangerously high injector duty cycles so i'd definately reccomend upgrading them.

[EvoVIII]

i'd go 720cc just for the hell of it. 680cc will do the job. Stockers are at dangerously high injector duty cycles so i'd definately reccomend upgrading them.
the stocker isn't running at a dangerously high injector duty cycles, unless you don't know how to tune it

[EvolvedDSM]

hmm..i see..so larger injectors itself do not add HP, but help contribute to a better tune(i.e. AFC, piggyback, standalone), than stock ones..

The only thing larger injectors do is require a tune. They aren't truely called for until you start pushing the 400HP level and 99.99% won't be seeing that out of a stock turbo.

[leif]

hmm..i see..so larger injectors itself do not add HP, but help contribute to a better tune(i.e. AFC, piggyback, standalone), than stock ones..

The only thing larger injectors do is require a tune. They aren't truely called for until you start pushing the 400HP level and 99.99% won't be seeing that out of a stock turbo.

probly even more than that. im rite around 400hp, if i had an 05 or hotside with my mods id be over it for sure, and i know my stock injectors are fine. save the money for something else...

[Widebandphillip]

i'd go 720cc just for the hell of it. 680cc will do the job. Stockers are at dangerously high injector duty cycles so i'd definately reccomend upgrading them.
the stocker isn't running at a dangerously high injector duty cycles, unless you don't know how to tune it

6510 +27.4 1592 100 90 00 +2.8 90.4 +16.1 +11.0 ECU. 1811 11.17
6587 +27.4 1655 100 90 00 +2.9 91.7 +16.5 +11.0 ECU. 1908 11.23
6653 +27.4 1661 100 90 00 +3.5 92.1 +16.7 +11.0 ECU. 1811 11.30
6653 +27.4 1672 100 90 00 +4.9 93.1 +16.8 +11.0 ECU. 1773 11.28
6788 +27.2 1689 100 90 00 +6.5 92.9 +17.1 +10.8 ECU. 1689 11.24
6858 +27.2 1689 100 90 00 +6.2 95.1 +17.1 +10.4 ECU. 1785 11.23
6915 +27.4 1700 100 100 00 +6.4 95.6 +17.1 +12.4 ECU. 1811 11.20
6887 +27.4 1700 100 100 00 +6.7 95.9 +17.1 +12.4 ECU. 1824 11.12
6901 +27.4 1718 100 100 00 +6.7 95.7 +17.1 +12.5 ECU. 1851 11.05

that's a log from a friend's utec that i've tuned. Low 11 afr and mid 90's injector duty cycle. 19 psi. Any richer afr or any more boost and you're talking high 90's or going static. Rule of thumb is to stay under 85% injector duty cycle. I don't know about you guys, but i think mid to high 90's is pretty damn dangerous.

[EvoVIII]

i'd go 720cc just for the hell of it. 680cc will do the job. Stockers are at dangerously high injector duty cycles so i'd definately reccomend upgrading them.
the stocker isn't running at a dangerously high injector duty cycles, unless you don't know how to tune it

6510 +27.4 1592 100 90 00 +2.8 90.4 +16.1 +11.0 ECU. 1811 11.17
6587 +27.4 1655 100 90 00 +2.9 91.7 +16.5 +11.0 ECU. 1908 11.23
6653 +27.4 1661 100 90 00 +3.5 92.1 +16.7 +11.0 ECU. 1811 11.30
6653 +27.4 1672 100 90 00 +4.9 93.1 +16.8 +11.0 ECU. 1773 11.28
6788 +27.2 1689 100 90 00 +6.5 92.9 +17.1 +10.8 ECU. 1689 11.24
6858 +27.2 1689 100 90 00 +6.2 95.1 +17.1 +10.4 ECU. 1785 11.23
6915 +27.4 1700 100 100 00 +6.4 95.6 +17.1 +12.4 ECU. 1811 11.20
6887 +27.4 1700 100 100 00 +6.7 95.9 +17.1 +12.4 ECU. 1824 11.12
6901 +27.4 1718 100 100 00 +6.7 95.7 +17.1 +12.5 ECU. 1851 11.05

that's a log from a friend's utec that i've tuned. Low 11 afr and mid 90's injector duty cycle. 19 psi. Any richer afr or any more boost and you're talking high 90's or going static. Rule of thumb is to stay under 85% injector duty cycle. I don't know about you guys, but i think mid to high 90's is pretty damn dangerous.
and his current mod is? if ur friends is running mid 90 plus duty cycle then he should have some very major mods done to his car

[Widebandphillip]

Stock cams, stock injectors, walbro fuel pump, stock intake, turboback. Just your run of the mill evo. I would show you my logs but i don't have the tuner pro to show you the afr. I have the innovative lm-1 wideband and you'd have to have the software to view the logs. I run 90's injector duty cycle aswell with a 11.3-11.5 afr if you can believe it.