2G Injectors, go big or go home?

[Kai Hefner]

I'm uninformed about fueling, bear with me.

When buying injectors, what stops someone from going straight to something like 1200cc? I've seen a lot of people buying something like 900cc injectors, maxing them out, then having to buy bigger ones anyways. Is it bad to run large injectors at a low IDC for lower-horsepower applications?

Wanting to avoid having to buy smaller injectors for my first lower-hp goal, then buying bigger injectors for my second, high-hp goal.

 

[Vegas Smith]

Smaller injectors tend to cost less so people will get a deal off a buddy and go with that. I've heard of people having issues with 1600+ injectors and gas. I have a hi-z 1650s on gas and I don't notice any issues. Basically, buy some nice, big injectors once and be done with it.

 

[ishnish]

6 years ago I bought 2150cc injectors for my car and still to this day don't regret it whatsoever. I have the same mentality as Vegas Smith above^^. Sure, I'm not using even a fraction of them at this point. Heck, my car still doesn't even have a boost controller installed yet . But, that's mainly because I'm trying to sort everything out regarding maintenance and running properly. However, when the time comes, it's nice knowing I'll be able to throw anything at it rather than if I had bought 1000cc injectors and having to upgrade from there.

I guess it all depends on the type of person you are. I like getting quality parts that last. I also like having a safe and reliable car so I will always try to over build.

Oh and btw, I'm in Cali. I run an Evo 3 16g (stock boost) on 91 crap gas and FIC 2150cc injectors and my car idles perfectly. No issues whatsoever. Not gonna list all the other mods (you can check the mod list) but trust me, you won't have issues with large injectors on low hp applications. I'm sure I'm barely over stock hp as it is.

 

[1990TSIAWDTALON]

The ONLY problem I have seen is with tuning the 2150's on gas as the global fuel adjustment tab just won't let you get quite to the real value that you need on gas but @ishnish has had good luck and is on that crappy 91, like I have around here. No 93.....BUT there is E85 and on E, those injectors are easy peasy to dial in (2150's). For most people a set of 1600 Hi Z or 1850 Hi Z injectors will be all they ever need, but here I am spouting that all while running 2150's.....just slap me!
I would like to add that the Hi Z injectors transition well between low and high pulse rates, unlike my Low Z 1650 BlueMax FIC's. Those things ran great at WOT and at idle but the transition in between was CRAP!

 

[Charliethatguy]

I have been told that when it comes to injectors anything over 1200cc Low z Idles like crap. It all depends on how much power your end goal is and what fuel you want to run (E85 needs more fuel) FIC has a chart on their website to help you determine injector size. Put in the fuel pressure and fuel you want to run and it gives you a table of what hp you can expect from the different sizes.

 

[Charliethatguy]

here is the link: http://fuelinjectorclinic.com/index.php?route=information/static

 

[MorrisonFab]

Like Marty, Vegas, and Charlie said, low impedance injectors seem to start having idle and part throttle driveability issues in the 1300cc range in e85 (from what we've seen). Sooner on pump gas, as the injector on time has to be so short to maintain the correct light load AFR that they become erratic. Over time and use, this seems to get worse. 1750 or 1850cc on pump gas and ~43psi base pressure have been hard to even get to run/idle to begin with.

High Z (high impedance) options are some magic that behaves incredibly well even being 2150cc. They actually tend to have better manners than low impedance half their size

 

[Kai Hefner]

Alright so High Z, 2150cc injectors, sounds good to me! Thanks a lot for the advice guys.

 

[1990TSIAWDTALON]

Kai, I am not sure if you will need THAT big of injectors but you are right that you would never buy another set. There have been a few Classified listings for some. The Hi Z 1800 FIC's are a dam good injector. You do realize that some of us are into the 5-6-700+ hp range, being the reason we need more fuel. If you ever plan on being in that range then the 2150's will be friendly to you.

 

[Kai Hefner]

I do plan on being in that range but it'll definitely be a while before I'm there.

 

[stillrunning]

Minimum injector pulse and operating in the short pulse range of the injector is the biggest issue with too big of an injector for the application for a street car.
Like filling your same beer mug up with fire hydrant hose or a beer tap, fire hydrant would barely crack before needing to be closed while a beer tap would be very controlled and metered.
There is ~20ms of time during the intake stroke to get fuel into the cylinder.
It really doesn't have any benefit to have an injector so big you meet your fuel requirements by using only 10ms of the available time.
Especially for a street car that might spend allot more time at idle, cruise & part throttle than WOT.
Can you run big injectors, absolutely but to a point, is there an advantage to running a bigger injector than required, not really.
Be realistic about your power goal and intended fuel and get a properly sized injector that can meter the fuel within the intended operating range.
If down the road you make significantly more power than today odds are you're going to want to address the tune again anyways.

 

[Vegas Smith]

some of us are into the 5-6-700+ hp range

Need to have a running car to claim that

 

[1990TSIAWDTALON]

I am in the 5 to 6 hp range right now...
You know I love you Vegas!!!