like i said, i ran my 60# injectors (the same ones supporting 850rwhp+ now) when i ran a boost engine NA a couple years ago. the HP was probably no more than 390rwhp, and the drivability was exceptional. in theory, yes i understand what you are saying and it makes logical sense. in practice, it’s not always the case.
let me ask you this. i know you are a young guy. are you speaking from experience, or something you read online?
^Turbo - it boils down to having high resolution control of the inj PW. IDK what the specs on HPTuners is, but you can run 160# injectors and get them to idle okay is you’re able to control the PW down to 0.01ms (for example).
I see NO PROBLEMS going big at first. If you have a set goal, and you know what your limits are then yes, dont go overkill. However if your not sure if you want a 300whp beast or a 700whp beast then theres plenty of turbos/injectors out there that will get you to where ya need to be. Obviously if your runnina 700whp turbo the efficiency will suffer down low, but not realy enough for someone with plans to realy give a shit. As far as injectors go, you can run whatever size you want but the bigger you get obviously the harder it will be to dial in battery offset voltages and cold start/warm start enrichments an offsets.
actually hybrid dynamics is a pretty nice place, know the guys personally, its probably just some retard who does not know what he is talking about
and i always buy injectors for my future goals so that way i don’t have to buy twice
with the injectors that are out there now and the software to tune with (atleast for honda’s) you can get a 1000cc injector to idle and drive like stock
yea - the rant is not so much about going oversized so much as it is not know WHY you “shouldn’t” unless you’re able to set them up properly.
and, well, the math is better then guessing parameters that do not affect the injectors at all.
w/e. its “your” money & time.
Here is a silly rule of thumb ive heard before that works ok for my application and is suppoused to give you “room”:
whp x 8 = total required injector capacity
Example:
For 500 whp 500 x 8 = 4000 / 4 injectors = 1000 cc
i hate you
Nikuk nailed it. I have no tuning experience, but if you CAN’T adjust the injectors at a fine level it won’t work. In your case with 60 pound injectors (~660 cc?) there shouldn’t have been any problems with tuning, they aren’t horrendously large.
You also have a larger engine than I was comparing to, which helps out a lot. Bigger engine means more fuel being burned at idle, which larger injectors like.
Side note: 850 hp? :tup:!
Injector sizing and injector control resolution isn’t the only thing that can lead to poor idle quality (stability of fuel pressure, combustion chamber geometry, injector timing, intake valve config/shape, etc.). But this is a very well put together post that does cover a lot of little things people say/do that bug me. Base what they need on what someone else did or said.
In all honesty, i don’t know enough about the science behind all this to make an educated decision for myself…which is why i’m glad the internet exists.
I can go on one of several Z forums, and see what people with the same setups/power goals have, see what they run, recomment, and of course there’s also tons of Z-specific shops that are always willing to help.
I’ve been spoiled with this information and due to that, have no real desire to take the time to learn all the science and specifics involved in making such an educated decision on my own.
Maybe some day…but for now i’m still learning how to wrench, as can be seen in all the little problems i have pulling a motor that an experienced mechanic probably would have no problems with at all…
1000 cc injectors are easy to tune and get dialed in. I have had a couple sets with out any problems on a 2.0 4g63.
Now 1600’s that’s a whole other story. The way i look at choosing injectors is what size turbo, how much boost, and what kind of gas i will be using. Through the years of tuning and such and taking logs of IDC I can estimate pretty easily what a suitable injector will be.
There are plenty of DSM guys running 1600’s on their 2.0 4g63 since they are running e-85 and need as much fuel as possible. and dual fuel rail set ups are becoming more popular.
1600’s, yeah…I hear those are fun to play with 
I think there’s a thread for every person who has installed those over on SF.
i originally had some 1600’s since i was planning on running e85 but plans changed and decided to just go with some 950’s and run 93.
I’m playing with these calculations and all I can say is that the rotary is not very efficient :(.
I just use experience. I know what injectors sizes I have used on the motors I have used in the past to get 300 whp, 400 whp, 500 whp. I can look at the injector duty cycle, and see when they are going to poop the bed, and plan accordingly.
I don’t fully agree with your argument with newman jokingly saying that you should get a 114mm turbo to have overhead. While it seems like a valid arguemnt at first, you will quickly see that turbo costs tend to keep going up. A 16g is going to be less than a 30r which is less than a 35r which is still less than a good precision 100mm turbo, etc… If you look at injector costs, I can get a set of 500cc injectors for roughly the same cost as 1000cc injectors.
This rule may not apply to everyone on the site, but I have pretty much maxed out my injectors on every car I have put aftermarket injectors on, so if you plan on ever using them, might as well buy what you can use upfront, instead of needing to buy more later. I have tuned 850cc injectors to run just as good as stock neon ones, so with modern tuning capabilities, I don’t think it’s nearly as big of a deal as it was in the past using AFCs to tune.
Anything from 240-850ccs will run about the same on most setups.
Then 900-1260ccs run well, but not quite like stock. You probably won’t feel any loss in drivability, but gas mileage will suffer.
1600+cc injectors will not run like stock on gas. Once you put some load on the engine they’re fine, but cruising at very light throttle where the injectors are at minimum pulsewidth will burn lots of gas on most setups with 1600s. They do not flow in a linear manner as you near minimum pulsewidth. There are some newer injectors that are better than the old Bosch ones, but they will not run like stock in terms of fuel economy.
This all assumes you’re running gas. If you’re on E85 this goes out the window. 1600’s will run fine.
Looks like a good post and seems you have put a lot of effort in putting it together,
though may be there are a few points that might be debatable but still thanks for the post.