Maximum power for stock injectors

[masospaghetti]

How much HP can the stock injectors handle? My H23A1 now has I/H/E, 260 cams, H22A high compression pistons, and a custom tune. I'm hoping at least 180 hp. Will I need new injectors and/or higher fuel pressure?

[Jarrett]

I would say so. You didn't say what tuning solution you're using. Is it possible to see what duty cycle yours are at when it's at full throttle?

Even if they're sufficient, aftermarket injectors have progressed tremendously in the past 10 years with the introduction of the Bosch EV14 format injector. There's a video on the internet where T1 Race Development here in Dallas takes a bone stock B18B1 Integra and puts ID2000 injectors in and tuned it. The injectors running at 12% duty cycle were able to make more power than the OEM injectors due to their improved spray and pulsation pattern. T1 Race Development has claimed elsewhere that similar tests have allowed improvements in economy, as well, with the only changes to the tune those that optimize injector capabilities. That's open-ended enough to not be reliable information, but there are plenty other advantages to going aftermarket.

https://www.youtube.com/watch?v=RX1xIvOWcNk

Your injectors will be new, as opposed to 25 years old.
They'll be quieter, and not in a noise competition with the roller followers.
You will have room to expand with additional power improvements in the future.
Your engine will be more reliable with a larger injector to combat combustion temps with that piston combination.


The only real downside is the cost.

[F22Chris]

They're about as expensive as any quality injector would be imho. And I don't think stock injectors would live up to 180. I can't remember if the stock H23's are 240 or 300 something. If they're 240, then absolutely not. Are you doing any head work to compliment the cam? What is the custom tune?

[masospaghetti]

I have a basemap from Phearable that was set up with the stock cams so I will be making adjustments myself. Hopefully i can dial it in sufficiently...I was considering having it dyno tuned somewhere. The stock injectors are 240cc.

Head is stock other than the cam although I did just have it rebuilt w/ a valve job.

Would the Bosch EV14 injectors be a plug-and-play? Could i use OBD1 H22 injectors instead?

[H311RA151N]

How much HP can the stock injectors handle? My H23A1 now has I/H/E, 260 cams, H22A high compression pistons, and a custom tune. I'm hoping at least 180 hp. Will I need new injectors and/or higher fuel pressure?

If you have a custom tune then you should have the ability to check and see for yourself. Whether that be by dataloging, tuner, ect. If not, I'd be getting on that first and foremost.

I would be more concerned about the tune you have being for stock cams... Not to mention it's a canned tune. I'd be more concerned with that.

Basically, you haven't a clue as to what's going on. Injector pulse width, duty cycle, etc would be the last of my worries. Right now.

If, once you get everything else worked out and aren't in the dark tuning wise, check and see if they are encroaching on 80% duty cycle. You don't have anything done to it that's going to require that much more fuel over stock so I highly doubt that it's near that high. But, canned tunes are known to be fat on the fuel to keep the odds of getting lean, down. I don't care who made the tune. I deal with this stuff more and more as time goes on. I see these things all the time.

Aftermarket injectors do have better spray patterns and all that. Helps with fuel atomization ect. Getting your stockers cleaned and balanced would help in this area but it's likely already on the fat side so you'd be peeing in the wind in a sense. An improvement could be made, but priorities.


You need fine tuning and a way to have a clue as to what's going on. And, when you do that, which you need to, these littler things will all be addressed at that time. And you will know what you need.

[wagon-r]

I can't remember if the stock H23's are 240 or 300 something.

OEM H23 injectors are exactly the same as F22 injectors - 240 cc.

OEM H22 injectors are 345 cc. I sent mine to Mr. Injector, who cleaned and balanced them and installed new filters, o-rings, spacers and pintle caps.

[masospaghetti]

Ok, I figured there was a standard rule of thumb "240cc injectors support up to 170 hp" or something. I definitely have some tuning to do on my own.

[Jarrett]

Ok, I figured there was a standard rule of thumb "240cc injectors support up to 170 hp" or something. I definitely have some tuning to do on my own.

While there are many variables, generally the industry sizes injectors on a hp per cylinder basis. There's a lot of overhead built in to that, and it generally refers to power made with pump gas vs. E85 or race gas, but it's a good starting point.

These things are old, worn out and weren't really great to begin with. So you have to consider that when sizing them. A tuning solution is the only thing holding most people back from upgrading injectors, usually. I'd do it just to have the peace of mind.