Your fuel injector opinion

[HondaFan81]

If you read my F22a1 all-motor project thread in this sub-forum, you'll get an idea for my setup. I'm just curious as to what you all have to say on the injector size I have planned for this setup.

As you see in my sig, I have purchased 315 cc/min injectors. I plan to make around 200 HP engine output and I figure these injectors are a tad on the larger side, but that is also because I'd like to retain stock-like fuel pressure so I have no future problems regarding higher fuel pressures, etc. I'm going for reliability.

I also plan on using a 255 lph walbro fuel pump, since I'll be running higher volume. These are Accel fuel injectors by the way and are saturated (got a good deal on them) and I know I have to convert them with some slight mods...but if you have reasons as to why I should not (I know stock is peak & hold type)...then please state why, etc. Will this cause probs for ECU tuning?

Please be detailed in your explanations. Thanks in advance. If you have personally built any Honda engine around this power range, etc...from your experience and injectors that you ended up using...am I far off here or in the ballpark? I've done the calculations using www.rceng.com and this is what I came up with.

[mrmike]

why not use obd1 H22 injectors. I'm not to sure about what size they are but they are quite large, around 320-340cc. They will support 200whp

[HondaFan81]

Originally posted by mrmike
why not use obd1 H22 injectors. I'm not to sure about what size they are but they are quite large, around 320-340cc. They will support 200whp

Yea, that's an option and if it's cheap enough, have them cleaned & balanced as well.

I called up RC engineering and asked them about this setup, the guy first said to get fuel psi regulator & bump it up (10-15% max, above stock) using stock 240 cc/min injectors and see if that works. If not, then 270 cc/min should be fine for me supposedly.

What gets me is, I put in the info for the injector sizing calculator and it tells me I need 315 cc/min to keep a stock-like fuel pressure setting.

So who is right?

[wed3k]

im having this debate as well.

BHP X 5
-------- = injector CC (flow in cubic centilitres)
No Cyls

i used that equation for 300bhp and came up with around 375cc's but im actyally shooting for 300 to the flywheel. so 370cc injectors should suffice.

sorry for the old bump :o

[HondaFan81]

FYI:

I'm using H22 345 cc/min rated injectors on my white Accord project that should make ATLEAST 200whp, more than likely more (I don't know how much more).

Anyhow, I had these injectors cleaned & flow tested at industry standard 43 psi and they ALL shot 355 cc/min, so that is the actual rating. They are Keisho brand (stock), which is apparently more consistent than IPTE who makes stock Accord 240 cc/min rated injectors. I remember those actual numbers to be 253-258 cc/min when cleaned & flow tested for red Accord project.

[wed3k]

FYI:

I'm using H22 345 cc/min rated injectors on my white Accord project that should make ATLEAST 200whp, more than likely more (I don't know how much more).

Anyhow, I had these injectors cleaned & flow tested at industry standard 43 psi and they ALL shot 355 cc/min, so that is the actual rating. They are Keisho brand (stock), which is apparently more consistent than IPTE who makes stock Accord 240 cc/min rated injectors. I remember those actual numbers to be 253-258 cc/min when cleaned & flow tested for red Accord project.
any actual hp goal that you are shooting for?

[preludeman92]

Would 345cc injectors be enough for your build Cisco? I'm about to buy injectors and can't decide if stock JDM h22 injectors would work or if I should step up to DSM injectors of some sort? I think auto DSM injectors are 390cc's and manual ones are 440cc's.

[HondaFan81]

Would 345cc injectors be enough for your build Cisco? I'm about to buy injectors and can't decide if stock JDM h22 injectors would work or if I should step up to DSM injectors of some sort? I think auto DSM injectors are 390cc's and manual ones are 440cc's.

According to my dyno tuner, yes. Keep in mind my red has stock F22 injectors and are holding up fine.

[preludeman92]

Cool. I just had a set of stock USDM h22 injectors fall into my lap. I guess I'll use them after they get cleaned/flow tested.

[HondaFan81]

Cool. I just had a set of stock USDM h22 injectors fall into my lap. I guess I'll use them after they get cleaned/flow tested.

Mine actually flowed 355 cc/min, not the rated 345.

[Grumpys93]

does this caculation also apply to FI ? And i am guessing no clys means number of cylinders?

[NAiL05]

does this caculation also apply to FI ? And i am guessing no clys means number of cylinders?

Should work I dont see why it wouldnt.

[Grumpys93]

well according to that formula then if i wanted to reach my gold of 350-375whp i would need 468.75 or just using my 450cc blue tops but that doesn't make sense i thought the blue tops would max out at 300? Or am i wrong?

[NAiL05]

Usually injectors (stock) work at around 80% efficiency. Maybe thats saying you need that big of an injector to make that power efficiently so you would go a size up or two.

What I calculated if I did it right. I took Wedek 300hp goal and got 375cc. Ok now you take 375/450 and you get an injector working at about 83% efficiency. Now I entered 350hp for your goal and did the same thing. The injector would be working at 97% which is pretty high. I might have done the calculations wrong but this is what I come up with.

[Grumpys93]

ya thats what i did. So in order to be safe i would have to go with a 600cc injector right?

[HondaFan81]

Would 345cc injectors be enough for your build Cisco? I'm about to buy injectors and can't decide if stock JDM h22 injectors would work or if I should step up to DSM injectors of some sort? I think auto DSM injectors are 390cc's and manual ones are 440cc's.

So far for the engine break-in 4000 rpm max limit I'm at while driving it, they are fine according to dyno tuner after doing the maps, etc.

However, at first he was concerned for the final tune up to 9000 rpm, then he was like..."Oh, your motor is not VTEC though." I said, "No". He then was like, "Oh, well the 355 cc/min JDM H22 may work then".

I'm looking at it this way, if I made 50-55 WHP more on my red Accord project and ran stock F22 injectors rated at 240 cc/min (actual flow 253-258 cc/min) with stock fuel pump, then I should be fine for my white project.

If I did upgrade, it would be like 440 cc/min, was thinking RC injectors but some had bad comments on that and said Precision. I quickly got a price on those, that's all the investigation I've done. It seems I may be fine with my 355 cc/min, I'll see come final dyno tune time.

FYI: My first post in this thread was in 2004, ignore all 2004 posts from me, they may not be relevant to my current project setups.