Fuel system questions - performance oriented

[HondaFan81]

Planned setup:

Race Engineering (Wiseco) 11:1 pistons 85.5mm & rings, forged rods, 0.020" overbore, align-hone crank journals, P&P cylinder head (maybe 3-angle job), seat valves, Delta camshaft 272 regrind, keep F22A1 stock valves & retainers, new stock valve springs, AEM CAI, F22A4/A6 header (4-2-1), stock cat, Apexi 2.25" world sport exhaust, H22/H23 intake manifold TB & top-half, F22A6 intake manifold bottom-half w/IAB, P72 ECU w/Hondata S100 ROM & dyno tune, 7mm wires, NGK BKR7E plugs, 255 lph Walbro fuel pump, B&M fuel psi regulator & gauge, Autometer air/fuel ratio gauge & elect. oil psi gauge, larger fuel injectors.

Questions:

1) I'm going with 255 lph fuel pump. What size injectors are needed?

2) I'll have a fuel psi regulator & gauge. If I recall, stock fuel psi is like around 35 psi (anyone know exactly? don't have book w/me). What fuel pressure do I set it at? I remember reading somewhere for an NA build-up...upgrade fuel pump & larger injectors @ stock psi. I just want to verify this.

www.rceng.com > good site, I know

[h22sparkle]

well im not much into buildint motors myself but you have my ass stumped bro good luck on that try the allmotor forum maybe someone should know there perhaps. How much hP you expect to get out of that motor goal.?

[BustedLX]

There are several factors used to determine injector sizing. The easiest quickest way would be to determine the desired amount of HP you are looking for.

In the case of the H22A an easy example the engine output is 200 hp. For a N/A engine is takes .5 pounds of fuel per hour to produce one horse power for turbo charged it can be .6 and in some cases more.

200 x .5 = 25 = 100

Now you multiply the number of injectors you will have by the duty cycle. 80% (.80) is the accepted industry standard.

4 x .80 = 3.2

Now devide your 3.2 by the 100 we figured out earlier.

100/3.2 = 31.25 lb per hour.

So now we know we need 31.25 pound per hour injectors. To convert this figure to the cc per minute factor you multiply by 10.50.

31.25 x 10.50 = 328.125cc per minute.

So basically we need at least 330cc injectors to make this setup run.

And that right there is the basics of the formula so much more goes into account. If you notice the 92-96 H22A ships with 345cc injectors where as the 97+ H22A ships with 290cc so there are some other factors used to determine the injector sizing.

Once you get everything together and get all your numbers together you can properly calculate what injector size you will need. You will also be able to figure out an adecuate fuel pressure to maintian that flow.

[93accordEX]

can I ask why you are keeping a stock header and cat?

[BustedLX]

Originally posted by fizzbob7
nice, long, drawn out explanation
good info though....

Why thank you

Originally posted by 93accordEX
can I ask why you are keeping a stock header and cat?

I guess he thinks the added back pressure will help his bottom end power.

[HondaFan81]

I guess he thinks the added back pressure will help his bottom end power. [/B][/QUOTE]

Yea & cuz I will simply transfer my F22A4 header to the F22A1 & it will improve flow...maybe not as good as DC sports but...that's $380 I save up front.

Also, I may hollow out the cat.

Anyways, header is a simple bolt-on. I'm concentrating on using money for engine build-up internally, ingition & fuel, ECU setup...then working the intake & exhaust to a decent setup. All about planning my friend.

Later, when I've been driving car around having some fun & at same time saving money up again... I fill in the minor details that are not as critical to my overall setup. Susp. work will follow as well, w/tires & rims

I'm being realistic as to what order & what i'll be able to afford....DC header is way later in my plan, I know it'll help though