Will a slightly bigger injector help?

[Popeye]

As of right now, it looks like I will have a Z1 block and A2 head going into my car next year. IF I can source a PRC intake mani, would I be able to benefit from slightly upgraded injectors? If so, would ya'll recommend RBC's, or an injector from a different Honda or Acura vehicle? (I think I saw an RDX injector at like 420cc's or so, and was like $100 less than the RBC's)

[AttarixEp]

those the only mods?

[Popeye]

i/h/e as well

[AttarixEp]

You don't need anything bigger than that.

[Ba82Ep3]

You can mod your stock injectors to flow 480cc for free. : )

[AKEP]

the 440s are cheaper than 310s? u can get a set of 310's for 100 shipped all day...

[Popeye]

But will they even help on a stock, or semi-stock motor?

[AttarixEp]

They'll just give you room to improve.

[AttarixEp]

Guy on here has a set of 310's for sale now

[AKEP]

They'll just give you room to improve. Guy on here has a set of 310's for sale now

pretty much, they dont add power or anything. those injectors (440), mind you, are pushing what, 4lbs of air's worth of fuel (from the rdx). u wont flow anywhere near that much air to need that fuel. its your call, we have nearly maxed a k20a2 with rbc+boltons on the dyno (like 96-98% @ 220 hp [@7000rpm/20degree vtc] on 310's), the 440's will be more durable for track days and whatnot i guess, since you wont be maxing the duty out or anything like the 310s.

[Ba82Ep3]

I never understood why most OE NA KAL's have the VTC cranked to 50 degrees that high up in RPM range. 30 at the most for the OEM cams i have run across. Hell even my BCstg3's didnt like that much advance... but that would have likely been different with more compression too.

I personally dont like anything more than 80% injector duty. I just like having that comfort zone...

[Popeye]

Wait, a K20A2 was MAXED OUT at 220hp? Ummmmmmmm....

[Ba82Ep3]

The INJECTORS were maxed out. That means their fuel flow ability was at its limit. Think of an injector as a valve. The more power an engine makes, the more fuel and air it needs to do so. Once the injector reaches its capacity... you need a larger injector before you can make any more power.

[Ba82Ep3]

An engine is an air pump. Anything you can do to increase the amount of air it can naturally ingest (and the fuel it takes along with it) the more power it will make.

[Popeye]

Yeah, I knew that. I was just confused about the "maxed out" part. The A2's "normal" power is not far from that. That's why I was kinda dumbfounded about that. Seemed like a crazy statement! lol

[whatsvtec]

You can mod your stock injectors to flow 480cc for free. : )

avg machine/engine shop work?

[Ba82Ep3]

avg machine/engine shop work?

10 minutes each with a Dremel and your own hands. ; )

[whatsvtec]

10 minutes each with a Dremel and your own hands. ; )

Any way to bench test everything? Is there much that can go wrong?

[Ba82Ep3]

You can send them off to have them bench and flow tested to know for sure how much each one flows. I sent off a dozen to get 4 that are within 1% of each other. A little overkill for pretty much anything you would do with a set of 480cc injectors (i doubt you could build a 9 second fire breathing k24 with a set in other words)... but at the time i was deep into stabilizing potential variables with my engine so my tuning was repeatable and more accurate. Again... more of a hobby for myself.


The 270's mod out to 480's with a great spray pattern, and 310's mod out to 540's if i remember right... but their spray pattern isnt as good.

As far as something going wrong... not really. Unless you have a really unstable hand and no patience. lol All you do is remove an atomizing screen from the actual face of the nozzle. For lack of a better description... imagine the atomizing screen attached to the face of the nozzle like a foil seal is attached to the top of a (insert any foil sealed container here... yogurt, asprin, sour cream... etc). Its attached to the outer edge of the nozzle... but covers the whole face of it. You use the dremel along the edge to break the seal without even getting close to the center of the nozzle... and the screen just pops off.

[whatsvtec]

Sounds simple enough. Definitely something the average person could take on.

I like the idea to get them tested, just to know that my engine will be running evenly and consistently. Like you said, hobby, or maybe it's ocd. IDK which really, but it's good peace of mind to know that you've got certain variables in spec. Just like your whole build basically!

Bump to see what Popeye does? Would modded oem injectors and a re-flash be a bad thing? I'm itching for a little more juice for cheap.

[Ba82Ep3]

Dude i dont get it... the DIY link is dead. I found the thread but it wont let me link it. WTF?

http://www.ephatch.com/forum/showthread
.php?43570-DIY-Modifying-stock-injectors-
(increasing-flow-rate)&highlight=modifying+stock+injectors

This is the entire link separated into three lines. Remove both [u r l] and [/u r l], make all three lines as one and you have the link to the thread... see if it works.

[Ba82Ep3]

Thats retarded...

search DIY Modifying stock injectors... the thread is titled "DIY Modifying Stock Injectors (increasing flow rate)". I found it on page 5 of the search returns...

[whatsvtec]

Thats retarded...

search DIY Modifying stock injectors... the thread is titled "DIY Modifying Stock Injectors (increasing flow rate)". I found it on page 5 of the search returns...

THanks for the efforts, I'll definitely bookmark it!

[Popeye]

Unless I came across some oem injectors, Im not taking the chance on JUST what I have. IF I were to do a mod like that, I would do it just like B82...do a bunch, then send 'em off and keep the best of the best. If all I have is 4, and I NEED 4? Not crappenin'!

[Ba82Ep3]

Im mocking up the RBC in my engine bay and since i had the rail out i figured i would take a few shots to show you what my injectors look like after being modded. Again... these are 270cc OEM EP injectors modded to flow 478-480cc...

http://i1140.photobucket.com/albums/n562/dwms73/photobucket-2448-1323456437579.jpg
http://i1140.photobucket.com/albums/n562/dwms73/photobucket-5461-1323456385935.jpg

... theyve been used like this for over 3 years with no issues. :mcool:

[Ba82Ep3]

Unless I came across some oem injectors, Im not taking the chance on JUST what I have. IF I were to do a mod like that, I would do it just like B82...do a bunch, then send 'em off and keep the best of the best. If all I have is 4, and I NEED 4? Not crappenin'!

I think the worst one out of the bunch flowed 472cc with the same pattern. You could seriously just mod the ones in your car, drop them in, put your injector size as 476cc in KPro (to split the % difference between your injectors) and the ECU will do the rest.

[Lucid Moments]

I'm surprised that nobody has mentioned in here. The thing about injectors is that in most cases if you are not maxxing out your current injectors then upgrading them serves no point. There are exceptions to that, but they are fairly few and far between.

[AKEP]

hes going to a basically k20a2 in the future, so he's wondering if a set of 440's would work instead of 310's. i mentioned 310's should be fine as we only nearly maxed out a set on an rbc+cai/rh/e. i'd only look for 440's as a NA track engine substitute as they would be less likely to burn out from the higher duty cycles.

[Popeye]

Why do they have to be maxed out to be the most effective? Kinda going off of what Ba82 said...can you not, with KPro, set a bigger injector to what you NEED? i.e. setting a 440 injector to 310?

[Lucid Moments]

Why do they have to be maxed out to be the most effective? Kinda going off of what Ba82 said...can you not, with KPro, set a bigger injector to what you NEED? i.e. setting a 440 injector to 310?

Its not about it being most effective maxed out. Its just that there is no benefit to using a bigger injector than you need. Your car can burn X amount of fuel. There is no benefit to being able to provide 2X fuel when you can't burn that much.

You certainly can use a bigger injector than is necessary (up to a point), and if you plan to upgrade in the future then there is nothing wrong with going ahead and running as big of an injector as you think you may need to match your plans.

[Popeye]

If a set of 310's were "maxed out" with a cai/rh/e, wouldn't I be better off going with something a little higher-rated?

[AttarixEp]

440's will allow you to grow too in the long run. Too big and you may have idle issues. Too small and you may max your duty cycle and lose potential power.

[Popeye]

Huh huh...you said "duty." lol
Ba...how much did it cost to have the oem injectors modded? Im just trying to figure out which way to go. Im sure I might need SLIGHTLY bigger injectors, but this build is already gonna cost me enough as it is. I dont have big bucks to spend here. But, I dont want to starve the motor, you know?

[Lucid Moments]

If a set of 310's were "maxed out" with a cai/rh/e, wouldn't I be better off going with something a little higher-rated?

Yes. If you are maxing out a set of injectors then bigger injectors should give you some more headroom.

[Lucid Moments]

Huh huh...you said "duty." lol
Ba...how much did it cost to have the oem injectors modded? Im just trying to figure out which way to go. Im sure I might need SLIGHTLY bigger injectors, but this build is already gonna cost me enough as it is. I dont have big bucks to spend here. But, I dont want to starve the motor, you know?


You should be able to mod the stock injectors yourself. I've not done it myself though so I can't say for sure.

[Popeye]

SHOULD be able to being the key word. lol I wouldnt have a problem with that accept for the fact that what IF I screwed something up? I will probably be doing the actually swapping of the motors at Ba's house. What if I screwed something up there? I wouldnt be able to get home because I would have no injectors. I wish I had $175 right now. Someone on here has some 310's I think.

[AttarixEp]

I think I have a set of 310's from my K24a2 when I did my swap.

[Twisted-X]

So at what point would the need arise to upgrade the fuel pump (the Walbro mod)?

[AttarixEp]

So at what point would the need arise to upgrade the fuel pump (the Walbro mod)?

I've seen guys pushing a little over 300whp. I would imagine you can't go much farther. For the price of a walbro in tank its worth every penny. You should see around 500whp capability on it too.