Fuel Injector question

[jugbugz]

Ok, what I've learnt is that running normal pin type injectors above 80-85% duty cycle is bad and will run down its life.

Also Lucas type Injectors have a higher cycle duty limit than the normal types, quicker response time and they also aid in tuning the idle and lower rpms.

The question is, why does honda run 100% cycle duty at redline?

Why does all B-series use the same sized 240cc injectors? 240cc with 46psi would only support about 150bhp at 80% cycle duty.

I'm thinking about upgrading the injectors because I'll be upgrading my cams to Skunk Pro series Stg 1 on my B16B(185PS), but some are saying theres no need to upgrade etc. I'm aiming for 210PS so thats a 35PS increase.

I'm just a bit confused especially why Honda used the same sized injectors for all B-series. I just dont have that piece of mind about using my stock injectors.
I've found RC Engineering 370cc Lucas type Injectors that I can run 70-80% cycle duty with 46psi fuel pressure for 210bhp. Or theres a 310cc injector which I will run about 80-85%.

Can someone please help?

[JasonGilholme]

RC are definately the go when it comes to aftermarket injectors.

There are also plenty of people runnin similiar cams on stock injectors with no problems. upgrade them if you feel the need to but from other peoples experiences it doesn't seem neccessary.

[dsp26]

also stock ecu can compensate upto the rc engineering 310cc

[jugbugz]

Thanks for your reply guys :)

Now for the next question, is $590USD shipped worth it for my setup? I know they should provide excellent idle and low rpm tuning.

[jugbugz]

Also any reason why honda run 100% cycle duty at redline? Also why the stock injectors can support such power increases?

[grumpy rooster]

Thanks for your reply guys :)

Now for the next question, is $590USD shipped worth it for my setup? I know they should provide excellent idle and low rpm tuning.

That is expensive for RC injectors.

PM me if you want some.

[jugbugz]

Grumpy rooster: Cool thanks!

Anyone any answers???

[Limbo]

Also any reason why honda run 100% cycle duty at redline? Also why the stock injectors can support such power increases?


Not all b- series hondas have the same injector size. B16a & ITR don't have the same injector size
Also the reason you run 100% is cost.
Use the smallest injector possible for that car to keep costs down and you pump max fuel to ensure also that you don't detonate or overheat at high rpm.

The other brand is precision injectors, i'm using those, quite popuar in the US also and abit cheaper in price

[jugbugz]

Not all b- series hondas have the same injector size. B16a & ITR don't have the same injector size
Also the reason you run 100% is cost.
Use the smallest injector possible for that car to keep costs down and you pump max fuel to ensure also that you don't detonate or overheat at high rpm.

The other brand is precision injectors, i'm using those, quite popuar in the US also and abit cheaper in price

hmm, I was told 2 things. B16a 240cc, B18C-R 290cc. But then I was corrected again and was told they are all 240cc. I guess the best way is to check the part numbers.

So your saying honda did it to keep costs down? Interesting though.

Are Precision injectors lucas type?

[delsol9000rpms]

b16a and itr injectors are the same size... 240cc

[EGB18CT]

i believe precision are lucas, so are delphi, lucas and another, i think they may either be made by rochester too or seimens... it one of them!

[Limbo]

hmm not sure i never looked at that, and i can't rem,but they are the same design as the RC injectors, also still need the obd1 clips for it.

Have a read http://www.hondata.com/techduty.html
seems like i may have been wrong, they hondata seem to think its to increase accuracy etc, but i still think it is cost cos they don't have to pay for larger injectors. (as you know larger injectors cost abit more)

On reading this article it says b16 & b18s were the same injectors with different fuel pressure. So i stand corrected

This is what else i found.

Honda/Acura Fuel Injector Stock Flow Rates

(source: TexasRacingScene, Genius)

Generally OBD1+ are Saturated, and non-OBD are peak and hold. There are a few exceptions however (as usual):

92-00 D16z6/y8, B16, B18b, B18c1/5, B20b/z - ~245cc, saturated
88-91 D16a1, B16, B18a - ~245cc, Peak and Hold
92-95 H22a, H23 - ~330cc, Peak and Hold
96-00 H22a, H23 - ~290cc, Saturated

A more detailed listings:
Honda/Acura Stock Fuel Injector Flow Rates
Engine Code Year Stock Flow Rate (cc/min)

G25A4 1995-1996 235
J30A1 1997 240
C32A6 1996-1997 240
B18C1 1996-1997 240
B18C1 1994-1995 240
B18B1 1994-1995 240
B18A1 1992-1993 240
B17A1 1992-1993 235
C32A1 1997 275
C30A1 1995-1998 325
C27A4 1995-1997 235
J30A1 1997 240
F22B2 1994-1997 235
F22B1 1994-1997 235
F22A6 1990-1993 235
F22A1 & F22A4 1990-1993 235
A20A3 1987-1989 235
BT 1986 235
ES3 1985 180
D16Y7 1996-1997 240
D16Y8 1996-1997 240
D16Z6 1992-1995 240
D15B7 1992-1995 235
D15B8 1992-1995 180
D15Z1 1992-1995 235
D16A6 1988-1991 235
D15B6 1988-1989 180
D15B6 1990-1991 235
D15A3 1987 180
EW4 1986 180
EW3 1985 180
B20B4 1997 240
D16Y8 1996-1997 240
B16A3 1996-1997 240
D16Y7 1996-1997 180
B16A3 1994-1995 235
D15B7 1993-1995 235
D16Z6 1993-1995 235
F22B6 1995-1997 235
H22A4 1997-2001 290
H22A1 1993-1996 325
F22A1 1992-1996 235
H23A1 1992-1996 235
B21A1 1990-1991 235
B20A5 1988-1991 235
BT 1985-1986 235
__________________

[dsp26]

b16a and itr injectors are the same size... 240cc

thought this was the case also... was researching this before... and they look the same to me too...

[EGB18CT]

i believe precision are lucas, so are delphi, lucas and another, i think they may either be made by rochester too or seimens... it one of them!

Correction:
Precision, MSD, Rochester are made by Delphi, RC made by lucas, then you have your bosch/ford i believe it was and denso.

[jugbugz]

hmm, I'm still stuck about upgrading my injectors. What I've learnt is that 80% cycle duty for pin type injectors(OEM) provides the best spray pattern(I dont know if that matters since B-series are not 'direct fuel injection'), anything more than that, the injectors start to fluctuate, especially the OEM pin type injectors.

Lucas (rotary) type has a higher 90% limit, and response time is very low. I cant remember the numbers.

Its still strange to me why Honda use 100% at redline. Is it because of the IM and port design that allows it to operate well? Is fuel pressure increase with stock injectors safe and would it stop the fluctuation? I'm stuck on this... My stock fuel pressure on the B16B is 46psi

I also know of 2 local B16as that are making 155whp+ with stock injectors. One of them are using TODA C, the other type R cams with a wild port polish.. Both have fuel pressure regs. I just dont have that peace of mind though.

[rosso]

Changing injectors, means chaning: fuel pumps and ecu haha plus tuning. I wouldn't go for it waste of time.

[nd55]

[Many opinions, few facts ahead. Reader beware]

Another difference between injectors is the saturated versus "resistor limited" aka peak & hold types.

Most modern (ie last 10 years) injectors are saturated.

ie. the resistor limited versions need an external resistor to limit the current through them, once they open.

The saturated injectors have an inherent design limit for electrical current, but will be a bit slower to react to signals.

I think the difference is 4 ohms versus about 16-32ohms.

I suspect the no-100% duty rules applies more to the saturated.

You can use peak & hold injectors in place of a saturated injector if you use an external resistor box.

extreme differences in upgraded injectors (ie 1000cc) will mean they dont react well enough with the current supply and you will require an external injector driver circuit.

US web forums often quote DSM 440cc injectors with an external resistor box to use on tight-arse upgrades. Find out the local equivalent perhaps?




> What I've learnt is that 80% cycle duty for pin type injectors(OEM) provides the best spray pattern

I've never seen the the spray pattern linked to the duty cycle, I think they're either wide or narrow pattern.

Incidently, late model CBR motorcycles use a 12 hole injector by denso which would be great for atomization. I think flow rates are about 240cc though.

Nick.

[jugbugz]

> What I've learnt is that 80% cycle duty for pin type injectors(OEM) provides the best spray pattern

I've never seen the the spray pattern linked to the duty cycle, I think they're either wide or narrow pattern.

Incidently, late model CBR motorcycles use a 12 hole injector by denso which would be great for atomization. I think flow rates are about 240cc though.

Nick.

Well I've learnt that running high duty cycle will cause flucutation and when the injectors fluctuate, fuel spray pattern gets stuffed. I guess thats the reason we all upgrade our injectors.

[jugbugz]

Changing injectors, means chaning: fuel pumps and ecu haha plus tuning. I wouldn't go for it waste of time.

haha, well I've got everything except injectors and I dont need to change fuel pump for my goal. 210bhp from 185PS on my B16B.

The question is, I've got everything, and theres the theory. But now, is it worth it?

[STOCK]

You should be fine with stock B16 items with a decent tune. Ive seen b series motors with more agressive camshafts and supporting mods tuned with stock b series injectors running just fine. Best thing to do would be fit your camshafts and put it on the dyno to see if you really are running out of duty cycle and leaning out.

[jugbugz]

You should be fine with stock B16 items with a decent tune. Ive seen b series motors with more agressive camshafts and supporting mods tuned with stock b series injectors running just fine. Best thing to do would be fit your camshafts and put it on the dyno to see if you really are running out of duty cycle and leaning out.

Alright :thumbsup:

I'll give that a go since it'll save me money for the time being. I'll consider RCs if its needed.;)

[Blue]

Just save your money for time being and wiat till your oring seals start not sealing then just go the whole hog and up the injectors to better items,

IMO bigger injectros are the go but its exe