Injectors selection

[A80Avant]

Hi all,
i know and read all the talks about the size of injectors and their capabilities. After a short talk with aelred as well, i found some calculators on megasquirt sites and according to those,by using 85% duty cycle and no more, my injectors are rated to be able to handle only 450hp!!! @ 3.8bar!

on the other hand as we have talked about this with jamo a fair amount of times about the orange porsche injectors and the ford cosworth im using and how these 2 types are basically very close to each other as far as potential with the green ford ones being slightly larger.

With what kind of calculations are the porsche orange capable of reaching 500hp without problems? Is it by using more duty cycle?

since im about to try VEMS i would like to know if im going to need new inj. for the CT358 with which i dont plan to go more than 550hp anyway for the time being....

It is just that the calculators are telling me that those injectors are way below my mark...

anyone care to help me clarify?

[Bram]

Wasn't there a rule of thumb to use the " number of ccm @ 3 bar FPR= crank HP" calculation for injector sizes? I think DC used in this calculation was 85%.

So in my situation I have 440ccm@3bar injectors (034MS green ones from their GT3071R kit which in theory should be enough to reach about 440 crank HP and a DC of 85%.....

I guess when you aim for 550 crank HP should you be looking into 550 ccm@3bar injectors or a bit more for some overhead room.

But these words are coming from a n00b w.r.t. injection system like me!!!!

[A80Avant]

after talking to Billman who also uses VEMS and megatune, i believe that the table and calculators that they have are more or less ultrasafe since they are designed to go for people who may tune completelly on their own,so maybe that is why.

On the same table it says that the 630cc siemens deka injct. are only good enough for 580-600hp @ 3.8bar... so i think they are quite a bit underrated

[aelred]

[QUOTE=bram;389809]
So in my situation I have 440ccm@3bar injectors (034MS green ones from their GT3071R kit which in theory should be enough to reach about 440 crank HP and a DC of 85%.....

I guess when you aim for 550 crank HP should you be looking into 550 ccm@3bar injectors or a bit more for some overhead room.QUOTE]

That is about right but you have to consider can the pump deliver the volume required, in same case you need 2 pump and you can use smaller injectors.
I run the orange ones on 650bhp engine, from memory they are about 550cc, but there is more to be deliver by them on a 2 pump set up, dc is quite low from memory again about 60%

[A80Avant]

do you use that equation of 440@ 3 bar or do you use the 3.8bar that the FPR on the ADU uses to make that assumption?

I mean, 440 @ 3bar = 496cc @ 3.8bar and 510cc @ 4bar

aelred,can you give me the part number on that orange injectors again?

[A80Avant]

orange porsche injectors are rated at 396cc @ 3bar so they are smaller than the 440cc green tops from ford. Im not sure why ultimot lists them as 440cc though

[aelred]

aelred,can you give me the part number on that orange injectors again?

0280 150 971

[A80Avant]

anyone knows any high impedance inj. that go between the 440cc @ 3bar and the siemens deka ones (630cc@3bar)?

[jade]

Hi

I have some RP injectors 3 bar, 524cc they are surplus to need, i got them of Marco, If interested pm me, I will be on the look out for some orange injector or similar

Regards Wayne

[porkkis]

Dekas are good so why not use them? Vems can handle them without problems and probably pretty good base tunes are available if you ask around.

[K7ERG]

i use 575ccm @ 3bar. Siemens deka 55lb injectors from 034. Work well with vems. Just my fuel pump that lets my setup down, but will have it sorted in the next week or so once i change cylinder head. (thats another story though). also a good site to use is www. vmax.de translate it to english and go to injector calculator. Very handy section.

[Bram]

do you use that equation of 440@ 3 bar or do you use the 3.8bar that the FPR on the ADU uses to make that assumption?

I mean, 440 @ 3bar = 496cc @ 3.8bar and 510cc @ 4bar

I think that is correct. I run OEM ABY 4 bar FPR btw and a 044 Bosch motorsport pump

But just stick to the ccm@3bar specifications in order to get an approx max crank HP number guideline for the injector size to choose. HTH

[repo]

ccm = hp in inline 5, but it has nothing to do with 3bar. Ccm in equation needs to be told on the pressure about to be used.

Single 044 pump is good for 550hp tops in our cars.

I've done 560hp from an I4 with a 630 deka and 4 bar fpr, so indeed, why not choose those?

[A80Avant]

i think that is what i will do.
i will get the siemens 60lbs ones

i was always worried of idle problems when the injectors become too big thats the only reason

[kritis17]

I have this problem with the 60lbs siemens dekka on idle, it runs very rich. Do you think it's the injectors or does it need better tuning??