Standard injectors

[DJones]

I cant seem to find it by searching.....

Whats the maximum power that can be achived with standard injectors?

Thanks in advance..

[ericd]

I cant seem to find it by searching.....

Whats the maximum power that can be achived with standard injectors?

Thanks in advance..

At the last RR Meet I came away with 340 on standard injectors, but I'm sure the spec is around 320/330, somebody will come along with the exact answer soon

[donce]

390 hp at 6 bar for 3b ones is theoretically easy to do

[LHD_Kid]

390 hp at 6 bar for 3b ones is theoretically easy to do

Really???????????

I remember Mihnea saying that at 400BHP the valves would be somewhere near the tailpipe...!
I am sure its nearer 330 max.... especially as the 3B has inferior spray pattern to the ABY...
I hope I am wrong, as I could keep my injectors for a while longer then...!

[Audi Parts Guru]

390 hp at 6 bar for 3b ones is theoretically easy to do

The flow difference between 3 bar and 6 bar is very very small indeed

[Jamo]

390 hp at 6 bar for 3b ones is theoretically easy to do

What a load of Bullsh*t, 330 - 340 @ 4 bar is the max you'll get out of them and even that nots healthy as they'll probably be at 100 % duty cycle.

[donce]

The flow difference between 3 bar and 6 bar is very very small indeed

make it like this: 310cc * sqrt(6bar/3bar) = 437cc max flow.
now make it 90% * 437 cc = 393cc
i dont know about the spray level,its just about flow level...

[Jamo]

Slight problem mate, flow rate is not proportional to pressure level.

Search and read the gospel of S2 central.

Plus standard pump will not flow at 6 bar.

[LHD_Kid]

But surely, if you then stick the fuel pressure at 15 Bar, you still will not increase the flow rate.... pressure increases, flow does not.....? Or have I got this concept totally wrong???

[Jamo]

Quote

The RS2 FPR is 3.8 Bar, not 4 Bar. Don't ask why they did it like that but it's not the same as the ABY.

Then, manifold pressure has to be added on top of the fuel pressure, so this means that when there's 2 Bar boost in the intake manifold, the fuel pressure at the injector is 6 Bar absolute with an ABY/AAN FPR. The FPR's rating is 4 Bar relative to whatever pressure it's being fed with, so if it's being fed with 0.5 Bar, you get 3.5 Bar fuel pressure (idle conditions).

The FPR is a linear device that always gives it's rating on top of the pressure it's being fed with, no matter if it's pressure or vacuum.
There's also rising rate FPRs out there that give even more fuel as boost pressure increases.

About 3B injectors, I knew they flow more than the ABYs, however, fuel flow rate increase isn't linear with fuel pressure increase, the actual formula is:

sqrt (newpressure/oldpressure)*old fuel flow= new fuel flow.

The fact is that the single hole of the 3B injectors means a worse fuel spray pattern and fuel particulate atomisation, which means that when an engine is running the same AFRs at WOT with 3B or RS2 injectors, the EGTs on the 3B injectors will be about 40 degree C higher than with the RS2 injectors, BTDT. 40 degree is pretty considerable, when one thinks that between 810 and 850 degs C there's about 20 HP gain/loss, so if one tries to achieve AFR=12.6-12.7:1 in order to get the most power out of the engine, the 3B injectors might be just the slight difference that makes one will have to lose power by running richer mixtures in order to keep the combustion chambers cool.

HTH,

Mihnea

[donce]

Slight problem mate, flow rate is not proportional to pressure level.

Search and read the gospel of S2 central.

Plus standard pump will not flow at 6 bar.

hmmm,cant you "sqrt" in my formula? the same thing is in mihneas post... so my numbers are not wrong...and! we are not speaking about fuel pump,we are interested in injectors now