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Discussion Starter #1
on the dsm sites ,i have seen mention of 625cc injectors.
for applications such as julians (super l) or anyone running close to the limit of the standard injectors,
can you do the calculations please for the required drop in base pressure to get to the same fuelling as the std injectors are now.
you told me that to fit 680cc ,it would need a drop of 47%,but this makes the base pressure too low.
and finding the info required to map the ecu to suit is proving difficult,not just for me,for everyone it seems.
why is this bit so complicated ?????
i am just thinking that maybe the 625 might just fit the bill for those of us not going any further.
p.s. my turbo is a 15 ,yes

Discussion Starter #3
Use this equation to calculate injector sizing vs. base fuel pressure.

Size_1 * Sqrt_Pressure1 |EQU| Size_2 * Sqrt_Pressure2

So for 625cc/min fuel pressure|EQU|? to match standard injector flow (ie. no ecu map changes)

Standard is 560cc/min with 3bar (43.5psi) (Correct me is this is not right)

So Pressure_2 |EQU| ((560*Sqrt43.5)/625)^2 |EQU| 34.9psi

Or the other way round
What base fuel pressure is required to get 625cc/min flow capacity from the standard injectors

P2 |EQU| ((625*Sqrt43.5)/560)^2 |EQU| 54.2psi

This would need to be tested on a RR with a wide band lambda sensor as any irregularities in the fuel system could affect the final flow. Especially when raising the pressure - you know all about the fuel restrictions! Good old VFAQ!

BTW - make sure the injector size rating is at the usual 3 bar when purchasing.

A compressor map for your turbo would be interesting. Seems to make better power than the 16g6.
I'll have a search of Japanese sites some time.

Discussion Starter #4
Personally I'd go for Nippon Denso unmolested injectors.

Not everyone in the DSM world likes RC's.

Discussion Starter #6
Lightspeed, where do you get the Nippondenso ones from (other than SARD)?

WHat is flow limit (HP) for the standard injector (if the pipework is fixed)?
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