DirtyJohn

iTrader: (8)

So I bought a set of "flow matched" lucas delphi 42# injectors and have been running them fine for about a month.
I still have some decel rich issues to work out but other than that they seem ok.

Before the injectors were shipped, the reseller flow matched them on their bench and included the numbers in a printout...


If I average out the lb/hr flow rate on the sheet it comes to 46.05 lb/hr @ 43.5 PSI.
The advertised flow rate for these are 42.9 lb/hr and I used that number in my computation for my IFR.
Just for fun I plugged in the calculated IFR from the popular excel file with the 46.05 rating and the car didn't like it (obviously).

If you could choose, would you go with the advertised numbers or tune around the actual tested numbers?

Any thoughts appreciated.

Thanks,
~T

jimmyblue

iTrader: (11)

If I trusted the test fuel pressure was accurate, I
would then use the test numbers. You have to
trust that they measured the test jig pressure at
some point during flow delivery and not just read
an indicator **** or something.

But I think your decel issue pertains more to the
injector offset characteristics, minimum allowed
pulse width and short pulse adders than the IFR.
Full-on flow is the easy part to get; short-pulse
info is slim and short pulse data, good enough to
fully populate the offset table, is none. Unless you
are using a Delphi injector off a vehicle that uses
a similar offset table scheme and someone can
read that table out for you.

DirtyJohn

iTrader: (8)

Thanks alot Jimmy.

I'm feeling like I do trust em. They are a vendor, and they DO offer injector services...
That could be a little naive I suppose but I may just try and get the car running with those computed IFR values from their test results.

As far as the offsets and Min pw issue, I've spent plenty of time trying to find a known good for these Lucas/Delphi 42# injectors and can't come up with anyone that has a "solid" set of data on the offsets OR min pulse widths for that matter. I have read at least twice that they misfire around 1.7 msec. So that could be my known good bottom to shoot for.

I tell you what I DID try tho,
I took the:
Injector Offsets, Min Injector Pulse, Default Injector Pulse, and Transient min fuel milligrams and subtracted 10%, 20% and 30% from all of the above to see if it made a difference.

I started with 20% and idle became very unsteady, then tried 10% and it was still unsteady, so I gave up.

I prob should have given it more time or recorded more data, but it looked like rain and I figured Id have alot of adjustments to make with all those table changes to determine if those were good or not.

I'd like to try that approach again once I get some time and see if I can make it run and decel ok with different offsets and pw's.

NEways, thanks for the comments.

If you or someone ever come up with a perfect offset and pw calculator for these popular after market injectors, I imagine you'll be a wealthy man.

~T