I know its well discussed, but can someone show me how to calculate which injectors I need?

HRC Tubro Kit Stage 2 with FMIC APEX'i Intercooler
9.5:1 JE Pistons, Crower Rods
I have a SAFC and the Fuel Pressure Regulator that came with the Kit.

So far, I was running my SAFC 20% Lean across the band @ a fuel pressure of 90-100psi (under boost) at 10psi Boost for a perfect A/F mixture. All of this on Stock injectors with the biggest baddest Holley (Walbro) intank fuel pump.

As I have kept my compression ratio roughly the same, I figure that with the boost turned up to about 16-18psi my stock fuel injectors can still handle it. Very Riskily though - I know.

That's why I want new injectors, and I would like to know any formulae or ideas/tips on how to calculate what I need, and what I might ever need...

Also could someone explain why I would ever need an aftermarket ECU for controlling injectors...

Thanks guys,

Guy
RS_Guy



13.9sec @ 105mph passes
w/ Blown piston rings,
on Stock Internals
at 10psi Boost....

Stupid of me....
I didn't see the link to this website on another post...
http://www.rceng.com/technical.htm

Why I can run my ECU lean @10psi boost is still baffling me....
Maybe I can make some sense out of these equations...




13.9sec @ 105mph passes
w/ Blown piston rings,
on Stock Internals
at 10psi Boost....

check out RC engineering's site .. www.rceng.com

The only reason you'd need a seperate computer to control your injectors is if you have the need to run something SO LARGE that the combination of the SAFC and the stock ECU just can't handle it... Like 700cc/min injectors :-)

-DarkOne
I'm so bad, i should be in detention.

Thanks for answering the "Fuel Controller" unit question.
Very clear!



13.9sec @ 105mph passes
w/ Blown piston rings,
on Stock Internals
at 10psi Boost....

WOw, that's high compression...how does your engine hold up with boost??


l e o n

At 10psi the engine was holding up to boost just fine, until at the track, some blow-by poured all the oil out of my engine.

It seems that lots of us seem to have problems with blow-by on stock engine internals. What exactly causes this, I dunno.. My car had about 95K miles before boosting...

Guy
RS_Guy



13.9sec @ 105mph passes
w/ Blown piston rings,
on Stock Internals
at 10psi Boost....

So, your running a Walbro in-tank fuel pump, and still leaning back the to get a good Air/fuel? I new it ran rich,, just didn't know htat much :)
I'm running about .96+v @ 7psi of boost. I haven't trimmed out the AFC yet.
man I'm lazy :)
Wyatt Leras
http://www.turbogs.com
98 Eclipse GS Star Stage 5,000 Turbo kit

LAST EDITED ON 01-Mar-01 AT 12:57 PM (PST)

OK, looking back at the receipt for my fuel pump...

It is a Holley (a repackaged Walbro) and yes I overpayed for the
"name", but I needed it pronto. I don't have the regular 255lph
in-tank. I ordered Model #12-918 "255 LPH Forced Induction".

This is what Holley Has to say about it:

New this year are 255 liter-per-hour-rated "forced induction"
pumps. These new pumps flow significantly more fuel at higher
pressure. For example, at 80 PSI the standard 255 lph pump will
flow around 132 liters (35 gallons) per hour. At that same 80 PSI
the equivalent forced induction fuel pump will flow over 210
liters (50 gallons) per hour.

I'd call it a good deal, considering it cost pretty much the same
as the "regular 255LPH".

http://www.holley.com/HiOctn/ProdLine/Products/FMS/FMSFP/InTank.html

That might also explain why it makes that WHINING sound...

Guy
RS_Guy



13.9sec @ 105mph passes
w/ Blown piston rings,
on Stock Internals
at 10psi Boost....

I think that holley pump is the GSS342 (the walbro 255 HIGH PRESSURE pump).



l e o n