Injectors for 9.5psi turbo (Focus)

[sutyak]

Thinking of running 39# Terminator injectors.

I've come across numerous "calculators" to determine the correct injector size.
One say they're too small and another says they'll provide more than enough fuel.

I figure I'll be looking at around 200hp/200tq @ 9.5psi.
Maybe lower, but doubtfully higher from other dyno graphs I've seen.
I'd like an injector that will support 250hp in case I decide to up the boost.

I guess the question would be does the stock Terminator injector support 500hp?
If not what does it max out at?
I figure I can just divide by 2 and get close to my answer.

Thanks! http://forums.focaljet.com/images/smilies/thumbup.gif

Mark

[Martin0660]

I'm sure you know some of this, but a few questions to get you closer to the answer ;)

Does the Focus use low or high impedance injectors? What about the donor? You can run highs on a low impedance driver, but not lows the other way.

Low impedance injectors can run out to 100% duty cycle, highs not so much.

What fuel pressure are you going to use, what fuel pressure was the donor rated at? (I assume you are going to boost reference your Focus). But base pressure wil laffect an injector size. Here is a sweet little calculato to re-size injectors based on fuel pressure......

http://www.csgnetwork.com/fiflowcalc.html

This calaculators seems to be about right for what i've played with......

http://www.injectorsonline.com/conversion.asp

For reference, the 2.3L low impedance brown tops (35#'s) are good to about 280 HP at stock fuel pressure (39) and will run out to about 300 at 45 psi, and have supported nearly 350 HP at 55 psi base (dont ask how i know ;) )

Based on out experiences with 30#'s in the 2.3's, they max out at something like 180 HP or so, and like I said 330 HP or so for 35#'s. These are low impedance so we have a little edge. In the low impedance world, you can also use 46# and 52# CFI injecotrs as donors.

I know these arent stright answers to your questions, but might get you a little closer.

Bob Myers

[sutyak]

Thanks Bob!
I know they are high impedance. I'll have to ask around about the pressure.

edit: Anybody know the stock fuel pressure for the Terminators? That'll help too.

[Stangman701]

I know the stock cobra injectors are good to at least 500rwhp, and possibly as much as 525-550. Not sure on the other questions though.

[sutyak]

I know the stock cobra injectors are good to at least 500rwhp, and possibly as much as 525-550. Not sure on the other questions though.
I did come across that in my research, but does that include the use of the KB Boost-a-pump?

I've been reading where the Lightnings have 42lb injectors.. anybody know what year and if they will fit the late-model Cobras (which would also fit my Focus) ?

[Stangman701]

I did come across that in my research, but does that include the use of the KB Boost-a-pump?

I've been reading where the Lightnings have 42lb injectors.. anybody know what year and if they will fit the late-model Cobras (which would also fit my Focus) ?

That does include a boost-a-pump, but that has more to do with the fuel pump than the injectors I believe. You could just take out the stock fuel pumps and replace them with larger ones and then you wouldn't need the BAP. FWIW the fully stock fuel system is good to around 480 rwhp I believe.