Low or High Impedance 550 Injectors?

[chriso]

Which style RC Engineering injectors is everybody using on the MKIII. The ones I have are PL8-550 and I was wondering if I have the right ones??? Also, is there supposed to be a pintle cap on the bottom of them where they go into the head?

Also, can someone post a pic of one of these, my camera is dead.

 

[JustAnotherVictim]

Low impedence don't require a resistor, unlike the high impendence. Direct fit. You shouldn't have to modify anything.

 

[chriso]

Low impedence don't require a resistor, unlike the high impendence. Direct fit. You shouldn't have to modify anything.

Whoa, fast reply, thanks but do I have the right ones. I think the SL8-550's are the high impedance ones. RC's web site specify them differently.

 

[JustAnotherVictim]

Yea, as long as it's low impedence they should run no problem. :evil2:

 

[tonysupra]

i just looked at my rc's in my closet and they say pl8-550. But no idea if they're low impedance. I sure hope so.

 

[chriso]

i just looked at my rc's in my closet and they say pl8-550. But no idea if they're low impedance. I sure hope so.

ditto

 

[Doward]

Ohm test them with a DMM.

 

[JustAnotherVictim]

Ohm test them with a DMM.

Yea, that would be the easiest way to tell. It's something like 2.4 ohms IIRC. Don't quote me, but it should be obvious which they are since I believe the high impedence are like 12+.

 

[Jeff Lange]

Low impedence don't require a resistor, unlike the high impendence. Direct fit. You shouldn't have to modify anything.

Umm... sort of right, sort of not.

Low impedance are direct fit, but they do require a resistor. The stock resistor. Using high impedance requires removal of the resistor.

 

[87targa]

i have peak and hold (low impedance) injectors and they work.

i heard that saturated (high impedance) injectors can be installed on low impedance ecu no problem but can't really put low impedance injectors on high impedance ecu. if i'm wrong about that some one correct me please.

 

[suprra_girl]

Low impedence don't require a resistor, unlike the high impendence. Direct fit. You shouldn't have to modify anything.

almost
but backwards high don't need resistor, low do

test them with a multimeter, that'll soon tell you what they are

if they're low, bolt em in
if they're high, bolt em in but bypass the resistor

 

[Doward]

It depends on the injector driver, and what it is capable of, from the ECM.

P&H (low impedence) generally allow for bigger injectors with a better idle than big saturated (high impredence) injectors, in my experience.

 

[figgie]

It depends on the injector driver, and what it is capable of, from the ECM.

P&H (low impedence) generally allow for bigger injectors with a better idle than big saturated (high impredence) injectors, in my experience.

well we are talking stock TCCS which does in fact require the resistor ballast for low impedance injectors

 

[JustAnotherVictim]

Umm... sort of right, sort of not.

Low impedance are direct fit, but they do require a resistor. The stock resistor. Using high impedance requires removal of the resistor.

Are you sure? Don't the stock turbo's come with low impedence injectors already? I could swear only the later N/A's had high impedence and that was the only time you had to change anything.
I.E. how the Rx-7 550's are a direct fit but the have the high and low impedence injectors. I know people who have used them without modifying anything. Unless the RC's have a different ohm reading than the Rx-7's. I'll see if I can find where I saw that.

Edit: You're getting too technical there Jeff. All I was saying was he shouldn't have to modify anything to make low impedence work, I wasn't saying he should take out the stock resistor.

 

[Doward]

well we are talking stock TCCS which does in fact require the resistor ballast for low impedance injectors

Too true - I didn't know for certain if it had the resistor or not, so I figured I'd give good info, and err on the side of caution :biglaugh:

 

[87_7MGTE]

how do you bypass the resistor in order to use high imp. injectors? is there something i jump where you unplug the resistor? or do you just wire them straight to 12 volts, im assuming this is what happens when you jumper the harness. hope that made sense.

EDIT: In the past when i had the stock ecu, i dropped some highx 550s in with the resistor in place but it didnt seem to have any ill effects. was something actually going on that i didnt know about?

EDIT#2: nm, found it. just in case anyone wants to know: http://www.supraforums.com/forum/showthread.php?t=343516

and if you dont have access to SF, it says splice all 4 wires together to bypass the resistor for highx injectors.

 

[JustAnotherVictim]

if they're low, bolt em in
if they're high, bolt em in but bypass the resistor

That's what I was saying, at least that's what I thought I was saying.

The MKIII turbo (and early NAs) use low impedance (3-4 Ohms) or "peak and hold" style injectors. High impedance (13-16 Ohms) or "saturated" injectors are the other kind. Peak and hold injectors are a bit faster acting than saturated and are therefore more desireable.

It is possible to use high impedance injectors in a low impedance system. However it is NOT possible to use low impedance injectors in a high impedance system (simple circuits->too much current flow = fried injector drivers)

So like I was trying to say you shouldn't have to modify anything if they are low impedence.

http://www.supras.com/06/techcenter/display.php?QID=21

 

[SublimeSupra]

Wow thanx for the info 87 7mgte i learned alot about injectors :icon_bigg i mean forum link err you know what i mean.