Emickelsen

REALLY REALLY sorry to bring this up again. One of my injector hose connectors ruptured, so I am going to replace them. Obviously . So I was thinking, again, about just replaceing the injectors all together. I did as much research on Rennlist about this as I could (i'm sure I missed something obvious though). Everything I found was for an '85 or later. Would the Ford injectors (I think part #M-9593-AA302), and most of the related information work for an '83 as well? Anything special for the earlier models and/or anything else I need to know? Thank you in advance, and again, for all your help. Any and all input is greatly appreciated.

danglerb

Unless you update to a new style fuel rail you are pretty much stuck with cleaning and reusing the factory barbed hose injectors, and nothing cheap used them, so they are still expensive new.

One of the regular rennlist vendors has I think a new oring style fuel rail upgrade for the early cars, Carl maybe. Must be a thread on here someplace.

AO

As long as the injectors are working, you shouldn't need to replace them. You could send them to Cruzin Performance in Michigan to get them cleaned if that makes you feel better. The hoses parts should be able to be replace with fuel injection hose and clamps available at most good autoparts stores.

Ducman82

i have a whole set of injectors and rails if ya want them to use. i just did the fuel injector and rail upgrade, so i dont need them.

ROG100

928sRus sell a kit for your injectors - includes the 50mm EFI hoses & clamps plus the two seals - large and small. $56 plus shipping.

Maleficio

MPDano over at Pelican installed Mercedez-Benz injectors, and he loves them. He said he paid $20 each for them.

Tom. M

On ebay..and expensive...but new according to listing...

http://cgi.ebay.com/ebaymotors/8-New...Q5fAccessories

hacker-pschorr

His car is CIS - totally different animal:

http://forums.pelicanparts.com/porsc...ors-today.html

Landseer

What is the electronic injector impedance rule?

Later (LH) can be retrofitted to earlier (L-Jet)? Or the opposite?

G Man

There are newer style injectors available with the correct impedance available for early cars. As stated earlier it is necessary to upgrade the fuel rail set up to be able to use these injectors. Carl has the kits to do this. The cost of one new injector for the L-Jet cars is crazy.

Emickelsen

Damn, shoulda waited. Still might get 'em.

EXCELLENT EXCELLENT STUFF!!! Thank you very much for the input. Sounds like I will be getting them cleaned. What is the average turn around for shipping them out?

hacker-pschorr

L-Jet = High impedance
LH = Low impedance

You can safely use high impedance injectors in a low impedance system. Not the other way around.

In other words, 85+ injectors are safe to use in an L-Jet car (in theory).
I say in theory because the high impedance injectors will not harm the ECU, just not sure how everything will run. I know it has been done with success with other cars, just being cautiously optimistic before trying it with a 928.

Hopefully I'll be testing this soon, 32V rails with 85-86 injectors in a stock L-jet 928.
If anyone would like to be the guinea pig for this, could probably offer a gread deal on the rails / lines. Details are still WIP until after SITM.


The reason is low impedance injectors take more energy to operate, they will overload a high impedance system without a low impedance driver inbetween (which are available). It's not as simple as plugging in a resistor either. Low impedance injectors operate in a "peak and hold" fashion, the LH or other high impedance systems do not.

danglerb

Most modern injectors are high impedance, ala 16 ohms, and only the older ones the low impedance, ala 2 ohm?

The drive power circuits just like stereo amps are built for enough current for a certain minimum impedance load, 2 ohm speakers on an 8 ohm amplifier and it overheats or just poofs. Early cars (some at least) are low impedance, so any injector should work. Newer cars can't use low impedance.

AFAIK there is no issue with a low impedance drive and high impedance injectors, they just draw less current to operate.

*************

As I understand the rail thing, the injector spacing is the same, its mostly a question of sorting out the rail mounting points and plumbing isn't it?

hacker-pschorr

For most production cars yes, not the high performance world.

Once you get much over 42lb - 50lb injectors, you start seeing more low impedance drivers.

Low impedance drivers operate in at "peak and hold" which means a large current is used to yank the injector open, then the current is lowered since less is needed to keep them open.
High impedance injectors need less current and are more like an on / off switch.

Overall you have more control with a low impedance, peak and hold system wich is simply not necessary with the 24lb-ish injectors most production cars use.

I am 99.99999% sure Todd has low impedance 80+lb injectors in his car using Autronic to control them.

danglerb

Since ours are fired all at once, 8 two ohm injectors in parallel driven with 12v is what, about 48 amps?

With 16 ohm I think its just 6 amps.