Injector Question....
 

What is the diff. in injectors early (83-85.5) and late (85.5-on up) 2.5 na.
Will the early injectors work in a late car?

The earlier car injectors have a different part number:
944 606 110 01

The later ones :
944 606 112 01

However, they both use the same seal kit:

944 110 901 00

Suggesting they are physically interchangeable at least.

Whether the flow rate is the same I don't know.

I just put bigger injectors in my 87 944 n/a. The stock injectors are 22#, I went up to 36# for a supercharger project that I am working on. These 36# injectors are Bosch and are not a part number for any Porsche. I put them in, bumped my fuel pressure down and the car runs exactly the same. I think they would work just fine based on the fact that I threw in a totally different injector and a different flow rating and my car is running just fine. Changing the injectors only takes about an hour of time at best.

Try a PM to Sid, Blown944, he has a lot of exeperience with them. He has an 83 and an 86 944.

The reason I'm asking is that I have a friend that has an 87 with a leaking injector. I know it only takes about 30min to replace. I told him I have a complete set the only problem may be is that they are from an 83.

Where is it leaking from? If it's the o-ring you can go to any parts store and get new Bosch o-rings for it.

Kinda figured that one:rolleyes: .... It's leaking out around the lower half of the body (where it's fitted together). Yes it's bad, I found it while tensioning his belts.

I would try the other injectors if it were my car. Espically if they're free. I just paid $250 with shipping for 4 new injectors.

just in case, where did you find them for that much?
I dont want to go screwing up his car, he did make a small donation for doing his belts, burning it up is the last thing I want to do.

The ones I bought are NOT the correct injectors for the car. The stock injectors are 22# injectors, the ones I bought are 36# for a supercharger project. I put the bigger injectors in and bumped down my fuel pressure. No problems.

Try sending a PM to Blown944. He knows a lot about these.

From what I read per clarks-garage.com the injectors should be the same with a minor flow rating difference. That is, they have the same impedence, but the early flows 236.5 cc/min
@ 3 bar while the late injector flows 229 cc/min
@ 3 bar. Negligable? I don't know. It's worth a shot, maybe you could get a secondary fuel pressure regulator and bump your pressure down just a tad and that would work if they weren't a direct bolt up.

That's only a 3% difference in flow. That flow rating is at 100% load 100% of the time, and that never happens in an engine. Now knowing these numbers I think you would be safe running either injector in either MY. I don't think a 3% factor is enough to even worry about adjusting 44 PSI of fuel pressure. Would you take the fuel pressure down 3% also? That would take it down to 42 or 43 PSI. I don't think it would make a difference.

Good job on the homework Brian, I'm a little lazy today... :)

Yeah, I'm pretty sure that the fuel system sees 1psi fluxuations on occasion (or all the time). So I'd just stick them in there and grin! Good luck, keep us posted.

John, I've been out of school for a few weeks now. I had to do some research or I'd loose my self worth!

Just check the ohm resistance between the 2 sets. The shold be about 2.6 ohm+-. Just use a standard multimeter across teh pins on the injectors. I am just saying this to make sure everything is correct. Maybe you could throw some part numbers out here and I can cross reference them for you.

If they are the same the small difference in flow will not be a factor.

Clarks says they have the same impedance, 2.4ohms, but it's always best to check them yourself like Sid outlined; as you always want to be sure before you do the work or have the work done.

The bosch number is on the plastic.

The 83's ohm out 2.8, 87's 2.7
83 B# 0280150201
87 B# 0280150158

put em in they are

229cc for the 158's and
236cc for the 201's

verify here http://users.erols.com/srweiss/tableifc.htm

if it runs richer at all (I seriously don't thiink it will) you can pull 3% from the dme driver via the FQS switch. Look on clarks and wilks for more info.

Cool. I see that if I turn the FQS to position 2 it would take away the 3%. Would this be a safe bet.
I may be hooking my buddy up then (for a very small donation).
As long as they fit size wise.

They'll fit, no question.

I wouldn't worry right away about the FQS, but is there if needed. You would most likely have to have it on a sniffer to tell, especially in the AFM signal range(off idle and not WOT) as the O2 will adjust it out anyway.

I'll give Tim (my buddy) the news. I'll be giving this a shot tomarow. He was not too happy when I told him not to drive the car, but he quickly undrstood when I showed him the leak.

Thanks again blown944