Bill Ball

You would not the first person to think so or the last to have rip-roaring fuel fire. There is some space below the injector tip in the manifold and the injector can get pushed down by fuel pressure and pop out of the rail. Seen it happen with stock injectors. If these are the same length, I would expect the same problem. I'm very careful to make sure the clips are seated properly.

Hilton - I appreciate the research including the PN's for the Bosch Design III stock flow rate injectors. I'm going to try some.

Landseer

EXCEPTIONAL thread. Thank you for this.

76FJ55

Roush Yates has the 30 lb M-9593-BB302 listed for $199 and 24 lb at $169 (no upper groove in the 24 lb).

928mac

Bill, are the injectors able to bottom out or will they push down to far.
The reason I ask is that I bought some fuel rails that do not have the supports for the clips.
I thought that I would be able to adjust the hight of the rail, but I never thought or heard of the injector pushing down until now.

Hilton

Brad, on an S4 the injectors can be pushed down too far. That's why I started this thread about fitment and subsequently began tracking down injectors with the groove to keep using the stock clips that hold the injectors to the fuel rail.

Its a secure system, and there have been reports here on Rennlist of fuel leaks caused by not seating the clips properly, or leaving them off, hence my preference for the grooves

Try it - stick your intake on top of a head and push the injector downwards into the intake port - if the large o-ring passes through the hole in the intake and leaves a gap, there's a possible leak.

You may also want to read this thread.

Z

I can think of around half a dozen instances that I know of where fires occured because of the clips not being installed by owners. They forgot one or more, installed them incorrectly, or didn't think that they were needed. One of them was a 5-speed GTS with around 13,000 miles on it, and looked like a brand new car before the fire. If it were me, I'd go with a design of injector that doesn't require you to do any cutting, fuel rails that hold those injectors well, and also make sure that the fuel rails are securely attached to the engine .

blazing928

Hilton,
i have the full yellow type, RH photo- post 1, 4 hole , purchased from fiveomotorsports .
I thought it had a metal band at the top, but know I am not sure, so I think i will have to pull the fuel rail off to check they are secure.
I think now that the clip secures it over the plastic band and that stops it coming out. From memory they were secure, now I am worried!

the spare Oring I have ffrom them, measures at 16.8mm OD and about 7.9mmID


update:

Ok had a real close look, the plastic band on the top of the GenIII , all singing and dancing yellow model, will stop the injector pulling out.
The clip slot fits into the fuel rail and there is no way, IMHO, the injector could be pushed out of the fuel rail.
Now maybe the clip is under some pressure as it is not in a groove, but i can't see how it could pop off.
Opinions welcome!

Hilton

I just bought a bunch of 0 280 155 746 (design III 19LB) injectors used (the Volvo ones from post #14's list) which have the correct grooves.

Buying some new caps, o-rings and filters for them, and will install them in my 87 when its getting TBWP and intake refresh imminently.

I'll post up fitment pics etc. when I have the fuel rails off the car and injectors in hand.

Nigel - I have some of the design III's shown in the first post's picture too - I'll compare and take photos of both design III styles to add to this thread when I have the bits handy.

If the design III's fit as I expect, I'll buy some of the 30lb ones for my '89.

Question for anyone with design III injectors - does the dwell time difference between the pintle and disc types affect the tune? (i.e. make the car run noticeably richer due to the slightly longer open duration with the disc type?). I suspect I may have to sharktune the stock motors too with the disc injectors Need to buy a cable to fit the 87's diagnostic ports with the STII

dprantl

Although I am currently running design II injectors, my research into newer injectors has led me to believe that the stock opening time of 0.94ms that the 928 LH is programmed for is way too large. For example, Ford Motorsports M-9593-C302 19lb injectors are specced for an opening time of 0.77ms @ 55psi fuel pressure. M-9593-A302 24lb injectors are 0.71ms @ 55psi! I believe these are all design II, but I would be surprised if the III's were much closer to the stock 0.94ms, if not further.

Dan
'91 928GT S/C 475hp/460lb.ft

White Lightnin'

So, if I am reading this thread correctly... this one is the injector in the pic on post #13 and the last pic in post #6? This would be the newer design, but all other specs would be compatible with a N/A street car?

Hilton

They're 30lb injectors.. the stock injectors for an S4 are 19lb.

I will need the 30lb ones in post 13 for a modified NA engine and will sharktune to compensate for the change.

In the short term I've decided to try fitting some yellow 19lb versions of the newer design to one of my 87 S4's.. the ones in bold below. I'll probably sharktune that car too, once I've had a chance to test fitment, and log AF.

PorKen

I don't know about the III's, but the metal body disc type outflow the stock pintles by a small amount at full duty. (I watched this on my rebuilder guy's injector flow bench.)

Interesting. I found that reducing the injector voltage compensation (= open time) with the higher pressure used with my S3 chips made the transition from throttle closed to throttle open smoother. IE. no hiccup from decel to/from slight throttle.

Landseer

Just ordered these for the 85/6 S3 ---
0 280 155 931 (Bosch)
packaged as--
M-9593-AA302 (Ford Racing)
(I think this is consistent with Simon's posts above)

http://www.blueovalindustries.com/en7400.html

Blue Oval guy confirmed they are EV6 (Design III) with EV1 connector (I think compatible w/ our harness).

Edits: In bosch-speak, our cars use the long body injector (both S4 and 85/6 32V). This particular set of 0 280 155 931 units seem to be rated at about 26.6lbs, though called 24 lbs.

I think I will need to cut an appropriate slot closer to the rail to accept the clips.
Might need a set of O-rings, TBD.
(Alternately, the 0 280 156 013 might be similar flow, and might have upper slots pre-cut, but it must not be in-demand because I could't find it at near the price and description was sketchy.) (EDIT 5/3/2011, more on this later at post 54)

Might also need to revert back to the stock FPR (am running 87 FPR right now) based on conversation just above. Car has Ken's chipset matched for that higher pressure w/ stock injectors. Not sure how this will end-up. Maybe I should ship the injectors to Ken instead!

Cross references of Bosch # suggested these are used for 2001-02 Camaro; 2001-2004 Corvette as well.

This Aussie Jeep thread had some good info about halfway through the post that led me towards them --- and if they don't work on the 928 I'll install them on my son's wrangler.

http://www.ausjeepoffroad.com/forum/...ad.php?t=92236


More to follow when they arrive early next week.


Great thread Hilton, hope this post is on-point, can eliminate if you prefer.

dprantl

Actually, with a higher fuel pressure, you need a slightly larger injector opening time because it is more difficult for the injector to open with that extra pressure behind it. When I switched from a 36psi regulator to a 55psi, I had to up the opening time on my 42lb injectors (M-9593-F302) from 0.79ms to 0.85ms as specified in the Ford Motorsports spec sheet for my injectors. Of course I had to modify the maps too.

Dan
'91 928GT S/C 475hp/460lb.ft

Hilton

Cool, very on-topic and please post pictures of them sticking in the rail etc. when you get them Tracking info for the 19lb ones I bought still shows them somewhere in the Bay Area in CA.

I came across the Ford Racing ones but didn't post their part no in post 14 as they're missing the upper groove.

The cheapest 0 280 156 013 I could find was $288 for a set of 8, so for $100 saving it's worth dremelling them.