mspiegle

To be honest with you... I have a list of about 7-8 "dumb" things that were done on my car (some on accident, some on purpose)...

Among those things... when I first had my kit running (first 85/86 prototype), I ran without a bypass valve for a few months. It should go without saying, but it only caused issues at idle. My idle was pretty rough and the engine would "rock" somewhat in the enginebay. It also made the car "louder" than necessary. I can't quite recall, but it may have also added some difficulty when starting the car.

After I got a bypass valve and everything was sorted out... the car still made 350rwhp on 5psi (eaton/noic) with perfect air fuel ratio and good compression (except for 1 cyl that was busted before the install). The car made a 1,000 mile (roundtrip) to Devek and back and never even hiccuped.

All i'm saying is that you're prolly ok to do it for a day... or 2

Bill Ball

Hey, here's another topic....

I can't find the note now, but didn't Andy or someone else indicate that the pulleys used on the Jag/Eaton have been changed and won't work with the quick-change mount I got? What do I do for pulleys and where do I get them if I want to go up to 6 or 7 lbs.?

mspiegle

eaton pullies are fun... here goes...


If you have a stock jag/eaton, you can do one of 3 things:
1: Use the pulley that came with it
2: Use an upgraded cobra pulley
3: Have a pulley custom made

Regarding #2, there are a few issues:
Issue 1: The jag/eaton supercharger has a different offset than the cobra/eaton. If you use a cobra pulley, it won't fit perfectly and may or may-not cause damage in the long-run. I ran my jag/eaton SC with a cobra pulley for at least 5K miles and the SC unit didn't appear to have any issues with it.

Issue 2: Since the offsets are different, there may have been a slight issue regarding alignment of the SC pulley in relation to the crank pulley. I don't recall exactly what this issue was, but I was able to get it running with slight modifications.

Issue 3: Cobra pulleys don't get much smaller than the pulley that comes stock w/ the jag/eaton. My guess is that cobras use a large crank pulley than the 928 does. IIRC - the smallest pulley I could find made 5psi on my 85/86 (stock jag/eaton pulley is 4psi).




Now comes Andy's quick-change adapter:
Once you press the quick-change adapter onto your SC, you will essentially be using the twinscrew pullies which come in an abundant number of sizes. The only drawback is that you need to get the pullies from Andy since he has to specially modify them to work with the quick-change adapter that he designed.

Bill Ball

Mike - thanks for the answer. I should have ordered some extra pullies from Andy I guess, unless the machining is something I can have done locally. I'll get some pullies and have a look. Thanks again.

Daryl

Thanks Mike,
I was thinking for just a few minutes at idle. Long enough to pull the injector wire on the suspect cylinder. If it also causes other engine running issues then it may not help anyway.

Bill, did you mention that your engine runs great when cold? That’s the way mine is. How can I trick the computer into thinking the engine is cold? That may give us at least an idea if it’s to lean or rich as John pointed out. If it smoothes out when doing this I will check the bad cylinder and see what difference it makes when I remove the injector wire. If that corrects it I am inclined to go with the higher fuel pressure and re-chipping the computer.

BrianG

Daryl & Mike:
If the theory that the culprit cylinder #6 or #7 is running lean, how about just cranking up the fuel pressure to see if the idle smooths out, as a diagnostic test. Since Daryl pointed out that this would be the "fix" he would use if this were found to be the case, you could do what we do in health care, which is what we call a "therapeutic trial". That is, "assume" the diagnosis, and test the assumption by applying the appropriate "treatment".

I fear that you are going to stumble across another health care situation in this case, however. That is something we call "untoward side effect". If you are right in your assumption of the culprit cylinder being lean, in the face of a good sampled total A/F ratio, enricheniing it by elevating the fuel pressure is going to push the rest of the systen rich, even if it feels better at idle.

Daryl

I don’t know if these pictures helps with questions regarding pulleys on the Eaton SC. The first is the way my SC was shipped. The pulley was way out of alignment. The second picture shows the 8 lbs boost pulley with a piece that pushes on to the SC shaft then the pulley bolts to it. Last picture shows the extended pulley that now lines up with the crank pulley.

John Speake

You will only be able to "fool" the mixture rich at idle when the car is running open loop with no O2 sensor active.

Otherwise - assuming the loop is holding the A/F at 14.7:1 then changes to the fuel pressure will be compensated for, and the loop will hold the A/F at 14.7 until you get to the point that the loop gets out of its range.

Daryl, I seem to remember that you told me you tried running open loop once ?

FlyingDog

If I understand how the bypass works, wouldn't #7 be running rich when the bypass is open? Wouldn't it be taking air from the manifold (near #7) and sending it to before the SC where it would pass through again and be distributed to all cylinders? With all the bypass air coming from near #7, that should have less air and run rich... right?

Daryl

Hi Brian,
In a previous post by John Speaks he alludes to the fact that our injectors are built to run at 43 lbs not 30 lbs as we are. He thinks the spray pattern may not be as it should in that case. I am thinking that alone could make the difference to cause this slight idle problem in an area that there may be a little turbulence caused by the bypass. Remember this is a minor problem only at idle. You might even say nit picking. Off idle I think the extra air movement corrects this. The engine runs perfectly and smoothly. Which says to me the air/fuel must be pretty good across the board. The spark plugs show this as well. In Johns post he alludes to the fact that the sharktuner can tune the existing computer to handle the increased pressure and provide the proper air/fuel at idle, cruise, and full power. That is just my gut thinking on this and I could be totally off base.
I could easily live with this and I am sure most people wouldn’t even notice but I know it’s there and would like to make it as close to perfect as possible.

In my case my fuel regulator is not adjustable.

FlyingDog

All pre-87 L-jet and LH-jet cars run at that pressure. Most fuel injected european cars run 2.5bar or lower fuel pressure regulators. Very few run as high as the 3.8bar regulator on S4s. I doubt that's the problem.

Daryl

Hi Matt and John,
I don't know if it is running rich or lean. All I can tell you is that the engine runs perfectly when it’s cold. When it warms to operating temp it starts to idle a little rougher. My thinking is if I could trick the computer into thinking the engine is cold just long enough to see if the engine idle improves. This might give us a clue as to if it is running rich or lean.

John,
Before I installed the SC my car was running in open loop. After the install it ran very rich. My a/f readings were in the 12s and low 13s across the board. It ran surprising well considering how rich it was but lacked the power I am getting today. I changed the pins so the computer would run closed loop and connected my O2 sensor to the O2 plug at the fuse panel. That’s as far as I have gone to date.

Daryl

Matt,
Are you aware we are running these injectors at 30 lbs pressure? They are designed to run at 43 lbs

Brand: Ford Racing Performance Parts
Product Line: Ford Racing High Flow Fuel Injectors
Injector Advertised Flow Rate (lbs/hr): 30
Injector Advertised Flow Rate (cc/min): 309
Quantity: Sold as a set of 8.
Injector Impedance: 11-18 ohms
Driver Type: 12V saturated circuit
Overall Height (in): 3.045
Seat to Seat Height (in): 2.563
Manifold O-Ring Outside Diameter (in): 0.545
Fuel Rail O-Ring Outside Diameter (in): 0.523
Outside Diameter (in): 0.982
Injector Plug Style: Bosch/Amp Style
Wiring Harness Included: No
O-Rings Included: Yes

Rick Carter

http://www.southfloridapulleyhq.com/index.html has an interchangeable pulley system that a machine shop should be able to machine the nose of your SC to accept. I think my Eaton SC takes a Kenny Bell pulley. A spacer had to put on the nose to bring it out far enough to line up with the crank pulley.

FlyingDog

All Bosch injectors are specified at 3bar or 43.5psi. They are designed to run at a wide variaety of pressures, to be consistant they test the flow rates at one pressure, 3bar. All pre-87 L-jet and LH-jet 928s have 2.5bar/36psi regulators that (should) run 30psi at idle. That is normal for fuel injected cars. Porsche is odd in running pressures as high as 3.8bar/55psi. Some GM TPI engines are over 50psi, but most American and European injected engines are 3bar or less. Mustangs, Neons, and OBD I Jeeps that run the same (19 or 24lb version) Ford/Bosch injectors you are running are 32-39psi (2.7bar regulator).

BTW, if you want to test the low idle fuel pressure theory, plug the vacuum line that goes to your regulator. That will give you 36psi up until the BEGI kicks in. That's the way Kibort runs his car (although I assume he is running a 3.8bar S4 regulator). You'll have higher idle fuel pressure than the cars that use your injectors from the factory.