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Cole,

For what it is worth, I very much like your approach. I am just not a big fan of jumping up to a modified fuel head. It takes a fair amount of work arounds to tame it.

I still have good hopes for the AMG/MBZ style metering plate for delivering a better fuel curve and more fuel up top. If it works, it would be such a simple, elegant, and efficient solution for all but the largest boost junkies.

Again, getting full range of movement of the metering arm is good for 'at least' one point higher AFR and from what I believe, even more. Andial, Rice, and others have done this by lowering control pressure. Lowering CP is one way but you should be able to also do this mechanically (hinge mod or metering plate mod).

Old 04-19-2009, 11:13 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #181 (permalink)
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Keith,

I wanted to tell you how much I appreciate the thread and your input. I talked with Rice and found him to be very CIS savey, Nice man and lots of experience. I have a couple of his articles around here some place I'l scan and post them later. Some good food for thought in them.
I can appreciate all the hard work that has gone into the many different devices made to elevate the CIS's capabilities. My thing is they all seem to be directed to more fuel and I am not convinced it's really not an issue in most applications. The average mods most of us have done to our cars might yield another 25-75 HP and that doesn't seem to me it would require more fuel than these fuel heads can provide as they are. I see the IA mod threads and they seem to cause more richness and drivability problems that they are worth. I want 11.9 - 121 afr's at 5600 on full boost but not at the cost of street ability and black smoke in the mid range. We even have people re shimming pressure regulators to lean them out. I think lowering system pressure is going to bite you in the a-- elsewhere.
Modifying the air metering unit is limited by the casting and not understanding the complexities of the inner contouring. Don't mind experimenting with the velocity cone and metering plate but hesitate go any deeper, machining etc.
My theory is KISS "keep it simple stupid" I use the MSD to get a good, clean, hot multiple spark and the boost retard to dial up more initial advance to get her launched and then back the timing down when boost comes on to stop detonation. Use a DWR to manipulate the afr curve and cut back the mid range richness and pour the fuel to her on the big end. Once the system has been tuned you can build multiple maps to load for any type driving you want to do.
KISS !!!

Cole
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Cole - 80 930 "The Old Sled"
Mods: TurboKraft Custom IC, 934 Headers, GSX 61, Zork, Port Work, SC Cams, Air Mod Fuel Dist Relocated, Water Meth Injection, BL WUR, MSD 6530, Greddy EBC, Synapse Bov, Short 2nd & 3rd with 8:37 R&P, Wevo Shifter, Coupling, and Mounts, MTX-L SSI-4, Big Brakes, Rebel Coilovers, Bilstein Sports.

Last edited by cole930; 04-28-2009 at 06:32 PM..
Old 04-19-2009, 12:26 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #182 (permalink)
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Well guys I got the fuel head back today. The air mods is done and Steve assures me the control plunger has full travel. I noticed some machining on both the top and bottom profiles of the venturi "cone". It wasn't opened up to a larger diameter, it looks like the angle was changed. The velocity cone is installed and shes ready to rock and roll. Here are a couple pics.






Cole
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Cole - 80 930 "The Old Sled"
Mods: TurboKraft Custom IC, 934 Headers, GSX 61, Zork, Port Work, SC Cams, Air Mod Fuel Dist Relocated, Water Meth Injection, BL WUR, MSD 6530, Greddy EBC, Synapse Bov, Short 2nd & 3rd with 8:37 R&P, Wevo Shifter, Coupling, and Mounts, MTX-L SSI-4, Big Brakes, Rebel Coilovers, Bilstein Sports.

Last edited by cole930; 04-28-2009 at 09:35 PM..
Old 04-28-2009, 06:45 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #183 (permalink)
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Cole,

Two thoughts.

First, I belive the new metering plate is not suposed to be put on top of the original. It is a replacement. That dose not mean it may not work. Just not as intended.

Second, what dose Steve mean by you have full pin travel? Dose this mean he has blueprinted the castings under the head? Dose it mean the new metering plate will no longer stall so you get full travel? There not being anything keeping the pin from reaching full travel is usally not the issue, keeping the metering plate from stalling is.

The best.
Old 04-29-2009, 10:35 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #184 (permalink)
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Just my thought...
If the origonal metering plate was not there it looks like there would be about a 1/4" air gap all the way around that smaller diameter convex one.

There's not alot of air being sucked through there at starter motor speed and I don't think the metering plate would move one little bit to turn the pumps on or send any fuel to the injectors with just that smaller diameter convex curved one in there. The intake air would just flow around the disc and through that huge round air gap not moving it at all.

I don't think you would ever get the car to start without the factory disc in there along with the smaller diameter convex one.

The fuel distributor sends absolutely no fuel to the injectors until the metering plate moves downward around a millimeter or two - while pushing the control plunger upward in the fuel head less than a millimeter.
I have checked that with the injectors removed from the ends of the metal lines so there was no resistance to fuel flow from the fuel head, and no fuel dripped from the lines while the pumps ran and the metering plate was at rest.

When the fuel head is removed from the cast aluminum air flow meter housing you can see the counterweight on the arm in there over to the right side, and also see and feel where it comes up and contacts two little lumps of aluminum on the inside of the casting that act as stops when the metering plate is pushed down as far as it will go.

I havn't tried it, but you could easily get a small cut off wheel in there on a die grinder and grind some aluminum off those two raised contact points or counterweight travel stops.
Then the counterweights could go higher before hitting the inside of the casting so the metering plate can go down farther and push the control plunger higher in the fuel head.. possibly exposing more of the metering slits in the control plunger cylinder and sending more fuel to the injectors.

I'm not taking a chance of screwing mine up by trying that though..
I would like to try one of those convex discs on top of the metering plate.
Old 04-29-2009, 11:14 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #185 (permalink)
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I went to a lot of work taking the metering assimbly apart to blue print of my metering arm travel so the pin could travel as far as possible. Did not help one bit that I could verify.

Even with a dramatic lowering of Control Pressure using the Andial Fueler frequency valve I still believe the metering plate stalls. This was supported by Lee Rice of the Rice Fueler who told me that even w lower control pressure he could run up a 930 on a dyno and flood it by pushing down the metering plate w a long screw driver. I just believe the MP stalls due to the design of the cone it rides in.

As to the metering plate, it sure would not hurt to try. If the AFR's do not look right then it could be experimented.

I believe why the new plate has the increased clearance around it is that the added profile above the plate pushes down on the plate and the way the air is accelerated over it also helps move it. Thus, to slow the plate down at idle and off idle the diameter had to be reduced to dump some air at first.

A side thought, with the plate moving less at first, the metering pin can be readjusted. This will give more fuel up top when the arm moves to its furthest position. This can be tried w/o the plate by setting idle fat. Such adjustment translates to more fuel up top.

Another way to say it, if we set the head adjustment to full rich, then trimed the MP plate back to spill air so a proper CO could again be reached, we would get more fuel up top.

I can not wait to see how the new plate works. Wish we could do AFR's w the stock plate then the modified plate.

Good stuff.
Old 04-29-2009, 11:40 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #186 (permalink)
 
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Keith & J,

Steve does not, understandably, reveal all he does. I respect his position and therefore would not reveal anything even if I knew without asking Steve's blessing first.
We are dealing with two different issues here.
No# 1 I ask Steve to do his magic on allowing the unit to pass more air. I do not know what he did except you can see where the inside and outside of the cones castings has been machined. The diameter of the opening was not enlarged but the angles were either cut back or the angle changed. He also does a modification to the metering plate arm assy. although it does not appear to be repined to a different position. One of the benefits of doing the air mod is it allows full travel of the plunger and give full fuel availability to the injectors.

No. 2 I gave Steve the velocity cone and the metering plate that came with it. I asked him to look at it and give me his opinion as to it being of any value to the system. His opinion was that the height and shape of the velocity cone would possibly be a benefit to better air flow/distribution and plate movement. He could not flow it without having to make a special fixture to get it on his flow bench so we will just have to wait and see what it does.

I am sure the cone mounts on top of the metering plate. I got the metering plate with the velocity cone. I also called one of the originators of the cone and ask specifically if you use the cone on top of the plate and he confirmed that you do.

Cole
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Cole - 80 930 "The Old Sled"
Mods: TurboKraft Custom IC, 934 Headers, GSX 61, Zork, Port Work, SC Cams, Air Mod Fuel Dist Relocated, Water Meth Injection, BL WUR, MSD 6530, Greddy EBC, Synapse Bov, Short 2nd & 3rd with 8:37 R&P, Wevo Shifter, Coupling, and Mounts, MTX-L SSI-4, Big Brakes, Rebel Coilovers, Bilstein Sports.

Last edited by cole930; 04-29-2009 at 04:14 PM..
Old 04-29-2009, 01:59 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #187 (permalink)
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Cole,

Thanks for sharing.

Interesting stuff if he is re-profiling the cone the metering plate rides in. If so, that would be the best way to reset the AFR curves. Only other builder I have heard of doing this deep may be Scargo for the NA CIS motors.

I have been wrong before and will be again. If you talked to the makers of the velocity plate then you must have it right.

Hope everything works out well.

The best.
Old 04-29-2009, 02:13 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #188 (permalink)
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"you can see where the inside and outside of the cons castings has been machined"

Hi Cole, I know that you said you wouldn't mention what all he did to your CIS housing, but I'm really curious what you meant by "cons castings"

I don't think anyone ever modified the pivot point of the arm inside the housing.

If you ever remove the housing from the intake manifold and look in there you will see that the cast aluminum arm is pretty elaborate and precise and then there is another hinged smaller arm on top of it for the CO adjustment.
At the far end of the arm there is a counterweight so the arm and sensor plate actually balance in there.

Here's why I don't think anyone ever changed the pivot point of the arm, and it would be practiaclly impossible unless you redesigned and refabricated the whole thing...

When you look at the cast aluminum arm and the bosses in the upper half of the housing that the bearings are inserted into, and the counterweight you can see it would be next to impossible to move the bearings and pivot point of the arm without destroying the housing and the integrity of the arm.

When you look at the housing while installed in the car you can see the bosses where the bearings are installed for the arm.
They are just to the right of the Bosch part number plate that is rivetted on the front, and a little to the left and below where the steel banjo fitting fuel return line is mounted on the fuel head.
There are steel caps about the size of a dime over the bearings with snap rings to retain them.

It would take so much fabrication to change all that, no one could make money doing it for such a small and possibly imagined gain.

It is possible he ground some metal off of the two internal cast aluminum lumps that act as stops the counterweight comes in contact with at the end of it's travel. That would take about 3 minutes at the most.
If the metering arm does go all the way to those stops then grinding some metal off of them would let it go farther.

There is no way to tell though unless the car is wide open on a chassis dyno at 6500 rpm and you tried to push the sensor plate down farther with a screwdriver or whatever like Keith said someone has done.

thanks for the pics and information...
Jim
Old 04-29-2009, 03:23 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #189 (permalink)
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I forget how large the pivot pin is? Is is large enough to substitute a smaller pin and just add offset drilled bushings?

I like extending the cone or adding profile on top of the MP for and easier way to increases travel.

The Andial Fueler and BL's modified WUR both lower control pressure so the metering plate will advance further. This indicates it dose not bottom out on most 930's so adding range by blueprinting the casting is not of much benefit if the arm is going to stall any way.

Again, I suspect one relatively easy test to see if it still has range left is to set the CO as fat as possible at idle and run it up to red line watching AFR at a peak rpm point like 6600rpm. If this helps the AFR, then the pin has not bottomed out. If the AFR stays the same, the pin may have bottomed out.
Old 04-29-2009, 03:36 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #190 (permalink)
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Here's a diagram showing the arm, the pivot shaft, and the bearings.


I took one of Cole's pics and drew a red arrow pointing at the cast boss where the pivot bearing is installed.
This is the back side of his CIS housing.
Old 04-29-2009, 04:20 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #191 (permalink)
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Just thinking out loud.

I would love to see a picture of metering plate pushed to the end of travel where we can see the cone.

The distance between the pivot center and the point where the metering pin is located is a very small distance. Thus, a small change in that distance should make a big effect.

If the distance from the pivot is say 1.5" and we can relocate the pivot 3/8's of an inch further away, we change the ratio by 25%. That would be a lot. 3/16's would be about 12.5%. Thus, the metering pin would move about 12.5% further with the same amount of movement of the metering plate.

Remember, if we do change this ratio, then we will see a like change at all points like with the IA head. That is, if we set the CO correctly at idle, we will be 12% richer at cruse, and 'up to' 12% richer at red-line.



????
Old 04-29-2009, 04:43 PM
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J,
When I referred to cone, I noticed I left out an e in my fat fingered spelling of cone's. I am actually referring to the venturi portion of the metering casting, that is what it has previously been referred to as. It appears the exterior leading edge and both profiles of the interior trailing edges have been machined. I also motioned it did not appear that the arm pivot point was changed. I looked at this because Keith had previously motioned he thought that may have been a path that would be taken in this mod.

Cole
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Cole - 80 930 "The Old Sled"
Mods: TurboKraft Custom IC, 934 Headers, GSX 61, Zork, Port Work, SC Cams, Air Mod Fuel Dist Relocated, Water Meth Injection, BL WUR, MSD 6530, Greddy EBC, Synapse Bov, Short 2nd & 3rd with 8:37 R&P, Wevo Shifter, Coupling, and Mounts, MTX-L SSI-4, Big Brakes, Rebel Coilovers, Bilstein Sports.

Last edited by cole930; 04-29-2009 at 06:08 PM..
Old 04-29-2009, 04:45 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #193 (permalink)
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As I look closer at the drawing it looks like it would not be hard to weld or bush and re-drill the hole the pivot pin is located in to relocate it. The stock pin, bearing, plate and circle clip could then be reused. Look across from 27 to see the relative size of the pin hole. There is a lot of room to re-drill the hole in any direction. The stock retaining plate dose not have to be centered to the hole.

If the pivot has been relocated, removing the circle clip (23) and retaining plate (24) should reveal such.

Old 04-29-2009, 04:55 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #194 (permalink)
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Steve at Rennsport is who dose the pin relocation mod. Never heard of anyone else doing such.

Dose it seem any machining done might have only been to make air flows through the metering opening flow a little smoother?

Sound like not reprogramming or extending of the metering cone has been done then.

Shucks.
Old 04-29-2009, 04:59 PM
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Keith.

These are not the best, hope they will do.

Cole




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Cole - 80 930 "The Old Sled"
Mods: TurboKraft Custom IC, 934 Headers, GSX 61, Zork, Port Work, SC Cams, Air Mod Fuel Dist Relocated, Water Meth Injection, BL WUR, MSD 6530, Greddy EBC, Synapse Bov, Short 2nd & 3rd with 8:37 R&P, Wevo Shifter, Coupling, and Mounts, MTX-L SSI-4, Big Brakes, Rebel Coilovers, Bilstein Sports.
Old 04-29-2009, 05:19 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #196 (permalink)
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To me it looks like as the end of the metering plate starts to get a little past cone area, air starts to spill over and around the plate and its rate of movement will slow dramatically.

I thought is the metering cone is designed to take us up to about 300hp plus a little margin. After that the metering plate hits an area in its travel is was not designed to reach. At this point the plat starts to stall or at least slow forward movement movement.
Old 04-29-2009, 05:44 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #197 (permalink)
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Wow, sorry for the wrighting and spelling, I was distracted and rushed.
Old 04-29-2009, 05:50 PM
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Keith,

If that's actually the case the velocity cone with it's indented center, added height, and rolled outer edge may be intended for overcoming that exact condition.

Cole
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Cole - 80 930 "The Old Sled"
Mods: TurboKraft Custom IC, 934 Headers, GSX 61, Zork, Port Work, SC Cams, Air Mod Fuel Dist Relocated, Water Meth Injection, BL WUR, MSD 6530, Greddy EBC, Synapse Bov, Short 2nd & 3rd with 8:37 R&P, Wevo Shifter, Coupling, and Mounts, MTX-L SSI-4, Big Brakes, Rebel Coilovers, Bilstein Sports.
Old 04-29-2009, 06:02 PM
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If I remember correctly, the added cone there to take advantage of the high velocity air passing over it. In theory, the cone adds spoiler effect to the metering plate, increasing downforce exerted on the plate to force it further in its travel. In theory.........
I never saw any scientific proof to support this theory, but it sounds good on paper.

btw, that cone is mounted properly. It only covers part of the metering plate.
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Old 04-29-2009, 06:08 PM
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