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  Topic Review (Newest First)
Yesterday 09:27 AM
alfaparticle This is a copy of my post to the 79 spider on the dyno thread

I soldered up the first set of 1 mm holes and I drilled another set at 3.9 from the top land - .5 mm lower than the first set. I manually read the data points from the Zeitronix logger and loaded them into Excel in order the make a clear comparison. My conclusion is that drilling the holes in the F16 tubes has not had much effect on the depth of the AFR dip at 4700 but it has raised the AFR on either side of the dip. The holes at 3.4 mm have had more effect below 4700 and the holes at 3.9 mm have had more effect above 4700 rpm.
10-16-2019 06:22 PM
65Sprint Your graph is prettier than mine... idle AFR is the same. I think you will find the logging capability well worth the cost. It would be almost impossible to set my emissions Dellortos up correctly without the ZT-2.
10-16-2019 05:51 PM
gigem75 Here is my first log. No rpm yet, that comes tomorrow. I told myself I would never learn another software program but alas, I must. To get the pretty stuff I had to import to Excel and then save as an image. Only problem is there are like 570 data points in the time axis but I figured out how to call out only a few for labels. The graph represents a idle and then a blip or two of the throttle. RPMs will be added tomorrow.
10-15-2019 04:12 PM
alfaparticle I seem to remember that he is grossly lean - high 14's. Smaller AC's will correct it if the main jet is not hopelessly small or the emulsion tubes are unsuitable. I suspect the latter.
10-15-2019 12:19 PM
Lean at 7000

Mark Robinson is running F15's and his motor goes very lean towards 7000
That is also a result from long airhorns, But Mark is running a factory Airbox/intake I believe so a .5 to 1.0 reduction(smaller) in Air Corrector size should remedy that. Lean meaning over 13.7 or so)
10-15-2019 09:03 AM
top end in 3rd and 4th is still a little lean.
It may depend a little on cams but in my experience the leanest range is always around 6200 rpm and I use air correctors to set that. Beyond that I see a slow richening up to 7000. Mark Robinson is running F15's and his motor goes very lean towards 7000. I had a similar experience when I tried F9's.
10-15-2019 08:36 AM
gigem75 I just talked to the Innovate guy and to log RPM as well I'd need what they call the SS-4. So it goes MTX-L (afr) to SS-4, to Pocket logger. With the SSI I have 3 more data channels to use for other data I might want to log at a future date. Basically the Pocket Logger last in the chain. Then take the SD card to the computer and bring it all into LogWorks software.
10-15-2019 08:20 AM
gigem75 Probably only in the Coupe with the Innovate. I doubt the Pocket Logger would have the same 4 pin connectors as the Zt2. If it did then the data would have to be in a format the Zt2 would recognize. I sure would be nice if it did.
I need to ask the Innovate folks if the gauge that reads vacuum, rpm, and MAP sensor data is the only one that will log RPM. There is no reason to buy something that uses a MAP sensor when I have no use for it. I'm sure it's a good part of the cost.
10-15-2019 07:23 AM
Pocket Logger?

I have a Zeitronix ZT2 in the Duetto and an Innovate in the Coupe. I wonder if the pocket Logger would work with both of them?
10-15-2019 07:14 AM
gigem75 Thanks. I'm asking to learn, nothing else. I don't think I said you were trying to make things richer. "I take it you are trying to lean out a specific rpm range?" and drilling holes in specific areas to do it. Which btw is pretty darn cool. I was thinking low holes = leaner at low rpm and visa versa but it's just the opposite. When I put the F16s in it appeared to richen the top end and it very well may have when compared to the F11s from before. I'm super happy with all ranges except the top end in 3rd and 4th is still a little lean. I might try soldering up one hole at a time in the 16s to add a little gas at the top end. Hopefully just there.
I ordered the Pocket Logger from Summit and it should be here in a couple of days. No rpm without spending 150 bucks so that will have to suffice for now. The pocket thingy was just 70 bucks and if I get a plot of AFRs worth every penny. I'll wait to do anymore runs until I see a graph. And thanks Ed for sharing I'm slowly getting there.
10-14-2019 06:51 PM
I thought Alfas were nimble?
It was on a narrow winding road with trees close to the road on both sides. Low light and driving briskly through tight turns and I barely saw it before I felt the bump.

I am not trying to make anything richer. My understanding is that holes make things leaner and high holes effect the low end and low holes affect the high end. I drilled holes 3.3 mm from the top and the weakening was centered at 3900. My rich dip is at 4700 so I relocated the holes a little lower. I filled the first set with solder and drilled a new set. I have a pin chuck that will grip very small drills and it is gripped in the chuck of my drill motor. Like this: Precise 3 Piece Pin Chuck Set - 3700-0501 - Penn Tool Co., Inc
10-14-2019 04:54 PM
gigem75 I thought Alfas were nimble?
I take it you are trying to lean out a specific rpm range? And are you using a dremmel to drill the holes? Maybe I'm getting something wrong but seeings how the F16 just has the holes around the bottom wouldn't the upper rpm range be richer? Which is what I'm trying to do. No braking and or emulsification of the fuel?
10-14-2019 12:14 PM
alfaparticle I modified my F16 tubes again - soldered up the holes that I had drilled and drilled a new set a little lower down. On the way to the test track I drove over some tree debris that took out my fuel pump. So it will be a few days before I can do the tests.
10-14-2019 06:46 AM
gigem75 Good information Ed, Thanks and I'm sure others do to. My mid range and low AFRs are good. It would really be good if I could log my data like you do and have a curve to look at but that would the only reason I have to get a laptop.
What I'm trying to do is get the AFRs down into the 12s and 13s at peak rpm in the upper gears. Everything else is good. It seemed better with the F16s but like I said it was a wet road and hard to keep any eye on both the road and the AFRs.
I have 200 ACs now and will order some smaller ones.

edit, I don't get it. I've talked with Innovate tech support a couple of times and I've or at least I thought I'd been told I needed a laptop to log data. I went to their site because I was thinking about getting a cheap used laptop so I could log. Lo and behold they have the pocket logger that writes to an SD card! No laptop required. It's also reasonably priced!
10-13-2019 11:40 AM
alfaparticle Mike,
Here is my take on emulsion tubes.
F9, F11 and F15 are identical except for the number and location of high holes. The diameter of the tubes and the orientation of the low holes is the same. So if you have data from an F11 then you should able to estimate the effect of changing to an F9 or an F15. The extra holes that I drilled in my F16's are 3.3 mm from the top land and their effect seems to centered on 3900 rpm so that may be a data point for estimating which rpm ranges are being influenced by the holes in the F9 series. Higher holes lean the mixture at lower rpm.

F16's are different. They are larger diameter and the single row of low holes are at 90 degrees to the axis of the tube. The low holes in the F9 series are angled up. I don't understand the effect of that. Pat Braden tried to explain it in his Weber book but he was confused about which holes were angled and which were straight so I am not inclined to follow his explanation.

So I would look carefully at the drawings for the F11 series and compare the positioning of the holes with your AFR curve and decide where you would like to tune it. Just about every AFR curve that I have seen for a Nord motor has a rich dip at about 4700 and I will try to find the location of holes that correspond to that rpm. I expect that the location will be similar between F16 and F11. If you switch to F16 you will probably have to change main jets and/or air correctors to get your AFR correct at peak power rpm - most likely around 6200 with your motor. If the air correctors end up being 200 or more then you may be able to go down 5 on the main jet and about 30 on the AC to get the same AFR at 6200 but leaner at lower rpm. The size of the rich dip at 4700 seems to be bigger with larger main jets so finding the smallest main jet/AC combo should minimize the dip. After that you may want to start messing with emulsion tubes but I would definitely optimize MJ/AC first.
My other observation is that air horns exaggerate the rich dip to the degree that you may see a significant corresponding dip in the torque curve.

I will update this thread after my next emulsion tube tests
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