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  Topic Review (Newest First)
10-19-2019 12:53 PM
alfaparticle Much better. What rpm are you at the left when the AFR is a little under 12 and what rpm for the lean peak?
10-19-2019 12:14 PM
gigem75 I see said the blind man. I guess a blind hog finds an acorn every now and then as well. I'm happy with the 140 main jets. I went back to the 50f8 idle jets after trying the 55s. It just idles better and no stumble at zero vacuum when moseying along the lake road in 4 gear @ 1900 rpm up and down the small hills. Wakes up pretty good too.
10-19-2019 10:43 AM
alfaparticle Typically what happens with an overloaded tach signal is that both readouts work accurately up to a certain rpm then one or both of them completely drop out. No algorithm can compensate for that.
10-19-2019 08:58 AM
gigem75 If the signal change is linear then you could enter the hot rod version of the cosmological constant and multiply that by the rpm and get the actual rpm. That is assuming the tach or that channel can be calibrated with the software. I would expect so.
10-19-2019 08:34 AM
alfaparticle
Quote:
Ed can probably answer that better than I can.
Plans are a foot to install my little netbook computer in Richard's race car then we can log straight from the ZT2. The only doubt is to whether the tach signal from his Crane box will drive both the ZT2 and his tachometer without a signal booster.
10-19-2019 06:11 AM
gigem75 You are probably right. The DCO Webers did not have bearings in the butterfly shafts just bushings which wore down. I always suspected I had air being sucked in past the shafts which made setting the idle a pita. That most likely contributed to the explosions under the hood. Time to try the 190 ACs. I might try the 140 main jets just to see what they do since I spent the $$$ to be able to log data. I like being able to add columns of data to the Excel chart to see AFR curves on top of each other. It can be done in the Logworks software but it's prettier in Excel Also going back to a question RJ had about compatibility between the Innovate and ZT components they could be used together if they both use 5 volt instruments. You would probably have to make your own connectors but if they were connected together they should work. Ed can probably answer that better than I can.
10-18-2019 07:37 PM
alfaparticle
Quote:
I am also running the stock Euro air cleaner. No stacks or anything like that.
That's good.
I have swapped idle jets between successive dyno runs and seen nothing. At WOT there is almost no airflow close to the bore and the velocity is shifted to the center. With little flow over the progression holes there is insufficient pressure drop to pull fuel from the float chamber. With true emissions Webers there is reverse flow of air through the progression circuit and into the well WOT and high rpm.
10-18-2019 07:24 PM
gigem75 I've had F16s in the whole time. Even the idle screws can make a difference at WOT. At least when I had them screwed in to far on my Giulietta Veloce it barked REALLY loud out the intake at WOT from being to lean. It actually sounded like a gunshot. They were 40 DCO Webers on that car and scared the carp out of me! I went down to 195 AC and will go down to 190 ACs tomorrow. I am also running the stock Euro air cleaner. No stacks or anything like that.
10-18-2019 07:11 PM
alfaparticle Don't expect to see much change at WOT when you swap idle jets.
I would install the F16's with your current main jets and air correctors and see where you are. The goal should be to be between 12 and low 13's through the broadest rev range. If you need to correct mainly the middle and high rpm then work on the air correctors. If you end up with big AC's - over 200 then try smaller main jets. The goal should be the smallest main jet/AC combination that keeps you in the 12.8 - 13.2 range at 6000 - 6500 rpm and never go over 13.5.
10-18-2019 06:06 PM
gigem75 I have 50f8 idle jets in there now and will try 55f8s after the 190ACs tomorrow. We'll see and yes just about everything is a compromise.
10-18-2019 05:53 PM
alfaparticle I make small changes (5) to main jets and larger (20 - 30) to AC's until I am very close to where I want to be. I swapped out my 190's for 170's today and it moved the peak AFR at 6150 rpm from 13.4 to 13.2 but is also made the rich dip bigger and the car was slower from 3600 to 6600. Everything is a compromise with Webers.
10-18-2019 04:50 PM
gigem75 Changing to the 195 AC brought it down (richer)
Thanks Ed, I had to go back and edit, I thought I had F15s but had F16s so I changed from 200 AC to 195 AC I have 190s and will try those tomorrow. As far as the mid range we'll see what the 190s do.
10-18-2019 04:09 PM
alfaparticle That is a fairly narrow rpm range. My test is hold it steady at about 2800 in 3rd and then step on it and get out at 7000. I understand that not everyone wants to take the motor to 7000 so you could back out at 6500. You are quite lean around 5000 and that must be costing a lot of torque there. I bet you would see a big dip in the torque curve if you had it on a dyno. I think that the F16's will make a significant change.
10-18-2019 02:37 PM
gigem75 I was half expecting to see a similar dip in the four thousands on mine. It is as I could tell just from looking at the gauge trending somewhat lean. Interesting that it's 12.67 at 59-6000 rpm and then jumps to 14.45 @ 6220 which is where I was shifting. It's a third gear run. I did get my ACs today and will try that and then the F16 tubes.
This is with 135 mains, F15 tubes, and 200 AC
Upon further inspection I already had the F16 tubes in and comparing the two I am leaving the 16s in. The 15s have holes at the top and mid as well as the lower ring of holes while the 16s just have the lower ring of holes. So it's the 195 or 190 Air Correctors tomorrow.
10-17-2019 09:27 AM
alfaparticle This is a copy of my post to the 79 spider on the dyno thread

Quote:
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.
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