Weber tuning with Lambda sensor - Page 6 - Alfa Romeo Bulletin Board & Forums
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post #76 of 225 (permalink) Old 11-29-2014, 12:14 PM
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You nailed it Ed. With the 130 main jets I was right under one half quicker covering the same distance. I need to go measure it exactly but it's not very far, maybe 700 ft or so. Significant. The mixture does lean out noticeably at the top end but at the same time the mechanical tach picks up acceleration at around 5800 to my shift points which were 6700. I don't even look at the digital tach, it sucks. On the second run it was more eager to get to 100 than with the 140's. I think I hit 96 with the 140's yesterday.


The passenger seat is 15 miles an hour faster than the drivers seat.

currently
2017 Giulia Q4
74 GTV restored daily driver
71 Berlina in 2L restored driver
the ones that got away:
1959 750 series Giulietta Spider Veloce
1962 Giulietta Spider normale
1965 Giulia Sprint normale
1972 GTV
1974 GTV
1974 GTV
1977 Spider
1974 Spider
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post #77 of 225 (permalink) Old 11-29-2014, 12:31 PM
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It certainly sounds good.
I am still tinkering. I tried 145 mains with 160 AC's and I am still a bit lean over 6000. I will run it tomorrow with 150 AC's but they are knock-offs and they have a countersink on the orifice which is not on the genuine Weber jets. I have also drilled out the top holes on my emulsion tubes from 1mm to 1.5mm in an attempt to lean it out in the 3000 to 4500 range.

Ed Prytherch
79 Spider
76 Suzuki GT500
2011 Jaguar XKR

A little government and a little luck are necessary in life, but only a fool trusts either of them. - P.J. O'Rourke
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post #78 of 225 (permalink) Old 11-29-2014, 01:13 PM
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Thanks. I'm not an expert and maybe you had said emission webers are different but I thought that if there are more holes along the emulsion tubes there is more air making more bubbles which makes for less gas which leans it out. The reason I ordered f16's is because there is no top hole, less air, = richer mixture. Be patient if you've pointed this out before Am I reading it right with my webers?

The passenger seat is 15 miles an hour faster than the drivers seat.

currently
2017 Giulia Q4
74 GTV restored daily driver
71 Berlina in 2L restored driver
the ones that got away:
1959 750 series Giulietta Spider Veloce
1962 Giulietta Spider normale
1965 Giulia Sprint normale
1972 GTV
1974 GTV
1974 GTV
1977 Spider
1974 Spider
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post #79 of 225 (permalink) Old 11-29-2014, 01:22 PM
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High holes should lean the mixture when the main circuit is just coming in - at least that is the way that I understand it. I can solder them up and re-drill them if it goes the wrong way.

Ed Prytherch
79 Spider
76 Suzuki GT500
2011 Jaguar XKR

A little government and a little luck are necessary in life, but only a fool trusts either of them. - P.J. O'Rourke
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post #80 of 225 (permalink) Old 11-29-2014, 01:49 PM
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Like your work guys, will have to get an AFR meter and have a go myself. One question, how do you know how close you are to pre-ignition or detonation? With your short runs testing you aren't holding high power for long, but sustained high speed running may induce something?

Past: '81 Giulietta 1.8, 500SL Pantah, 650 Allazurra. Present: '79 Alfetta 2.0, '82 Sportiva II, '91 75TS, Van's RV-4, Giles G-200, Pazmany PL-1. Sunny Australia.
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post #81 of 225 (permalink) Old 11-29-2014, 01:53 PM
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Right, I went back and re read it. I'm getting to old to trust my memory if I ever could. I actually meant to order F15's we'll see what I get.

The passenger seat is 15 miles an hour faster than the drivers seat.

currently
2017 Giulia Q4
74 GTV restored daily driver
71 Berlina in 2L restored driver
the ones that got away:
1959 750 series Giulietta Spider Veloce
1962 Giulietta Spider normale
1965 Giulia Sprint normale
1972 GTV
1974 GTV
1974 GTV
1977 Spider
1974 Spider
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post #82 of 225 (permalink) Old 11-29-2014, 03:36 PM
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Quote:
Like your work guys, will have to get an AFR meter and have a go myself. One question, how do you know how close you are to pre-ignition or detonation? With your short runs testing you aren't holding high power for long, but sustained high speed running may induce something?
My Zeitronix will take a thermocouple input for EGT and I have considered installing one to be on the look out for detonation, but the probability of that is low if I keep the AFR below 13.5. So I make small changes!

Ed Prytherch
79 Spider
76 Suzuki GT500
2011 Jaguar XKR

A little government and a little luck are necessary in life, but only a fool trusts either of them. - P.J. O'Rourke
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post #83 of 225 (permalink) Old 12-03-2014, 02:12 PM
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I wouldn't be doing this if Ed hadn't started this thread, thanks Ed!
Over a given distance I've knocked another 3 tenths of a second off by switching the f11 emulsion tubes with f15's. That is 6 tenths of a second improvement over 700 ft from 140 mains f11 tubes to 130 mains and f15 tubes. Flat amazing. The motor is also smoother during the transition to the mains and running with a feathered throttle.

The passenger seat is 15 miles an hour faster than the drivers seat.

currently
2017 Giulia Q4
74 GTV restored daily driver
71 Berlina in 2L restored driver
the ones that got away:
1959 750 series Giulietta Spider Veloce
1962 Giulietta Spider normale
1965 Giulia Sprint normale
1972 GTV
1974 GTV
1974 GTV
1977 Spider
1974 Spider
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post #84 of 225 (permalink) Old 12-03-2014, 05:49 PM
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Quote:
I wouldn't be doing this if Ed hadn't started this thread, thanks Ed!
But you are the father of the Redneck Dyno!

Ed Prytherch
79 Spider
76 Suzuki GT500
2011 Jaguar XKR

A little government and a little luck are necessary in life, but only a fool trusts either of them. - P.J. O'Rourke
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post #85 of 225 (permalink) Old 12-15-2014, 11:32 AM
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The 130 mains work best running 32 chokes. I'm taking the 30's that were in the webs when I got them and turning them to 33's. Then I'll try the 135 mains again.


The passenger seat is 15 miles an hour faster than the drivers seat.

currently
2017 Giulia Q4
74 GTV restored daily driver
71 Berlina in 2L restored driver
the ones that got away:
1959 750 series Giulietta Spider Veloce
1962 Giulietta Spider normale
1965 Giulia Sprint normale
1972 GTV
1974 GTV
1974 GTV
1977 Spider
1974 Spider
gigem75 is offline  
post #86 of 225 (permalink) Old 12-15-2014, 01:35 PM
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This is GREAT! Reminds me of my grunt days at AUSCA when I did this all-day to re-profile chokes, coming home looking wrapped in aluminum dust! With some choke sizes, performance can be improved by just modifying airfoil shape. As 30's are so common, they are easily made any size you want using the "step-cutting" method you show and finishing smooth. I used aluminum templates to get the air-foil shape I wanted. Last set I made were for my GTA engine at 35.3 mm. Worked better than 35 or 36 mm. I made a spare set, but gave them to one of my customers vowing NO more aluminum dust for me!


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post #87 of 225 (permalink) Old 12-15-2014, 02:01 PM
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I followed the under 2.5 TransAm religiously back then and Horst Kwetch was my hero. I hope he was a straightup kinda guy. Nobody wants their heroes to be not so nice guys. Please don't bust my bubble by telling me anything but that he was a great guy. I would have hammered valve seats and been covered in aluminum dust all day long to be working with those guys. I figure this project put me in the black on my lathe, with all the things I've made the totals are up to about what it cost to buy it. It's been worth every penny.

The passenger seat is 15 miles an hour faster than the drivers seat.

currently
2017 Giulia Q4
74 GTV restored daily driver
71 Berlina in 2L restored driver
the ones that got away:
1959 750 series Giulietta Spider Veloce
1962 Giulietta Spider normale
1965 Giulia Sprint normale
1972 GTV
1974 GTV
1974 GTV
1977 Spider
1974 Spider
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post #88 of 225 (permalink) Old 12-15-2014, 02:49 PM
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They were a wild but honest bunch. Horst likes and still likes his beer. Ron Neal had so many kids the crazyness of Ausca was "time-off". When something went bad, if >you< were involved, you got the silent treatment for a to-be-determined amount of time. The hangers on, like me, got the nasty jobs. If you paid attention, you learned a whole lot, and in my case, become a car guy for life.
From my experience.


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Gordon Raymond
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and sometimes, CONFUSED AND INCORRECT, but Larry helps me out.
Now:
Illinois Chapter Director AND Charter Member of THE CONFUSED AND INCORRECT
Gordon Raymond is online now  
post #89 of 225 (permalink) Old 12-15-2014, 03:29 PM
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If they were half as wild as Smokey Yunick they are lucky to be alive! His autobiography was one of my favorite books on several levels.

The passenger seat is 15 miles an hour faster than the drivers seat.

currently
2017 Giulia Q4
74 GTV restored daily driver
71 Berlina in 2L restored driver
the ones that got away:
1959 750 series Giulietta Spider Veloce
1962 Giulietta Spider normale
1965 Giulia Sprint normale
1972 GTV
1974 GTV
1974 GTV
1977 Spider
1974 Spider
gigem75 is offline  
post #90 of 225 (permalink) Old 12-15-2014, 03:42 PM
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I would say they were. My Ausca spider runs negative camber on the rear wheels. A Smokey trick also used by Ausca on most race cars. There were also the sleeved intake runners with the chokes down by the valve bowl. Engines were lowered with dry sumps, and a couple moved further back. Tech inspectors had a lot of fun with Ausca Alfa's, but many ideas and designs went directly to Autodelta, and all were interesting even if ineffective or determined to be not within the rules in effect at the time.


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Gordon Raymond
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and sometimes, CONFUSED AND INCORRECT, but Larry helps me out.
Now:
Illinois Chapter Director AND Charter Member of THE CONFUSED AND INCORRECT
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