Weber 40 IDA 3bbl jet starting point for a 2.7 /6 |
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Weber 40 IDA 3bbl jet starting point for a 2.7 /6 |
tornik550 |
Jul 13 2016, 03:10 PM
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#1
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Senior Member Group: Members Posts: 1,248 Joined: 29-January 07 From: Ohio Member No.: 7,486 Region Association: None |
I have a freshly built 2.7l with 9.5:1 compression pistons. I currently have zenith 40 tin carbs with 34mm venturi's. The engine runs very well however I stumbled upon a nice set of weber 40 IDA's. I am much more familiar with weber carbs so I purchased them.
What would a good starting point for the following be? venturis idle jets main jets emulsion tubes air correction jets Also, are weber idf jets and vents interchangable with 3BBL IDA's? Thank you |
mskala |
Jul 13 2016, 03:40 PM
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#2
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R Group: Members Posts: 1,925 Joined: 2-January 03 From: Massachusetts Member No.: 79 Region Association: None |
I won't speculate on your settings as I have a smaller motor, but all the
jets and emulsion tubes are different parts, not interchangeable with IDF. I have a freshly built 2.7l with 9.5:1 compression pistons. I currently have zenith 40 tin carbs with 34mm venturi's. The engine runs very well however I stumbled upon a nice set of weber 40 IDA's. I am much more familiar with weber carbs so I purchased them. What would a good starting point for the following be? venturis idle jets main jets emulsion tubes air correction jets Also, are weber idf jets and vents interchangable with 3BBL IDA's? Thank you |
Perry Kiehl Clone |
Jul 13 2016, 05:11 PM
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#3
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Unregistered |
Jetting shouldn't be that different from the Zeniths.
I'd start with 34 venturis, 145-155 mains, 175 or 180 air corrector, 60 idles and F3 emulsion tubes. |
Luke M |
Jul 13 2016, 05:22 PM
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#4
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Senior Member Group: Members Posts: 1,371 Joined: 8-February 05 From: WNY Member No.: 3,574 Region Association: North East States |
Here's a good chart with some starting points then you will have to fine tune it.
Attached image(s) |
tornik550 |
Jul 13 2016, 06:24 PM
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#5
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Senior Member Group: Members Posts: 1,248 Joined: 29-January 07 From: Ohio Member No.: 7,486 Region Association: None |
Next question- Where can I find 34mm venturis?
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Mark Henry |
Jul 13 2016, 06:58 PM
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#6
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
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6freak |
Jul 14 2016, 03:12 PM
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#7
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MR.C Group: Members Posts: 4,740 Joined: 19-March 08 From: Tacoma WA Member No.: 8,829 Region Association: Pacific Northwest |
says NLA mark?? (IMG:style_emoticons/default/smile.gif) |
Mark Henry |
Jul 14 2016, 03:22 PM
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#8
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
says NLA mark?? (IMG:style_emoticons/default/smile.gif) Works for me...$105./set (IMG:style_emoticons/default/confused24.gif) http://youroil.net/venturi_s.html I think you are looking at the velocity stacks, the horns on top of the carb. They are NLA BTW I used them for jets, vents and best price I found for a complete carb gasket set (2 carbs, not just one) and it was all quality stuff. |
tornik550 |
Jul 14 2016, 03:47 PM
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#9
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Senior Member Group: Members Posts: 1,248 Joined: 29-January 07 From: Ohio Member No.: 7,486 Region Association: None |
says NLA mark?? (IMG:style_emoticons/default/smile.gif) Works for me...$105./set (IMG:style_emoticons/default/confused24.gif) http://youroil.net/venturi_s.html I think you are looking at the velocity stacks, the horns on top of the carb. They are NLA BTW I used them for jets, vents and best price I found for a complete carb gasket set (2 carbs, not just one) and it was all quality stuff. The vents are in stock. I ordered a set last night. I agree- it's the stacks that are nla. |
Mark Henry |
Jul 14 2016, 04:25 PM
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#10
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
The most valuable tool for jetting your carbs is a wideband O2 meter.
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JmuRiz |
Jul 14 2016, 05:43 PM
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#11
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914 Guru Group: Members Posts: 5,426 Joined: 30-December 02 From: NoVA Member No.: 50 Region Association: MidAtlantic Region |
I plan on running an O2 sensor in mine too, gives full rev range info to help with setup.
Got a bung installed on my headers and everything. Question: will just one sensor bung work, or does it need to be on each bank (I'd guess one is fine) |
GeorgeRud |
Jul 14 2016, 05:55 PM
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#12
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Advanced Member Group: Members Posts: 3,725 Joined: 27-July 05 From: Chicagoland Member No.: 4,482 Region Association: Upper MidWest |
I'd imagine a bung for each cylinder would be most accurate but probably overkill.
My 2.7 conversion has similar jets as the chart, but a bit fatter on idles and mains. We used a Dyno to do the final tuning setup, which also is a good idea to extract the most from your engine. |
Mark Henry |
Jul 14 2016, 06:21 PM
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#13
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
I plan on running an O2 sensor in mine too, gives full rev range info to help with setup. Got a bung installed on my headers and everything. Question: will just one sensor bung work, or does it need to be on each bank (I'd guess one is fine) I'd just run one in the muffler, you could put a bung in each side and just swap them. One per cylinder doesn't make much sense, are you going to jet one side different than the other? Or the other extreme every cylinder has different jetting? If you are getting this much variance then there's likely something mechanically wrong with your engine or at least your linkage. BTW badly adjusted linkage is the first thing I look for with carb tuning issues. |
tornik550 |
Jul 14 2016, 06:49 PM
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#14
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Senior Member Group: Members Posts: 1,248 Joined: 29-January 07 From: Ohio Member No.: 7,486 Region Association: None |
Does anyone know if Weber IDF velocity stacks will fit on Weber 40 ida3c?kr
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Mark Henry |
Jul 14 2016, 06:56 PM
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#15
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
Measure the ID and the hole spacing center to center.
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Perry Kiehl Clone |
Jul 14 2016, 09:37 PM
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#16
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Unregistered |
Mark speaks the truth on the O2 sensor. It makes dialing in mixture easy. You can do it with one in the muffler and still tell when you are adjusting any barrel. I've only had one car in here with the wide band O2 sensor (a big hot rod 4 that you know very well Tornik) and I was really impressed.
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Mark Henry |
Jul 15 2016, 12:18 PM
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#17
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
I have a good O2 meter and I put it on every car I tune.
Carb cars I install the O2 meter and with my kit of jet reamers I head out on a country drive. Since I'm almost always going up in size, due to a bigger engine, the reamers work good. I'll go along watching my meter, stop on a side road, pull the jets and ream them to the next size (or half size) pop them back in. Repeat as needed. I'll have them dialed in in less than 10 miles. I'll buy the venturis, emulsion tubes and air correction as needed, but I haven't bought idle and main jets in years. |
6freak |
Jul 15 2016, 03:24 PM
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#18
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MR.C Group: Members Posts: 4,740 Joined: 19-March 08 From: Tacoma WA Member No.: 8,829 Region Association: Pacific Northwest |
says NLA mark?? (IMG:style_emoticons/default/smile.gif) Works for me...$105./set (IMG:style_emoticons/default/confused24.gif) http://youroil.net/venturi_s.html I think you are looking at the velocity stacks, the horns on top of the carb. They are NLA DUH! (IMG:style_emoticons/default/biggrin.gif) BTW I used them for jets, vents and best price I found for a complete carb gasket set (2 carbs, not just one) and it was all quality stuff. |
6freak |
Jul 15 2016, 03:27 PM
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#19
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MR.C Group: Members Posts: 4,740 Joined: 19-March 08 From: Tacoma WA Member No.: 8,829 Region Association: Pacific Northwest |
says NLA mark?? (IMG:style_emoticons/default/smile.gif) Works for me...$105./set (IMG:style_emoticons/default/confused24.gif) http://youroil.net/venturi_s.html I think you are looking at the velocity stacks, the horns on top of the carb. They are NLA DUH! (IMG:style_emoticons/default/biggrin.gif) BTW I used them for jets, vents and best price I found for a complete carb gasket set (2 carbs, not just one) and it was all quality stuff. SOB (IMG:style_emoticons/default/laugh.gif) |
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