/6 Weber Carb Questions -> Jets, Who said you can never be too rich? |
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/6 Weber Carb Questions -> Jets, Who said you can never be too rich? |
Carl |
Jun 18 2004, 04:14 PM
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#1
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Ummm ... what? Group: Members Posts: 781 Joined: 17-January 03 From: San Jose, CA Member No.: 163 Region Association: Northern California |
I'm trying to lean out a car that goes through gas like a drunken sailor. To start the process, I want to convert the carbs back to the original factory jetting then address the performance issues if that setting is too lean. Hopefully, there are authorities on carbs out there that know the answers to the following questions:
/6's came with Weber 40IDT3C's, as did the 911T (same engine). The /6 factory manual says the jetting should be: 45 idle jets 105 mains 170 air jets F1 emulsion tubes The Pat Braden book on Weber's has the following jetting for 40IDT3C's for the 911T: 50 idles 110 mains 185 airs F2 emulsion tubes Which is correct factory jetting for the 914/6? There are different jetting arrangements for 40IDA3C's. Braden says the IDA's were on the 911L engine. Were they used on other P engines? There are more references to IDA's in the printed material than IDT's. This doesn't make sense to me if they only came on 911L's because there weren't a lot of them produced vs the 911T's. What are the differences between the IDA's and IDT's? The external appearance is the same but the jetting is different for engines of the same displacement. The engine in my car has a 911T crank and case with a 2L 911E pistons, cyls & cams. The 911E was an MFI engine. I've been told there are differences between cams for MFI engines vs carbs. Is this true? If so, how are they different? Should my engine be jetted differently because of it? and finally, how come a dropped nut will always land in a location that's the most difficult to see, reach, or both? (IMG:style_emoticons/default/idea.gif) Thanks for the help. |
krk |
Jun 18 2004, 04:44 PM
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#2
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Senior Member Group: Members Posts: 997 Joined: 27-December 02 From: San Jose Member No.: 22 |
This of course is funny. I learned most of my weber stuff from you.
Anyway. I bet on the /6 factory manual for the /6 factory settings. I'm pretty sure Mr Yellow's IDT carbs were set up to the factory manual -- the silver car is a mixture of things, including IDA's instead of IDT's. On the diff twixt IDAs and IDTs -- Matt Blast (Eurometrix) said it was nearly irrelevant. To the point that selecting between two sets, you pick the one in the best condition. iirc, the diff is in the idle circuit, and more precisely, something to do with where the transition point is. (this conversation took place 2 years ago -- my "iirc" may not be too "c" -- heh) I have both. I've had them both apart -- the diff was certainly not obvious. I thought there were way more IDA's out there than IDT's. I could be wrong of course, but it seemed to me they came on several 911 models and the IDT's were only on a couple of years. (I'll dig into what weber materials I have -- prolly the same things you have of course.) IDT's are certainly not often up for sale, where IDA's are fairly common. Have you had the car on a gas analyzer? kim. |
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