Setting up IDA's for a stock /6, jets, and so forth |
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Setting up IDA's for a stock /6, jets, and so forth |
krk |
Feb 7 2004, 03:55 PM
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#1
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Senior Member Group: Members Posts: 997 Joined: 27-December 02 From: San Jose Member No.: 22 |
Folks,
I picked up a set of IDA's in good condition that were set up for a 2.8 (maybe an RSR?) -- anyway, the IDA"s on my /6 have throttle shaft issues, so I figured I'd just swap some parts back 'n forth to get the correct setup for my stock 2.0L /6. Turns out my original IDA's weren't exactly stock either. There are several parameters here. Idle jets are currently at 55 on both carbs. (stock is 45) I'll be using 55 initially. Mains are 125 on my current set, 155 on the new ones, stock is 105. I'll be using the 125's. Emulsion tube on mine are F26's (same as 911L), and on the new ones they are F3's (911S). The originals used F1's. I've no clue which one I'll use -- if I'm lazy, I'll leave the F3's in there. Air correctors are 180 on both IDA's. Original's used 170s. I'll use 180s. Pump Jet is 50 everywhere. In the picture you will see two different auxillary venturis -- the shorts ones are stock /6, and the tall ones I've not seen before. No clue what to use. Lastly, and I've not got this far as I have to cut wires, but from an eyeball estimate, the actual venturis on the originals were quite a bit more restricted. I'll pop both of them out shortly to see what they are --- i'll use whatever is closest to the manual I guess. Comments welcomed. kim. This post has been edited by Gint: Feb 8 2004, 10:47 AM Attached image(s) |
Carl |
Feb 8 2004, 01:17 AM
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#2
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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 |
As I understand it, the emulsion tubes slow the flow of fuel to the main jets by bleeding air into the chamber that feeds the mains. The air mixes with the gas making it less dense. As engine speed increases, the fuel level in the chamber is drawn down thereby exposing more of the holes in the emulsion tubes. As more holes are exposed, more air is drawn through the holes and the engine runs leaner.
Without the tubes, the vacuum through the carbs would draw too much fuel through the mains and the engine would run rich. Why this wouldn't be solved with smaller mains, I don't know. The number on the emulsion tube has no bearing on a measurement or size. It only relates to the experimental sequence the factory went through to make them work. For example, F1 was their first successful design, F3 was the third and F26 was the 26th. I think I read this stuff in a book somewhere ... Carl |
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