Leon

Just let me know when you'd like to come by! BTW, I'll be at the J-tin show in San Leandro tomorrow and can bring it with me if you're going.

Takashi, I have one you can borrow.

Took a look a few days ago (forgot to post ) and I have both 50F9 and 55F9 idles as well as 170 airs. Let me know if you're interested!

Isn't this all in the diagrams? I did some "custom" wiring on mine and didn't have a problem with following the given schematics.

This needs to be labeling "NSFW"...

I don't think you understand what "non-trivial" means...

If you haven't already, open that R180 up and check the ratio stamped on the ring gear.

Always a good read, thanks for posting these John.

Setting up the linkage is non-trivial. There are some very good threads on this if you search classiczcars.com, especially pertaining to the Cannon manifold. Bigger chokes don't affect the idle circuit, they only boost vacuum in the mains. Progression also should not really be affected. The idle circuit gets its deltaP from the downstream side of the throttle butterfly. I would venture to guess that people upsize idle-jets on larger choke setups in order to cover up holes that weren't as prevalent with the smaller chokes. Rather than upsizing idles, I'd play with e-tubes.

Bah, forgot! Sorry about that. Setting an alarm reminder to check tonight.

I wouldn't mind that at all, as long as WOT AFR is richer (~13:1).

FYI, chokes don't affect the idle circuit. They're for the mains.

Nice, I've had good experiences with them as well. They're pretty close to me so shipping is always quick. Only thing I didn't order from them are the stiff internal throttle return springs, since Spruell in ATL charged way less for them. Typically though, Pierce's prices are very good.

Good post! I'm a fan of both. I wouldn't mind having one Z with triples and the other with ITBs. With that said, nothing good comes easy.

If you didn't understand it to that level, then you really didn't know what an emulsion tube does. Keith's stuff might be more expensive up front, but it's a hell of a lot better than assorting a hoard of jets without guarantee that you'll get anything right. He allows returns and jet swaps for free, as well as education. His stuff is cheaper in the long-run IMO, but that's just my thought process. With that said, I didn't buy his stuff until we did a "Weber test day", and with Keith being local, he brought his stuff and let us try it out. I understand the confidence issues here, but I'm happy being the test mule. EDIT: as far as matching jetting to your engine, that's the part where Keith helps you.

Right, and the original question was purely asking about the control arms.

250hp? Turbo is cheaper and probably easier. Just bolting on a head with some headers and tossing in a big cam won't get you very far. You'd be lucky to hit 150hp.

As Jim already mentioned, the control arms are the same. It's the bushings that determine which side they're put on, as you can see in your photo.

My god, I'm in love with this project! This is possibly the coolest Z-project I've ever seen!

I'm sensing confusion and uncertainty of what the e-tube does. It's not voodoo, but it is somewhat complex and it seems almost nobody understands it. Here's my interpretation, basically what I've learned from Keith's research. It may help to have a tube in hand, or even better, a cutaway drawing open. First, why is the emulsion tube even needed? Liquid gasoline has non-negligible viscosity. If we plug off the air-supply to the main circuit, the engine will run leaner at low speed and richer at high speed. This is because at low speed, the lifting force from engine vacuum is not strong enough to pull up enough of that viscous fuel. At high speed, the effects of fuel viscosity are lessened (higher vac signal) thus too much fuel gets pulled in. Now, if we introduce air into this fuel column, this effectively makes it less viscous. At low speeds, the air helps to draw in more fuel even though the vacuum signal is "weak". At high speeds, where viscosity matters less, the air dilutes the fuel and thus slows down liquid fuel flow-rate. This helps the carburetor to achieve a flat fueling curve. My explanation may be a bit simplistic but this is why these carburetors use emulsion tubes! The e-tube controls the fuel-metering of the main circuit. It does so in two ways, (1) outside diameter, or impedance as Keith termed it, and (2) hole size and location. The main circuit draws in fuel from the float chamber via the "main" (wet) jet and that fuel mixes with air drawn in through the "air corrector" (dry) jet. The e-tube gets its air supply from the dry jet which sends air to the inside of the tube. In order to reach the venturi, fuel must flow up between the e-tube and e-tube well. This is where the air mixes with the fuel via the small radially-located holes on the e-tube and continues towards the venturi (in two-phase flow). Here's the important bit, the radial holes in the e-tube must be below the fuel (float) level! All a bleed hole above the fuel level does is diminish the vacuum signal to the main circuit. While this may be OK for high-speed operation, it's absolutely terrible for low-speed. Once you understand this, it's no wonder why so many people have low-RPM bogging issues... As Keith discovered (as well as I can remember), pretty much all of the Weber F-series tubes were designed for their down-draft carbs, which have different fuel levels and well dimensions! As it turns out, pretty much all of these F-series tubes are terrible for sidedrafts. Keith did find one F-series tube that would work OK, that being the F7 but it's necessary to play with plugging holes in order to obtain proper performance. It also lacks enough impedance to provide optimal gas mileage (impedance plays a role in mid/high RPM part-throttle operation, not so much at WOT). This is just what I've gleaned by following Keith's work, all the proper details are in the Sidedraft message board. I'm not trying to advertise for him and am not benefitting from this in any way. However, this is exactly the reason why I decided to ditch the Weber stuff and go for Keith's jetting (custom e-tubes and adjustable idle jets). Like I mentioned in previous posts, I don't get any bogging anywhere and I also get better gas mileage to boot.

I may have some air correctors and idle jets that'll work. I'll have to check my jet inventory tonight.

Simply AWESOME! That thing looks like a beast, Frank.

Seconded!

I have the exact ones for sale. They came off a '71 I had and are pictured in my FS ad.

The idle/progression circuit does go to higher RPM, but only at partial throttle. There is absolutely no good reason to be 12.5:1 at idle or partial throttle. Part throttle means you're cruising and getting good mpg and producing less emissions is (or should be) in your best interests. At WOT, when you want max power, you're using the main circuit which is a whole different ball-game. BTW, it is not "the nature of the DCOE carb to give best performance at 12.5:1". It is the nature of the internal combustion engine, no matter how you're fueling it. I consider mpg a "performance aspect" of my engine. I can see not caring much if it's a pure track car since you'd always be on the mains and at full power, but anything else and it makes zero sense to dump a ton of fuel into your engine when you don't need to. This is the whole point of having multiple circuits in a carburetor.