Turbo E-tubes for Weber DCOE?

brookester · Post by **brookester** » Mon Dec 08, 2008 10:39 am

Is anybody using turbo emulsion tubes in a Weber side draft with good results?
Where can I get some? CB no longer carry them.

If I set my idle circuit correctly then it runs too rich at cruise at around 3k rpm. A/F is at 12.5 at WOT. I'm using F16s now.

shag55 · Post by **shag55** » Mon Dec 08, 2008 11:01 am

Turbo e-tubes don't work to well on the street. Use f-11s. What size motor, cam, heads, and compression?

brookester · Post by **brookester** » Mon Dec 08, 2008 12:40 pm

2161cc
8.25:1
044s 42x37
TCS10
Weber DCOE 45 w/32mm vents

I tried F11s and they worked well except for that spot. I have also tried:F2, F20, F7.
I'm tempted to cover up some of the progression ports to see if that helps.

shag55 · Post by **shag55** » Mon Dec 08, 2008 2:18 pm

Well I've had best luck with the f-11s. The 45 is tough to get good throttle reponce and a smooth transition with.

brookester · Post by **brookester** » Mon Dec 08, 2008 5:05 pm

Found a crack in my header so I'll fix that and report back.

Joe vw · Post by **Joe vw** » Mon Dec 08, 2008 5:24 pm

The problem with all side drafts is they have to be jetted rich to prevent lean transitions. The Idle mixture and full throttle are the easy to set but cruise is difficult because two idle circuits feed your cruise mixture and two butterflies combine feeding one port.
I am working on a split shaft vacuum secondary DCOE for a friend due to this very problem. My wideband reads between 11-12 to 1 at cruise with a 40DCOE and 30mm venturis. Any leaner jetting causes a flat spot and untuneable idle mixture.
I have tried all combos of jet holders and idle jets also.
I guess everyone just deals with poor economy as a tradedoff. I was told that 18mpg was average running a DCOE.
Anyone here with a different experience?

brookester · Post by **brookester** » Tue Dec 09, 2008 5:55 pm

Does that mean you can use different sized venturis on each side of the vacuum secondary setup? Maybe real small on the cruise side and real big on the wide open side? Sounds cool, but difficult.

I fixed the header, No change but I discovered that one of my main jet assemblies wasn't screwed in all the way. Cruises smoother now but still reading 9.5 a/f at the richest point during cruise[momentarily]. The best gas mileage I have seen is 17mpg.

I think I will drive around with the F11s in for a while to see how it feels.

shag55 · Post by **shag55** » Wed Dec 10, 2008 8:26 am

Ust a not, you can stagger the jets since both barells are use in one plenum. I use both f-11 and use a 50 and 55 idle jets. And use 155 and 160 mains to get it tuned as close as possible. I realy like the progressive design. I know a guy the modified one like this. He used a 40 then bored out the secondary to a 48 and cut the shaft and made his own progressive linkage to open the 48 bye a vacume diaphram of a rodchester. I would like to know where this carb is today. He sold the car back in 92.

brookester · Post by **brookester** » Wed Dec 10, 2008 2:17 pm

What are you using for accelerator pump jets?
If you mash the pedal do you get that lean stumble? I can't totally get rid of that and I'm already down to 32mm venturis. I'm afraid if I go any smaller I will lose too much top end.

Do you have any pics of the changes you made to the carb? Sounds pretty interesting

shag55 · Post by **shag55** » Thu Dec 11, 2008 9:08 pm

no pics. I put a 0 one way valve at the bottem of float bowl to increase the fuel pressure to the squirters and open up them up to 50s or 60s

brookester · Post by **brookester** » Fri Dec 12, 2008 4:56 pm

I'm using 60 f9/65 f9 idles, 165/175 mains, 175 airs and 75 pump jets with a heavier spring and a 0 size valve at the bottom.
I wish I could find a way to have a little jets located near the end castings that would give a quick squirt when I mash the throttle.

Kinda like moving the pump jets closer to the cylinders.

Joe vw · Post by **Joe vw** » Fri Dec 12, 2008 8:07 pm

Ok here's a couple pics:

shag55 · Post by **shag55** » Mon Dec 15, 2008 8:45 am

Nice Joe,
Is the shaft split and does is open all the way under vacume and how much does it take to open it?

klrskies · Post by **klrskies** » Mon Dec 15, 2008 3:24 pm

Could good results be had with a progressive weber, or some other progressive?

Joe vw · Post by **Joe vw** » Mon Dec 15, 2008 6:11 pm

Yes, the throttle shaft is split, the secondary will open all the way and is Vacuum adjustable with a screw (can open with very little vacuum). If you notice the 3 shaft collars in the middle, one is just a spacer, another is a modified accel pump actuator (offset) and the other has a stop that hits a tab on the pump actuator collar to close the secondary and limit it's opening to the same angle as the primary.
While a progressive 2bbl downdraft will work, it is much smaller than a 40 dcoe. most are 32x36 and are difficult to tune (jet changes) as well as space constraints.
It hasn't been installed yet, but everything is smooth and bench tested correctly.
This carb also had bronze bushings for the middle if the throttle shaft. I made a boring bar tool and aline bored the carb for 8mmX19mmx6mm sealed ball bearings. Each throttle now has 2 bearings.