Reversion with Webers

[Rick Parker]

Here is a link to a good Dyno video of a Weber (IDFs??) equipped Ford. Notice the mist above the stacks when they are leaning on it.

http://youtube.com/watch?v=Dfz_pNjrWJ4

[eschaider]

In the late 60's we had a similar problem with 4500s on Individual Runner (IR) manifolds on Hemi's. As soon as we put a plenum between the 4500s and the runners the fogging went away and the power made a significant step upwards.

If I remember correctly at certain rpms the IR manifold produced a standing wave that pushed some of the atomized fuel out the top of the carburetor. Changing runner lengths only changed the rpm the standing wave would form at and didn't get rid of the problem. The plenum under the carbs fixed the problem.

Ed

[Rick Parker]

That may answer the question I have had regarding the different design of the runners of IDA Manifolds aside from how the carbs themselves mounted on the manifold. Some used on the GT 40's had a "bulge" immediately under the Carb mounting face that created a small plenum(?).

Example of each:

1. http://cgi.ebay.com/ebaymotors/Cobra...spagenameZWDVW


2. (RRRGHHH) cannot find the other, it was on Ebay last night. Maybe it was pulled

[RICK LAKE]

Rick Parker RWJ has the pictures of the GT-40 manifold you are talking about. I think he even owns one. He is on the FE forum. As for the mist, that could be coming from the cam have not enough LSA. Webers like 112 min, 114 is alot better. The other issues are the back carbs get dirty air and air doesn't like to turn 90 degrees. A sealed airbox with clean air is good for 10-20 HP. I will let you know when the 498 is done with the TWM 58's. Rick L. Ps you you going to feed that cat on the pole?

[Driveway Bob]

Originally Posted by Rick Parker

That may answer the question I have had regarding the different design of the runners of IDA Manifolds aside from how the carbs themselves mounted on the manifold. Some used on the GT 40's had a "bulge" immediately under the Carb mounting face that created a small plenum(?).

Example of each:

1. http://cgi.ebay.com/ebaymotors/Cobra...spagenameZWDVW


2. (RRRGHHH) cannot find the other, it was on Ebay last night. Maybe it was pulled

Is this the manifold with the bulge?

[Rick Parker]

Yes, that's the one!

[speed220mph]

The standoff is a good case for running an air cleaner or housing on the carburetors. When running a Super-V at Daytona in the early '70s we found that the standoff was blown away at high speed . . . carbs projected out in the airstream . . . on the high banks, leaning out the engine . . . not good. When jetting for the high banks, the engine was way too rich on the road course. Solution was to install a ram-air housing on top of the carbs to provide some pressure on top of the carbs, but also to contain and use the A/F mixture (standoff) that would otherwise be blown away. Car was much faster and fuel consumption was less.