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I'm going to try a Weber 32/36 on my ITB Pinto, couple questions...
Does anyone sell an adapter? (2.3)
If so, is it a good design?
If not, any advice on DIY design?
I was going to get a DGV 5a , or would the DFV be better? Seems like the DFV would have the primary/secondary on the same side as the Holley 5200. Does this matter?
Thanks
Ajg,
There are a few options here. Be specific about the carb to use. A "32/36" should be a Weber DGV, available in a few models, which vary by type of choke...ergo different suffix letters. The carbs are identical in mounting pattern to the Holley/Weber 5200, except for the following points:
Throttle bores are wider apart than the 5200, and they are reversed in position. The wider spacing means the DGV will not fit the original EGR plate, which has pre-placed holes of appropriate sizes for the primary/secondary bore positions. The different positions of the throttle bores will necessitate revision of the throttle linkage to change the pull from one throttle shaft to the other.
If you remove the EGR plate from the intake manifold (four bolts), you will see the pattern on the manifold is identical to the Holley 350/500 two barrel carb. There fore an adaptor will mate the base intake manifold to the DGV/5200 four bolt pattern.
The "adaptor" can be made from a commonly available one inch spacer made for the Holley 350CFM/500CFM series, available in ANY speed shop. Most are crude castings, oval centers, and should be machined by hand to shape the flow. To be an adaptor, you must only drill and tap four metric holes, mount the original studs and then the carb to those studs. Commercially available adaptors are located at Racer Walsh, and Esslinger. I made my own.
For general information, I was able to mount different carbs on a flow bench and found the following information. DGV flows about 25%more air than the 5200, and coincidentally, has a 25% larger inlet (choke housing) to the same size venturi. Theory is that the straighter flow to the venturi is responsible. I had experiences like this working with velocity stacks on Holley four barrels carbs. The float bowl is a bit larger, but I never had difficulty with the 5200, so this was not a reason to change carbs. All main jets, air correctors, emulsion tubes are interchangeable between the two carbs. Floats are different...plastic for the 5200, typical brass for the DGV.
The engine does not care about the position of the primary throat, since the throttle shaft is properly placed parallel to the crank shaft in true Weber style. One must read the Weber Master Catalogue to know why this is a necessary relationship.
Air cleaner style and location are CRITICAL to flow thru the carb (5200 or DGV...same height of choke housing). The top of the air cleaner housing should be the MAXIMUM distance from the edge of the choke housing. It affects the flow over the choke housing edge...straighter shot means less turbulance thru the venturi...actually more flow thru the carb. I used a design of air cleaner that was nothing other than a filter, open at the top, that pressed on the undersurface of the hood...the hood was the top of the "housing"... ergo maximum height.
These may be points to ponder for you. If you need more information, please e-mail me at:
[email protected]
Good racing.
Bill :024: