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Reply to "48IDA Weber abnormality"

You sync them at idle with the vacuum sync tool that sits on the stacks.

You usually can only sync one of the throats on each carb.  They have a common throttle shaft and normally even new are a hair off from the factory.

Original Weber 48ida's have soft brass throttle shafts and will twist with time so at some point they will need to be changed out IF you use too much return spring pressure on the linkage system.

You should be able to operate the entire linkage system with one finger, with little tension on it. That's what you need to aim for. Otherwise you will twist the carb shafts.

You also need to remove the solid tube located in the stock throttle cable assembly so it is flexible to bend to the connection point on your linkage otherwise the linkage will constantly hang up open. Any throttle cable has to be snaked through from the firewall and it has to be very flexible.



There are lines on the clear tube on the gauge. Three if I recall correctly? You need to get the carbs within one bar/line for each.

More importantly though, you have to have the linkage zeroed. If you don't you will have constant trouble getting the engine to idle down after a WOT run. It will idle at a higher rpm then you set it at since there is at least one carb throttle that is out of sync and holding the others open.

THAT can be the difficult part. It isn't like setting up a multiple Holley carb system at all. Those open progressively. The IDA's are tied together and all open as one.



I've got 12 inches at idle. The Pantera booster needs more then that. Somewhere around 18 inches. A Ford Bendix can get by with about 14.

What happens with the brakes is that the booster provides something like 150 to 200 psi more pressure to the brake hydraulic system. If you measure the pressure to the brakes, the fronts will show around 350 psi without any boost and the engine off. It will make the pedal feel artificially harder then it normally is.

With this brake system you want at least 550 if not more. 18 inches is what it is designed for and with that will give you something like 700 psi in the front.

The rear on the other hand will show 150 ish without any vacuum boost and if you do ANY kind of rear upgrades then needs to be restricted down to 80 to 100 depending on your car. So an in line pressure reducer needs to be installed AND the front pressure reducer needs to be removed.

This gets tricky and you run the risk of locking up the rears first before the fronts and the rear will come around faster then you can react to in any kind of a panic stop. In fact, you should never be able to lock up the rears at all even if you hit the brakes by standing on them. They are ALMOST just along for the ride.

The factory set up was done like that for a reason. The "average" Pantera buyer would not be able otherwise to handle the car safely.



I am running the Compcams vacuum pump. The only drawback is that it is noisy almost like a "construction air compressor" for a nail gun, BUT with a solid lifter cam and 180° headers on the car already, the noise just gets lost in the crowd and you don't hear it in the cabin.

Last edited by panteradoug
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