Stupid question? Difference between Weber IDA and IDT?
 

Hi all,

Not sure if this is a stupid question, but I am trying to understand the differnt Weber models. Did an archive search but didn't find much. I'm trying to figure out the difference between the Weber IDA and IDT carbs.

Is the Weber 40 IDT 3C the OEM version of the Weber 40 IDA 3C? Are there differences? Do they work the same and use the same jets. Is the IDT less desirable?

Thanks for bearing with me.

Charlie

IDT was the version for the samller T cars and the IDA was the versions for the S cars.

The venturi, jets and several other components are different and will need to be switched out in order to get the same performance.

If you are going to use carbs it is probably in your best interest to find a set of IDAs because they are more flexible.

Both were OEM parts but for different models.

Hopefully someone will chime in with some precise infromation.

Adam Roseneck

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1978 911SC 3.0
roseneck@cyberbeach.net

Hi;
The IDT was used on 911T's and does not have the high speed enrichment circuit that comes on the IDA (I believe). Other than that they are just as rebuildable (i.e. they use the same type of jets, removable throats, etc.). IDAs would probably be more desirable for racing, but dont pass up IDTs for the right price. Just my humble opinion. RSY

Oh yes, also,
Depending on your specific application you will allmost certainly need to rejet your carbs any way. RSY

The above is true, but it's the IDS that has the high speed enrichment that came on the 67 S model. The only real difference in the IDT besides the jets and venturis is the idle mixture screws which are more fine tunable on the IDT for more accurate adjustment since they were set so lean to pass emissions in those years. There is nothing wrong with the IDT other than the fact that the newest one is going to be 30 years old! Which is ok as long as its not shot.

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Tyson Schmidt
72 911 Cabriolet
92 C-2 Cabriolet