I have a pair of good Weber 44 IDF carbs but thinking they may be too small for the 2.7l Type4 being rebuilt. Anyone have some coaching on carb sizing?

Edit - maybe up to a 2256?

Thanks!

See the following for a formula on cylinder volume vs. rpm vs. venturi.

http://www.performanceoriented.com/throttl...-venturi-sizing

My guess is you would want a 40mm venturi, so a 48mm IDF or DRLA.

Run the 44's, I'd use 36mm vents for a car that sees the street.

Thank you for the responses.

Guidance on this seems to be all over the map, but I think I’m more concerned about giving it too much carb rather than not enough. I’d rather have good off idle behavior and what worries me about the 48s is they may ultimately produce more power but it’s at a RPM that all rarely be at in a streetcar.

I assume that’s behind your suggestion Mark Henry?

Great resource @yeahmag

The Performance Oriented site info is for a six and IDA Webers.
I'd spend my coin on better heads, etc. before I worried about the 44's.

The single cylinder chart still works. It's similar, if not the same as what is in the CB Superformance book for Dellortos and I've used the model many times. Granted, I'm not really after low end for my cars, but I drive them around town easily.

I ran dual 44s on a 2056 and they were necked down as far as I could get them and they were still too big. All my power was from 4k-6K rpm. For a 2270 44s would be about perfect.

That said -
Get fuel injection.

Zach

Thanks for all of the ongoing discussion, very helpful.

@VaccaRabite - I have a barely used set of Weber 44 IDF carbs that came with the race car, so I would love to put fuel injection on this but I think I’m gonna try running these first. FI would be a great upgrade at some point however!

...if you can afford it.

In a perfect world I'd have EFI and electric a/c on the 914 and 356

I built a 2.7 engine for a speedster replica back in the mid 2000's and I used 44's. I know I posted some pics but I did a search and I can't find it. Very fast little car, but the bug gearing was too short.

Similar experience here. I ran 44's on a modified 2.0L with headers. The carbs were too big and powerband was similar to what is mentioned above.

Thanks for all of the responses and shared experiences.

Brought the 44's to the shop and explained my drivability goals and they agreed with the coaching you all have provided.

It has been very helpful to get all of this feedback from you - thank you again.