Dual down draft Carb selection for 2056 Options

[technicalninja]

I'm looking at the Empi dual down draft carb kits and had a quick question regarding differences in the carbs themselves.

It looks like they have HPMX or Dual D carbs available.

Which one would you choose?

Should I lean towards real Webers or Dellotos?

The intention here is to use the kit in its stock form initially and later change to port fuel injection using the carbs as throttle bodies much like MB911 is doing with his EFI conversion.

http://www.914world.com/bbs2/index.php?showtopic=363246

Being able to remove everything in the bores is critical for me. No fixed boosters or venturis is a requirement.

I'm planning on starting with an 8.5-9.0 compression 2056 with a webcam #86.
I am planning on having the final engine as a 96mm bore/78mm stroke, but this will be in the future.
I believe I should start with 44 mm carbs instead of 40.

Suggestions, tips, and opinions would be greatly appreciated.

[technicalninja]

Choose a 40 IDF combo for the 2056 914. I hear the Empis are pretty good for the $$ and can be set up to run well. If you can get the Weber or Redline the parts all fit well and the jets and such interchange as they should
Unless the engine is reving over 6k headers and head work you will not be needing the 44 and may be more than necessary and can be a bit more on the tuning and possible less throttle response

That said I LOVE my 44's on my 2056 but she live in the upper RPM range most of the time

I see the 40mm as at top of its range on a 500cc cylinder.
It should have better low and midrange fueling vs the 44mm.

But, I will not stay 2056 very long.
I'd prefer to start with 2270 if I could.

I am on a very tight time schedule as I am building this car with my 82-year-old father (who is the REAL Porsche nut in my family) and he has Multiple Myeloma...

He got this shit from exposure to agent orange in Southeast Asia...

It will not be long till he goes "wheels up" for the last time and I have to get this car to a usable status rapidly.

I'd rather start with a stroker, aftermarket FI, and a bunch of extra stuff but time dictates this will start carbureted, COP, and small (2055).

I believe I should spec out 44mm carbs as these have more "headroom" over 40s

Thanks for the replies everyone.

I was hoping to use the cheaper Empies as I don't think they will be delivering fuel for very long and they will end up being simple butterflies in the throttle tract.

Brand new Webers are $350 more. Strangely PMB says "Made in Spain" and back when I was screwing around with DCOEs the real Webers were made in Italy...

A Datsun L28 has 460cc cylinders and they definitely preferred 44s.
The very best carbs were Mikuni 44PHH. I've had multiple sets.
I saw a nice Z-car set sell on BAT for $6,666...
UNBELIEVABLE!

[Superhawk996]

I believe I should spec out 44mm carbs as these have more "headroom" over 40s

Don’t spec out carbs for headroom. Spec for what you have.

You can get up to 36mm venturis for IDF40s which will be big enough and will still retain driveability.

When you get to the point that your pushing 600cc / cylinder and it’s being choked at above 6000 rpm, then you could justify 44s but you’ll end up choking those down to 38 vents.

This is the standard chart for Venturi sizing vs Displacement and RPM. This chart is all about top end flow and top end HP assuming headers and open exhaust. This chart does not reflect the what is best for street driveability.