-6 venturi sizing Options

[mb911]

I am starting my carb build for 2.4 s piston solex cammed engine. In my research it looks like 34mm venturi sizing is correct. Any feedback from those that have been there?

[gereed75]

My motor is a 2.4 mod Solex (DC30) JE 9.5 CR T distributor (crane optical) stock heat exchanger, heads ported to 36 intakes, stock exhausts (33 - 34 IIRC). Intake manifold port matched to head and carbs.

My 40 Weber s are set up with 32 venturis, 60 idles, 180 airs 140 mains 110 air bleeds and I think F26 tubes.

Car runs really well. Tuned using O2 sensor and A/F's are all in the 12 - 13.5 range.

Carburetes cleanly from low RPM up to a 7200 limit.

34's might work but I suspect you will sacrifice some torque and low speed and transition smoothness.

Worked with Paul Abbott at Performance Oriented on this set up. Followed his blue printing procedures to a T. One of his customers had this motor with this setup on a dyno and as I recall it made 195.

[mb911]

That helps that is what I will go with to start.

[johnhora]

Ben...go here for Weber set up...

http://members.rennlist.com/webercarbs/Web...et_Settings.htm

[914Toy]

32's are a good "street" choice, 34's will likely give acceleration hesitation.

[brant]

it depends so much on how you intend to use it
if you want torque in the mid range, or hp at redline.


I ended up with 35mm venturi's on my 2.0/6, but its all about HP at redline for our set up, and we determined that after trying 32's, 34's, 35's, and 36's on the dyno.

not the set up you'd want on a street car

brant

[mb911]

Mine will be all street. I have 27mm venturies so will just machine out to 32 and use that as a starting point.. Then probably do some jet drilling.

[gereed75]

The chart calls for 135 mains. This would probably work out ok in combo with the F3 tubes. I think that the F26 tubes lean out the mains at a lower rpm than the F3 tubes and thus you get a similar transition with either combo - smaller mains not leaned by the emulsion tube or larger main leaned earlier by the F26 tube.

I think I have too much spare time today!!

[porschetub]

Great replies here,when I was researching it seemed the 34mm will work with a 2.7 better,for example earlier on I ran 32mm on my 2.2 and it felt flat until the rpm climbed,started to pull hard but generally it was time to change gear anyway.
It was definitely harder to tune and just seemed fussy,I realized my mistake and when to 30mm....things came together then so that's where I'am now.
Good luck Ben.

[914Toy]

34's work well "street" in my 2.7 with 40 Webers.

[Larmo63]

We had issue with the 34s that Paul Abbott specified. I changed them to 32s on a 2.4S spec motor, and it runs much better.

Do 32mm.....