Twin Webber Carbs

[Guest alexpink]

Bike carbs on a decent manifold look awesome, work beautifully, stay in balance well, sound incredible and make power as well as Webers will on that spec of engine. Webers are much more expensive to purchase and set up in comparison. The DGAS is a good budget option but doesn't make the right noises for this type of car!

Would recommend if you are aiming for that power range to run 37mm carbs off a 600, rather than using R1 carbs (unless you already have these); you don't need the extra flow at this power, and you will actually get more low down torque with the smaller carbs.

[Del1968]

I know the engine been rebuilt and has an fr32 Kent cam fitted bot sure what else will look if I went bike carbs I take will need new manifold where would I get one for my engine and would it then need to go on rolling Rd to set up I am gonna change the dash and dials but also want best performance from the engine

[Guest lotusPaul]

Just RE reading this a few times over before I spout off rubbish.

 

There are a few mis conceptions with IR individual runner, type induction systems.

 

Firstly Webber or Dell's are not thirsty. It's how they are set up AND a lot has to do with how you drive. And that means we all like a Sunday blast, so it's gonna be using fuel like its going out of fashion. It's the nature of the beast.

 

Secondaly, they don't produce any more power on full throttle than anything else. It's only a matter of air flow requirements and fuel.

In fact most are set up for max power at max revs, its then generally worked to give a good idle, and the rest interpolated throughout rev range.

It's the control over the fuel atomization that carbs inherently lack that makes fuel injection better in rev range.

Dell's are better in my opinion than webbers here as they have more tunable circuits.

 

It's been said many a Times here and on other forums. But to get the best out of every engine package, all components MUST be selected carefully to match each other and work in harmony.

 

All our collective best guesses on settings and timings are only that, best guesses based on knowledge,maths, or simply a similar engines settings.

 

BUT to get the best out of your engine it simply must be set up on a rolling road by a competent opperator.

[speedtripledan]

which is why my 2.0l zetec with high lift cams and 45dcoe webers returned 35mpg average in scotland driven hard. They are correctly set up and stay set up.

Edited May 21, 2016 by DanE

[Snapperpaul]

For a tuned, cammed 2.1 if you are insistent on Webers or Delortoes then 45's is what you need

To get a proper pulse signal the choke size should be 7mm less than bore size therefor max choke size in a DCOE 40 is 33mm and max choke size in a DCOE 45 is 38mm

The 38DGAS is good if jetted properly but in my opinion the veriable venturi bike carbs give the same power potential with a smoother delivery and at much less cost

[Guest lotusPaul]

I wouldn't agree with that but I can understand the theory. For instance my lotus had carbs and it needs 32mm chokes mathematically speaking. In actuality 36mm chokes worked best.

 

Once choke size is worked out multiply it by 1.25 for carb size. That would make mine as 32 x 1.25 = 40mm. In fact 36mm in 40 dcoe worked well and gave a torque curve that was very flat.

 

As a point of reference.

 

2.0 with peak power at 6000rpm.

36mm choke x 1.25 = 45mm barrel.

A 36mm choke will also fit in a 40mm too.

Choke x 4 = main jet size (initially )

Main jet + 50 = air corrector size

 

These will get you started for now and are very close to a 2.1 too, to get you started.