Benefits of a carburetor venturi

[IdriveSlideways]

What are they and what do they do? I know that they restrict the airflow into the carb, but isn't that the opposite of what you'd want? More air more power right?

 

[Certified Mike]

As far as I understand, the venturi does make it smaller BUT... That actually moves more air. Its a funky principal... The shape is also supposed to help make the air/fuel mixture finer and thus help burn more fuel creating more power. That's the idea in 1:1 and on Harleys anyways....
You're getting closer and closer to me having to confiscate that kyosho! Every question, 1 step closer...

 

[IdriveSlideways]

As far as I understand, the venturi does make it smaller BUT... That actually moves more air. Its a funky principal... The shape is also supposed to help make the air/fuel mixture finer and thus help burn more fuel creating more power. That's the idea in 1:1 and on Harleys anyways....
You're getting closer and closer to me having to confiscate that kyosho! Every question, 1 step closer...

That makes sense. If you want it you can fork out the 270 to buy one or come TRY to take it from me lol

 

[Certified Mike]

So what you're saying is that there MIGHT be a chance I could get it... Hmmmm... And Dad's optima too.... Hmmmmm.... Yup... I think maybe during the fireworks there might be a few loud bangs a lil closer than the rest as I fall in the floor thru the bathroom window... LOL!!!
Of course you know I'm kidding!!! Tempting just the same...

 

[IdriveSlideways]

So what you're saying is that there MIGHT be a chance I could get it... Hmmmm... And Dad's optima too.... Hmmmmm.... Yup... I think maybe during the fireworks there might be a few loud bangs a lil closer than the rest as I fall in the floor thru the bathroom window... LOL!!!
Of course you know I'm kidding!!! Tempting just the same...

You might have a chance if @Rolex drives the get away vehicle

 

[Certified Mike]

If we don't get away, we'll look good getting caught!

 

[olds97_lss]

What are they and what do they do? I know that they restrict the airflow into the carb, but isn't that the opposite of what you'd want? More air more power right?

If your talking about carbs that have multiple venturi inserts, they are for tuning purposes to fit the track/driver better, also to improve fuel economy. Usually, engines that have multiple's are racing type engines that have gobs of power, so a smaller venturi will calm down the low end grunt a bit to make a vehicle less twitchy on the low end. Or they may just use a smaller one because the engine has plenty of power and they are trying to get more laps per tank. So, less air means leaner fuel settings, which gives you less punch and lower peak RPM, but it would be a balancing act so the driver can adjust things how they want them.

For a basher, large bore all go no stop power is typically what is wanted.

 

[Certified Mike]

Lol! I guess the latter was what it was all about for a few friends with the venturis on their bikes. I never ran one personally (too much drama tuning them) for a big hole to suck rocks into and blow gas and flames at my leg. Seen them in hot rods too and it was the same thing... It was (as I had learned) about increasing the air flow and creating a better mixture of air and fuel mixture. I think this is the first time I have heard of using a venturi for power restriction (saving fuel) but it makes sense. Maybe something to play with some day when I run out of projects... Lol!
Would be fun to experiment with... See if I could work out a way to save fuel, keep temps in reason and still have power...

 

[olds97_lss]

Well, probably different for these engines as it's not something you add to the carb, it's something you replace on the carb. LIke this engine:
https://www.amainhobbies.com/o.s.-s...tion-buggy-engine-turbo-plug-osm1a200/p415825

Comes with 2 venturi's. 6mm and 6.5mm that you pop out/switch.

I'm guessing on 1:1, it's the intake stack to create a rounded edge for the air intake which aerodynamically accelerates the air as it's taken in and pulled over the curve, vs taking it into a straight walled tube.

 

[Certified Mike]

Yes, the venturi That I'm talking about is like a funnel shape... Totally different than a venturi type carb (pretty sure it was Ford in the late 70's or early 80's, not a particularly sucessful design) they were about creating a smaller opening which increased the airflow and should have created a finer air/fuel most providing a fuller burn and higher power. Created a swirl effect in the carb/intake which should (or at least could) have also slightly increased the over all cubic inch of air per piston, per stroke... Ideally. I guess I missed the boat with the rc venturi... I would swear I have seen very similar to what I am talking about for rc tho... I would imagine for similar effect.
So I am thinking that sheen you replace the venturi in that carb, it is the red ring as well as the tube that it's attached to?

When***

 

[olds97_lss]

Nah, just the red thing. It just pops out of the carb. If you look at the other photo's for that engine, they show the second insert taken out.

 

[Certified Mike]

Ahhh, ok. Yeah, I'm pretty sure what I saw had the whole funnel shape etc... Then again, when I'm tired, I have an amazing ability to overlook the obvious!

 

[ninnon]

Extra customization for the driver, to suit whoever drives it on the track.

 

[Certified Mike]

It seems like a reasonably easy way to customize as needed, with a lil tuning and not much investment (no pipes and carves etc...) I think once I get my current projects settled, I'll look into them... Just for the experience of nothing else.