My 3D printed carb horns

[Dantheman]

Your stock air cleaner.... if its sss l18 i would be interested in buying if you have no further use for it. And the air horns are quite nice. Good work.

[Tristin]

Not sure about those 'swirl inducers'.

I was thinking the same thing. Awesome work on making the horns, but the "vortex generator" just reminds me of the Fuel Cyclone or whatever it's called. Supposedly was suppose to spin your air/fuel to atomize it better for increased fuel economy.

 

Was proven to be bunko.

[TENDRIL]

i would say it needs to be re designed, less angle  and a lot less ridge maybe even sunk below the walls  to creat any kind of usable flow, as the best flow would be the least amount of resistance 

[Dguy210]

Think golf ball dimples. You want a turbulent boundary layer to reduce drag at the interface and maintain a laminar flow.
 

[JNHEscher]

I was talking years ago about golf ball dimples to fellow classmate who was working closely with our drag racing teacher. The idea sounded brilliant and last I heard they had it in use and thought well of it. I've yet to experiment with any spare runners or heads.

[_UNKNOWN]

I'll take a set of printed NRCAs please? Bahaha XD

 

These are really badass and the fact you used a 3D printer makes it even more raw.

[smoke]

Here is something for you, in case you're ever on Jeopardy and velocity stacks are a category.

 

I find the velocity stack to be one of the most misunderstood pieces of tuning equipment. That's probably because good info on them is lacking. All the average tuner sees is ads that sell them.

 

First, VS are not for looks. They correct an airflow problem non-plenum carbs have at certain engine speeds.

 

A "plenum" is just a space or area. V8 builders have a plenum area under their big 4bbl carb manifolds. The plenum space allows a common area from which the cylinders draw an air fuel charge, and the plenum acts as a cushion to dampen the violent reversals of air velocity that occur between the carb throat and the intake valve.

 

Yep. The air coming into a carb and intake manifold is not just on a one-way trip. The intake valve slams shut as the air is flowing, and a shock wave created by the sudden halting of flow shoots straight back up the manifold into the carb. The force of this "reversion" can be made worse by some cams.

 

A plenum design gives that shock wave a place to dissipate.

 

Plenum designs are much easier to tune than non plenum systems, which covers the Weber, Dellorto, and similar designs.

 

The disadvantage of the plenum system is it is not as tunable as the Weber type system.

 

Webers are forced to have velocity stacks, because at certain RPM ranges, the return shock wave from the intake valve literally forces air/fuel out of the top of the carb. The velocity stack (sort of a misnomer) is just an extension of the carb to contain that air/fuel revulsion.

 

If there is no VS, the air/fuel mix gets messed up, and a carb fire is a good possibility with aerated gas now being ejected into the engine compartment. Just let a high-rev valve float on an intake valve allow a manifold backfire ... and this is why many old time Weber tuners think of air filters as fire safety devices ... flame arrestors.

 

VS stack height is related to manifold length.

 

Race tuners know there is a specific length from the carb mouth to the intake valve that produces the best power at a specific RPM. For racing, you can change this by just changing VS!

 

For the street, you have to compromise. The short Weber manifolds most kits have work just fine with the appox 3" high VS in the same kit. For variable RPM road racing, a 1.6 engine redlined at 6000 needs about a 16" runner length, meaning the total measurement from carb mouth to intake valve.

 

Shorter runners lengths give more power at high RPMS, longer lengths give more power at lower RPM's.

 

By the way, the Solex carb design sold by Kadron is a plenum type and needs no VS, even though you can buy them. And, a last oddity between plenum and non-plenum carbs is there is no direct comparison between performance and venturi sizes.

 

Plenum carbs don't need the same size venturis as non-plenums to give equal performance.

[97_luder]

Thanks for the support and knowledge. I love running ideas across people who have the same passions as you. This started out as a project while i was board and know it has grown into a decent tread. But I have had the horns on there all week and the heat has not been an issue at all. My printer is a Makerbot Replicator 2X and I design in SolidWorks. I am open to making parts for our cars. I just found out one of my coworkers can make a cast part from my printed parts. So shoot me some ideas of parts to make. Looking forward to the suggestions.

[MikeRL411]

 

Thanks for the support and knowledge. I love running ideas across people who have the same passions as you. This started out as a project while i was board and know it has grown into a decent tread. But I have had the horns on there all week and the heat has not been an issue at all. My printer is a Makerbot Replicator 2X and I design in SolidWorks. I am open to making parts for our cars. I just found out one of my coworkers can make a cast part from my printed parts. So shoot me some ideas of parts to make. Looking forward to the suggestions.

 In order to make a properly sized cast part, the plastic "mother" needs to be oversized to account for shrinkage as the cast metal cools. Trial and error ?

[97_luder]

 

 In order to make a properly sized cast part, the plastic "mother" needs to be oversized to account for shrinkage as the cast metal cools. Trial and error ?

That is correct. I print the parts at 102% to account for that.

[Buzzbomb]

That is awesome! If you're worried about heat from the carbs going to the the horns, why not lessen the thickness of the base a little and make some gaskets with material you can get from the parts stores? You're probably already doing this anyway, but I couldn't see a gasket in the 1st pic. That sure is cool...The possibilities with technology like this for old car owners is really great! The only thing missing from this equation when it comes to turning some of those parts into metal is a backyard foundry :D !

[Ratwagon1600]

RW loves 3D printers!

 

This is nice work dude, well done.

 

Im with some of the other guys as far as the swirl inducers but hey, they look great.

 

This is a pic taken from a British guy who modifys the early Minis. Its a flow chart for different ram tubes (for SUs) and gives the best shape/angle to optimize airflow.

 

 

PM me with an email address if you would like a bigger copy.

 

Cheers

[97_luder]

Hello Everyone. I'm back with version number 2. Please leave comments

[Ed-datsun521]

Black ones look good like the number 9 on the chart up there

[97_luder]

I just came up with a neat idea, tell me if you guys like it

[ArchetypeDatsun]

Now make some ITBs you know those would sell like hot cakes!

[97_luder]

I was thinking about printing the silhouette of the car in the side of the horn

[Laecaon]

Can you design the opening to take a filter that is already on the market? Just a simple velocity stack filter would be awesome.

[97_luder]

Can you design the opening to take a filter that is already on the market? Just a simple velocity stack filter would be awesome.

Are you referring to these?

http://www.hybrid-racing.com/store/hybrid-racing-velocity-stack-and-filter.html

[tr8er]

RW loves 3D printers!

 

This is nice work dude, well done.

 

Im with some of the other guys as far as the swirl inducers but hey, they look great.

 

This is a pic taken from a British guy who modifys the early Minis. Its a flow chart for different ram tubes (for SUs) and gives the best shape/angle to optimize airflow.

 

 

PM me with an email address if you would like a bigger copy.

 

Cheers

I'm baffled by the airflow discrepancy between 1 & 2.  Anyone care to chime in on why the fuck a #2 with sharp edge gets better flow that #1?  and why #3 with a radius edge gets again gets better flow?  this relationship between the first three makes no sense to me.  

[smoke]

it's really a bit of tripping over mouse turds, however, think of the stack submerged in water instead of air. Then start pulling that water in to the stack with a very high volume pump. With a radius bent over like that, you are going to see a lot of swirl and disruption in the water as it gets pulled by it. Air and water are similar in this aspect, they are both surrounding the stack and both will be pulled from around it (air even more easy) there will be a low pressure area on the outside of the stack when it's pulling really hard, with that curve, you are impeding some of its flow and are probably even making it come in all bent out of shape.

[smoke]

Oh and I see what you are saying about number 2 and I can't really answer that one, aside from maybe causing and odd swirling effect.

[housew]

love me some 3d printers. We send stuff out to get printed at work a lot for prototype stuff. I found one on CL for 2500 local, really been thinking about all the fun I could have with it. So many things to make.

 

I drew up a custom coil cover for my sr20det that's 15.75"*3"x~1/2" a its thickest. That something you would be interested in printing for me? PM me a price if so, or I can send you the file and you can think it out. Its just for looks really so any plastic would do. What are you printing out of for material?

 

I have no imput on velocity stack shape, although I find them quite interesting. Very cool thing to play around with though :)

[hotvwnut]

very nice work  love the 3d possibilities 

[Laecaon]

I dont understand how 1 and 2 are so vastly different, but they should be different. The sharp edge will help stop the turbulence at the edge, making it air either choose to go in our out, and not just hit a flat (albeit small) flat wall. 3 helps even further, as it aids in grabbing more air from around the stack. the air going in in the center will grab the surrounding air and scoop it in. That is why you see ALL of the stacks with that curve on the opening pulling more air.