Triple Carb Individual Runner Intake

[crazycasey]

Ok, so I am back bouncing more odd-ball ideas off my favorite Mopar folks.

I have a fabricator friend that used to run an old flathead dodge and he said he made it go way fast with a stainless steel individual runner style intake (no plenum) with three small one barrel motorcycle carbs. He said that the stainless steel made the air/fuel charge cold which crammed more fuel into the chamber, without the puddling effect you get in a plennum. He also said that he added balance tubes in between the three runners. He is itching to build another one of these setups, and I am the likely guinea pig, but I was just curious if anybody had any practical experience with a setup like this? Also, do you think that a setup like this could still be streetable, as my motor is mostly stock, except for a shaved cylinder head (which I am doing right now).

Thanks!

[greg g]

Bike carbs maybe ok but you might want to look at 2 Solex carbs from a triumph or Jaguar on a similar manifold set up. They come in lots of throttle bore size from 1 inch on up, and they have adjustable main jets

or a couple weber side drafts

[Kustom52Mopar]

I don't know much about all that technical stuff but I'd love to see it!!!

[Normspeed]

I say give it a try. Even with a stock motor you'll have fun, and later if you open up the exhaust system a bit that will help performance too. I'd start with something like the carbs he used on his first one since he says that ran real good.

Some Honda carbs even had accelerator pumps. I had a 78 CX500 that I added 80 CX 500 carbs to, with pumps. Rejetting is also usually pretty easy on the motorcycle carbs.

[crazycasey]

Can anybody help me to determine the proper size for my carburetors? Is there a formula to determine size? I was over at the Ford Six Performance site and a lot of folks are running three 34mm webers on 200 cid inline sixes. I was thinking that that oughta be pretty close, and they are $108 each brand new.

[48mirage]

Here is a link to a CFM calculator. You will need to divide by 3 and then find the closest carb you can based on the CFM ratings.

http://www.csgnetwork.com/cfmcalc.html

[Don Coatney]

Sounds interesting but I dont much believe the stainless runs colder theory.

[crazycasey]

Sounds interesting but I dont much believe the stainless runs colder theory.

From my limited materials knowledge, the stainless doesn't transfer the heat like the aluminum (or cast iron for that matter), so while the aluminum will cool faster, the stainless will take longer to get warm in the first place.

[martybose]

The biggest reason the stainless manifold/bike carb setup would run cooler is the total lack of any exhaust or water heat into the manifold. The material is almost irrelevant.

Marty

[Tony WestOZ]

Here`s a simple S/U set up

[crazycasey]

Well...I'm sure it's negligible, but my thoughts are, stainless is strong, doesn't rust, polishes up nice, it's easy to fabricate, and if it doesn't transfer heat as much as mild steel or alloy then that's just a bonus.

I'm really interested in hearing your thoughts on the carburetors though. The Weber 34 ICT's are a very compact 34mm single barrel design that flow approximately 150 cfm each. They are a down draft design and would be installed on a U-shaped manifold with no plenum...I know it's going to look bad ass, but does anybody have any thoughts on how it might perform? Does anybody know of somebody running this carb on a mopar six?

[48mirage]

3 of the Weber 34 ICT's would be about half again too much. Two of them would be right if you were running a 230 cubic inches at 100% volumetric efficiency at 4500 rpm. Take a look at S&S carberators for motorcycles. I run a Super E on my 74 cubic inch HD and it's fully fits the bill. They are readily available easy to work on and jets are plentiful and easy to replace.

[Kustom52Mopar]

Here`s a simple S/U set up

That is really neat!! Is that car in Australia or some jazz?? The master cyl is on the pass side firewall.

[Tony WestOZ]

I cannot remember if its Australian or New Zealand.

[david lazarus]

I cannot remember if its Australian or New Zealand.

We are crazy enough to try what was pictured.....I know a guy who's father ran MOPAR flatties in his racing boat (1960's to mid 70's). His old man could get them to rev to 5500 rpm !!! 6 motor cycle carbies, lightened flywheel, straight pipes, only one compression ring and one oil ring !!! He would only get 1 season out of an engine!!! Said they were indestructable engines..but his were a limited life item.

[crazycasey]

3 of the Weber 34 ICT's would be about half again too much. Two of them would be right if you were running a 230 cubic inches at 100% volumetric efficiency at 4500 rpm.

I have to ask the question...with such wickedly large over carburetion, is she going to run like complete and total garbage...I mean, not that the Ford guys are that sharp or anything, but they are running three of these on 170 and 200 cid OHV motors and talking about great performance, drivability and economy. Hell, the vw guys are running two of them on 100 cubic inches.

Also, I just came accross a beautiful trio of Holley 94 (Model 59's)...they flow 155 cfm a piece, but they look sick in a row on top of the flatty. Can I jet these carbs down to make them work.

Also, remember...the manifold that I am running is an individual runner design, so I want have 450 cfm feeding a 230 cid motor. I will have three 150 cfm carburetors feeding three 77 cid motors.

Also, in the tradtion of our past time here, I am willing to live with a vehicle that's a touch tempermental to achieve an aesthetic that is as crazy as hot roddings past.

[48mirage]

As far as the Furd guys. I'll bet they are running a more open exhaust. The Overhead valves would be less restrictive, most likely a bigger cam and higher rpm. All of these would effect the volumetric efficiency of the engine. I'll also bet their idle is a little rough.

I don't know anything about VW's.

I run a single Holley 94 model ECG with 1 1/16" venturi's (one of the bigger ones) and my rpm runs a little high. I could probably jet that down but I'm only talking about 50-100 rpm too high so I'm not in a hurry to "fix" that. There are still parts available for the Holley's. An internet search will locate several vendors and notes on working them right.

http://s262.photobucket.com/albums/ii86/jacobsheir/?action=view&current=Holley94.jpg

The most common problem you will have with over carberation is sluggish low speed response.

I would suggest using the link http://www.csgnetwork.com/cfmcalc.html or any of the other carb calculators out there and figure what will work best for your engine and how you plan to drive it. I'm sure there are a number of choices out there for carb's that will satisfy you desire's.