Convert progressive 2x4 linkage to one to one.

[6667fan]

I wish to try one to one linkage on my tunnel wedge equipped 483. Can this be done using the OEM 2 x 4 linkage set-up?  If modifying any of the components is required that is fine. I expect the carbs to match from off idle to WOT. I also expect some retuning of the carbs as a result of this change but I’m down for that. Anyone have a pic of what they have done? Thanks much, JB

[WConley]

Be prepared for a big downgrade in street manners!  The progressive linkage gives you more control at low rpm / taking off from a stop.  With the direct linkage change you'll have a lot more airflow right now as you press the pedal.

I worked on progressive throttle bodies at Ford for awhile.  They really help control the bucking when you have a big herd of horses.

[BattlestarGalactic]

I made my own 1:1 linkage for my pickup years ago, still use it today on the wagon.

I use the factory crossbar linkage, but made my own threaded rods/ends to hook to the carbs.   Pretty simple actually.  I custom machined the rod ends from 1/2" square bar stock, then threaded it(so they stack up on the crossbar pin).  I don't think I have a good picture handy, but I can get one tonight/tomorrow and post it.

The pickup has factory progressive on it, I always set it up to be able to cruise along at 35-40 mph before it would start to pull into the second carb.

[e philpott]

Be prepared for a big downgrade in street manners!  The progressive linkage gives you more control at low rpm / taking off from a stop.  With the direct linkage change you'll have a lot more airflow right now as you press the pedal.

I worked on progressive throttle bodies at Ford for awhile.  They really help control the bucking when you have a big herd of horses.

Bill will it make as much difference on the single plenum Tunnel wedge as it does on the dual plane 2x4 ? , seems like it would starve a few cylinders out on the Tunnel wedge at part throttle

[Heo]

Be prepared for a big downgrade in street manners!  The progressive linkage gives you more control at low rpm / taking off from a stop.  With the direct linkage change you'll have a lot more airflow right now as you press the pedal.

I worked on progressive throttle bodies at Ford for awhile.  They really help control the bucking when you have a big herd of horses.

I have that problem on the Chrysler hotrod, not a big heard but no weight. With a wideratio toploader and 3.50 rear gear
I have to start in second or mash the pedal to the floor and hang on, otherwise i jump like a frog

[WConley]

Bill will it make as much difference on the single plenum Tunnel wedge as it does on the dual plane 2x4 ? , seems like it would starve a few cylinders out on the Tunnel wedge at part throttle
[/quote]

Good question!  I haven't heard of a part-throttle misfire (fuel distribution) problem ever showing up on a decent street intake by using a progressive linkage.  I imagine that on one carb, the flow velocities tend to be low enough in the plenum that the fuel stays in suspension.  Sure the air / fuel has to go farther to get to some cylinders, but the fuel would still get there.

I'm all ears if some of the racers have other tales!  My experience is with more street-friendly applications.

[6667fan]

I’m looking at it from how can cylinders 4 and 8 get a fair shot when the mixture is being dropped on cylinders 2 and 6 initially? This intake of course was not delivered on production cars. So it’s intended use of WOT or close to it has to be taken into consideration for street use. I put the intake on because they look so darn tough, not because it was going to be a home run for street usage, lol. I will report back about the 1 to 1 drive-ability.   JMHO, JB

[Drew Pojedinec]

I would think it wouldn't be an issue....
Despite just two throttle plates opening, all are bleeding fuel constantly.  Even a racy vehicle, when the throttle is opening slightly the pump shot fires and vacuum drops initially but rapidly rises.
This is with a slow opening, with a rapid opening, well it doesn't take much progressive linkage before the second carb is firing it's pump shot.

With my car and such a loose convertor I'm giving it a good bit of throttle to get rolling anyway.

I don't see any harm in trying it both ways.

[Stangman]

Besides the distribution do you think there is any performance gain going 1 to 1
over a progresive set up. Or do you think the mashing of the trottle negates that

[e philpott]

Only speculation on my part as it remains untested for me , my progressive linkage is hard to control spin with my street tires when in race mode  , it's like a trip hammer with the gas pedal all or nothing , my thought was 1 to 1 would give me more throttle control over the 2x4's during wheel spin situations , I now run drag radials so the immediate problem is solved and I'm still run progressive linkage so I don't know for sure , I'll just enjoy better gas mileage while cruising easy for now

[Stangman]

i also run progressive. I dont think there would be any performance gain although hell might as well ask to see what anybody else thought different. On the street progressive is the way to go.  I dont think 1 to 1 would be better at controlling wheel spin.

[6667fan]

Initial impressions: slight stumble off idle, no tuning of accelerator pump system has been attempted yet, no time to tune, just a run around the block. After that much better throttle response from idle up to 3500 or so. That area was not super impressive previously, until the second carb came in via the progressive linkage.
I like it a lot and am looking forward to more tuning. My A/F which was fat 2500-3000 with the progressive is now much better. I expected to see the opposite with the second carb coming in sooner but that may be due to the motor pulling harder on the one carb before?
Now the fatness 11.8/1 is moved higher up 3-4 K but I expect to sort that out via hi speed air bleeds and my A/F monitor.
It should be noted the intended use of this car is for thrashing, as such this attempt at increased low end performance with the possibility of some bad manners is not a hardship. Car has been to track twice and I’m all about getting it back there this fall.
Thanks for all input and would love to hear more.
JB

[Falcon67]

I ran 1:1 on the tunnel ram with the Eds.  I'm sure there is plenty of configuration dependent issues but once tuned I never had any problem with the 1:1.  On a dual carb dual plane, I'd for sure do 1:1.  Assume the front barrels on a 2x4 with vacuum carbs are wide open and offering 300 CFM each carb.  The dual plan pulls from only half the available carb area, so basically the open throttle area looks more like a 300 CFM 2 BBL to the engine than two 4 bbl carbs. 

You'll still have to field the "1200 CFM on a XXX CID, that's way too much" comments. 

[Heo]

There is a this Formula that say so........  ;D

[TimeWarpF100]

I wish to try one to one linkage on my tunnel wedge equipped 483. Can this be done using the OEM 2 x 4 linkage set-up?  If modifying any of the components is required that is fine. I expect the carbs to match from off idle to WOT. I also expect some retuning of the carbs as a result of this change but I’m down for that. Anyone have a pic of what they have done? Thanks much, JB

Here is what I did on my 482 Tunnel Wedge Combo 1:1 but I am running EFI