<VV> 4x1 4 carb engines

[Mark Durham]

Jim, thanks for the information. I'm sure you have read Craig Nicol's
articles on his 140 hp EFI? He did add a fuel injector at each intake, and
a throttle body to replace the single carb, all off a Pontiac Fiero, and
the system worked great.

It is good to note that the carbs supply sufficient air for the engine,
well, at least the four do. That tells me that there is no need for me to
bore out the venturi in the carbs, to increase airflow. I fully agree on
the location of the fuel injectors. In the intake manifolds would be best,
but that means a head modification I do not want to do. My thought process
is to add the fuel in just about the same location as in the carb, just
above the throttle plate,

My concern is that in a progressive linkage setup, the secondary carbs are
shut off completely, so there should be no fuel being sprayed in there
either. Hence, my question on a setup where all four carbs run, even at
idle. If a stable appropriate idle speed can be had by reducing how much
each throttle body flows so they are all the same, then my plan to add the
extra carbs as throttle bodies and install a fuel injector in each, would
work. However, if it is not possible to get a good idle speed with for
operating throttle bodies, then I will have to find a different solution. I
know I could weld the fuel injector bosses to the manifold. that would
solve the problem..

Regards  Mark Durham

On Wed, Jan 11, 2012 at 4:13 AM, James Davis <jld at wk.net> wrote:

> I ran my 1965 Corsa 140 with the early Eico  manifold and a 390 Holley
> 4-barrel #6299.  The Holley was modified by Redline to use Weber emulsion
> tubes and jets.  I ran this setup for four years in Fort Worth , TX  and
> six years in Limestone, ME.  I can say it never worked well.   The major
> problem was low speed bog.  This is because of the distance between the
> intake valve and the carb venturi.  The vacuum signal to the carb was
> insufficient to provide the correct mixture during acceleration.  I
> modified the carb with a 50 cc fuel pump and tried different cams to try
> and cover the lean condition during acceleration.
>
> After a highway run when the ambient was 40 to 70 degrees, the manifold
> runners would be coated with ice.  I ducted air from the left engine lower
> shroud to the carb to try to help the icing problem.  This did help some.
>  With fuel injection in the heads next to the intake valves both of these
> problems vanish.  There was no noticable increase in power with this
> conversion.
>
> At 6,000 rpm the engine needs 284 cfm assuming 100% volumetric efficiency.
>  The stock carb supplies 86.5 cfm @ 1.5 inches.  4x86.5 = 346 cfm  so the
> stock carbs are not the limiting factor.
> Jim Davis
>
>
> On 1/10/2012 11:34 PM, Mark Durham wrote:
>
>> Gents, I'm looking for people who have converted their engines to the 4
>> carb using the 4X1 conversion kit, to get their expereince on the
>> driveability of the engine and on how the linkage works.
>>
>> Has anyone done the kit and removed the progressive portion of the
>> linkage,
>> so all 4 carbs come in together?  I believe Clarks mentions the
>> progressive
>> as the better solution, however, I seem to remember an article back in the
>> 60's that says non progressive works, too.The article on the 4X1 back in
>> the late 60's I ran across somewhere but lost. Does anyone have a copy I
>> could get? I think it speaks to this situation.
>>
>> The reason I am asking this question?  I am working on a EFI conversion
>> for
>> the car. My original intention was to convert the two carbs to throttle
>> bodies by boring out the venturi to the 1.25 bore at the throttle plate.
>> This gives approxinately 17% more air.
>>
>> Another option is to add the 4X1 kit to double the air supply, so the
>> engine can breath the best it can. I would then, add a fuel injector at
>> each of the 4 throttle bodies. But in this scenario, each carb must open
>> at
>> the same time so there would be appropriate fuel flow to the cylinders
>> from
>> all four carbs. Alternatively, I could find a place to add the four
>> injectors to the intake runner, rather than in the carb, as planned.
>>
>> Hence, my question, if anyone has a running a 4X1 without the progressive
>> linkage. Or has anyone experimented with it and likes one over the other,
>> and why.
>>
>> I know there are those who have commented that I should change out the
>> heads to 140's and so forth. Some say that adding the extra carbs only
>> burns more gas, and so on. There is no doubt that the 140 heads and bigger
>> valves provide more breathability potential. My heads have been ported,
>> the
>> chambers welded up and modified like a 140's, and the spark plug hole
>> moved
>> closer to the exhaust valve. So, I think I have a good set of heads and
>> will modify them to be the best they can be. I already am running 140
>> manifolds and dual exhaust.
>>
>> I've read all of those remarks and we don't need to go over those items
>> again. I've got all that data, and just need to fill in a few holes to see
>> what will work well for my intended conversion.
>>
>> I've also started a thread on Corvair Forum asking for the same
>> information.
>>
>> In the mean time, I'm replacing upholstery side panels, rear and kick
>> panels, tuxedo carpet, and seat covers this winter! I'm also adding a
>> three
>> point shoulder/seat belt system in the car and adding seat belts to the
>> rear seats.
>>
>> Should be a busy winter!
>>
>> Thanks in advance
>>
>> Mark Durham
>>
>
>