<VV> 4x1 4 carb engines

Wed Jan 11 22:13:52 EST 2012

Mark- Just to be sure, the 92 Camaro is a batch triggered injection system right? or is it sequential (timed) injection? however the injectors the fired, it is good to mimic that with your injector placement (sequential systems must be port injection, batch triggered may be port injected, but have a rougher idle)- If I'm not mistaken, the system you are going with will use four injectors, 2 firing simultanueously-correct? If so, I think you will have less problems if the injectors are mounted in a place where they wont be firing straight across from a wall- that is to say, I think the four injectors might work better if they are not mounted in the manifold log as the tendancyfor the fuel spray would be to hit the wall of the manifold (causing needless fuel puddeling), any time the air flow within the manifold was unusually slow-too tall ofgear with the throttle slammed open, for example. Perhaps a better injector placement might be to mount the injectors at the throttle bodys, like you were pondering. The system that I'm going to be using is also a batch triggered system, but the injectors are mounted at the top of each individual intake port, and the injectors areaimed to hit the backside of the intake valves- a really nice advantage with this approach is that it helps keep the intake valves cooler and helps control carbon build-up.It will have a somewhat rougher idle than stock- but whatever, if all I cared about was a smooth idle I wouldnt bother with the efi- it idles fine with the yh!Kevin Nash63 spyder, daily driver, soon to be efi
 Date: Wed, 11 Jan 2012 12:39:44 -0800
Subject: Re: <VV> 4x1 4 carb engines
From: 62vair at gmail.com
To: wrokit at hotmail.com
CC: virtualvairs at corvair.org

Kevin, great information. I will go look. You are correct, when you widen the venturi to that large, it tends to reduce the vacuum needed for fuel flow at lower rpm's, hence the problems. My computer should compensate for the amount of airflow to get the mixture correct.

I'm using the second generation GM computer, a 1223370, out of a 92 Camaro. It has wide use in Pontiac Fiero upgrades. The Fiero runs a 2.8 V-6 motor, and is within a couple hundred pounds of my Corvair, with similar horsepower and torque curves,. This is a OBD-I, I think, no cam sensor, but allows for a distributerless ignition system, and does use throttle position, heated EGT, vehhicle speed, knock, Inlet Air temp, MAP as you said, and coolant temp sensors, which Ted Brown figured out how to mimick in his kits. I'm doing the same thing. It also uses a idle air control. There is a fiero guy to programs the computer chips, I am going to use. My DIS and IAC came off a Lumina. 

I've got all of the theory worked out, and have taken suggestions from different people on how to solve each of those sensor's needs for the hotter runing Corvair based on their expereince, so, when done, I should not have many issues??  

Thanks   Mark Durham

On Wed, Jan 11, 2012 at 8:59 AM, kevin nash <wrokit at hotmail.com> wrote:

>
> Message: 4
> Date: Tue, 10 Jan 2012 21:34:09 -0800
> From: Mark Durham <62vair at gmail.com>

> Subject: <VV> 4x1 4 carb engines
> To: Virtual Vairs <VirtualVairs at corvair.org>
> Message-ID:
>       <CAEEoEu6nPPGAjcTS_=+JTDr2T=LoAYLDEimquZz+La9+Xy6BtA at mail.gmail.com>

> Content-Type: text/plain; charset=ISO-8859-1

>
> 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
>

> 1962 Monza Coupe, Red/Red
> 64-110 engine, 4 speed
>
 Mark- I have not done this, however there was a post on fastvairs awhile back (5-6months ago?)- the gist of itwas that the linkage worked well, but at the carburetor throat size they were running (1.5 inches ), the throttle responsewas poor, and was only of benefit for racing. Since you are going to efi, you dont have to worry about low rpm throttleresponse because the efi doesnt need any vacuum to run correctly. Therefore, you can run 4 1.5" i.d. throttle bodyswithout the driveablility problems that you would have on carburetors that size.Kevin Nash

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