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Fuel Injection Questions
Posted by: OttawaCorvairGuy ()
Date: January 09, 2018 10:51AM

FI Owners - I have some questions.

What size engine are you running?

What kind of Fuel Injection are you using?

What MM is your setup?


I'm looking at 2 engine builds.

1. Smaller Big Bore 3.0 / 3.1 (I forget which one it is) with least amount of machine work and cost. More for reliability with Ted's TBI setup for PG Ultravan use...

2. Smaller Big Bore (same size as above - but with a "nice" cam and some extra goodies and FI Stacks and a 5 speed. I was told to run at least 45mm stacks... Honestly, I have no clue what would be best.


Thank you, Tony

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Re: Fuel Injection Questions
Posted by: 63turbo ()
Date: January 09, 2018 07:36PM

For #2, based on 40mm throats and 3 per side for individual runners for 2.7 liters, that same area to displacement translates to 42mm per throat for a 3 liter engine... 45mm is getting huge unless you plan on revving it unusually high.
For #1, use what Ted recommends

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



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Re: Fuel Injection Questions
Posted by: OttawaCorvairGuy ()
Date: January 10, 2018 03:48AM

63turbo Wrote:
-------------------------------------------------------
> For #2, based on 40mm throats and 3 per side for
> individual runners for 2.7 liters, that same area
> to displacement translates to 42mm per throat for
> a 3 liter engine... 45mm is getting huge unless
> you plan on revving it unusually high.
> For #1, use what Ted recommends


Not 100% sure I can get 42mm stack FI.

I was told it is better to go bigger and choke the down some, (if needed) than to go to small and need to buy all new FI bodies.

If the above is true. What would happen if I had 45MM and choked them down by the design of the intake runner - where the FI will mount to?

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Re: Fuel Injection Questions
Posted by: DAVECS1 ()
Date: January 10, 2018 10:14AM

You really cannot size your throttle body to big with EFI. It is not like a carb, you are not depending on the venturi effect to pull fuel out of a bowl. The concern is being able to meter the air on tip in and idle with reasonable driveability. you would have to go pretty large before that becomes a significant issue

I am using the throttle body from a GM 3.1L V6.
I have 2 30lb Genisys Fogging injectors due to placement
I am using a modified corvair turbo log as my manifold
The ECM is a Holley Commander 950

1964 Monza Convertible
110 4 speed
Peoria, IL

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Re: Fuel Injection Questions
Posted by: OttawaCorvairGuy ()
Date: January 10, 2018 02:25PM

DAVECS1 Wrote:
-------------------------------------------------------
> You really cannot size your throttle body to big
> with EFI. It is not like a carb, you are not
> depending on the venturi effect to pull fuel out
> of a bowl. The concern is being able to meter the
> air on tip in and idle with reasonable
> driveability. you would have to go pretty large
> before that becomes a significant issue
>
> I am using the throttle body from a GM 3.1L V6.
> I have 2 30lb Genisys Fogging injectors due to
> placement
> I am using a modified corvair turbo log as my
> manifold
> The ECM is a Holley Commander 950


Dave,

Thank you for the info. It is interesting. I've read some of your threads before.

I'm not sure we are on the same page about my project. (More than likely it is me)

I'm don't want to use Throttle body injection as we know it.

I want to use STACK Injection. What was once (years ago) only found on race cars.
It will be individual stack injection - one per cylinder.

The above mentioned means that ONE Stack injection unit will feed ONE cylinder only.

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Re: Fuel Injection Questions
Posted by: DAVECS1 ()
Date: January 10, 2018 06:09PM

We are on the same page. I am basically saying, your probably safe to use whatever stacks you find. The biggest challenge will be getting a common signal from all cylinders to register load in the form of vacuum. The EFI will use a map sensor and RPM to select the running condition of the engine and deliver the amount of fuel needed. If uou look at a common kinsler injection, they do a pretty good job of hiding this common manifold. So are you going to run a modified head like they do for the webers?

1964 Monza Convertible
110 4 speed
Peoria, IL




Edited 1 time(s). Last edit at 01/10/2018 08:19PM by MattNall.

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Re: Fuel Injection Questions
Posted by: 63turbo ()
Date: January 10, 2018 06:21PM

I had never heard of STACK injection before, and then I thought perhaps it was the name of a company.... I looked it up and sure enough it is. Those throttle bodies they sell are sure trick looking!! I belive what they are doing is they've figured out how to bury the injectors within the throttle bodys to look
just like downdraft ida's.... good for them! the bolt patterns look just like ida's the fuel connections look darned near identical to how ida's would be connected. Cool stuff. anyways they are injecting below the throttle plate, and I can tell by looking at their other set-up that uses nearly identical throttle bodies with the injectors external and the fuel rail external. The reason that auto stuff is usually injected under the throttle plate is that it is a bit safer and less likely to give off a gas smell.
Anyways, DAVECSl is right, the sizing of throttle bodies isn't like carb sizing, the concern with way too big is that they will have a tendancy to be jumpy and bucky at small throttle openings- so for what you are doing, I tried
to size your throttle bodies based on what has been done in the past and known to work well with a stock displacement and then re-sized based on your wanted displacement. It isn't "wrong" to go somewhat bigger if 45mm is the next biggest size, but it isn't exactly wrong to run 40's either. Probably, the thing that would matter most is if the point of injection is interrupted more
with the bigger 45 sitting over a smaller manifold opening or less interfered
with the smaller 40. The best way would be to measure the manifold opening at
the mounting point and ask the manufacturer of the throttle bodies which way
would work the best for your application. If it were me, I would probably put the 45's on and hand blend the manifold to properly fit the throttle bodies, as
going big to small is better flow wise than going small to big.

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



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Re: Fuel Injection Questions
Posted by: Seth Emerson ()
Date: January 10, 2018 07:17PM

Kool!

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Re: Fuel Injection Questions
Posted by: 63turbo ()
Date: January 10, 2018 08:10PM

here's some cool too!
[www.eightstack.com]

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



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