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Hi all and happy New Year.

In one of my 2018 dreams there is a potential electronic fuel injection conversion for my 1965 Corvair engine. I am not 100% committed to it but I would like to explore my options with your help. I know little about EFI so don't hesitate to lecture me.
My Corvair engine is equipped with 4 single barrel weber carbs (new) and up until now my thought was to stay with it. I understand however that some power gain should be expected from the EFI conversion. Here is the list of my questions:

1- with no on board computer or trigger (other than the 1965 dist) how could I set up EFI
2- what power gain would be expected. The 1965 Corvair is a 2.7 L 6 cyl , it will be modestly supercharged ( about 6 psi with waste gate). Engine stock rated 140 hp. Now with my mods: mild race cam, header, enlarged cylinder to .060 and charger... my expectations are 180 hp (with carbs).
3- Any advice re products. There seem to be great differences in prices out there.

Thanks

You can modify the distributor to hold a sensor and be the crank trigger.

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-Andrew
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Peak power will remain the same as a well setup carb. However, you will gain power and throttle response everywhere else. The biggest advantage is not the fuel control, but spark control. You can flatten out the torque curve and make more power down low. Modern engines with EFI and cam timing make nearly peak torque around 2000rpm which makes for much more useful power on a sportscar.

I'm a bit out of the loop for who is good, but one thing to consider is whether or not the car can be tuned real-time. It makes life easier to be able to have someone drive the car while you watch the tune and make adjustments. Tends to be more expensive though.

Cheers.

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Build log: viewtopic.php?t=9291

Good luck on this project, Phil! I'm interested in seeing how this works out. If you can make this work for a non-computerized engine like a Corvair, that opens up a whole new horizon of possibilities! Keep at it and keep us posted!

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Mike - Read my story at http://twinlakesseven.blogspot.com/

In the most basic of installations, old style engines that use a single coil and a distributor like the Corvair, the points can be used to signal a Megasquirt without any modification to the distributor. To take advantage of the flexibility of the MS's infinite timing capabilities I would recommend locking out the vacuum and centrifugal advance. But then you will still be left with the maintenance of occasionally adjusting the points as the rub block wears.

How deep you wish to go will determine the complexity of the setup.

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Chuck.

“Any suspension will work if you don’t let it.” - Colin Chapman

Visit my ongoing MGB Rustoration log: over HERE

Or my Wankel powered Locost log : over HERE

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As others have said you will really see little gain in peak numbers with an EFI conversion. The gains are all across the board below the peaks though. Fuel economy should increase as well as cold running and part throttle.

I've done a lot of Megasquirt conversions on non-efi vehicles. The best way to go is to mount a trigger wheel to your crank pulley and ditch the distributor. This gives you much better timing control. The ECU is constantly updated with engine position instead of just once per cycle. Also it gets rid of any mechanical slop inherent to the gear driven distributor that can alter timing. You can buy the trigger wheels and really everything else you need from www.diyautotune.com . Here is a direct link to the wheels- https://www.diyautotune.com/shop/sensor ... er-wheels/

For throttle bodies with fuel injectors I saw some at one point that were a direct replacement for weber carbs. Some other advice I'd give on Megasquirt is to get the Megasquirt 2 at minimum. The one is a bit cheaper but is so much harder to work with to make any cost savings not worth it. Also budget for a wideband O2 sensor. I can road tune a car in an hour or less with one. With out is considerably longer and much more frustrating.

Having done both, I'm firmly in the EFI camp.

For typical Locost engines, side-draft carburetor are the norm which aren't anywhere as popular as they once were, which can make finding complete sets of jets and chokes difficult. Also, don't forget that you'll need a complete set of jets and chokes for each barrel. Additionally, as side-draft carburetors become less popular, the prices of even used ones is getting high, some close to ECU pricing.

To me, the biggest advantage of EFI is that with a laptop you can adjust things to your heart's content, all without getting your hands dirty. Plus, if you set something wrong and it runs worse, it takes about 3 seconds to set it back. As an analogy, think of carbs as a typewriter and an EFI system as a word processor - changes are infinitely simpler. That said, with great power comes great responsibility - set ignition, fuel, or cam timing wrong and you can destroy the engine in the blink of an eye.

Caveats:
1. Properly wiring an EFI setup is a big deal time-wise, especially if you're using oddball sensors which will require custom scaling and require mating connectors.
2. If you're using a V8 with a ubiquitous down-draft 4-barrel, you'll be fine since parts are still available.

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Midlana book: Build this mid-engine Locost!, http://midlana.com/stuff/book/
Kimini book: Designing mid-engine cars using FWD drivetrains
Both available from https://www.lulu.com/

Take the distributor and whittle off all but one of the teeth and use it for a cam signal for semi sequential stuff on your 6 cyl.

Accuracy of the cam signal is not critical.

Most will need to keep the distributor to drive the oil pump anyway.

I would avoid Throttle Body injection if possible, best setup is to spray right at the back of the valve.
TBI has issues with wetted walls and the fuel adds weight to the air reducing airflow.

For the ultimate Corvair setup, I would fab up a long runner (6) (Incorporating injector ports into the head) intake to a common (2 liter) plenum with a single throttle body.
The long runners will provide more area under the curve.

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Honey anyone?

Thank you very much to all of you for taking the time to educate me about EFI conversions. I share what you have suggested and your various points have helped me make a decision. Which is :I will proceed incrementally. First fuel management only, then later in life I will learn about ignition computerised management and set up Megasquirt , etc. I am aware that going about doing both at this time (when I am about to rebuild the Corvair engine from the ground up) would be more efficient, but I know my limitations (digitally challenged) and I prefer to take smaller steps.

In 2018 my EFI conversion will be based on this affordable MSD product:

https://www.summitracing.com/int/parts/ ... /overview/

My 1965 Corvair 6 cyl engine features built in intake manifolds (cast with the heads). The system is based on 4 carburetors. Many modifications of this engine have included in the past setting up single center 4 barrel single carburetors common in V8s. For me to buy a EFI unit designed to work with this type of system makes some sense. Although I agree with some of you who have suggested a 6 multipoint injection arrangement (injectors closer to each intake port) would work better . The bottom line for me is to keep this project manageable. The MSD EFI unit will work with pressures up to 2 bar boost which is far more than what I want my supercharger to produce (which is about 5-6 psi). The unit is self tuning with its own ECU. All it requires is a 58 psi fuel pump.

So this is what I am about to do. It will not be perfect but it will be good enough for my build which is not designed to be a tire burner. I will keep this group posted when this all happens. Thanks again.

How about going the other direction -

1. Get the car running with a completely stock - carbureted - engine.
2. When ready, upgrade just the ignition to electronic.
3. Once that's working fine and you've learned the system, then add injectors.

_________________
Midlana book: Build this mid-engine Locost!, http://midlana.com/stuff/book/
Kimini book: Designing mid-engine cars using FWD drivetrains
Both available from https://www.lulu.com/

First of all I am not pointing out system design parameters for max power, I don't play the horsepower game.
I shoot for "area under the curve" fuel mileage, efficiency, and throttle response.
Overall drivability and ease of operation and tuning.
I have either made the compromises and paid the price or watched others blunder.
I have enough experience with EFI now that I can avoid the pitfalls.

Having had multiple bad experiences with proprietary systems from major players, having spent months and countless $ chasing problems.
Having spent an eternity on the phone with multiple "engineers" every time having to go through the same handstands and hoop jumping for support.
I can say without any reservations that I would never use a proprietary system again.
I will not drink the marketing coolaid again for EFI systems that don't allow full access or make wild claims.
One of the systems was a Holley and the other was an Edelbrock neither system EVER worked better than a carb even after extensive work.

From what I understand, MSD did not design that system, they bought it from someone who made it just good enough to sell the design.
It was designed for folks who are afraid of EFI and not willing to learn or don't know enough about EFI, to bolt on in place of a carb.

Lastly that system violates many of the known issues (stumbling blocks, points of failure, etc.) for a proper fuel system.
The idea of EFI is to move forward from legacy concepts and all the entrapments of a carb.
Not encapsulate it in proprietary electronic control and keep all the short comings of a carb.
I can list all the shortcomings of that system but I have already made most of them clear, I'm not here to bash a system.

In short you are better off with a carb than wasting money on that MSD EFI system.
That Holley carb that you probably already have will work just as well.
Maybe better, if you buy that EFI don't sell your carb.....
Do not forget why all NASCAR MSD installs had two boxes!

NOTE:
Years ago we found a single Holley 2 barrel worked best on that 4 barrel adapter on a Corvair (in an even higher HP build than you propose).
Knowing what I know now, that was probably due to the 2bl being able to better meter & mix fuel in that application.

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Honey anyone?

I have done three EFI conversions, 2 using the FiTech setup. Just as easy as it can be, not a problem to be found. The last one was a Dodge 440, big cam loppy idle. Starting the car from cold was always an issue, idle was poor, AC switching on would stall the motor sometimes, carb was always gummed up each spring. There is an amazing difference, starts perfectly, idles well, no longer has AC problems and it just smoother to drive everywhere, small part throttle is now perfect. The wife and daughter will now drive the car something they would never do before, so the entire family is getting more use out of the vehicle. It runs the same hot days cold days, mpg is dramatically improved. driving it around town is super easy now. I spoke to a Hot Rod shop in the Chicago area, these kits are keeping them in business selling a lot of systems

Graham

Also remember that EFI fuel pumps don't like to suck, they need a flooded inlet (3/8 hose minimum) also a return type (2 line system) is best to cool the pump and fuel rail, and purge air bubbles.
You will need a swirl pot or an in-tank pump (which adds challenges) and return line.
Any air in a single line system has to leave through the injector, displacing fuel causing a lean misfire and loss of power.

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Honey anyone?

Bent Wrench, you really hate EFI systems I can tell:)

Sucking pumps work fine I run one on my 7, Return Less systems are becoming more common, I also run one on my 7. Thinking about it I am running return less without a swirl pot, really living on the edge:)

This simple unit from FI Tech solves all the pump and return problem, you leave the stock pump in the tank and it feeds this header talk with all the EFI trickery installed.

http://fitechefi.com/products/40003/

Graham

I see a lot of people using the corvette fuel filters now with an internal pressure regulator & a return. They seem to be a hybrid of the single and dual line systems. The filter lives near the tank and likewise so is the return fuel line. It lets you purge air that may get into the pump back into the tank but you only have one line that runs forward to your injectors.