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Hi Folks,

I am restoring a '74 Spider and am kicking around the idea of converting it from SPICA to EFI. I'm not finding much info in my search efforts. If someone can supply a link for this type of project, I would appreciate it.

Thanks,

Joe G.
'74 Spider project
 

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Lots of luck. It would be sooo much trouble and expense to hardly be doable or worth the effort. You would need a complete EFI donor car because you would be needing;

1. Complete Jetronic or Motronic engine complete with all manifolds and sensors
2. Both computer "brains" and the entire wireing harness from the computer compartment forward (actually the entire wireing
harness)
3. Just guessing here, but you would probably need the canister in the trunk and all it's hoses.
4. The over fuel return line back to the trunk
5. The EFI fuel tank and both the EFI fuel pumps. The one in the tank and the one under the car.
6. Probably the ignition switch (it tickles the cold start injector)
7. EFI exhaust system
8. EFI bellhousing from EFI donor car
(I keep remembering more and more items)

If you like the body style of the 74 it will be far easier and cheaper just to convert it to webbers.

Robert

Better to just sell the 74 and buy an 82 - 93
 

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...If you like the body style of the 74 it will be far easier and cheaper just to convert it to webbers...
Probably even easier/cheaper to just restore the Spica. Yes, EFI is a generational step forward but hardly worth the effort a conversion would require and Spica has it's own set of virtues.
 

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If you are set on converting to EFI I'd suggest you look into an aftermarket system. Megasquirt & SDS are a couple I am aware of (but have no experience with). You would likely have to add in the cost of some dyno "rolling road" tuning to get it set up but they are usually quite tuneable with little more than a laptop computer connection.
 

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Discussion Starter #6
Thanks for the feedback everyone. I have seen the debates over SPICA, carbs, etc. As far as I'm concerned, it's a personal preference. I don't fault a person for going one way or another. I just want to see an example(s) of efi conversion. : )
 

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lh 2.2 of a 85-88 saab 9000 hot wire type, digital system, and you can program it.. easy to get from any wrecking yard, and easy to adjust the harness to our car..i have on in my car now for 8 months works great.. questions ask me..i am still here
 

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I am restoring a '74 Spider and am kicking around the idea of converting it from SPICA to EFI. I'm not finding much info in my search efforts. If someone can supply a link for this type of project, I would appreciate it.
Go for it! you can find a lot of information on applying Megasquirt to V6 engines but not so much on 4 cylinder motors. I once sold a set of SPICA throttle bodies to a guy in Australia who was building a turbo motor with electronic FI. A recent thread talked about an EFI system from Vick Autosports for Bosch Spiders that some of us thought was overpriced and is based on Megasquirt. This should be a great project if you are interested in learning about programmable engine management. You will become an expert and Alfisti who are interested in performance will seek your knowledge and wisdom.
 

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Go for it! you can find a lot of information on applying Megasquirt to V6 engines but not so much on 4 cylinder motors. I once sold a set of SPICA throttle bodies to a guy in Australia who was building a turbo motor with electronic FI. A recent thread talked about an EFI system from Vick Autosports for Bosch Spiders that some of us thought was overpriced and is based on Megasquirt. This should be a great project if you are interested in learning about programmable engine management. You will become an expert and Alfisti who are interested in performance will seek your knowledge and wisdom.
Do you know if the Spica Throttle bodies can take the boost without leaking? I'm curious about that one.
 

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It would depend on the adapters you fabricate but the original SPICA injection pressures are far greater than EFI, something like 400 psi if I remember correctly, so I don't imagine the manifold would be a problem.
 

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It would be easier to implement with an L-Jet throttle body. Does anyone see a significant advantage in using Spica equipment?
 

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I'll be doing this in the future, using a SPICA manifold and megasquirt.

I've done several adaptations to different engines. It's not particularly difficult.

However, I have several projects in front of it, probably won't get to it until sometime next year. I'll document it for this forum when I get going.

Bob
 

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It would be easier to implement with an L-Jet throttle body. Does anyone see a significant advantage in using Spica equipment?
Maybe having four throttles would look and sound better but probably no real performance advantage. Wouldn't all of the air, it at some point, have to pass through a common port for the AFM to function?
 

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Hi Paul,
There will be no AFM with Megasquirt. It uses Manifold Atmospheric Pressure, RPM and throttle position to calculate the fuel delivery (with temperature correction, etc).
 

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It would be easier to implement with an L-Jet throttle body. Does anyone see a significant advantage in using Spica equipment?
I was thinking on using a Spica TB due to simpler throttle linkage.
Neither L-jet Spiders or Spica cars are common over here in Portugal.

The Spica TB is the most intersting deal on TBs to install in my GT Junior.
I need the full linkage system though, I've read that they are very different from the factory carb setup...
 

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We adapted a Hilborn 4 pot onto a blower manifold for an early Hemi. Worked slick. Just needs dyno time for tuning.
 

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See below, IR runner design due to the work in the manifold.
 

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If you go with a Spica TB setup, then I would recommend that you fit a throttle position sensor. If you make an adapter, it can go on the end of the throttle shaft on the rear end of the intake assembly. The Alpha-N fueling algorithm is preferred for most individual runner applications. We tried to use the mixed TPS/MAP algorithm, but ultimately went full Alpha-N Additionally, you will need to machine the Spica injector ports so your EFI ones fit and add some mounting points to hold the fuel rail in place.
The nice thing about using an L-Jet Spider manifold is less modification, and you can use both a TPS and a MAP sensor, if you want.
 

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IMO, this is not a good idea unless you are a very experienced engine builder. You can transfer an entire EFI engine, wire harness, and computer into an earlier chassis, but trying to convert a Spica engine to EFI is probably WAY beyond your credible capability, judging from the fact that you're even asking the question.
 
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