Hi all,

I've recently become interested in possibly putting EFI on my Barracuda, and have been trying to read and digest the info in this forum. It's all very intriguing. The problem is there are some 320 differently-headed posts and I'm not finding any basic entries that outline how to do it. Is there a post or posts that detail everything? And has this been successfully done to a daily driver? I would like to try this, but don't want to re-invent the wheel or spend the rest of my life trying to tune whatever I may put together. I have read DiBiase's "Electronic Fuel Injection for the Slant Six", but this was written nearly 10 years ago. Is there something newer that, perhaps, uses a later generation GM system? As always, thanks for any help to this EFI noob.

Roger

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Others who have converted to EFI will chime, I am sure. I have read posts from people who have adapted throttle body EFI, batch fired efi, and sequential fired EFI to the slant, some with turbos, some with superchargers. It can and has been done. The trick is to get an engine management system that will work for you.

The DiBiase article is good in that it will get you familiar with the various components and subsystems of an EFI retrofit. Then you have to decide what type of EFI you want: sequential? Batch fired? Mass-Air? Speed density? Throttle body or dry manifold? Once you have that decided, you then have to pick what management system. EZ-EFI? Megasquirt? Something else?

For several years now I have been working out a slant six mass-air based sequential fired fuel injection system for the slant six that is basically an adaptation of the Ford late 80s and early 90s fuel injection system. It has several benefits, but I am still working out the details and haven't even started any actual fabrication. The best thing you can do is read a lot, pick the system you think you want, and go do more in-depth research. I am not aware of any parts list or start to finish manual to put fuel injection on a slant six.

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Casually looking for a Clifford hyperpak intake for cheap.

Whatever which way you do it, all the design, engineering, fabrication, adaptation, testing and tuning will be on your own. There's no ready-fab kit. There are some, not many, fuel-injected slant-6s running in the real world. Each of them is different from all others. My (untested, untried) idea for a relatively low-cost, low-effort TBI conversion is here (added detail further on down that same thread). At the other(!) end of the scale is this very impressive (high cost, high effort) setup. Sam Powell on this board has a really nice fuel injected and turbocharged '69 Dart; he's been tweaking and tuning his custom EFI setup for quite awhile. I think Reed's on a very promising track with his Ford adaptation. I've also thought of trying to adapt Bosch K-Jetronic, a purely mechanical injection system fitted to many Volvos, but I haven't ever taken even a single step towards actually doing it.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

The megamanual includes plenty of general theory and operation. This isn't a one size fits all project so you won't find a step by step click by click how-to. Search by my username and text "efi" and check the earlier posts for my efi project thread.

What is your budget and how much fabbing are you willing to do?

Given the cost of parts and the amount of custom machining and fabrication work necessary, I would ballpark an EFI conversion as costing $1000 and up. The price depends on what system you choose, where you source your parts, and how much the fabrication costs you. This is a very general estimate, but is a good rough estimate for the cost of a low-priced conversion.

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Casually looking for a Clifford hyperpak intake for cheap.

I concur with Reed's estimate ($1k and up), based upon my reading too (and I'm confused too, along with the OP, with all the possible ways to go). If I make the plunge, I think I would probably collect all the parts, intake manifold and maybe even exhaust manifold too, and find a week that I could take off from work. Push come to fail, I could swap on all the unmolested items at the end of the week. Assuming the vehicle wasn't locked up in the garage for the duration of winter, that is.

At some point I'm going to get smart and either start printing off the pages detailing their installation; or at least start jotting down ideas.

Thanks for the replies, guys. I don't really have a budget in mind but $1000 would be within my means. My main goal in all of this is to improve my mpg, but extra power is always welcome. I think I can do a lot of the fabrication, and farm out what I can't.

Thanks for the link, Dan. I will check it out in detail.

I have been reading about Sam Powell's setup, including his recent switch to the Megasquirt ECM. I also like Al's "Big Red" 1960 Dodge with the Thunderbird SC supercharger and EFI setup. That seems like a fairly self-contained package, but I'm not sure it would fit under my hood and I don't want to cut any holes in it. I noticed that granfurygraham mounted the same supercharger further back than Al did, and that might provide more room. I'm leaning toward adapting EFI first, then maybe adding a turbo or s/c if I decide to later - which would restrict me from starting with the T-bird setup. Speaking of which, has anyone besides Al used that setup?

As for DiBiase's article, it is a very good introduction and I like his idea of using existing production components. However, the cars he was recommending as donors are around 25 years old now, and I'm sure imrovements have been made since then.

As you can see, I'm still considering all options. Lots more reading still to do. I appreciate the advice and suggestions so far, please keep it coming. Hopefully, I can compile enough info to put together a basic pointers post. Happy holiday to all.

Roger

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I've come across one or two TBI installations (here? elsewhere?), and I'm somewhat intrigued by that setup. I'm not 100% sold on the surge tank but it seems like a low buck method to get most of the advantages of EFI (ease of tuning, ease of starting, etc) with the least amount of work.

The setup I've read about uses the stock fuel line to the stock mechanical fuel pump. That pump feeds a surge tank, pint or so in size, that then feeds a conventional electric pump. The return line from the regulator goes to the surge tank instead of the regular fuel tank--as you can see, no need to drop the fuel tank, no need to change existing fuel lines.

[Why a 15psi electric pump needs a return line is beyond me; I guess it has to do with how the regulator works. Maybe there are more recent pumps with integrated (and adjustable) regulators that don't have a return line? Need to do more research on that bit.]

[Of course, if you ever have to drop the tank, before or after EFI conversion, then it'd be an ideal time to install a bigger fuel line, and the return line, in anticipation of an eventual EFI conversion. I don't see why one couldn't set this up in advance and still use a carb--just cap off the unused line(s).]

I'm not sure what is the "best" throttle body, but I've seen mention of the GM 4.3L two barrel TBI. Seems about the right size, and GM made a bazillion of them; I'm guessing if winds up too small (for a hot slant) the 305 (350?) version might be an upgrade. I'm guessing a Super Six intake is best, although I don't think a heated manifold is as required with TBI as it is with a carb (since there is an air/fuel mixture going through the manifold, I'd think the extra heat wouldn't hurt with vaporization--but the big gain is the smaller fuel droplets, so I'm guessing it's not nearly as required). Since, for me, the desire behind EFI is better drive-ability and mpg's (and maybe even emissions) rather than raw horsepower, I'd probably go with the heated intake.

I'd probably just ditch the GM controller though, and go with the Megasquirt controller instead. I love my netbook; it should be easy to tune such a setup in-vehicle. Rather than sending out PROM's for flashing, which I believe would be required with an OEM controller. I'd add the wideband O2 sensor, along with the typical throttle and temp sensors. I'd probably go MAP instead of MAF: as I said, it should be easy enough to tune via a netbook, so the flexibility of a MAF shouldn't be as required. I probably wouldn't bother with a knock sensor, at least not initially (maybe later on, if I were to explore the outer limits of lean mixtures?).

That would just leave ignition. I'm not sure if I would roll that in initially. I'd prefer to have it, but sometimes a project can get just too big to accomplish in a reasonable amount of time. Maybe if it was an uncoverted Leanburn setup I would, as it'd be just that much more work to convert to a conventional distributor (and then back again at a later date).

Of course, on an automatic one would have to figure out the kickdown cable. And, one should start off with a slant in good working condition (no slop in the timing chain, maybe even make sure it's degree'd properly, good compression, etc). I'm not sure if a higher output altenator is required; I'm guessing it may be, depending upon year (would have to see what the Megasquirt pulls, if it's only a couple amps more then perhaps all is well).

Edit: oops, you posted just before I posted this. My ramble for above would be for a normally aspirated, low buck setup (although I don't see why nitrous oxide would be ruled out). For eventual turbo/supercharging, I'd probably make the jump to port injection first. I'm not too familiar with non-NA setups, but it seems very much popular practice (for very good reasons) to go port injection. Learn how to tune such a setup first, then play with adding in the turbo/supercharger.

$1k is the bare minimum - this is the type of project that will nickel and dime you to death. Fittings, hoses, wiring, other random stuff adds up very quick. Don't be surprised if your $1k on paper budget turns into $1.5-2k in real life for this. Been there, done that.

I had a GM TBI setup then switched to MPFI. If I were doing it again I wouldn't bother with the TBI, just go directly to MPFI. The cost difference, percentage wise, is minimal vs the total cost of the project.

Wise choice. TBI is, in my opinion, very inferior to MPFI. It doesn't solve fuel distribution issues, and is little more than a highly accurate carburetor. Going to MPFI allows much more flexibility since it is a dry manifold- no need for manifold heat, much easier to incorporate turbos and blowers, more precise fuel control, better MPG and performance.

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Casually looking for a Clifford hyperpak intake for cheap.

I have to admit, for myself, the intake manifold modifications required for MPFI are rather off-putting. Welding in bosses, then drilling and tapping, then making a fuel distribution manifold--not saying it's impossible nor impractical, just that it's seemingly out of my abilities.

For some reason that conjures up having to first draw it up in AutoCAD (a program that I am not enamored with, mostly due to unfamiliarity) and then having to figure out basic metal working, before I could get very far. Mental hangup on my part, I know.

But I can't argue that MPFI isn't where it's at. Even direct injection (DI) has its drawbacks at the moment (not to mention how impractical that would be to retrofit onto an old engine).

Actually, modifying the intake manifold for injector bungs isn't that hard. Doctor Dodge posted a great how-to article ten years ago. You can see it HERE. There are companies online that sell extruded fuel rail for $10 per foot. These same companies can pre-machine the rails for fittings and fuel hookups, or you can do it yourself with the tools sold by those same companies. Any competent machine shop should also be able to modify your intake for fuel injection.

I'm anxiously waiting for the good doctor to post the promised fuel rail construction article.

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Casually looking for a Clifford hyperpak intake for cheap.

I have owned/driven enough TBI-equipped cars to say ohhhhhh yes manifold heat is every bit as necessary with TBI as with a carb, for the same reasons. I don't agree that TBI gives smaller fuel droplets than a carburetor.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Reed: I missed that article by Doc, that does look promising. Daunting, but promising.

Dan: thanks for the correction. I guess there is only so much that can be done with 10-15psi (whatever it is that TBI winds up with at the injector).

TBI driveability is also a lot better with a working thermostatic air cleaner…again, just like a carb. I did a lot of experimentation with the last TBI vehicle I owned ('89 Dodge D100 318). Even using 50% higher fuel pressure with smaller injectors for maximum possible atomisation, driveability improvements were not radical. A wet-manifold system is a wet-manifold system, as it seems; TBI just improves on a carburetor because no venturi restriction and many fewer parts and systems that can make trouble by getting out of adjustment or out of operating range, plus easy computer control for much more precise and accurate fuel metering in accord with engine load and operating conditions.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.