Carbs vs EFI

Engine, Transmission and related drivetrain.
Chickenman
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Carbs vs EFI

Post by Chickenman » 08 Oct 2015 13:45

I've started another thread so that we can discuss the Pro's and Cons of EFI. This is from some of the discussion from " Fun with needles". Feel free to chime in.

Richard

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Re: Carbs vs EFI

Post by Chickenman » 08 Oct 2015 13:48

okayfine wrote:EFI's great, but stock EFI is set up with compromises all its own. Once you get into modifying EFI, the learning curve is at best similar, and at worst a world more complex. There are results for that, of course, but I'm just saying that EFI isn't a magic bullet unless you leave it stock.
Not quite following there.. particularly the last sentence. And not quite sure what you mean by Stock EFI is set up with compromises all it's own. Modern EFI is a big part of why we now have 600 HP Corvettes and Muscle Cars that idle smoothly, have great drive-ability, pass stringent emissions standards and still get decent MPG on the HWY. I don't see where the compromise is. Can you explain your thoughts further?

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Re: Carbs vs EFI

Post by okayfine » 08 Oct 2015 14:34

On EFI not being a magic bullet - EFI introduces an entirely new world to a carb'ed engine owner. The learning curve can be steep, and doesn't stop once everything's hooked up. Troubleshooting an issue with EFI can be a trial. On example: on my wife's Toyota Tacoma, you can't pull the connector to the coil-on-plug trying to isolate a misfiring cylinder that doesn't throw a code (takes forever for Toyota ECUs to throw misfire codes). If you pull the connector off the coil-on-plug, the engine dies, so you have to pull the coil. But to get to the point where you can pull the coil on #3 or #4, you have to disassemble the intake tract, so it's pointless. My '00 Subaru has a habit of having onto revs between shifts when the engine is cold. This goes away if I plug in an OBD-II scanner and reset the ECU. But it comes back. It's not a big deal, but it's not 100% perfect EFI, so IME EFI isn't a magic bullet. Stock EFI is way more concerned about emissions and driveability, good things to be sure, but compromises all the same if your goals don't align.

Flip side, a Nissan engine and harness in good condition, competently installed, will likely have very good reliability. My experiences with Nissan EFI engines has proven that out. Turn-key performance is a wonderful thing. But from the discussion in the other thread talking about delving into the EFI innards and making modifications - the gains are there to be had if you're willing to put up with compromises that the OEMs engineered around, and 10-fold if you're talking turbo engines. But flip a bit wrong and there's disastrous potential (especially talking turbo).

Relative to Steve's thread, SUs are full of compromises. IMO, EFI has compromises of its own. They're different, but still there.
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Re: Carbs vs EFI

Post by 510rob » 08 Oct 2015 15:32

Richard, how are you making out with the install of your Haltech E11 system?

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Re: Carbs vs EFI

Post by okayfine » 08 Oct 2015 15:41

Hey, threadjacker, yeah, you...go start your own thread!

Kidding, even I know Haltech is EFI writ custom
Because when you spend a silly amount of money on a silly, trivial thing that will help you not one jot, you are demonstrating that you have a soul and a heart and that you are the sort of person who has no time for Which? magazine. – Jeremy Clarkson

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Re: Carbs vs EFI

Post by Chickenman » 08 Oct 2015 15:44

280Z is still on the road. Haltech E-11 system will be a Winter project. Still gathering parts. Need Z31 chopper disc for 280ZX Turbo dizzy, Pallnet fuel rail, Toyota Supra Injectors ( non Turbo 295cc ), Aeromotive fuel regulator and miscellaneous AN fittings and lines. Just got hit with some other unexpected expenses, so I won't be starting for a while. And the cruise to Merritt made me buy some more suspension goodies.... sigh... it never ends does it?

I'm going to set up a Bench power supply just so I can play with things on my Laptop before hand.

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Re: Carbs vs EFI

Post by 510rob » 08 Oct 2015 16:47

Julian, as it was Richard who started this thread, I thought I'd ask him about his own first-hand experiences with EFI - perhaps a bit of an old Socratic trick of sorts, but that itself is merely a process for discovering truth, which is (I hope) what we are seeking.

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Re: Carbs vs EFI

Post by okayfine » 08 Oct 2015 17:50

Joke, since this thread started to avoid threadjacking Steve's thread more than we had. I'm all for threadjacking, for the reason you state and more.
Because when you spend a silly amount of money on a silly, trivial thing that will help you not one jot, you are demonstrating that you have a soul and a heart and that you are the sort of person who has no time for Which? magazine. – Jeremy Clarkson

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Re: Carbs vs EFI

Post by 510rob » 08 Oct 2015 18:40

I get jokes :P

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Re: Carbs vs EFI

Post by duke » 08 Oct 2015 19:23

Expense. I would bet that an EFI system (custom, not OEM) would be at least double, if not more, the cost of carbs. Yes, there are ways to do it on the cheap, but if you're comparing something like a Weber or Mikuni side draft setup vs a similar ITB EFI setup, the EFI is going to be much more expensive and most likely make similar peak HP.
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Re: Carbs vs EFI

Post by Byron510 » 09 Oct 2015 09:00

Duke, I'm on complete agreement with you. My EFI conversion, with myself fabricating and machining every part that was needed to make the L series EFI system, well I was into the swap for close to $5k by the time the dust settled. And did it work right out of the box...NO! Do I like it, yes – well most of the time anyways…
A new set of 44’s/45's on a manifold with everything needed to make the swap these days will run you about $2k. So another $2k buys a hell pf a lot of jets, air correctors, accel pumps and emulsion tubes :D

Still, comparing the EFI to Carbs is a bit like comparing my old L motor to an SR20 (which itself is getting old!). It's what you like and what you want to go with.
My next project, whenever I get to it, will again be carbureted, twin choke side drafts. But I will have two things I have never had on previous carbureted cars - a nice fast feedback wide band O2 and a proper crank fire ignition system. Both are gold in either situation, and both are needed to make a fair comparison. Still, the carbs won’t have altitude correction, nor cold air compensation aside from your choke. But sometime simple things are quite enjoyable as well. I'll get back to this thread in a year or two with that fair comparison.

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Re: Carbs vs EFI

Post by RMS » 09 Oct 2015 12:39

I like were your going Byron, I too want to run a wide band O2 on a carbed L and the crank fire will see you through the deepest puddles. how are the twin choke side drafts on inclines and bounce ? ive never been able to out drive the stock Hitachi on the z24, neither the steepest hill nor roughest road has been able to make it sputter. in my mind heavy service vehicles need carbs because when it all goes bad you can still get the woman to sit on the fender and pour gas down the carb to get you home.
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Re: Carbs vs EFI

Post by 510rob » 09 Oct 2015 12:50

The current price for a TWM twin "DCOE" throttles setup is...
TWM Borla 45mm DCOE setup.jpg
TWM Borla 45mm DCOE setup.jpg (82.01 KiB) Viewed 1290 times
...which does not include things like connectors for the injectors, throttle linkage gadgetry, an air filter setup, or electronics to run any of it.

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Re: Carbs vs EFI

Post by gooned » 09 Oct 2015 18:30

RMS wrote:. in my mind heavy service vehicles need carbs because when it all goes bad you can still get the woman to sit on the fender and pour gas down the carb to get you home.
So true for anything going to a far away land...


But for hot laps near the pit wall EFI everyday.

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Re: Carbs vs EFI

Post by Chickenman » 09 Oct 2015 19:42

I haven't had time to respond to this thread, but I wanted it to go more in the Direction of what can be done Technology wise with modern EFI " Stand alone " systems rather than a battle about costs. Especially the advantages of EFI on Turbo systems. The new AEM Infinity is simply amazing and so are the current Haltech systems. Most now have automatic Tuning Wizards that will dial in the base settings as you drive. And the pre-configued Maps get you 75% to 80% of the way there to start off with But those are pricey if you want them brand new....

You can pick up a good used used stand alone ECU that a generation or two old for very reasonable money. Lots of perfectly good Haltech's and AEM etc on the market if you know where to look. Honda forums always have them up for sale as the Drag Racers have to have the latest and greatest. Megasquirt 2 or MS 3 Pro is also an option as is SDS... but SDS seems to be falling behind the times for advanced Turbo support features.

For the DIY'er, the VW/Audi Bosch ME7.1 ECU can do Sequential injection, Coil on Plug ignition, MAF & MAP or MAF-Less, individual cylinder ignition timing trim and individual cylinder fuel trim, Wide band closed loop of course, Electronic Boost control, Dual sensor knock control, can be configured for injectors from 180cc to over 1,000cc, and more.... for around $100 used. It's an extremely powerful ECU... but I won't kid you, the learning curve is very steep. With Open source code, open source flash software and Open source Tuning programs you can add, Antilag, Two step launch control with Boost build, and even Boost by gear. The VW/ Audi Bosch ME 7.1 as used on the VW/Audi 1.8T and 2.0T Turbo engine can do all of that with the Open source programming and Maps available, and are plentiful in the junk yard. You can find them for $50 to $100 easy. There is also an Normally Aspirated version available. You can also get Custom tunes for anywhere from $300 to $700 depending on what you want. It's an option if you don't want to DIY.

Biggest problem on the 4 cylinder L-series engine is an Intake manifold. It's not an issue on engine swaps with a more modern engine ( SRD20 or KA24 etc) or 6 cyl L series that already have an EFI manifold. But an Independant Runner FI manifold is the MOST expensive and complicated option. You can build a plenum manifold cheaper. It would be nice if there was a reasonable cost Plenum manifold that would bolt on to an L20B etc. Perhaps there is something out there or perhaps this could be a New Project for someone like Byron? Perhaps modify a KA24 plenum manifold to L-series flange? Custom Plenum Creations will make a custom plenum style manifold, but they are probably pretty pricey. A group buy may be an option though:

http://www.customplenums.com/

There is another way for manifolds and the is the Conrad Pistner option. He would have taken a stock L-16/18/20B manifold, welded on some injector bungs, hogged out the carb base and welded on an adapter for a Universal throttle body. Good used Mustang TB's are dirt cheap ( get a 3.8 L V6 one ), come with Integral IAC and TPS. $35 at the junkyard ( Pick A Part ) or E-bay, $70 for Chinese made billet TB in any size you want, Mustang, Supra ( NA and Turbo sizes ) and Bosch injectors are dirt cheap. You can get fully re manufactured ones for $90 a set ( Four ) on E-Bay.. or $10 each used at Pick- A- Part.

Perhaps Byron can chime in and give us an idea on what it would cost to modify an stock L 4cyl manifold for Injector bungs, hog out the carb mount and weld on a Universal TB base. May not be as pretty as twin Mikuni's or DCOE's but it would be relatively efficient as it's a dry system. Would be great for a Turbo application as well. For a Turbo engine ( L seriers ) take Keiths Box blow thru design. Swap out the Weber DGV 32/36 for a Mustang TB, weld on some Injector bungs, used or Re-man Mustang/Supra/Bosch injectors , used VW/Audi 1.8T ME7.1 ECU and you could have a very powerful EFI system for around $1,000 to $1,200.

Hopefully this gets some people thinking about EFI conversions more and discuss some of the technical advantages of EFI, especially for Turbo conversions. I don't want to have everyone get hung up on the cost issue. There are alternatives. You can make things as expensive as you like, but a little ingenuity can go a very long ways. I know there are some VERY smart people out there and I'd like to see more of a Technical discussion.

I'll post back tomorrow with some more musings on the Technical side of EFI conversions and answer some questions from the beginning of the thread... but right now I have some other things that need my attention.

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