Since we are talking about EFI "Carbs"
is there anything like that for a 1600-2000cc motor ?
Since we are talking about EFI "Carbs"
is there anything like that for a 1600-2000cc motor ?
In reply to californiamilleghia :
Jenvey, I think, make devices that look like DCOEs but have hidden sensors and injectors. This is if you don't just want to use throttle bodies that are obviously fuel injected.
If you mean to replace a single downdraft, there are any number of junkyardable options for a throttle body injection system. You probably won't find a self tuning plug and play setup because those are typically geared for V8s, which IMO is fine because those don't work all that well on V8s either.
In reply to tripower4speed :
Yo. We're on page 2. When do we get to see and hear more about the Camaro? 
I'm surprised holley doesn't have a plug and play kit for this requirement.
californiamilleghia said:Since we are talking about EFI "Carbs"
is there anything like that for a 1600-2000cc motor ?
Could adapt a TBI from an Iron Duke. But I'd rather use Weber DCOE pattern ITBs on a suitable manifold - much better fuel distribution and a lot more wow factor.
Couple data points that might be helpful:
I did a MS2 roll your own approach and described it here
https://nastyz28.com/threads/24x-sbc-crank-trigger-conversions.329776/page-2#post-3813801
My application is a relatively high strung 377ci SBC in a dedicated auto-x car.
Gimp's application is similar but his setup is a bit more plug and play. Details somewhere in here:
agreed with port > tbi in every way except if you are trying to go EFI as cheap as absolutely possible (and have a low power engine)
Don't forget fuel supply. Fuel injection often requires a return line, provisions for that in the tank, possibly larger supply lines and a pump that can handle it. Some can get away with just an in-line pump but others have had issues priming and using just the inline.
I converted our bronco to fuel injection hoping for easier starting and better running for my wife. I had to run a new supply and a return line. New fi tank with pump in tank.
started with Fitech but it sucked so bad I eventually replaced with a sniper system. Had a problem that required Holley to diagnose and repair and had two wires transposed that I tracked down and fixed.
plus interference issues wreaked havoc and I was able to fix it with no small amount of work.
It finally works decent and runs well but still requires an attentive startup (turn key on, wait until you hear the prime shot THEN start).
frankly, it ran amazing on the carb I rebuilt and installed initially to break the motor in with. I wish I had just left it as such.
with all of that, I'd highly recommend a factory fi system if you're going to go fi.
In reply to jfryjfry :
You gloss over an important point. If this is a new build engine it needs to start and run for 20 min at over 2k rpm in order to break in the cam. (assuming its is a flat tappet) Preferably not too rich that you are washing down cylinders. Good luck getting your new never used Fitech or sniper to pull off that trick out of the box.
The purpose of the conversion is important. I started my speeduino conversion because of heat induced inconsistencies with my carb performance. Lo and behold long after converting to efi we put that carb (summit brand autolite) on another car and had exactly the same issues. Switched to a demon carb and all issues went away. I still have the efi on my car(and am pleased with my conversion), but it is likely that I could have switched carbs and been just as happy. This would have saved me some money. I also suspect a holley sniper would have suited my needs just fine as well.
I think it would be fun to use a tpi manifold and a dropbear speeduino ecu if we are throwing out ideas :)
I only converted a personal car to EFI because it was cheaper than a carburetor at the time, (engine was set up for EFI, just needed a fuel pump, a $80 Megasquirt from a GRM forum ad, and a $60 wiring harness from a now defunct company, in 2009) and I liked the idea of making tuning changes with a laptop instead of pulling the carb apart, making a change, etc.
The car that replaced it is carbureted and will be for the foreseeable forever 
I have nothing against fuel injection the way some people do, just as I have nothing against carburetors. You pick the tool out of the toolbox that works with what you're trying to accomplish.
I'll say that port EFI completely tamed an engine that idles in the low single digits for vacuum, and it WAS fun learning lots of new things along the way. But at the same time, I don't feel a need for an engine that raunchy in my life anymore, just too loud and pain to drive in the city and the emissions is quite awful even with a really good tune.
But a fairly mild engine that doesn't need to both try to idle at 1200 and make good power everywhere up to 10,000? Carbs are fine and simpler and depending on the setup, more economical to drive.
All THAT said.
The idea of a hot SBC with a tunnel ram intake with twin throttle bodies and a set of port injectors makes me absolutely giggle.
There are port EFI versions of mechanical FI manifolds now, too! I forget who makes them. Stacks sticking through the hood! Being independent runner with the throttle blades close to the intake valves, it would really tame a raunchy cam for drivability, too. But now we're talking about Styrofoam coolers full of cash to pay for it.
Thanks to everyone that has posted! @nermalsnert I have started a build thread and will update it to get us to the current day status.
@Pete. (l33t FS) I have been thinking about a Quickfuel as a possible solution, but I am growing weary of messing with it. I had the OEM Holley 780 restored, along with the stock distributor and have dialed everything in as best I can without having to mod the IFR circuit which I think is the next step to solve the off idle stumble. It all worked great on the Dyno and I was happy with the power and Tq numbers but the drivability is a different story.
Ok, so we're trying to improve drivability on a difficult-to-tune engine. That narrows it down. I'll start with what options aren't the right tool for this job, and why.
1. You don't want a TPI manifold. These things look awesome, particularly if you want this car to look like it was a high dollar build in 1986 that sat in a barn for 30 years. But they're so optimized for low end torque that they don't make much power over 4500 RPM.
2. You don't want an OEM ECU unless you know exactly who's going to tune it and they have a good track record grafting these ECUs onto other engines. These have a massive collection of tables that are all precisely optimized for a very different engine. It's a better bet to go with an ECU designed to be tuned by one guy with a chassis dyno, not a team of factory calibration engineers.
3. You don't want a throttle body injection setup here. They won't get you nearly as much drivavbility as port injection - unless you count a set of four Weber IDA-pattern throttle bodies on an independent runner manifold, which is going to be pretty similar.
4. You don't want to rely on self tuning. You can get some of the fueling taken care of, but you will want a good manual tuning interface for transients, and if the engine has a lot of cam, you'll also want to dial in the idle fueling by hand.
So, here's what you do want for this project.
1. For an intake manifold, you could either use a carb-like intake that has injector bungs, or a dedicated EFI manifold, but one matched to your engine's airflow needs. It is possible to rework the manifold you have, and that might be price-competative with a new EFI manifold depending on what you need. I'd need more details of the engine to know what would fit.
2. Run it with an aftermarket standalone with 8 channel sequential injection. You mentioned Haltech; their Elite 2500 would be the logical fit here. Other items to consider would be a Holley HP or something in the MegaSquirt-III family - they've just released a box called the MS3Pro Mini that covers 8 cylinder sequential applications on a budget if you don't need a ton of I/O.
3. To control sequential injection, you'll either need a dual sync distributor (cost effective) or a cam sync plus a crank trigger (more accurate). The crank trigger can run with a distributor or distributorless ignition. Chevy used a cam sync on their Gen 1 based Vortec engines, so there are some very affordable options out there that will perform every bit as well as a $500 billet cam sync piece.
4. I'd recommend something to help avoid fuel slosh when the fuel tank is low. Carburetors are less sensitive to fuel slosh in the tank since the float bowl gives them a reserve of fuel to cover any point when the pick-up is grabbing air. I've found simpler is often better; on my Dart, I welded a cake pan under the gas tank as a fuel sump.
JMcD said:Couple data points that might be helpful:
I did a MS2 roll your own approach and described it here
https://nastyz28.com/threads/24x-sbc-crank-trigger-conversions.329776/page-2#post-3813801
My application is a relatively high strung 377ci SBC in a dedicated auto-x car.
Gimp's application is similar but his setup is a bit more plug and play. Details somewhere in here:
agreed with port > tbi in every way except if you are trying to go EFI as cheap as absolutely possible (and have a low power engine)
My setup is a 377ci on a dedicated autocross car too. Holley Sniper setup. I got the until that looks like a carb, but wouldn't recommend due to a progressive throttle issue. Just get the regular unit if you go that way.
https://www.youtube.com/watch?v=AbcHgkTxwKs&t=1s&ab_channel=TeamZip-Tie
https://www.youtube.com/watch?v=FbW1Gf-UqPo&t=386s&ab_channel=TeamZip-Tie
https://www.youtube.com/watch?v=aJ5y8NLexsQ&ab_channel=TeamZip-Tie
https://www.youtube.com/watch?v=HVqEg5E-80M&ab_channel=TeamZip-Tie
https://www.youtube.com/watch?v=u7xeoTDXLiw&ab_channel=TeamZip-Tie
The Holley works well enough and supports my power levels, but for other reasons (mainly traction contorl) I'll eventually be going to port injection using a Haltech.
One thing that will make fine tuning of the driveability is injector aiming. I've seen this over and over, and whenever there was an issue with the injector spray going badly, it caused transient problems that were hard to dial out. The reason I would not like TBI is that you are injecting totally onto the manifold- insuring that you will have a fuel puddle to deal with- which changes over many conditions. The best we did for transients was a pattern that focused on the back of the intake valve(s).
Transient control is what really makes a car easy to drive, especially at low power levels- like parking lot driving.
I know it can be "dealt" with, but to do it really well, the transient fuel control is pretty complex. Or you have to deal with tip in hesitations that will drive you crazy over time.
BTW, given we are talking mostly home calibrated systems here, the transient fuel compensations have to fix both fuel and air problems- as it's really hard to know when you have a transient air issue.
The first step for me would be to add a wideband O2 sensor into your current setup. This will give you alot of information about what can be changed on the carb to fix your issues. Without a wideband it's mostly "guess and check" (for me anyway). If off idle hesitation is your main problem with the carb I would spend some more time/money trying to fix it instead of taking on the EFI conversion project. Its likely that adjustment of the accelerator pump circuit or power valve could improve your situation.
yupididit said:I'm surprised holley doesn't have a plug and play kit for this requirement.
They don't seem too far from having that, really.
https://www.summitracing.com/parts/sne-550511bpksbc/make/chevrolet - Throttle body injection + fuel pump + distributor
Add a dual plane carb intake of your pick with maybe a mild cut to the divider between sides (there's debate on this one, some EFI units have sensor ports where that divider runs, causing issues) from about anywhere. Maybe a little work to the tank for a return? Seems pretty complete and not cheap but not insane either.
pres589 (djronnebaum) said:yupididit said:I'm surprised holley doesn't have a plug and play kit for this requirement.
They don't seem too far from having that, really.
https://www.summitracing.com/parts/sne-550511bpksbc/make/chevrolet - Throttle body injection + fuel pump + distributorAdd a dual plane carb intake of your pick with maybe a mild cut to the divider between sides (there's debate on this one, some EFI units have sensor ports where that divider runs, causing issues) from about anywhere. Maybe a little work to the tank for a return? Seems pretty complete and not cheap but not insane either.
The "kit" would have to be pretty comprehensive including an install technician-in-a-b0x, since the guy doing the install might be the weakest link in the entire conversion; you just don't know what you don't know until you succeed or give-up at doing an install.
A kit cant solve the electrical noise issues that the TBI kits suffer from
A kit wont deal with exhaust or intake leaks that are endemic to headers and intake systems, especially if you involve china. These will drive the EFI nuts and you even nuttier. Never met a header flange that was flat. The kit needs to include a smoke machine to verify that your intake and exhaust are sound.
A kit cant educate you on the glossary of technical terms that are going to be required for you to play the game.
A kit wont resolve the issue of putting delicate electronics that have been under-tested in a high-heat, high-vibration operating environment
A kit wont keep you off the forums where you go to ask for a button pushing tune from some rando who may or may not have his car running correctly.
A kit wont help you decide if any of the wonderful new sensors in the EFI kit are performing properly or just driving you nuts. ( as far as i know fitech is still delivering systems with temp sensors that are calibrated wrong)
The carb with a wideband O2 reader and a smoked intake and exhaust system works really well.
The wideband is going to be of only limited help with transient conditions, however. It works best in relatively steady conditions.
MadScientistMatt said:The wideband is going to be of only limited help with transient conditions, however. It works best in relatively steady conditions.
??? Can you elaborate?
Unless you mean you need data to know the transient conditions- like engine speed, throttle/MAP, and air fuel... That I'm totally in agreement on.
First off, that car RULES and we need a build thread!!!
I'm running a MSD Atomic 2 setup on my 1979 Dodge Power Wagon with a 5.9 Magnum V8 under the hood. It's very similar to the Holley Sniper 2 that came out recently, except this one has a fuel return (I believe the Sniper is still returnless). They just discontinued the Atomic 2 in favor of the Sniper 2 in the recent Holley Product Purge, but most of the same stuff applies.
Pros:
-Fairly easy to install
-It starts right up no matter the weather/temperature/etc.
-Tuning is fairly simple and can be done with some self-education and a laptop
-There's a HUGE community for these and most problems people have run into have been solved by now
-It's nice and dumb and more of a "set it and forget it" solution
-Uses sensors/injectors from late model vehicles you can actually find at any parts store
-Most importantly, you can actually see what the engine is doing and what it wants through the handheld screen (or laptop with the right cable) and data logs
Cons:
-It is not exactly cheap; figure about $1500-2000 all said and done if you want the whole deal with the Hyperspark ignition and distributor, which I STRONGLY RECOMMEND
-It runs an external fuel pump, but you can get internal setups on the aftermarket for F-Body cars reasonably cheap (the setup for my truck is NOT cheap)
-Not as dead simple as a carb setup
For something I drive regularly, I love it. It just does the thing, and that's all I need it to do. I really like the whole setup, even though I've had a few tuning hiccups since installation, one of which I'm still dealing with here and there (lean spikes on tip-in, but I think it's due to my throttle cable, not the EFI). I've had it on the truck since 2021 and on two different engines, and it's worked well on both. Datalogging is easy, and I just recently got a splitter cable so I can live tune with a laptop. Really looking forward to that!
Pete. (l33t FS) said:All THAT said.
The idea of a hot SBC with a tunnel ram intake with twin throttle bodies and a set of port injectors makes me absolutely giggle.
There are port EFI versions of mechanical FI manifolds now, too! I forget who makes them. Stacks sticking through the hood! Being independent runner with the throttle blades close to the intake valves, it would really tame a raunchy cam for drivability, too. But now we're talking about Styrofoam coolers full of cash to pay for it.
This confused me for years. When I was a kid in the '70s and '80s all the smart gear-heads cautioned against using tunnel rams on the street. They looked cool but they were said to only be advantageous at silly high rpm. And disadvantageous everywhere else. They killed torque they said. Granted, these were carburetor and both air and fuel were coming down those longer runners. But then Chrysler used crazy long runners in the '60s in a bit different way - where they actually fit under the hood - and that was said to increase torque. Then in the '80s and '90s they again made the runners as long as possible but this time with EFI so only the air column was coming down the pipe prior to the injector. And again, more torque. The fact is, I'm still confused. Do longer runners always increase torque?
A 401 CJ said:This confused me for years. When I was a kid in the '70s and '80s all the smart gear-heads cautioned against using tunnel rams on the street. They looked cool but they were said to only be advantageous at silly high rpm. And disadvantageous everywhere else. They killed torque they said. Granted, these were carburetor and both air and fuel were coming down those longer runners. But then Chrysler used crazy long runners in the '60s in a bit different way - where they actually fit under the hood - and that was said to increase torque. Then in the '80s and '90s they again made the runners as long as possible but this time with EFI so only the air column was coming down the pipe prior to the injector. And again, more torque. The fact is, I'm still confused. Do longer runners always increase torque?
There are a couple factors in play with tunnel rams: The runners look longer than they are because they go up instead of sideways, and many of the drivability issues aren't from the runner length so much as from using two enormous carburetors, often with mechanical secondaries.
??? Can you elaborate?
Unless you mean you need data to know the transient conditions- like engine speed, throttle/MAP, and air fuel... That I'm totally in agreement on.
I should have put that remark in context: Adding a wideband O2 sensor system on its own to a carbureted engine will only be a small amount of help with transient tuning. You already know if it stumbled or didn't stumble. It will be difficult using just the wideband data, even if it's data loggged and not a gauge, to tell what went wrong. It won't be easy isolating the accelerator pump effects from the transition circuit or jetting, and a misfire will often read lean on a wideband even if the misfire resulted from too much fuel instead of too little.
In reply to A 401 CJ :
Yes. However what tunnel rams have in spades is plenum volume, which hurts the metering circuits' vacuum signal (velocity pulses through the venturis) until high revs.
"Vacuum signal" is why you want a small carb with a large plenum and vice versa. Tunnel rams are a huge plenum and two huge carbs
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