Plenty of owners love the mechanical simplicity and period-correct look of Weber DCOEs or restored SU carburetors. Other drivers like the very reliable consistency and efficiency that modern EFI gives you, no matter the temperature or altitude. When it comes to price, you're looking at anywhere from $200 for a carburetor rebuild all the way to $4,000 for an EFI conversion, and that's before factoring in the wiring harnesses and fuel system upgrades. Performance numbers are really strong, though - Electromotive systems have literally doubled the horsepower outputs in some builds, and Megasquirt installations usually bump fuel economy up by about 30%.
These two systems work differently for driving, so your ownership goals will determine which one makes the most sense to go with.
Here's which fuel system will make your S30 Z run its best!
Table of Contents
How Each System Handles Real Driving
Cold mornings with an S30 will teach you everything you need to know about the differences between carburetors and fuel injection. With a carb setup, you'll pump that gas pedal a few times and then wait for the choke to warm up and do its job. Sometimes the engine will crank for what seems like an eternity (maybe 10 seconds or more) before it finally decides to catch and run. EFI systems are a very different story - just turn the ignition and the engine fires right up, no questions asked.
When you drive through mountains or take weekend canyon runs, you'll quickly see how differently these two systems respond to changes in elevation. Carburetors are stuck with whatever jet sizes you've installed, and they can't adapt when the air gets thinner at higher altitudes. A Weber that's been tuned just right at sea level might run way too rich as you climb to 7000 feet, and suddenly you're down on power right when you need it most. EFI systems have sensors that constantly check the air pressure and automatically adjust the fuel mixture to compensate for any altitude changes.
Each system also gives you a very different driving experience when you're actually behind the wheel. Carburetors give you this very direct, mechanical connection between the accelerator pedal and what the engine is doing. Press down and the fuel flows through the venturi - no delay, no interpretation, just pure mechanical response. Plenty of drivers love this raw and unfiltered feedback - even though it means that you'll sacrifice some accuracy in the fuel metering.
Electronic fuel injection delivers steady performance really well, no matter where you are in the RPM range. The computer always makes small adjustments (we're talking hundreds of times per second) to line up the fuel delivery with what the engine needs at that particular time. This accuracy usually means somewhere between 10% and 20% better fuel economy than what you'd get with a comparable carburetor setup.
The summer heat in the S30's engine bay can turn into a genuine problem on longer drives. Carburetors are likely to experience something called fuel percolation when the temperatures climb too high. The gasoline literally starts to boil inside the float bowls, and it causes rough idling or stalls at the worst possible times. The EFI systems handle high temperatures much better because the fuel always remains under pressure throughout the entire system.
Budget for the Complete Project
A quality carburetor rebuild is going to set you back somewhere between $200 and $500, and that's only if you're willing to do all the work yourself. An EFI conversion is a very different animal, though - most kits start around $1,500 and can climb past $4,000 pretty easily. These prices are just for the basic parts that come in the box.
What gets expensive are all the extra parts that somehow never make it into the first conversation. EFI systems need a completely new wiring harness, and you'll have to upgrade your fuel pump for the pressure laws. On top of that, you're going to need different fuel lines and most likely a return line back to the tank. All these little additions can tack on another few hundred dollars to your total, and they add up fast.
After the installation comes the usual maintenance costs, and that's where the differences really show. Carburetors are going to need a rebuild every few years when you drive your Z quite a bit - plan on spending another $200 to $300 each time that rolls around. EFI systems don't need as much attention, which is nice. But the sensors do fail over time. When one goes bad, replacement sensors usually run anywhere from $50 to $200 each.
Most Z owners find that 40-year-old wiring harnesses and vacuum lines are tricky to work with. Professional installation for an EFI system can add another $1,000 to $2,000 to your project pretty easily. Even carburetor work might need a professional's touch when it comes time for the final tuning and adjustments.
The tool laws alone tell you something about what you're getting into. Carburetor work just needs basic hand tools and maybe a synchronizer to get it right. EFI systems demand at least a laptop with the tuning software. Getting a proper tune means that you'll need to add a wideband oxygen sensor to your shopping list.
At the end of the day, your budget is probably going to make the decision. The best system is always the one that you can afford to install correctly and maintain over the years.
Do You Have the Right Skills
The actual question has less to do with affording parts than it does with having the skills to actually install and tune them correctly. Carburetors need a solid understanding of vacuum systems and mechanical linkages, and you'll be spending hours with a screwdriver and vacuum gauge in hand to get the fuel mixture dialed in correctly. Most of the work is done by hand, and the great news is that you probably already have all the basic tools sitting in your garage.
EFI is a very different animal, though. Wiring diagrams and sensor voltages become your new language, and a laptop turns into your most important tool. The diagnostic software alone can run a few hundred dollars, and every adjustment has to be made through a computer screen instead of with wrenches and screwdrivers.
The learning curve depends on your background and what you're comfortable with. Mechanics who grew up around carburetors can usually hear that slight stumble off idle and know just what needs adjusting. Ask that same mechanic to interpret oxygen sensor data, though, and they'll probably give you a blank stare.
This brings up a particular challenge for Z owners in particular. Most of the mechanics who really know these cars inside and out learned their trade back in the 1970s and '80s. These guys can rebuild a set of SU carbs blindfolded with no problem. Modern EFI tuning, though, tends to be completely outside their area of expertise and means that you could end up alone with nothing but a laptop and whatever forum threads you can come across for help.
I see plenty of owners who pick a path and then find out halfway through the project that they don't actually have the skills they need to finish what they started. A triple Weber setup looks great on paper. But when you have to synchronize 3 separate carburetors at the exact same time, the process gets a little complicated. The plug-and-play EFI kit means that half of your engine bay needs to be rewired for the whole system to work.
EFI Options for Your S30 Build
EFI conversions for your S30 have grown tremendously over the past few years, and the options might overwhelm you. MegaSquirt has stayed popular as the budget-friendly choice for owners who don't mind rolling up their sleeves and doing some DIY work. The catch is that you'll need to break out the soldering iron and then spend lots of time on the tuning side. The learning curve can be brutal at first, and plenty of owners underestimate just how much time they'll need to invest.
Holley Sniper and FiTech systems take a very different approach and bolt right onto your existing intake manifold without too much hassle. These self-learning systems are smart enough to adjust their own fuel maps as you rack up the miles. It sounds almost too simple to be true. The downside is pretty big, though - they'll run you about twice what a MegaSquirt setup costs. What you're paying for is the convenience of not having to deal with all that complicated setup and programming work.
Lots of Z owners go in a third direction and adapt ECUs from Nissan's newer engines like the SR20DET or RB-series motors. These computers already know how to run an engine right because that's what they were designed for from day 1. And you get the reliability that aftermarket systems don't always deliver. The challenge is that your entire engine bay needs to be rewired from scratch to make all the parts talk to one another.
Your S30's original electrical system was never designed for modern ECUs and all their loads. Most conversions mean that you'll need to upgrade the alternator at a minimum and then add lots of new relays throughout the car for the extra electrical load. The stock gauge cluster is another headache because it won't read anything right unless you add signal converters between the ECU and the gauges or just bite the bullet and swap to aftermarket gauges altogether.
All these different paths create a whole new problem for Z owners who just stay frozen with indecision. Month after month goes by as they read every forum post and watch every YouTube video out there, yet they never actually pull the trigger on anything. The irony is that the fear of picking the wrong system means that their cars stay on carburetors indefinitely. Having so many options to choose from can make it harder to commit than having only 1 or 2 paths forward.
How Each Choice Affects the Value
Resale value brings in a whole other layer to the carburetor versus EFI debate, and it's actually a lot more nuanced. A numbers-matching S30 with pristine Weber DCOEs or vintage SU carburetors will certainly command attention from dedicated collectors. These are the buyers who have deep pockets, and they're specifically after cars that look just like they did when they rolled off the showroom floor back in 1972.
The market is changing, though, and it's happening faster than a lot of traditionalists want to admit. Younger buyers who grew up with fuel injection don't automatically view EFI as a sacrilege. A lot of them actively want a car they can drive every day without the need to fiddle with carburetor adjustments every few weeks. A clean EFI conversion done with quality parts can increase the appeal for this growing segment of the market, and they're getting to be a bigger part of the buyer pool every year.
The best way to protect your car's value actually relates to how you handle the modification from day one. When you keep all the original parts and document each step of the conversion process, you're setting up future owners with the best of 2 worlds. They can stick with the EFI setup if they like it, or they can swap everything back to carburetors if that's what they want. This flexibility alone really matters when you're ready to sell.
I've seen some owners develop a middle ground strategy that works brilliantly. They'll run the EFI during their normal driving season and then swap everything back to carburetors for shows or certain events. Yes, it means that you'll maintain the 2 systems, and that's certainly some extra work. The payoff is worth it, though, because the car runs reliably whenever you need it to, and it still looks period-correct when appearance is the main priority. Documentation is what makes or breaks this entire process. You need to save every receipt you get, and photos are just as important - take them at each step as you're working on the installation.
Build Your Dream Car
Carburetors and fuel injection have been a hot topic in the Z community for decades, and what's going to work best depends on what you actually want from your car. Lots of Z owners swear by carburetors and won't hear a word against them - they love how simple the mechanics are and how authentic it makes their car feel. But other drivers just want to turn the ignition and have their Z start up every time, no matter what - the middle of winter, the middle of summer, it doesn't matter. Both camps have valid points, and I've seen excellent builds from each side that are an absolute blast to drive.
Your fuel system is one part of the equation to get your Z where you want it. Carbs or fuel injection, either way, the rest of your build needs that same attention to detail and quality parts. At Skillard, we've earned our reputation with Z owners by making custom bumpers, aluminum door cards, center consoles, spoilers, and tons of other parts that are engineered for the 240Z, 260Z, 280Z, and other classic Datsuns. Every piece we make fits like it should, looks right at home, and means that you'll spend more time driving and less time fighting with universal parts that never quite work. Check us out at Skillard.com to browse our catalog and to find what your Z needs to become the car you've been dreaming about.
