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Carb vs. Injection

Are Carburetors Dead?

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With all new cars fuel-injected and many race-sanctioning bodies allowing electronic engine-management systems, fuel injection is rapidly approaching critical mass. But hard-core domestic V-8 lovers won't surrender their carbs without a fight. To get the lowdown on the coming battle, Car Craft consulted leading industry movers and shakers. Their consensus: Don't hold a wake for your carb just yet!

Is the carburetor dead?

Jim McFarland, McFarland and Associates: If carbs are left as they are today, with no technical improvements, they have about seven to eight years left. But there are tech improvements on the horizon that will prolong their life. Carbs will last longest in motorsports. In the future you may not recognize them as carbs, but they’ll still rely on pressure differential to meter fuel.

How long will it be before EFI outnumbers carburetors on street machines?

Butch Bass, Holley: Electronic fuel injection may never become more popular than carburetors on street machines. Many street machiners want to emulate Pro Stock race cars that still use carburetion, and they prefer the simplicity of carburetion--no return lines to the fuel tank and no electronics package to mount. However, as prices come down and the driveability aspects of EFI become more widely appreciated, fuel injection will gain a much larger following.

Kevin McClelland, Flowmaster: It will be upwards of 10 years on domestics. That’s due to the cost of conversion on cars not factory-equipped with fuel injection, not fear of new technology. Look at the import market: there high-tech is embraced. Import kids are computer literate, and the cars are already fuel-injected, so the cost to get into the program is less.

Steve Johnson, BG Products: Not anytime soon. EFI makes more power, but our EFI system costs $2,400, compared to $400-450 for our Speed Demon carburetor. You only gain about 10 hp at the peak, so for a lot of guys it isn’t worth the money. Off-roaders will probably go to EFI before street machiners because it helps them overcome steep grades and vibrations that cause trouble with carbs.

Mark Hamel, ACCEL: Most likely it’ll be six to eight years, sooner if the import market continues its rapid growth. Eventually, it will happen. How long will old musclecars be around at affordable prices?

When will we see EFI in big-time racing like Pro Stock or NASCAR?

Butch Bass: You are not going to see EFI in NASCAR for many years. The cars are fast, competitive, and they don’t fail. NASCAR is also concerned about having more onboard electronics that could enable the highly sophisticated teams to disguise something akin to traction-control within the EFI system.

Myron Cottrell, TPI Specialties: There’s already injection in Formula 1, CART, IRL, and many SCCA road-racing classes. You’ll see it in the holdout sanctioning bodies as soon as younger folks are put in charge.

Jason Scott, Lingenfelter Racing: ASA stock cars will use "spec" GM-assembly-line-built LS1 430hp EFI engines this year. Except for hotter cams, modified computer calibration, race-type exhaust systems, and Lingenfelter-installed dry-sump systems, these are the same engines used in the Corvette.

Carl Olsen, NHRA: No time in the foreseeable future. Pro Stock is healthy now, with extremely close competition. If it ain’t broke, why fix it? EFI could cause big problems. The sophisticated microprocessors used with EFI systems can do more than just meter fuel. The technology already exists to drive the car by itself. Factory-backed favorites could gain an unfair advantage using EFI.

Warren Johnson, Pro Stock racer: There’s no excuse for not moving to EFI. The traditional sanctioning bodies are 180 degrees reversed from reality. The "self-driving car that we can’t tech" excuse doesn’t hold up. The old guard has always used that excuse, but it’s time to bring the tech department into the 21st century. EFI is more user-friendly than carburetion and will help the more novice tuners. They can perfect the combo on the dyno, then the EFI will self-correct for atmospheric conditions. After a short learning curve, EFI actually levels the playing field. Anyone can learn to tune an EFI, but there are only about two to three legitimate carb experts that can really dial in carbs for Pro Stock.

Lenny Imbrogno, IHRA: EFI will be legal in IHRA Pro Stock in 2001, although racers can continue to run carbs if they wish. The ECM can control everything from the firewall forward--including the fuel and ignition--but in Pro Stock we won’t allow inputs for traction control or the transmission. There won’t be a spec controller, but we will control the number and function of the pin-outs. Any manufacturer who conforms to the standard may participate. IHRA welcomes some of the new technology. We can control it and keep it simple enough, inexpensive enough that it won’t gouge the racers. As for advanced technology in Top Fuel, never say never. We’re looking at traction control there--it could lead to much closer racing. The goal is to provide a better show for the fans.

Which makes more power--carburetors or EFI?

Butch Bass: A properly sized manifold and carb can make as much absolute power as EFI. Although EFI tends to produce a broader torque curve, ultimate horsepower is simply a case of flow and distribution.

Jim McFarland: If you boil everything down to combustion efficiency, ultimately full-sequential port-EFI systems will make the most power. Carbs are not good providers of mixture quality when tuning one cylinder at a time.

Warren Johnson: Properly tuned, carburetors make more peak power than EFI in a Pro Stock engine. A carb’s pressure differential atomizes the gas a lot better than spraying fuel through an orifice. But EFI has a broader powerband and superior cylinder-to-cylinder fuel distribution. The 1,100- to 1,300-cfm dual carbs are good only over a narrow range, about 1,500 rpm at most. EFI performs well over 2,000 rpm or more. On average, if optimized, both systems perform about the same as far as how fast you get down the track. However, the EFI system is much easier to tune than a carburetor.

Will EFI systems become cost-competitive with carbureted systems?

Butch Bass: The primary component that is keeping prices of EFI systems higher is the cost of the ECU. Although the cost of electronic devices is rapidly coming down, companies like Holley continue to upgrade the features and capabilities of their ECUs, so we haven’t seen a large decline in overall costs yet. The overall cost of EFI will probably remain more than carburetion simply because there are more components. If you consider EFI’s price-to-value factor (better fuel economy, longer engine life, and reduced emissions), then it makes more sense financially. Ultimately it will be the consumer who determines how much EFI costs. If he embraces EFI and the demand is there, the economies of scale will take over and costs will be reduced.

Myron Cottrell: You can pick up an entry-level Holley carb for $99 (more like $199--ed.). You can pay thousands of bucks for a TPI system, and if you’re modifying the engine, it probably won’t run right out of the box. On the other hand, if you’re going to drive 25,000 miles per year, with the improved reliability, decreased maintenance costs, and better fuel economy of an EFI system...then the economics start to come back.

Mark Hamel: They’re not that far away now. A trick aftermarket carbureted intake, a Holley Dominator carb, and a high- volume fuel pump will set you back over $1,000. ACCEL can sell you a complete system for $1,800-2,000. The difference is that the EFI system is complete, one big price hit all at once, but you can piece the carburetor system together separately, so it appears more affordable.

Bill Howell, Howell Engine Developments and GM Motorsports tech rep to ASA: The ASA stock car LS1 spec engines cost one-third less and last three times as long as last year’s engine--that’s $12,000 compared to $30,000. They make 430 hp with rpm held to 6,500 max. They use a GM computer, which any Chevy mechanic can scan with the normal dealer diagnostic tools. Seal the motor and seal a production ECM, and you can keep control and have fast, reliable, and affordable racing.

Warren Johnson: Most Pro Stock racers farm out the carbs to a specialist, and generally you have a set of carbs custom-tailored for each engine. EFI has a bunch of nozzles but only one controller per vehicle. Both systems require custom intakes. Either way, you’re looking at about $7,000 for a complete Pro Stock system.

How far are we from an affordable, self-programming EFI system for the masses?

Mark Hamel: It&8217s a lot easier said than done. If we can control the total motor combination from the cam up, the technology is there to do it; otherwise, there’s a lot of variables you need to overcome.

Butch Bass: The performance aftermarket is already offering EFI systems that have "self-programming for the masses." Take Holley’s 4D systems, for example. They are delivered with a fuel map pre- installed. The consumer is able to fine-tune the idle, power, and cruise fuel ratios by simply turning a few dials on the control module. Holley&8217s more sophisticated 4Di units are programmable with a laptop computer; there are basic fuel curves developed for various power levels that can be automatically loaded into the ECU. They are close enough for most engine combinations but can be fuel-mapped very precisely if you desire. Other Holley EFI aftermarket systems will simply use the existing original-equipment manufacture ECU, and all you have to do is install the hardware (manifold, air valve, fuel pump, and injectors); there’s no programming involved at all.

Is there a limit to the power level EFI can support?

Mark Hamel: There’s no limit as far as the electronics go. The limits are presently available hardware and injector sizes. Right now 2,000 hp is not a big deal.

Warren Johnson: When you get to Top Fuel, there is an immense learning curve to develop an integrated EFI system that could deliver fuel at the needed rate, but I won’t rule it out. It has the potential to reduce downtime because there’d be fewer oildowns. That makes Top Fuel a better show for big-time TV. And it gets rid of grumbling in the stands. Who wants to sit for three hours in 95-degree heat watching them clean up the oil?

Why should anyone still run a carburetor?

Butch Bass: If you are doing a total restoration, then you will want to stick with what the vehicle came with. In many cases EFI just isn’t available for your model of engine, and unless you are pretty sophisticated at selecting individual EFI components and have the fabrication skills to build your own manifold and fuel-rail setup, carburetion is the way to go.

Steve Johnson: Cost is the big thing, followed by ease of installation and repair. Of course, certain classes still require carburetors. There are also safety issues in circle-track racing, where mechanical fuel pumps tied directly to the engine are preferred over high-pressure electric pumps.

Why run fuel injection if your car isn’t factory-equipped with it?

Butch Bass: Anyone who has driven a modern fuel-injected vehicle can answer this question. EFI simply enables the engine to be more efficient throughout the rpm range. From cold-starting to throttle response, a properly designed EFI setup is hard to beat. Engine management is the key to overall engine performance in the future, and when you control fuel and spark together, you have the ultimate tuning capability.

Mark Hamel: Fuel injection does everything right--improves driveability, makes more torque, solves cold-start problems, lowers emissions, and improves gas mileage. You can make 450 hp and drive the car every day. Myron Cottrell: EFI is for the guy who wants to learn. It is for the guy involved in the technology of today.

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