The Honda F20C Engine Manual. The Honda F20C engine is one of the company’s crowning achievements. The F20C is a magical engine found in one of the most cherished Hondas to ever leave the assembly line, the S2000. The F20C’s 9,000 rpm redline has enthusiasts salivating. For over a decade, it also held the record for the highest specific output from any normally aspirated engine.
The F20C has received numerous plaudits over the years, including high dependability, widespread aftermarket support, reasonable factory performance, and placement in one of Honda’s most iconic sports cars. They certainly explain the cult mystique that still surrounds the F20C today.
We’ll cover all you need to know about the Honda F20C engine in this article, including engine specs, comparisons to previous Honda engines, typical problems, and a few performance enhancements.
Honda F20C Engine Specifications
The Honda F20C is a naturally aspirated four-cylinder engine designed to be installed longitudinally in the S2000 for rear-wheel drive. The engine made use of novel engine technologies to improve both performance and dependability. The F20C is built entirely of aluminum, including the block, cylinder head, and forged aluminum pistons.
In terms of power, there is a tiny difference between the US and JDM-spec F20C. The JDM-spec F20C features a greater compression ratio than the US-spec version, giving it an extra 10 horsepower. Here are the numbers in list form:
- F20C USDM-Spec F20C JDM-Spec Engine
- (AP1) Honda F20C Engine Design
Because the F20C was designed with certain characteristics in mind, it featured unique engine construction that distinguished it from previous high-performance Honda engines. The majority of the technology came from Honda race engines.
The F20C, for example, has a ladder-frame main bearing stiffener. This decreases engine vibrational forces and strengthens the main bearing. Roller followers help to reduce frictional stress in the dual-overhead cams. This permits the engine to breathe more easily. Both the intake and exhaust camshafts feature VTEC technology, which increases airflow.
The F20C engine also used new materials to boost structural stiffness and strength. The insides of the F20C cylinder walls are coated with fiber-reinforced cylinder liners, allowing them to endure the high rpm. The piston skirts of the F20Cs are coated with molybdenum disulfide, which significantly decreases friction along the cylinder walls.
The F20C relied on these innovative technology to handle the engine’s high piston speeds. With a mean piston speed of 4,965 ft/s, the F20C outperforms any other engine ever created.
F22C1 Engine Variant (AP2)
Honda created the F22C1 variation of the F20C engine for the North American market in 2004. The F22C1, like the F20C, was only utilized in one Honda car, the S2000. The F22C1’s construction is fairly identical to that of the F20C, but displacement has been significantly adjusted. The displacement of the stroked F22C1 is 2.2L, 0.2L greater than the F20C.
Because of the longer piston stroke, the F22C1 has a significantly lower redline of 8,200 RPM. Despite the larger displacement, the F22C1’s horsepower output remained constant at 240 hp. However, torque was boosted by 7 lb-ft to a maximum of 162 lb-ft. For the 2004 and 2005 model years, the F22C1 was used in US-Spec S2000s. It eventually replaced the F20C in JDM-Spec automobiles starting in 2006.
Honda S2000 Engine Issues
When it comes to Honda engines, dependability and ease of maintenance are always top priorities. That mantra also applies to the F20C. Because of the quantity of heat and friction generated in the combustion chamber, high-strung engines are typically the most problematic. This usually results in more frequent wear of parts and consequent engine difficulties.
Honda, on the other hand, tried everything in the book to mitigate these concerns. As a result, the F20C is as dependable as any of Honda’s other well-known engines. Most other high-performance sports cars develop engine problems at relatively short mileages as compared to other civilian-oriented vehicles. That is not the case with the S2000 equipped with the F20C or F22C1.
In most situations, the components surrounding the F20C engine begin to fail before the engine itself. Only minor faults tend to occur prior to the 300,000-mile milestone if the engine is maintained with regular oil changes and tune-ups.
That being said, there are a few unique F20C engine problems that are more prone to occur than others. The following are the most typical issues:
- F20C engine oil consumption is high.
- Transmission buzzing while decelerating
- Valve spring retainers with cracks
- High Oil Consumption in the F20C Engine
High oil consumption is one of the most frequently mentioned problems with the F20C engine. High oil consumption is a common side effect of owning a car with a high-revving performance engine. According to Honda, a quart of oil should be added to an AP1 F20C-powered S2000 every 1,000 miles. If your S2000 consumes more oil than that, there could be a more serious underlying problem.
Symptoms of Honda S2000 Excessive Oil Consumption
High oil consumption in an F20C-powered S2000 is rather simple to identify. There are only a few strategies to detect excessive oil usage. These include an oil-burning odor, a low engine oil level, and smoke emanating from the exhaust.
While the smell of burning oil almost always indicates that the F20C engine is eating oil, low engine oil could also signal that there is an oil leak somewhere on the engine. S2000s typically consume oil through the piston rings and valve seals, but only on high-mileage engines. If your S2000 hasn’t logged many kilometers and isn’t smoking from the exhaust, an oil leak is most likely to blame.
Fix for F20C Engine High Oil Consumption
According to many S2000 owners, a clogged PCV valve is a common cause of high S2000 oil consumption. This issue is more common in F20C (AP1) powered vehicles. This is a good place to start if your S2000 is consuming an unusually big amount of oil.
Valve guide seals are also notoriously difficult to replace in high mileage F20Cs. This is a more difficult repair because the engine must be opened and the cams must be removed. While replacing the seals is not the simplest task, the parts themselves are relatively affordable.
Finally, using a viscous oil or a different brand of oil can assist reduce oil burn-off. S2000 owners frequently advise against using Mobil 1 oil in F20C engines. This is because Mobil 1 has a higher burn-off rate than most other brands. A thicker, non-synthetic engine oil can help alleviate the problem.
S2000 Transmission Buzzing While Deceleration
Many S2000 owners complain about erratic or noisy transmissions. A common complaint, particularly with F20C gearboxes, is a buzzing noise emanating from the transmission tunnel when decelerating between 4,000 and 3,000 RPM. This happens most frequently when moving from third to second gear. Owners who have experienced the problem say the sound is comparable to heat shield rattle.
Honda later detailed the issue in a bulletin. According to Honda, the sound is caused by clearance concerns between gearbox gears. Because the S2000’s transmission is situated between the driver and passenger seats, the noise is exacerbated. When the car slows down, the weight of the vehicle, combined with engine pulses, excites the transmission gears, causing them to buzz or rattle. Honda also stated that the clutch disc hub springs within the transmission clutch disk are a source of the issue.
Fix for F20C Transmission Buzzing
Because gearbox buzzing is a known issue in S2000s equipped with the F20C, Honda provided a factory solution. This includes a new clutch disk with a redesigned design that reduced noise.
The clutch disk replacement that resolved the problem was initially covered under warranty. Since the launching of the Honda S2000 in 1999, most F20C-powered vehicles have been out of warranty. If the problem can be diagnosed by a qualified Honda dealership, a goodwill agreement with Honda can be used to have the problem rectified outside of the manufacturing warranty. To be considered, you must apply to the Honda District Service Manager or a Honda-certified service center.
The modified clutch disk can also be ordered using the part number given below. A specialized Honda repair shop may be able to install the clutch disk for less than the dealership.
F20C Transmission Clutch Disk Modified Part Number:
- H/C 6855126, P/N 22200-PCX-055.
- Cracked Valve Spring Retainers F20C
Valve spring retainers are an essential component of the valvetrain of any engine. They are in charge of constantly applying the right amount of spring pressure to prevent valve bouncing. When a valve spring retainer fractures or breaks completely, valve spring tension is lost, causing serious damage to the valves and other engine components.
Because the F20C is an interference engine, this is especially true. This indicates that the piston may come into touch with a floating valve. Because the F20C has a high-revving engine, fractured valve spring retainers are more prevalent than in a lower-revving engine.
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Symptoms of a Cracked Valve Spring Retainer on a Honda S2K
A damaged valve spring retainer will usually create a slew of instant symptoms. However, determining if the valve spring retainers are to blame may be challenging because the accompanying symptoms can be caused by a variety of other issues.
A broken valve spring retainer is most commonly identified by a loss of power or misfires at high RPMs. Even if a valve spring retainer is damaged, an S2000 will most likely start and idle normally. The problem will manifest itself at 4,000-5,000 RPM, when the valve springs are unable to keep up with the rest of the valvetrain. If the retainer failed and caused the spring to fail, a consistent misfire at all engine speeds would be expected.
If you suspect a valve spring retainer has failed, you must fix the problem as quickly as possible. In the worst-case scenario, the retainer could get so broken that the valve falls out of its housing. This would allow it to penetrate the cylinder head and combustion chamber, causing damage to every component.
F20C Valve Spring Retainer Crack Repair
A vacuum test on the engine is the simplest technique to determine if one of your valve spring retainers has cracked. Connect a vacuum gauge to the vacuum port of your F20C’s intake manifold to accomplish this. The engine can then be started. At idle and increasing engine RPMs, check the vacuum gauge. If the valve springs/retainers are the source of the problem, the vacuum readings will oscillate as the RPMs rise.
The only other option is to remove your F20Cs valve cover and cams to inspect them for flaws. The retainers are placed on top of the valve springs. Because they have a consistent circular shape, a crack or chip should be easy to spot.
The only way to fix a broken or damaged spring retainer is to replace it. Because retainers deteriorate with time and cause loss of spring pressure, it is always advisable to replace all of them rather than just the one that is damaged. Replacing all retainers ensures that all valve springs receive the same amount of spring pressure.
Best F20C Performance Enhancements
The Honda F20C is a favorite among aftermarket performance enthusiasts in addition to being exceedingly reliable. Once again, the F20C’s high-revving nature is something that tuning businesses and other performance part manufacturers capitalize on and grow on.
The aftermarket Honda community is dominated by forced induction. This is particularly true for the F20C. Because of its forged internals, the F20C can endure high boost pressure and produce some hefty horsepower ratings. Using stock internals, the F20C can produce 400 horsepower without breaking a sweat. The F20C’s remarkable durability is what makes it such a potential candidate for radical aftermarket improvements.
Although forced induction is popular in the S2000 modding community, there are numerous worthwhile performance upgrades for those who prefer to keep their F20C naturally aspirated.
Forced Induction Modifications for the Honda S2000
Forced induction is universally acknowledged as the best approach to extract the most performance from an F20C engine. The F20C’s short-stroke configuration, forged internals, and 11.0:1 compression ratio create the perfect storm for excellent forced induction performance. An F20C turbocharger or supercharger kit, on the other hand, is quite expensive.
Considerations for F20C Forced Induction
Several more issues must be considered when integrating forced induction into any engine. We’ll keep it basic here because the specifics of F20C forced induction get pretty intricate in terms of varied setups for different applications. In general, the following are the key supporting mods necessary for F20C forced induction:
- improved clutch
- Fuel injectors with high pressure
- improved fuel pump
- Rail fuel
- Engine management system upgrade
- The intercooler and its pipes
- Spark plugs for high performance
- Upgraded exhaust components (optional)
In many ways, the F20C comes factory prepared for forced induction. The F20C can handle the extra strain thanks to forged pistons, and the stock exhaust system is relatively unrestrictive until high horsepower figures are attained.
Superchargers are the most popular forced induction option in the S2000 community. While an F20C can still be turbocharged, superchargers provide greater linear power. Because superchargers are directly connected to an engine’s crankshaft, the extra power is accessible immediately. This differs from a turbocharged configuration, where the lag in power delivery is caused by the turbo spool time.
Supercharger Kit for S2000
Since the F20C engine has been around for a while, there are a plethora of supercharger kits on the market. There are so many that it can be tough to select amongst them. We found that the HKS GT2 F20C Supercharger Pro Kit offers the best value for money, build quality, and performance after conducting extensive research.
HKS is a well-known aftermarket brand for Japanese domestic vehicles, and they are noted for their five-star build quality. The GT2 F20C supercharger kit is promoted as a high-performance package that retains the engine’s durability. It is suitable for both daily and race-spec S2000 usage. The kit was created with linear power improvements in mind, and it delivers power in a manner quite similar to a standard F20C.
The package includes practically everything you’ll need to get started. Along with the kit, Evasive Motorsports supplies updated engine management systems, injectors, fuel pumps, and batteries to flesh out the setup’s other components.
Price: $4,725.00 (excluding any further supporting components)
Gains in power: +74 hp and +58 ft-lbs
Upgrades to the Honda F20C Exhaust System
Outside of forced induction, the greatest way to enhance horsepower is with a full F20C performance exhaust and a solid tune. A performance exhaust system enhances the F20C by boosting the exhaust side of the engine’s breathability. While the factory exhaust is highly respectable and does not limit the engine in stock form, a tuned performance exhaust system will add a few more horsepower.
An upgraded test pipe, catback exhaust, and a tune can provide an additional 20-25 horsepower. It is crucial to remember that an S2000 with this setup will almost certainly fail emissions tests. The installation of a test pipe in place of the F20C catalytic converters will almost probably cause problems at the emission center. Those who opt to operate a catless arrangement must replace the test pipe with the factory cats when their registration is renewed.
Exhaust System for Honda S2000
In terms of S2000 exhaust systems, there are numerous solutions available. Most enthusiasts buy catback systems separately from an improved test pipe. In general, a higher-flow catback system will provide more horsepower than an improved test pipe. However, if you keep your factory F20C catalytic converters and only add a catback system, your S2000 should pass emissions tests just fine.
Invidia is our preferred choice for an enhanced S2000 test pipe and catback system. The majority of S200 owners think that a 70mm exhaust diameter is the ideal compromise between reducing backpressure and preserving exhaust gas velocity. As a result, the Invidia F20C test pipe and catback system are both 70mm in diameter. Both of them are made of 304 stainless steel. This saves weight without sacrificing stiffness.
If you plan on turbocharging or supercharging your F20C in the future, both components support forced induction. Even if you do not use forced induction, it is critical to tune your car after replacing exhaust components. An exhaust tune will allow the F20C to recognize the new setup’s higher flow capability, unlocking horsepower.
$778.40 Invidia 00+ S2000 70mm Dual Titanium Tip Catback Exhaust
$70 Invidia 00+ S2000 70mm Test Pipe with CEL Fix
Gains in Horsepower: +25 hp and +25 ft-lbs
Upgrade of the Honda S2000 Engine Management System
You’ll need an engine management system to fine-tune your F20C to a higher level. Upgraded engine management systems, in general, allow you to fine-tune critical components of engine performance such as air/fuel mixture, idle control, and ignition timing. If you intend to install any big engine modifications, it is usually a good idea to have an improved engine management system.
While there aren’t many engine management systems available for the S2000, the AEM Series 2 F20C EMS is clearly the best alternative, according to most S2000 owners in the performance modification community. It makes use of factory sensors and plugs straight into the factory wire harness for convenience. Unlike many other EMS choices, the AEM comes with free tuning software that does not require a monthly membership.
An updated EMS is the key to unlocking the power potential of your S2000. Without one, you will undoubtedly be leaving performance on the table. Upgrading your F20C engine management system isn’t the cheapest upgrade, but it’s undoubtedly one of the most beneficial.
Gains in horsepower are entirely dependent on other engine upgrades.
Summary of the Honda F20C Engine Guide
The Honda F20C engine has many advantages. One of the key reasons for the S2000’s popularity is the F20C. The F20C has performance covered with a redline of 9000 RPM, dual-VTEC, forged pistons, and the highest specific output of any production engine.
In addition to being a high-performance engine, the F20C strengthens Honda’s reputation for dependability. It is quite rare for the F20C to develop major problems at mileages less than 150,000. Even at greater miles, the engine has very few frequent problems. That being said, it is critical to be careful with F20C maintenance to avoid any difficulties down the road.
The S2000, like most other high-performance Hondas, has a thriving aftermarket. The F20C is a very customizable engine with massive power potential. F20Cs benefit greatly from forced induction and are almost ready from the factory for a turbocharger or supercharger. F20Cs with naturally aspirated engines are likewise readily customizable. Exhaust system changes and an updated engine management system are among the most notable N/A F20C modifications.
There’s a reason why the Honda S2000 is still one of the most popular Japanese sports cars today. Even after 20 years, the F20C is still adored by a large number of aficionados who like rev-happy, efficient, and dependable engines.