Honda F20C Engine Guide

The Honda F20C engine is one of the company’s masterpieces. Found in one of the most beloved Hondas to ever leave the production line, the S2000, the F20C is magic for a few reasons. Enthusiasts drool over the F20C’s high-strung 9,000 rpm redline. It also held the record for the highest specific output from any naturally aspirated engine for over a decade. 

High reliability, extensive aftermarket support, respectable factory performance, and placement in one of Honda’s most iconic sports cars are just some of the accolades that the F20C has garnered over the years. They sure explain the cult mythos that surrounds the F20C to this day.

In this guide, we’ll cover everything you need to know about the Honda F20C engine, including engine specs, comparisons to preceding Honda engines, common issues, and a few performance upgrades. 

Honda F20C Engine Specs

The Honda F20C is a naturally-aspirated 4-cylinder that was designed to be mounted longitudinally for its rear-wheel-drive application in the S2000. The engine utilized unique engine technology to bolster both performance and reliability. The F20C features full aluminum construction, including the block, cylinder head, and forged aluminum pistons. 

There is a slight discrepancy between the US and JDM-spec F20C in terms of power. The JDM-spec F20C has a higher compression ratio than the US-spec version, which gave the JDM version an additional 10 horsepower. Here are the stats in list format:

Engine	F20C USDM-Spec	F20C JDM-Spec
Configuration	Inline-4 Cylinder	Inline-4 Cylinder
Displacement	1,997 cc (2.0L)	1,997 cc (2.0L)
Aspiration	Naturally Aspirated	Naturally Aspirated
Fueling	Fuel Injection	Fuel Injection
Head Material	Aluminum	Aluminum
Block Material	Aluminum	Aluminum
Valvetrain	DOHC, 16-Valve	DOHC, 16-Valve
Bore x Stroke	87mm x 84mm	87mm x 84mm
Compression Ratio	11.0:1	11.7:1
Horsepower	237 hp	247 hp
Torque	155 lb-ft	150 lb-ft

(AP1) Honda F20C Engine Construction

Due to the fact that the F20C was designed with specific parameters in mind, it featured unique engine construction that differentiated it from other high-performance Honda engines that came before it. Most of the technology was derived from Honda race engines. 

For instance, the F20C features a ladder-frame main bearing stiffener. This reduces the vibrational forces within the engine and strengthens the main bearing. The dual-overhead-cams benefit from roller followers, which greatly reduce frictional stress. This allows the engine to breathe better. VTEC technology is used for both the intake and exhaust camshafts, also increasing airflow. 

The F20C also utilized advanced materials within the engine to increase structural rigidity and strength. Fiber-reinforced cylinder liners coat the insides of the F20C cylinder walls, allowing them to withstand the high revs. The F20Cs piston skirts are lined with molybdenum disulfide which greatly reduces friction along the cylinder walls. 

The F20C used these advanced technologies in order to handle the immense piston speeds within the engine. With a mean piston speed of 4,965 ft/s, the F20C is unparalleled by any other engine ever made.

(AP2) F22C1 Engine Variant

Honda developed the F22C1 variant of the F20C engine in 2004 for the North American market. Like the F20C, the F22C1 was used in only a single Honda vehicle, the S2000. The construction of the F22C1 is very similar to the F20C, but displacement was altered slightly. The stroked F22C1 has a displacement of 2.2L, 0.2L more than the F20C

As a result of the longer piston stroke, the F22C1 has a slightly reduced 8,200 RPM redline. Despite the higher displacement, horsepower output of the F22C1 remained the same at 240 hp. Torque was increased, however, by 7 lb-ft to a peak of 162 lb-ft. The F22C1 was used in US-Spec S2000s for the 2004 and 2005 model year. It eventually replaced the F20C in JDM-Spec cars from 2006 onward.

Honda S2000 Engine Problems

Reliability and ease of maintenance always top the priority list as far as Honda engines are concerned. That mantra rings true with the F20C as well. Typically, high-strung engines are the most problematic due to the amount of heat and friction generated in the combustion chamber. This usually leads to parts wearing more frequently and engine problems subsequently arising.

However, Honda threw everything in the book at reducing these issues. As a result, the F20C is as bulletproof as any of Honda’s other notoriously reliable engines. Most other high-performance sports cars begin to have engine issues at relatively low milages compared to other civilian-focused vehicles. That isn’t the case with the F20C or F22C1-equipped S2000. 

In most cases, it is the components around the F20C engine that begin to fail before the engine itself encounters issues. As long as the engine is maintained with regular oil changes and tune-ups, only minor issues tend to arise prior to the 300,000-mile mark.

With that being said, there are a few uncommon F20C engine issues that are more likely to rear their head than others. The most common problems are as follows:

• High F20C engine oil consumption
• Buzzing from the transmission while decelerating
• Cracked valve spring retainers

F20C Engine High Oil Consumption

One of the most commonly cited issues with the F20C engine is high oil consumption. In most cases, high oil consumption is a normal consequence of owning a vehicle with a high-revving performance engine. According to Honda, it is normal to have to top up an AP1 F20C-powered S2000 with a quart of oil every 1,000 miles. If your S2000 is consuming any more oil than that, there might be a more significant underlying issue.

Honda S2000 High Oil Consumption Symptoms

High oil consumption from an F20C-powered S2000 is pretty easy to diagnose. There are generally only a few ways to diagnose high oil consumption. These include the presence of an oil-burning smell,  low engine oil level, or smoke coming from the exhaust. 

While the smell of burning oil will almost certainly indicate that the F20C engine is consuming oil, low engine oil could also mean that an oil leak is present somewhere on the engine. S2000s usually consume oil through the piston rings and valve seals, but that usually only occurs on high-mileage engines. If your S2000 doesn’t have a ton of miles on the clock and isn’t smoking from the exhaust, an oil leak is more than likely the culprit. 

F20C Engine High Oil Consumption Fix

Many S2000 owners state that a clogged PCV valve is a common source of excessive S2000 oil usage. This problem is more prevalent in F20C (AP1) powered cars. If your S2000 is consuming an abnormally large amount of oil, this is a good place to start. 

Valve guide seals are also notoriously troublesome in high mileage F20Cs. This is a more involved job to fix, as it requires the engine to be opened up and the cams to be removed. While the process of replacing the seals isn’t the easiest, the parts themselves are relatively inexpensive. 

Finally, switching to a more viscous oil or a different brand can help reduce oil burn-off. S2000 owners often advise steering clear of using Mobil 1 oil in F20C engines. This is due to the fact that Mobil 1 has a higher burn-off rate than most other brands. Switching to a heavier, non-synthetic engine oil can help mitigate the problem.

S2000 Buzzing From Transmission While Decelerating

Quite a few S2000 owners complain about temperamental or noisy transmissions. A noted issue – regarding F20C transmissions in particular – is a buzzing noise coming from the transmission tunnel when decelerating between 4,000 and 3,000 RPM. This occurs most often when downshifting from third to second gear. Owners who experience the issue claim that the sound is similar to heat shield rattle.

Honda later outlined the problem further in a bulletin. Honda states that the sound arises due to clearance issues between transmission gears. The noise is amplified since the S2000’s transmission is mounted between the driver and passenger seats. When the vehicle decelerates, its weight, together with the pulses from the engine, excite the transmission gears, causing them to buzz or rattle. Honda added that the clutch disc hub springs within the transmission clutch disk are another cause of the problem. 

F20C Transmission Buzzing Fix

Due to the fact that transmission buzzing is a recognized issue from S2000s with the F20C, Honda offered a factory solution to the problem. This included a replacement clutch disk with a modified design which reduced the noise. 

Initially, the clutch disk replacement that solved the issue was covered under warranty. Since the Honda S2000 was released in 1999, most F20C-powered cars are now outside of factory warranty. If the problem can be diagnosed by a certified Honda dealership, it is possible to apply to have the issue fixed outside of the factory warranty through a goodwill agreement with Honda. To receive consideration, you need to apply to the Honda District Service Manager or at a certified Honda service center.

It is also possible to order the modified clutch disk with the part number listed below. A specialty Honda repair facility might be able to install the clutch disk for a lower cost than the dealership. 

Modified F20C Transmission Clutch Disk Part Number: 

• P/N 22200-PCX-055, H/C 6855126

F20C Cracked Valve Spring Retainers

Valve spring retainers are an integral part of any engine’s valvetrain. They are responsible for ensuring that the proper amount of spring pressure is being applied constantly to prevent valve bounce. If a valve spring retainer cracks or breaks entirely, valve spring tension is lost which can severely damage the valves and other engine components. 

This is especially true for the F20C as it is an interference engine. This means that the piston can contact a floating valve. Since the F20C is a very high-revving engine, cracked valve spring retainers are more common than in a less rev-happy engine. 

Honda S2K Cracked Valve Spring Retainer Symptoms

Usually, a cracked valve spring retainer will cause an array of immediate symptoms. However, it might be difficult to determine that the valve spring retainers are the culprit, as the associated symptoms can also be caused by a number of different issues.

The most common sign of a broken valve spring retainer is a loss of power or misfires at high RPMs. If a valve spring retainer is cracked, an S2000 will likely start and idle just fine. The issue will come to light around the 4,000-5,000 RPM range, as the valve springs will not be able to keep up with the rest of the valvetrain. If the failure of the retainer has caused the spring itself to fail, a persistent misfire at all engine speeds would likely be noticeable.

If you suspect that a valve spring retainer has failed, it is extremely important to address the issue as soon as possible. In a worst-case scenario, the retainer can become so badly damaged that the valve could fall from its housing. This would allow it to enter the cylinder head and combustion chamber, damaging every part involved. 

F20C Cracked Valve Spring Retainer Fix

The easiest way to know if one of your valve spring retainers has cracked is to perform a vacuum test on the engine. You can do this by connecting a vacuum gauge to the vacuum port of your F20C’s intake manifold. You can then start the engine. Read the vacuum gauge at idle and at progressively higher engine RPMs. If the valve springs/retainers are the issue, the vacuum readings will oscillate as the RPMs climb.

The only other way is to remove your F20Cs valve cover and cams to look for any imperfections. The retainers sit atop the valve springs. They have a uniform circular shape, so a crack or chip should be easy to identify.

If a spring retainer is cracked or damaged, the only solution is to replace it. It is always a better idea to replace all of them instead of just the one that is damaged, as retainers deteriorate over time and therefore cause loss of spring pressure. Replacing all of the retainers ensures that all of the valve springs are receiving a uniform amount of spring pressure.

Best F20C Performance Upgrades

In addition to being extremely reliable, the Honda F20C is a favorite among the aftermarket performance crowd. Once again, the high-revving nature of the F20C is an aspect that tuning companies and other performance part manufacturers capitalize and expand on. 

Forced induction occupies a huge space in the aftermarket Honda community. That is especially true for the F20C. As the F20C features forged internals, it can withstand high boost pressure and pump out some serious horsepower figures. The F20C is capable of 400 horsepower without breaking a sweat using factory internals. This extreme durability is what makes the F20C such a promising contender for extreme aftermarket upgrades.

Although forced induction accounts for a huge part of the S2000 modding community, there are many worthwhile performance upgrades for those looking to keep their F20C naturally aspirated.

Honda S2000 Forced Induction Modifications

It is unanimously agreed that the best way to squeeze the maximum amount of performance from an F20C engine is through forced induction. The F20C’s short-stroke setup, forged internals, and 11.0:1 compression ratio combine to form the perfect storm for very good forced induction performance. It is, however, quite pricey to spring for an F20C turbocharger or supercharger kit.

F20C Forced Induction Considerations

When introducing forced induction to any engine, multiple other factors need to be considered. As the specific details surrounding F20C forced induction get very involved in terms of varying setups for different applications, we’ll keep it simple here. In general, the primary supporting mods required for F20C forced induction include the following: 

• Upgraded clutch
• High-pressure fuel injectors
• Upgraded fuel pump
• Fuel rail 
• Upgraded engine management system
• Intercooler and intercooler piping
• Performance spark plugs
• (Optional) Upgraded exhaust components

In many ways, the F20C is prepped and ready for forced induction from the factory. Forged pistons allow the F20C to cope with the added strain, and the factory exhaust system is largely unrestrictive until high horsepower numbers are reached. 

Superchargers are the most common option for forced induction in the S2000 community. While it is still possible to turbocharge an F20C, superchargers deliver more linear power. Superchargers are directly intertwined with an engine’s crankshaft, so the added power is available immediately. This varies from a turbocharged setup, where turbo spool time causes a lag in power delivery.

Best S2000 Supercharger Kit

Since the F20C engine has been around for a while now, there are quite a few supercharger kits available. So many, in fact, that it can be difficult to choose between them. After extensive research, we have concluded that the HKS GT2 F20C Supercharger Pro Kit provides the best balance of price, build quality, and performance.

HKS is one of the most reputable aftermarket brands for Japanese-domestic vehicles and is known for their five-star build quality. The GT2 F20C supercharger kit is marketed as a high-performance kit that maintains the reliability of the F20C engine. It is fit for use in both daily-driven and race-spec S2000 applications. The kit was designed with linear power gains in mind, delivering power in a very similar way to a stock F20C.

The kit comes with nearly everything that you’ll need to get going. Evasive Motorsports sells upgraded engine management systems, injectors, fuel pumps, and batteries alongside the kit to round out the other components that are needed to complete the setup. 

Price: $4,725.00 (Excluding additional supporting parts)

Power Gains: +74 hp and +58 ft-lbs

Purchase Here: Evasivemotorsports.com

Honda F20C Exhaust System Upgrades

Outside of forced induction, a full F20C performance exhaust, with a good tune, is the best way to increase horsepower numbers. A performance exhaust system benefits the F20C by increasing the breathability of the exhaust side of the engine. While the factory exhaust is very respectable and doesn’t limit the engine in stock form, a tuned performance exhaust system will garner a few extra ponies. 

An additional 20-25 horsepower can be gained from an upgraded test pipe, catback exhaust, and a tune. It is important to note that an S2000 running this specific setup will likely fail to pass emissions. Having a test pipe that replaces the F20C catalytic converters will almost certainly cause issues at the emission center. Enthusiasts that choose to run a catless setup have to change out the test pipe with the factory cats during registration renewal time.

Best Honda S2000 Exhaust Setup

There are quite a few options available as far as S2000 exhaust systems are concerned. In most cases, enthusiasts purchase catback systems independently of an upgraded test pipe. In general, an upgraded test pipe will garner more horsepower than a high-flow catback setup. However, if you retain your factory F20C catalytic converters and install a catback system alone, your S2000 will likely pass emissions just fine.

Our top pick for both an upgraded S2000 test pipe and catback system are made by Invidia. Most S200 enthusiasts agree that a 70mm exhaust diameter is the perfect middle ground between limiting backpressure and maintaining exhaust gas velocity. For that reason, both the Invidia F20C test pipe and catback system are 70mm in diameter. Both of them are constructed from 304 stainless steel. This reduces weight without compromising rigidity.

As an added benefit, both components support forced induction if you plan on turbocharging or supercharging your F20C in the future. Even without forced induction, it is extremely important to tune your vehicle after changing exhaust components. An exhaust tune will allow the F20C to recognize the higher flow capabilities of the new setup, unlocking horsepower.

Price: 

Invidia 00+ S2000 70mm Dual Titanium Tip Catback Exhaust – $778.40

Invidia 00+ S2000 70mm Test Pipe W/ CEL Fix- $70

Horsepower Gains: +25 hp and +25 ft-lbs

Purchase Here: throtl.com

Honda S2000 Engine Management System Upgrade

In order to tune your F20C to a higher degree, you’ll need an engine management system. In general, upgraded engine management systems allow you to adjust important aspects of engine performance including air/fuel mixture, idle control, and ignition timing. It is always a good idea to have an upgraded engine management system if you intend on installing any significant engine modifications. 

Most S2000 owners in the performance modification community recommend the AEM Series 2 F20C EMS. While there aren’t a ton of engine management systems available for the S2000, the AEM Series 2 is unquestionably the best option. It utilizes factory sensors and plugs directly into the factory wiring harness for ease of use. Unlike many other EMS options, the AEM includes complimentary tuning software that doesn’t require a monthly subscription to use. 

An upgraded EMS is the key to unlocking your S2000’s power potential. Without one, you’ll unquestionably be missing out on performance left on the table. Upgrading your F20C engine management system isn’t the cheapest modification, but it is certainly one of the most worthwhile.

Price: $1,680.50

Horsepower Gains: Entirely dependant on other engine modifications

Honda F20C Engine Guide Summary

The Honda F20C engine has a lot going for it. The F20C is one of the primary reasons that the S2000 is so desired. With a 9000 RPM redline, dual-VTEC, forged pistons, and the highest specific output of any other production engine, the F20C has performance covered.

In addition to being a high-performing engine, the F20C further reinforces Honda’s reputation of reliability. At mileages under 150,000, it is extremely rare that any serious issues arise from the F20C. Even at higher milages, there are very few common issues with the engine. With that being said, it is extremely important to be diligent with F20C maintenance to prevent any complications down the line.

As with most other performance Hondas, the S2000 has massive aftermarket support. The F20C is a highly modifiable engine with a ton of power potential. F20Cs benefit a huge amount from forced induction and are practically ready for a turbocharger or supercharger from the factory. Naturally aspirated F20Cs are also highly modifiable. Chief among N/A F20C modifications include exhaust system upgrades and an upgraded engine management system.

There is a reason why the Honda S2000 is one of the most in-demand Japanese sports cars to this day. Even 20 years down the line, the F20C is loved by a huge number of enthusiasts who appreciate rev-happy, efficient, and reliable engines.

If you enjoyed reading about the Honda F20C, you might like some of our other Honda engine articles. If you are interested in Honda D-Series engines, check out our Honda D15B Engine Guide. As always, safe driving!