MENUGuide to performance tuning the F Series engine from Honda
"Honda F Series Tuning"
Our guide to tuning the popular Honda F Series and best F Series performance parts.
Honda smashed the 100bhp per 1000cc power barrier with the F series making it one of the best engines we've ever played with and a tuner dream.
As the F series is fitted to the S2000 we are going to focus on improving the C series of the engine.
There's no reason why you can't apply these mods to the F20A or even the F18 and improve things there but a swap to the C version makes a lot of sense, as it is so much stronger and better designed, saving you some tuning work.
We review and look at F Series tuning and provide tips on the ultimate mods that work.
We rely on our visitors to pass on tips and tell us about their projects and what worked on their car, and this article is the culmination of the feedback we have received. First let us look at the history and specs of this engine and then consider which tuning modifications work best on it.
History of the F Series Engine
The F series is a lovely engine, very free revving and incredibly well built and solidly tuned from the factory, especially the F20C versions fitted to the S2000.
The F20C shows what is possible on this F Series block with the right head and setup, showing the way for lower power versions.
The F20C made some great power figures from the factory
- Power: 240 bhp (179 kW) at 8,300 rpm
- Torque: 206 N⋅m (152 lb⋅ft) at 7,000 rpm
The F20C1 was further improved and the rod stroke length and camshaft profile was tweaked to lower the peak power point and raise torque.
- Power: 240 bhp (179 kW) at 7,800 rpm
- Torque: 220 N⋅m (162 lb⋅ft) at 7,000 rpm
- 1.8 L Honda F engine#F18B
- 94–02 (Accord) VTEC
F20
- 1988 2.0 L F20 (Accord) VTEC
- 92–97 F20A4 (Prelude) SOHC
- 00–05 F20C (S2000) (Japan)
- 00–03 F20C1 (S2000) (America)
F22
- 05–09 F22C (S2000) (Japan)
- 04–09 F22C1 (S2000) (America)
- 90–96 F22 (Accord/Prelude/CL/Odyssey/Isusu Oasis/Isuzu Aska) VTEC & Non-VTEC
- 98–02 2.3 L F23 (Accord/CL/Odyssey/Isuzu Oasis) VTEC
What are the most effective F Series modifications
When talking about the best optimum for your F18 F20 F22 Series engine, we are going to concentrate) on the modifications that give the best value for money.
Significant gains can be made from cam upgrades. Altering the cam profile alters the intake and exhaust durations on the engine and can dramatically change the torque and power output.
Fast road cams commonly increase the bhp and torque through the rev range, you may lose a little low end bhp but the higher rpm power will be better.
Motorsport and race cams, increase the higher rpm power band but as a result the car will not idle smoothly and low end power nearly always suffers.
On a daily driver must carefully try to optimize your torque band to your usage of the car.
I'd never have thought a Race cam is a pleasure to live with when driving around busy urban areas.
Each engine responds better to less aggressive camshaft durations than others.
The ecu map and injectors and fuel pump also will make differences on the bhp gains you'll achieve.
Extending F18 F20 F22 exhaust or intake durations can alter the bhp band and on most engines the exhaust and intake durations do not need to match, although most cams and tuners use matched pairs there are some advantages to extending the intake or exhaust durations.
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How to tune your car
- Improve the handling
Focus on Suspension improvements, such as coilovers and make sure the bushings are in good order and that the alignment is correct. Then focus on improving the brakes, with a big disk brake conversion kit and fast road brake pads.
- Remove restrictions
Focus on the intake and exhaust with filters being the common point of restriction in a tuned car. Intercoolers may also become restrictive on turbo engines so this may also need to be uprated.
- Burn more fuel & air
Increase the fuelling so it matches the air coming into the engine. The ratio is important so you need to improve the fuel pump and injectors, so the head mods, big valve conversions, fast road camshafts and forced induction upgrades extra supply of air is adequately met.
- Test and replace any weak parts
Weak areas are commonly the clutch, the turbocharger and pistons and crankshaft in a highly tuned engine. Makes sure these components will cope with your power aspirations.
- The Tune or Remap
A cars ECU controls the fuel, timing, spark and even the turbo in some cases, so to fully extract your gains you should remap the car last and this will fully release the power. Some cars are easy to map, and others require piggyback ECU's or aftermarket ECU's but this is the most vital step of your tuning project.
Modifying to Stage 1:
Fast road camshaft, Drilled & smoothed airbox, Panel air filters, Sports exhaust manifold, Intake headers, AEM EMS.
Modifying to Stage 2:
high flow fuel injectors, Ported and polished head, induction kit, fuel pump upgrades, Fast road cam, Sports catalyst & performance exhaust.
Modifying to Stage 3:
Engine balancing & blueprinting, Adding or Upgrading forced induction (turbo/supercharger), Twin charging conversions, Crank and Piston upgrades to alter compression, Internal engine upgrades (head flowing porting/bigger valves), Competition cam.
We would recommend that all F Series tuning projects include some attention to the valve train, installing upgrade springs and retainers (TorqueCars rate Ferrea springs for the S2000).
We recommend that you do a compression test which will help to determine the state of the engine and highlight the possibility of excessive wear.
If you measure a loss exceeding 20% then it should be investigated more fully.
A 3 angled valve job on the head will improve flow, (4 or 5 angles are better but there is insufficient room to do this effectively on the S2000 head).
The F Series power plant make great tuning projects and we're happy to report there are increasing numbers of parts and tuning parts about.
Remaps helps to establish the full potential of all the tuning parts you've done to your F Series.
It will usually give around 30% more power on turbocharged vehicles and 15% on NASP engines, but you mileage will vary depending on the tuning parts you've done and the condition of your engine.
Feeding air into your F Series is the main goal to any tuning project.
Air Intake manifolds transmit the air during the suck phase from the filter and allow it to be sucked into the engine cylinders with fuel for the squish phase.
Structure and rate of flow of the Air Intake manifolds can make a large change to fuel atomisation and engine efficiency on the F Series.
On popular non F22C series production engines the plenum chambers are begging for a performance upgrade, although a few car makers provide well optimised plenum chambers.
Larger F18 F20 F22 Series valves, carrying out F Series port enlargement and head flowing will also improve power, and as an added benefit will allow you to get increasing the power increase on other parts.
The F Series block can handle quite a bit of power before it needs strengthening with people quoting power figures in excess of 350bhp.
NB: The S2000 F22C series of engines is one of the best OEM setups we've seen, and aftermarket parts such as flowing the head, revising the intake and exhaust modifications do not improve things very much at all.
F18 F20 F22 Series turbo upgrades - which are best?
The more air to get into an engine, the more fuel it can burn and uprating the induction with a turbocharger upgrade makes massive power gains.
Be careful adding boos because the 11:1 compression ratio will force you to run a pathetically low boost, unless you perform some extensive engine modifications to lower the compression ratio (you should ideally aim for around 9.5:1), and you may see power figures approaching 350bhp.
A build we saw recently that hit over 400bhp at the wheels included the following popular parts...
- NGK 7173s
- Garrett GT3582R
- ARP head studs
- Apex'i race blow off valve
- AEM 3.5 bar map sensor
- Precision 600 intercooler
- Walbro 255 fuel pump
- Siemens 875cc injectors
- Science of Speed 70mm throttle body
- InlinePro 3mm head gasket
If you change pistons you'll also need to change the sleeves.
NASP engines need quite a lot of work when you add a turbo, so we have a separate guide to help you take into account the pros and cons of going this route on your F Series
However you will find an engines have limits especially when it comes to fuelling and reliability.
We recommend you find these limits and fit stronger pistons, crank and engine components to handle the power.
We see many guys spending a loads on turbo upgrades on the F Series only to suffer the indignity of watching the engine block explode when it's been finished.
Large turbochargers tend to experience no power at low rpm, and smaller turbochargers spool up more quickly but do not have the peak rpm torque gains.
You'll commonly see there's a restriction in the air flow sensor AFM/MAF on these engines when considerably more air is being drawn into the engine.
We note 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor was restricting performance at a much lower level.
Adding a supercharger or additional turbo will make large power gains, although more challenging to configure. We have a twincharger power adding guide if you want to read more.
Fuelling
Don't overlook the need to ramp up the fuelling when you are increasing the bhp and torque - it makes the car more thirsty. We would recommend you to be generous with your flow rate on the injectors.
875cc injectors would see you reach around 450bhp
450cc injectors are good for modest boosting to around the 300bhp mark.
The rule of thumb is to add 20% capacity when buying an injector, this takes into account injector deterioration and provides some spare capacity should the engine need more fuel.
F18 F20 F22 Series Exhaust
You may need to increase your exhaust if the current exhaust is actually causing a flow problem.
On most factory exhausts you should find that the exhaust flow rate quite well even on modest power gains, but when you start pushing up the power levels you will need to get a better flowing exhaust.
Don't go with the largest exhaust you can buy this will slow up the exhaust flow rate - the best for power gains are usually between 1.5 to 2.5 inches. It is the shape and material more than the bore size.
Common exhaust restrictions can be located the emissions filters installed, so adding a faster flowing performance alternative will help avoid this restriction.
Weakspots and problem areas on the F18 F20 F22 Series
The F Series engines are generally reliable and solid as long as they are regularly serviced and maintained.
Regular oil changes are vital on the F Series, especially when tuned and will help extend the life and reliability of the engine.
Watch the clutch, it's a know weakspot on tuned F series engines.
Test the compression ratio, worn engines can lose a lot of power.
For more information on Tuning your Honda engine please join us in our friendly forum where you can discuss F Series tuning options in more detail with our F Series owners. It would also be worth reading our unbiased Honda tuning articles to get a full grasp of the benefits and drawbacks of each modification.
Please help us improve these tips by sending us your feedback in the comments box below.
We love to hear what our visitors have got up to and which modifications work best for them on each model of car. Comments are used to improve the accuracy of these articles which are continually updated.
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