Honda S2000 Pre-Tuning Checklist

Everything you need to know before dyno tuning your Honda s2000.

12 Things You Should Know Before Dyno Tuning Your Honda S2000

1. Best Naturally Aspirated Bang for the Buck 

For a naturally aspirated F20c/F22c the best bang for the buck modifications are an intake and test pipe.  Those modifications give the best horsepower per dollar spent in conjunction with a custom tune.  Quality intake brands are K&N, AEM and Injen, Invidia and Berk are both quality options for test pipes.  If a test pipe is not allowed in your area, a high flow cat is the next best option.  Gains of 20-40 ft-lbs of midrange torque and 10-20 whp are possible with a custom tune, aftermarket intake and test pipe.  

2. Supercharged boost levels for stock engine

For supercharged s2000s we recommend keeping boost around the 12 psi range on 91 octane, and 14-15 psi on 93 octane on stock compression/stock engines.  Anything higher and too much ignition timing is pulled in the tune to keep knock levels in check.  This actually reduces power, and you end up making the same power at 14 psi as you would at 18 psi.  If you are using E85 or race gas, run as much boost as you can achieve with your particular supercharger kit without over-spinning the supercharger (Kraftwerks) or having belt slip issues (SOS, Vortech, CT, etc).  

3. recommend supercharger modifications

On supercharged s2000s the OEM headers and exhaust are more than adequate for making great power.  A test pipe is HIGHLY recommended, though.  The OEM cat breaks down quickly, as well as aftermarket high flow cat options.  We have done many back-to-back tests with aftermarket headers and exhaust, and have not seen substantial power gains for the money spent.

4. clutch upgrades

We recommend upgrading your clutch in any forced induction application on the s2000s.  While this may seem obvious, over the years we have had many s2000 clients come in for a dyno tune with a stock clutch.  Once we start turning the power/boost up the clutch slips, and the tuning session is cut short.  The most popular clutch/flywheel set up has been the OEM AP1 flywheel, ACT pressure plate and OEM disc.  This seems to hold around the 350-400 ft-lb of torque capacity, and will drive almost like the OEM clutch.  SOS and Competition clothes are both other great options that we have installed successfully over the years. 

5. tubular style exhaust manifolds

On a turbocharged s2000, we recommend using a tubular style exhaust manifold to achieve the best possible power.  The s2000 cylinder head flows VERY well and does not tolerate high back pressure in the exhaust.  A log style manifold essentially chokes up the cylinder head flow, and is no where near as efficient as a properly designed tubular style manifold.  We have seen 80-100 whp increases in power at the same boost level when compared to a log style manifold.  In addition, there is a higher knock threshold on the same octane fuel.  This leads to increased power, increased efficiency and more reliability.  

6. spark plugs

On supercharged and turbo applications we recommend at least a step colder spark plugs, along with decreased spark plug gaps.  We have found that NGK makes the best plugs for Hondas, and we use them exclusively.  If installing a bolt on supercharger kit or turbo kit and using pump gas, the NGK Iridium BKR8EIX plugs are needed.  Plug gap should be between 0.018~0.028" depending on the condition of the ignition coils.  If using E85, race gas, or pushing pump gas to the limit NGK Iridium BKR9EIX plugs are what we recommend. 

7. ignition coils

The OEM s2000 ignition coils are a hit or miss on what kind of power they can support.  We have seen the OEM coils support very high power levels (800 whp+), but also have issues even with decreasing spark plug gap greatly at 400 whp power level.  We have found the best replacement for the OEM s2000s are from 06+ Civic Si / K20 coils.  We have personally tested the K20 coils with small plug gaps to around 1200 whp on our drag s2000.  There are several ignition coil options on the market for s2000s, but for the cost of new OEM K20 coils (under $300.00 for a set of 4 at the dealer) you cannot beat OEM reliability.  

8. fuel pumps

We have installed most every aftermarket in tank fuel pump on the market into an s2000, and found the best drop in option to be the Walbro 255 LPH HP pump for 500 whp and under.  No rewiring is needed, and you can even use the original fuel pump filter/sock.  When installing higher flowing aftermarket fuel pump options (AEM 320 LPH, Aeromotive 340 LPH, Walbro 400/450/480 LPH, etc) the pump NEEDS to be rewired with heavier gage wiring and an aftermarket fuel pump relay.  SOS sells an inexpensive fuel pump rewiring kit that works very well and is very complete.  The most reliable drop in fuel pumps we have worked with are Walbro brand.  ***Please note that if you are installing any of the Walbro 400 LPH or higher pumps you MUST install an aftermarket adjustable fuel pressure regulator.  The OEM regulator cannot bypass enough fuel, and base fuel pressure will be super high.  

9. Banjo bolts

00-03' s2000s can suffer from oil jet banjo bolts that do not flow adequate amounts of oil to the cylinder walls.  The FRM liner on the s2000 cylinder block walls needs to have a constant oil supply in order to prevent scuffing of the piston.  The banjo bolt/oil squirters provide this.  Number 4 cylinder is the most prone to have the damage, even in 100% stock engines (we have done several rebuilds for this very reason on bone stock 00-03' s2000s).  When compounding this weak link with turbo or supercharging, it leads to a much faster failure.  In late 03' model years (check your VIN# for your particular production date) and later, Honda addressed the inadequate oil banjo bolt design with increased oil on a new bolt.  If you have an early AP1 s2000, consider doing the oil banjo bolts.  Its inexpensive for the bolts, labor takes 2-4 hours depending on how familiar you are with working on an s2000.

10. valve spring retainers

s2000s can suffer from cracking valve spring retainers.  This can lead to dropped valves as the retainer holds the valve to the spring.  A dropped valve will lead to a catastrophic engine failure, usually resulting in needing to purchase a new long block.  We have seen countless failures of this nature over the years that could have been avoided by simply changing the retainers.  Fortunately, you can visually inspect the retainers for hairline cracks/fatigue with the valve cover off.  In 04+ model years, Honda addressed this issue with a revised retainer design.  A retainer swap takes between 2-4 hours depending on skill level and quality of valve spring compressor tool.  

11. gauges

If you desire to add gauges to your car, we recommend oil pressure and wide band  AFR gauges.  If a boost gauge is desired, AEM makes a boost and wideband all in one gauge.  This will allow you to only have 2 gauges in your car, which is also what the aftermarket gauge pods are made in (single or dual gauge versions). 

12. fuel system sizing

On forced induction applications sizing your fuel system to achieve your power gals is essential.  

For 00-05' s2000s on 91/93 octane:

  • 500 whp > : ID 1050x and Walbro 255 LPH HP fuel pump

  • 500-700 whp: ID 1300cc, Walbro 400 LPH fuel pump, SOS rewiring kit and adjustable fuel pressure regulator 

For 00-05' s2000 on E85: 

  • 400-425 whp and less: ID 1050x and Walbro 255 LPH fuel pump

  • 425-600 whp: ID 1300cc, Walbro 450/480 LPH E85 specific fuel pump, fuel pump rewiring and adjustable fuel pressure regulator 

  • 600-750 whp: ID2200cc, Walbro 450/480 LPH E85 specific fuel pump, fuel pump rewiring and adjustable fuel pressure regulator

For 06+ s2000 on 91/93 octane:

  • 350-450 whp: ID 1050x with Walbro 255 LPH HP fuel pump

  • 450-500 whp: ID 1050x, Walbro 255 LPH HP fuel pump, SOS in tank fuel pressure regulator and SOS fuel pump rewire kit

  • 500 whp+ requires converting to a return style fuel system with 1:1 rising rate pressure regulator, SOS sells conversion kits refer to 00-05' fuel sizing recommendations after return line conversion has been done.