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Velocity Headwork

An internal Combustion Engine is an air pump and the key to making more power is pumping more air in and out of the engine. The 2 most effective ways to pump more air is increasing displacement or RPMs, the former increases the amount of air per pump, the latter increases the number of pumps per time. For most, increasing engine displacement or redline is typically fixed due to cost or practicality of building a custom motor with larger bore or stroke or lightening internals and valve train to increase RPM.

The next opportunity to increase power is to improve volumetric efficiency. Most common upgrades are less restrictive intake, header or exhaust improving air flow into and out of the engine. However, no matter how much you optimize there, there is always a bottleneck, the head itself. The head ports are the last influence of air flow in and out of the combustion chamber and are the most critical part of the air pumps flow tract.

S2000 Head History

More than 20 years later, the S2000 is one of the best flowing normally aspirated heads ever. When it was launched, it out flowed every Sport Compact head by a large margin, even heads that had larger valves. Honda had been planning the S2000 for is 50th anniversary and the original power goal was 220 hp to hit a target power to weight ratio. The S2000 ended up coming out a few hundred pounds overweight and Honda needed to increase power to 240 hp to hit its power to weight ratio. Honda found most of the power increase by enlarging the head ports, improving the peak air flow. The problem is the larger ports made the engine lazy, and it didn’t rev hard until 5000 RPM. The 2.0L engine needed high RPM to reach a minimal air velocity to become responsive. The future increase to 2.2L improved this by being able to move more air per stroke and port velocity starts to come alive around 3500 RPM.

Air Velocity Focus

There is more power to unlock with the head without making the car lazier. The key is not making the ports larger but focusing on the port shape, specifically areas that slow down flow. Most head porters simply enlarge ports as it’s easy to do and it looks good on a flow chart and looks good visually. However, large ports and touching all parts of the port will slow down air velocity reducing responsiveness, torque and power.

New Direction

We have spent a few years looking for a new head porter after our legendary head porter retired. To find someone that focused on air velocity and not head flow, we went in a new direction, motorcycles. High performance, motorcycles rev much higher and thus use a larger operating range than S2000 and improving air velocity is even more critical for motorcycles. We believe we found the best head motorcycle head porter in the world and when we interviewed him about head flow, he noted “I haven’t flowed my heads in years”. He scans the shape of the port, looks for areas of air velocity slow down, optimizes them and then runs them on a dyno or on track.

We confirmed our smaller port, higher velocity design by making more power with stock sized valves and not cutting many parts of the OEM port and making more power vs an oversized valve on our stroker motors.

We would like to reintroduce our NEW velocity head program with new designed head by a world class motorcycle head porter.

Velocity headwork

• CNC headwork, touching only the parts that need it (best air velocity on the market)
• Full radius valve seats (vs the typical multi angle) lot of gains here
• Valve guides modifications
• Includes assembly of provided or our valve springs

Valve Options

• Stainless Steel with Black NItride coating
• Titanium with Chrome Nitride coating (a must for >9K RPM, also significant valve train stress reduction)

Valve Spring Kit Option

• High strength CrSiV with large wire diameter providing 341 lbs/in spring rate
• Single spring design reducing spring weight ~10% vs OEM raising redline support
• Reduced spring coils supporting higher valve lift of 0.650” or 16.5mm
• Spring surface and heat treatment maximizes lifetime with no pressure degradation
• Strongest (~30% higher) and Hardest (7 points harder HRC) Titanium alloy (Ti-17) retainers vs typical Ti 6Al4V retainers
• Uses OEM bases and AP1 keepers for simpler install (don’t need to remove seals) and reduced cost
• >30% lower cost than typical premium spring, high RPM and long life spring kits

Chamber work Option

• Increases chamber diameter to 89 mm to match bore
• Improve quench pad and combustion dynamics

 

Would it be better to buy an Endyn Sprint S2000 Cylinder Head from 4 pistons? I see your old post stating that you work with Endyn on your motor, so I assume that this headwork is also just working with them.

 

Yes, we used to work with Endyn. The owner retired 3-4 years ago.

We work with a new porter with a specialty in Motorcycle cylinder heads. Motorcycle heads are more optimized for velocity and thus difficult to make gains on.
Even, 25 years old, the S2000 cylinder head is more optimized for velocity vs 99% of automotive cylinder heads and also difficult to make gains.
Our new porter has come up with a shape were we touch less of the port and not increase valve size and we are gaining power on our 350+ hp motors.

So we are confident that our current heads are the best available NA head for the S2000 motors.

 

39 Velocity Heads sold..

Please email us at urge(at)urgedesigns.com for questions or quotes