Honda S2000 - Project AP1 - Honda Tuning Magazine

Honda S2000 - Project AP1

At times I just don't understand what's wrong with me. My S2000, an AP1 model with decent mileage, was running just fine. After adding Downforce fenders and side diffusers, an AP2 front bumper with JDP Engineering front lip and rear wing, and a set of 17X9.5 +40 SSR Type F wrapped in Falken Azenis tires, I was more than happy about the look. Under the hood was an AEM cold-air intake, Skunk2 header, and HKS exhaust, as well as Hondata's K-Pro. With a little over 200 whp, the car was certainly no powerhouse, but it was fun to drive. Why am I using the term "was" when describing the S2K? Well, it's sort of in pieces right now. Let me see if I can recall where everything is, as it's been down for quite some time. The entire front end (fenders, bumper, hood) is at Rywire's shop since they're a pain to transport being that they're quite long. The transmission is sitting pretty at Synchrotech where they'll be taking it apart to see what does or doesn't need replacement or repair. I'm expecting minimal changes as the car shifted nicely prior to the tear down, though it did tend to grind Third gear at high rpm on occasion. The actual chassis was delivered to ASC Speed Metal where some metal "massaging" will take place before it goes to a body shop for an engine bay respray. That leaves the engine itself, which we'll get into in this installment of the build, as well as showing what Rywire has been up to while under the hood of the AP1.

Inline Pro

Initially, the plan was to install a turbo kit with a company that had been itching to revamp the kit they'd produced years ago, but unfortunately, that fell through. Rather than pouting, I took it as a sign that maybe the car should stay naturally aspirated. I started looking at different NA options online and just wasn't impressed by even the most complex of setups. Though some were able to find more horsepower, it was the incredible lack of torque that really needed a fix.

I began looking at the feasibility of a K24 swap, but realized it was a little more than I wanted to do. Don't get me wrong, I like the original F-series engine and all of its high-revving beauty, but I've simply grown tired of having to rev it out to 9k in order to feel any real power. In fact, I was more than willing to give up that sky-high revving ability in order to find some true, useable mid-range torque. That's when I started looking at stroker kits and found my way to InlinePro.

It's no secret that the F20/22C engine shares a few similarities with the K-series family, and as such, InlinePro has put together a number of stroker kit options to find some much-needed torque for the F series. Based upon a reworked, OEM K24 crank, the kits increase displacement to the 2.4L mark, and while there are other alternatives on the market, the idea of using a factory crank was definitely a big plus. Attached to that crank will be InlinePro's signature H-beam connecting rods produced in billet aluminum, dressed in ARP's long-established, tried and true hardware. Various compression ratios are available to suit your needs. I selected a set of 12.5:1 JE Pistons to allow for the use of pump gas.

Honda s2000 project AP1 InlinePro stroker kit connecting rod 05   |   Honda S2000 - Project AP1 Honda s2000 project AP1 InlinePro stroker kit connecting rod 06   |   Honda S2000 - Project AP1 Honda s2000 project AP1 InlinePro stroker kit connecting rod 07   |   InlinePro has a knack for putting together parts that make Hondas go fast. Period. They offer a variety of stroker kit options for the S2000’s F-series engine, and they even offer their own signature connecting rods complete with ARP fasteners. Honda s2000 project AP1 OEM K24 crank 08   |   The foundation for InlinePro’s F24 kit is this OEM K24 crank, which they modify to fit the F-series block properly. Honda s2000 project AP1 inlinePro F24 kit crank 25   |   Honda S2000 - Project AP1 Honda s2000 project AP1 inlinePro F24 kit connecting rod 26   |   The InlinePro F24 kit rotating assembly was properly balanced to 10,000 rpm. The crank was cleaned up, including chamfered oil passages. The connecting rods smaller ends and shoulders were mildly shaved in order to fully balance out.

JE Pistons

When it comes to discussing custom or off-the-shelf-style pistons, JE is a name that you'll undoubtedly hear mentioned time and time again. After over 60 years of producing pistons that help power some of the quickest and fastest domestic and import builds on the planet, you quickly realize that JE didn't just pop onto the scene on a whim; they helped establish it. A custom order was called in, completed, and delivered in quick fashion. The new pistons, InlinePro's connecting rods, and K24 crank were then headed straight to their next stop.

  • Honda s2000 project AP1 JE piston 02
  • Honda s2000 project AP1 JE piston 03
  • Honda s2000 project AP1 JE piston 04

JE supplied a set of their ultra-high quality forged pistons. I requested 12.5:1 for my build, but they can custom-make virtually anything you can imagine. The same exact qualities you find in one-off offerings are also found in their off-the-shelf sizing.

Golden Eagle

The InlinePro stroker kit does allow you the option of using factory sleeves, but I chose to sleeve the block with Golden Eagle Mfg. Why not company X, or company Y? Well, for a few reasons. First and foremost, GE has done a ton of sleeve work on some of the fastest cars in the world, past and present, in the U.S. and abroad. Go to any track event, straight line or curved, and you'll see Golden Eagle Mfg. stickers plastered on various cars every single time. They rely on CNC equipment for a precise installation and their tolerances are second to none. They were at the forefront of four-cylinder sleeving technology years ago and have remained at the top of the food chain ever since. I got the chance to stop by GE's in-house production area to see how the material for the sleeves arrive, how they're cut, and what they look like before being installed on a block. I also had a chance to see my sleeved block just before it was headed to the clean room for final assembly. (see photos and captions)

Honda s2000 project AP1 ductile iron 18   |   Golden Eagle relies on ductile iron for their race-proven sleeves. Long iron stock was cut down to be prepped for sleeve duty. Honda s2000 project AP1 golden eagle sleeves 20   |  
GE’s sleeves in raw form.
Honda s2000 project AP1 golden eagle sleeves 19   |   Honda S2000 - Project AP1 Honda s2000 project AP1 golden eagle sleeves 21   |  
The finished product ready to be installed in its new home.
Honda s2000 project AP1 engine block 22   |   Honda S2000 - Project AP1 Honda s2000 project AP1 golden eagle sleeves 23   |   Here you can see a block that’s already been prepped for sleeving, waiting in line for installation. Honda s2000 project AP1 F20C block 24   |   Here is my AP1 F20C block after receiving Golden Eagle’s sleeves, ready to hit the assembly room.

Rywire

While the engine is out for some major surgery, I thought it might be a good time to clean up some of the engine bay. While some would opt to shave the entire engine bay, hiding any factory unused holes or sheetmetal wrinkles, smoothing out every nook and cranny, I'm just not interested in any of that. I do, however, think some careful relocation would free up some space and ease some of the clutter. The factory battery will be moved to the trunk, and the underhood fuse box will make its way to the cabin, while the ABS and A/C will remain in tact, they'll also be moved. Rywire offers an ABS kit that lets you keep the factory system, but rather than sitting inside the engine bay, the unit is moved to a cavity just behind the front driver-side fender. Rywire's custom lines are routed and connected through a new bulkhead, freeing up a good amount of space behind the intake manifold and everything remains fully functional. For the A/C, a reroute kit that I found on s2ki.com includes the fittings and hoses necessary to direct the lines behind the engine, along the firewall, and under the intake manifold toward the front of the car. This eliminates the fat A/C hardline in plain view that juts straight from the firewall, high along the passenger side of the bay. It won't be the naked engine bay that you might see at your local car show, but it certainly looks much cleaner than stock and will free up some space to give the bay an overall organized appearance.

Honda s2000 project AP1 battery tray 09   |   Overhead shot of the engine bay from the passenger side. Here the battery is removed and will be relocated to the trunk. The fuse box will be moved under the dash with easy access, and the thick A/C line will be removed and replaced by a kit that routes the main line behind the engine and along the lower half of the driver’s side. Honda s2000 project AP1 fuse box and AC line 10   |   Honda S2000 - Project AP1 Honda s2000 project AP1 factory ABS unit 11   |   The factory ABS unit will still be in service, but is now moved to the cavity located behind the driver-side fender using the Rywire.com relocation kit. Honda s2000 project AP1 rywire ABS relocation kit 12   |   Here Ryan Basseri of Rywire runs the new lines from his kit to a new bulkhead made in the chassis. Honda s2000 project AP1 rywire ABS relocation kit 13   |   Honda S2000 - Project AP1 Honda s2000 project AP1 chassis bulkhead 14   |   Honda S2000 - Project AP1 Honda s2000 project AP1 ABS lines 16   |   Honda S2000 - Project AP1 Honda s2000 project AP1 ABS unit 15   |   The lines are fed through a factory opening and connected to the original ABS unit, which is mounted securely to the chassis. Honda s2000 project AP1 old engine components 17   |  
A portion of what was removed from the AP1’s engine bay.

Next up is headwork prior to bolting everything together on the engine. ASC Speed Metal is hard at work on a few bits and pieces, which will show up in the build series a little later, and once they're finished, it's off to the body shop to respray the bay. There's still the transmission, installation, tuning, more fab work with ASC once the car is running, and much more. Stay tuned as the AP1 build continues...