AP1 Transmission - Taller Gearing, Moar Speeeeeeed!!!

When last season ended, I had two thing on my list of TODOs for this year. The first was to swap back my old exhuast so I'd never have to deal with blowing the sound limit again and we did that before the season started. The second was to swap in an AP1 transmission. I guess technically "swap back" is the correct term since Bumblestook is actually an AP1 chassis with an AP2 drivedrain so I'm just going back one step here. I was getting destroyed all of late last season by not having enough gearing, topping off at around 63mph in 2nd gear whereas others were hitting 70mph. That's a lot of speed to leave on the table on big, fast concrete courses. I was able to source a decent mileage (60K miles) from a parts reseller on Ebay based in Florida and had it shipped directly to Steve at SJF Performance.

Getting ready for surgery
SJF Performance - 5/31/2015

AP1 transmission waiting to be installed
SJF Performance - 5/31/2015

Since this was Steve's first time swapping a transmission on a S2000, it took us a bit longer than usual but mostly because it had to be done right. Thanks in part to having a transmission next to us to look at and a pretty detailed DIY on S2ki, a few annoying bolts and a slight drop in the front subframe later the AP2 transmission was disconnected and ready to be set aside to be reused for another project soon ;)

AP2 transmission out
SJF Performance - 5/31/2015

AP1 and AP2 tranmissions bolt up the engine the same way but AP1 transmissions use slightly narrower bolts than AP2 transmissions on the driveshaft side. The correct thing to do would be to swap out the output flange of the trans to an AP2 flange so that everything bolts up nicely using the beefier AP2 bolts. The silly way to do it, thanks to the SCCA's BSP update/backdate rule, is to keep the AP1 flange and use the smaller AP1 bolts in the larger holes. You'd expect this to be a problem but it's been proven that this isn't an issue if you torque everything down and locktite it so using new AP1 bolts and washers, a generous dab of loctite red, all 6 bolts were torqued down to the AP2 spec of (36ft/lbs). We filled it with 2 quarts of Honda MTF but we'll be flushing that soon with Amsoil once I come back for an alignment in a few weeks.

AP1 Transmission installed
SJF Performance - 5/31/2015

New AP1 bolts and washers
SJF Performance - 5/31/2015

After a small snag in the connection of the clutch fork that was easily corrected, we verified that all 6 gears and reverse worked as it should but I won't be able to put her through her paces until the NNJR SCCA event next weekend. The major upside to the AP1 transmission is the taller gearing so I should easily be able to hit 70+mph in 2nd gear depending on how high I rev the F22C. This finally completes the maximum prep level I can take Bumblestook to the current rules.

The remaining issue that's been plaguing me is the nut behind the wheel. Between being limited to fewer events in the area due to the extra time I need for towing Bumblestook to and from events and not having enough time to drive in general, lack of seat time is starting to erode at the progress I've made the past 2 years as a driver. I've figured out how to address that but that's a side story that will be shared shortly.

Big thanks to Steve (and Pete) for spending a very rainy Sunday working on this little project.