Hello,
I race a caterham with the F20c engine and box, after 3 seasons of racing the standard box is in bad shape as the syncros need replacing and Honda will only sell me a complete gear set not the syncros After looking through the forum I see that a lot of you guys have replaced the AP1 tranny with the AP2. am I correct in saying that it has carbon syncros? also I need first gear to be a lot longer and sixth to be shorter, does the AP2 Tranny have different ratios than the earlier version? What year did the Ap2 tranny superseed the earlier version? Sorry for the long post but I dont want to fork out a large amount of money and find out the gearing is useless!..lol I have got advice from Quaife and Tran-x but unless I go for the top of the range sequential box they say that the rest of their range is not suitable for 9000+rpm! Thanks for the advice, this forum has really helped me figure out a lot of things when I was building the car.

 

Yes, the AP2 trans has carbon syncros instead of brass, its generally a bit smoother to shift but it can still grind on fast shifts with a short throw shifter.

You can find the exact ratios in the S2k Talk FAQ that charts the changes between 2003 and 2004 S2000, but I believe the AP2 has according to Honda literature: "aggressive gearing in gears with higher final drive; Gears 1-4 = 4% lower for performance; Gear 5 = 1% lower; Gear 6 = 2% higher".

GB I believe got the AP2 chassis and transmission starting in 2004 although the AP1 F20C engine was retained.

If you really want a longer 1st and shorter 6th, you may have get custom gears made, or order a set of 4.44 or 4.57 aftermarket gears and get shorter ratios across the board.

 

Yeah at the moment im using 2nd gear for the starts! and I still have to feather the throttle until I change into 3rd..lol I really need something like a 2.1 first gear instead of the 3.333 I think that I have at the moment. Looked into PPG gears but they seem very expensive when the shipping VAT etc is added. Im running a 4.1 diff ratio as it matches the 3rd, 4th and 5th gears to different corners on the track perfectly. Probably just go for a new replacement gearset from Honda although they quoted me £800 which seems to be a complete rip off. Thanks for the help much appreciated.

 

You can probably pick apart a used transmission at a junk yard.

 

For an accurate depiction of AP1/AP2 ratios and spreads, read:
https://www.s2ki.com/forums/index.php?showtopic=732099