What specifically breaks in the transmissions?
 

What part of the transmission breaks when second gives out. I’m not referring to the synchros, rather the explodes heat sets. Is it the entire housing? Is it the secondary shaft? I’ve seen cryo’d gear sets offered, but it’s my guess that the gears become misaligned via flexing of the shaft caused by high torque. I can’t find any pics online. My little Hayabusa transmission handles it, so I can’t believe an S2000 transmission can’t do the same if properly modded.

think most of that can be explained straight cut vs. helical gear. the contact surface is much greater since there is no lateral/sideways load

I have had decent success with heat treated gears. Racerstev offers it at a reasonable price. PPG made gearsets and I think that is the best option for our cars. For whatever reason shops started pushing trans swaps and that ruins these cars in my opinion. I believe its because it was the best way for them to make $$.

So funny, just this morning I came across and read a lengthy thread by a guy who heat treated his ap2 trans gears, then broke the cases, replaced them and then flogged the tranny for years. He goes by the user name Umair, LOL.
Looks like heat treating the gears and even the car works. I sure wish someone would make an external case brace. I’ll look into finding a source to fab that set up. At this point the CDOO9 and T56 option are noisy, don’t do well at 9k rpm and the v160 is high in cost and low in parts. I’ll update when I find a exterior case support.

LOL good one. I forget what exactly happened but I believe the cause was something during install. A few guys went really fast with a PPG set.

The cost of the PPG set is so ridiculous it almost makes no sense to go that route unless you really love rowing the s2k box (and a lot of people do). I like to stay passionate to a point, though....If I blow my stock trans, I'd probably end up ponying up the money for a Quaife sequential.

I agree the cost is way too much. If they made the pricing more competitive they would have sold more. Too bad no one really makes gearsets anymore for our cars.

If I ever turbo'd my car, I'd love to keep the OEM gearbox if possible. The PPG gearset pricing was ridiculous. Idk why it needs to be that high but maybe it does? Much cheaper to fit a CD009 and much cheaper if/when it breaks. I'd much rather be rowing the S2k box though.

The shifter/trans is one of the best parts of driving this car. Makes me wonder if thats the reason why all these boosted s2ks end up for sale.

I think a lot of people turbo/supercharge their car without realizing all the things that need to go into it. Lots of people seem to think that they'll just buy a "kit", bolt some stuff on, and continue to thrash it like it's a factory car. They likely don't do the necessary work up front to make sure the whole car has been thought through or understand the other components weren't rated for double the power. The trans and diff become weak points that are not particularly easy/cheap to address.

I think another group of people have gotten bored of the car and think they just need more power. Then they boost it and fall into category one, are underwhelmed by the results, or are just the type that wants to move on to something newer, bigger, better. Some just like chasing parts to build a car and the chase is more important than the result.