[nikitopo]

You won't find many people in this forum (if any) suggesting a bigger tb. I believe there exists a single NA dyno of the Grams tb with no gains, but this has a 72mm input and output diameter. They didn't follow the factory tapered entrance, hence it is a very pure design. I think the best product is the Toda tb, because it is a good design and at the same time it solves the high rpm issue on idle. You usually have this issue if you change to a bigger tb. About gains, there is a dyno from a partner that shows a gain of 2whp without a tune and a gain of 7whp with a tune that increases the rev limiter. So, it looks that it helps the air flow on very high rpm's. Of course, this is not an independent dyno and many are questioning the validity of the results. At least for Toda it looks that the gains were real and even more important better in comparison to a catless header. Just for the history, their bigger tb was available for sale back in 2012 and at the same period they had a prototype exhaust manifold. The exhaust manifold was never released for sale before 2016. Reason was that they waited to have ready the bigger capacity engine kit (2.3lt) and they suggested to use the manifold together with the kit. So from their point of view, the dimension and flow of the stock manifold was not that bad. We forget here the torque dip, since it doesn't really matter in racing. Apart of whatever gains, another advantage of a bigger tb is that it provides better throttle response and a more responsive engine. This is also very important in racing.