It's not just the OD boxes that don't like shifting at higher RPM.agreed That RPM is dictated by the weight of the disc (mostly). If you think about it...the disc has to speed up and slow down with changing engine speeds. The heavier the disc, the harder it is to speed up and slow down. Add a bunch of RPM to it and it makes it even worse. Agreed; the disc is "attached" to the input gear. The brass can only do so much. And that's why the 3217 rpm drop at 7000,with brass only, for me ,was unacceptable. The GVOD splitter changes that to 1540. And after I swapped back to the deep-low box, the splits got even tighter. The shift from 1-od into second is .80, and at 6000, (all ready a high shift rpm for a 230* cam), this is just 1200 rpm, and from second to 2od is just 1320 rpm. And second-od gets me 93@6140, and my eighth is done. 4 ratios to get there, two of them electric power-shifted and one tug on the stick.
In the deep-low box, I slick shifted only second and third, leaving the brass in . I don't get into 4th when banging,until over 100 with 3.55s, and that very rarely ever happens. So I left that one alone.
The 36 teeth on the gear and inside the sliders is too fine to allow the synchro to slow things down enough to make heavy disc, high RPM shifting clean. That's why slick shifting, pro shifting and face plating make it easier to shift.Agreed
On my drag stuff I slick shifted them until I tore them up (ouch)or wore them out. Then I had them pro shifted. On the street I slick shift the gears, sliders and syncros. I've shifted as high as 8k with a sintered iron disc. And it up and down shifts like a stock box. (Nice)
