Done two things this evening, gearbox related:
- Changed the gearbox oil to Millers. Really improved the gear shift on the old car. New car has a much better shift anyway, but I figured that as I had a bit of the Millers left over, I'd swap it out for the good stuff. Easy job with the car in the air.
- Replaced the transmission mount with the stiffer STI mount. A mod I did with my old car, and I recently found out the part numbers were the same, so ordered one for this car too. Installation would be straightforward, but the front pipe makes getting to two of the bolts an absolute ball ache. Really I should have dropped the front pipe, but that's a bit of a job in itself , I was running out of light, and I'm stubborn - didn't want to abandon it, and have to come back and jack the car up again another day when I already had it up on stands. In the end I managed to just unbolt the front pipe from the mid pipe, slip the bolt out of it's mounting hook, and that allowed just enough movement to get the transmission mount done....but it was an absolute chore. Had to refit the bolts blind, using the tips of my fingers and only being able to tighten them a few degrees at a time. Much swearing was had.
Took it for a drive straight away and the result is noticeable. I guess it's a combination of both the better oil and stiffer mount, but it's taken an already good shift feel and made it sublime. Shifts are smoother and feel tighter; it's hard to explain, but because the transmission is mounted more firmly, it feels like when I push the stick into a gear, there's less energy being wasted pushing the whole transmission around, and it's all being directed to pushing the gear into position....it's a bit less rubbery feeling. It almost feels like the shift feels physically shorter. At the same time, the shift feels very smooth, which I guess is the better gear oil. The car was stone cold when I drove it; it hadn't been driven at all today except a couple of minutes before and after jacking it up to do the work. But it felt as if it was fully warmed up as soon as I took it for a drive, and dropping down into second was much improved. The real test will be when the weather gets properly cold though.
I also think it's helped with the jerky acceleration when accelerating hard in lower gears; it's not eliminated it, but it certainly feels more secure and less "kangaroo" when you don't get it quite right. And the throttle feels a little less elastic when you make quick movements on the pedal. So I definitely think that the amount of slop and movement in the driveline is contributing to that. I reckon STI engine mounts would improve it further; and although I did those on the old car too, I was able to do it without removing the Ace manifold I had, whereas I believe the OEM manifold needs to come off for engine mount replacement. Don't think I'll bother.
On the whole, very pleased. I won't say it's a night and day difference, as I think the shift on the newer model is already an improvement over the older car anyway. And the part was £130 ordered from Nengun.com, so it took a couple of weeks to arrive from Japan (Fensport also sell it for ~£160, but I was willing to wait and save 30 quid). There are cheaper options such as the Whiteline positive shift kit, a poly insert which is placed in the void of the mount bushing. It was a popular mod for the old car; given the transmission mount is the same in the GR86, then one of those would also fit it. But they come with their own compromises. If anyone's interested, I might make a dedicated thread with more detail about the change, but I'll drive it for a few days first to really get the measure of it.
I was intending to give more of the underside a going over with some ACF50 while the car was up on stands. Unfortunately I ran out of daylight, so that will have to wait.