2gear problem at the track?

[thielepr]

I’m lucky enough to live 5 minutes from the bmw performance center in South Carolina and we had an autoX this past Saturday. It’s one full lap at the time format. My car didn’t want to downshift to second coming from third several times. It got better with heel and toe but still felt weird. It worked fine on my way home.

There was another Z4M roadster at the track and he also experienced the same.

I’m using Redline with less than 4,000 miles on it considering swapping that to Motul. Any other suggestion/experiences with the second gear?

[The HACK]

This autocross course required a shift to third? Must be a long straight.

2nd gear synchro has always been wonky on this car, but I've never had an issue when heel-toe properly to get it down from 3rd into 2nd. The 1st to 2nd shift has always been the harder of the two shifts.

I've had the OE fluid, Redline, and then Motul, and I can tell you the fluid doesn't make enough of a difference to justify IMO. In my experience, the 2nd gear synchros work better when engine speed is higher than output shaft speed, i.e. the RPM needs to be higher when clutched in to facilitate a smooth 3rd to 2nd downshift.

[wdb]

I've had what I've heard called "2nd gear refusal" when downshifting under high stress situations. I've been shifting gears for over 50 years so I don't think it's me. I put a Autosolutions short shift kit in, and no more refusal.

[F360C]

Originally Posted by thielepr

I’m lucky enough to live 5 minutes from the bmw performance center in South Carolina and we had an autoX this past Saturday. It’s one full lap at the time format. My car didn’t want to downshift to second coming from third several times. It got better with heel and toe but still felt weird. It worked fine on my way home.

There was another Z4M roadster at the track and he also experienced the same.

I’m using Redline with less than 4,000 miles on it considering swapping that to Motul. Any other suggestion/experiences with the second gear?

Just to be clear you were trying to downshift from 3rd to second without heel toeing and were having problems and then switched to heel toeing and it got better?

[belcom]

Originally Posted by wdb

I've had what I've heard called "2nd gear refusal" when downshifting under high stress situations. I've been shifting gears for over 50 years so I don't think it's me. I put a Autosolutions short shift kit in, and no more refusal.

Did this short shift kit also help smooth out the shifts? Do you need to drop the exhaust for that install?

[wdb]

Originally Posted by belcom

Did this short shift kit also help smooth out the shifts? Do you need to drop the exhaust for that install?

Effort is higher and feel is more mechanical. Deliberate. I like it but then I liked the chunky gear changes in my STi too. I am going to try different oil in the gearbox when it comes due, hoping to lose a bit of the synchro notchiness that was there even before the shifter mod.

I’ve seen instructions where they did not drop the exhaust. I was pulling the gearbox out anyway so I can’t comment on how that might go.