Allright, Sunday at Road Atlanta my 5th gear synchro (Evo IX) just quit. Granted, dozens of 7000rpm 4-5 shifts a day are not normal use, I was wondering if there are any upgrades to the 5th gear synchro package I can look into before I pull the tranny and look into a rebuild?

This car sees regular track time and will see even more in the future.

It was grinding into 5th even shifting at 2500 rpm's driving down the road in front of the speedway. That's the other surprising thing, it went suddenly in the 2dn session Sunday. Fine going out, grinding by the end of the session.

 

On my old evo it only took one high rpm sift to mess up the fifth gear synchro. I've read that shep doesn't even recommend high rpm 5th gear shifts. You should look into evo8 3rd and 4th.

 

I've got Evo 8 3rd, 4th and 5th in it (all are taller). Not an option at RA not to use 5th gear as I spend most of the back straight in 5th to top out at 140+.

 

I have a shep built tranny with the double synchro 5th. I went with that as it was recommend by shep to prolong the life of the 5th gear

 

1 high rpm shift with my shep double 5th synchro and it was toast that is why it is out of the car now lol.

 

I guess I am lucky as I was only pushing 425 when doing that.

 

So is the double synchro an upgrade over the stock setup? I'm only in the 360-370 range, but road racing presents a whole different kind of wear and tear.

 

It might be time for a high revving 2.0. You won't need to shift to 5th.

 

He's talking about road racing, not drag.

 

Won't a higher revving engine making the power not force him to shift to fifth regardless of drag or road racing?

 

If he's hitting 140+ mph on the back straight I figure he'll have to shift to 5th anyways - plus, running high revs for a 10 sec drag run is one thing, but running them for a whole 20 minute lapping session is a different ball-game I think; oil temp and EGT would play a role here more than they would on the strip, if I'm not mistaken.

 

Correct. I shift to 5th right at the Mazda pedestrian bridge around 105-110. I also shift to 5th in the front stretch right past the flag stand and also in the stretch between turns 5 and 6.

Drag racing setups (high power at high RPM) are not idea by any means for road racing. In each lap of RA (1min 44 sec for me) my car probably spends more than a minute at WOT. In a 20 minute session the car probably spends 12-13 minutes matted on the floor. A tempermental 9k aluminum rod engine would not last too long.

 

This is good. My car is stock but i often track (and Shift into 5th) and I can tell i am on borrowed time. Not broken but at WOT i have to make a granny shift in order not to get a slight to not so slight grind. I have a TRE Stage two rebuild too. hope it hold on for another clutch rthen i can deal. I am talkin road course by the way Anyway, have my eye on this

 

If you have to rush a shift into 5th you already lost the race. Use your fingertips and feel it go in.

 

Does shep even double 5th any more. When I had mine built last dec, it was not available.