Carbon-lined Synchro Testing

2nd Gear synchro

We had our trans fitted with the new carbon-lined synchros from Synchrotech.  Our '05 Elise (ArtCar v2) was once again our trusty test mule.  I ran almost 150 miles at Spring Mountain on these synchros.  The shifting and specifically the downshifts were really crisp.  Road use was also good with no negative behavior or characteristics.

rebuilt and ready to go in

The trans has stock gears, clutch/fly and no LSD.  The car was also equipped with our new shiftR111 and SMOOTHoperator but no short-shift kit.  We debated internally whether or not to run a short shift kit and ultimately decided not to have it installed.  We knew that the 'feel' of these new synchros would be important and anything that might influence feel would be another variable.

We ran on the 3.6mile Fittipaldi course.  This configuration uses 2nd,3rd,4th &5th gears.  There are some really fast sections and plenty of slow 2nd gear corners - with a couple of them heavy breaking zones.  Proper heel and toe downshifts are critical on many of the corners so it was a good test of the synchros.

a fast course with plenty of shifting from high speeds/rpms

Overall the car shifted nicely.  The feel was immediate and frankly crisp.  The down shifts were great and even at times when I did not get enough of a blip, they seemed to engage really well.  I drove the car on the 'street' a bit around the shop and grounds of SMMR.  Again the shifting was nice and confirmed that it can work fine on street cars - with no negatives,

taking a slight breather between sessions

David@Synchrotech referred to synchros as the brakes for gears.  As it turns out, there are many manufacturers who use synchros of this type for 15+ years.  Our kit uses brass, carbon and construction that have been refined by Synchrotech over several generations - mostly in Honda applications.  This is especially important to us as the Honda run 9k rpm trans that are similar to our 8k rpm gearboxes.  Essentially, the carbon can deal with high speeds far better than just the brass - as found on our stock synchros.  David did change the design slightly from stock to improve performance and my testing confirms that these changes are acceptable.  If you compare them side by side with a stock set, you may see some differences.  Our trans rebuilder, Jeff@Transaxle, was also duly impressed with the kit.  His opinion was key as he rebuilds many, many gearboxes for Lotus Cup racers.

I believe they are suitable for road & track.  The stock brass synchros are the weak link in the Toyota gearbox so these bits will be very welcome and will extend the life of the gearboxes.  Of course, you still need to heel and toe your downshifts!  Yes, these will allow for faster shifts but we still suggest clients be smooth and gentle.

We are going to get production products and release these parts.  You can find them: HERE