GR Yaris Altocumulus's Gen1

[Altocumulus]

At my last track day the standard clutch started slipping. I was actually expecting this, as I'd started to notice something similar to a misfire when applying maximum torque on road 'opportunities' - it was very hard to tell whether it was a spark misfire, traction control intervention or clutch issue (spoiler: it was the clutch starting to go).

I like to think I'm quite easy on the driveline (driving hard while expressing mechanical sympathy is an underrated art!), but the nearly 40,000 kms and 5 track days had taken their toll on the original clutch.

I wanted a clutch that could handle increased power/torque, without being too heavy for daily driving duties. I was originally keen on the Uniclutch Track unit, but after discussion with my mechanic I decided to fit a Uniclutch Sport. This is an organic twin-plate clutch.

I had fitted a cat back exhaust not too long ago (Fujitsubo Authorize R), which I think sounds fantastic: it has a great note, not too loud and zero drone. I was more than aware that as the clutch was being changed, it would be an opportune time to upgrade the downpipe.

I picked up a Lamspeed 100-cell catted exhaust downpipe and link pipe to fit while the clutch was being changed. There are numerous reports of turbo oil drain lines cracking after fitting aftermarket exhausts. Although the Lamspeed downpipe has a flexible joint, given the ease of access to replace the oil line at the time of clutch replacement, I played it safe and bought a flexible Artec oil drain line to be fitted at the same time.

I'm looking forward to picking the car up in a few days.

I have a few more track days and sprints scheduled in the next 6 months, I'm hopeful that this clutch will outlast the original's mileage.

 

[Altocumulus]

Clutch and downpipe are now fitted. The high-flow cat downpipe combined with the Fujitsubo cat back sounds excellent. Not loud at all when cruising, but emits a satisfying noise volume as revs rise. Engine response and performance is noticebaly better with the aftermarket downpipe.

I've also fitted aftermarket coilovers (Shockworks). This is an Aussie company that sell a quality Korean product, they've set up many GRY's with their suspension and know their stuff. I set them up 20mm lower to retain a lot of the original car's road practicality, and all aligned. Stock photo of the coilovers below. I fitted some of String Theory's wheel spacers, as I run semi-slicks on standard width wheels at the track.

The car rides very differently now: much stiffer springs, but the plush (adjustable) damping has reduced some of the harsh stock rebound, and a lot less body roll. The performance, handling response and clutch engagement is sharper because the stiffer suspension is resulting in a quicker response through the driveline; the softer stock suspension soaks some of this up. This alone makes it feel like a much more hard core 'sports/track' car. It reminds me of older Evo's. The ride overall is not much more harsh than the standard suspension, but it has pushed the performance window even further out (which is considerable now!).

I have a timed track even in a couple of weeks. I'm really looking forward to dialing in some harder compression and rebound for the track. I suspect the recent changes (downpipe, clutch, coilovers) will push an already capable track car into excellence.

Since all of this I received a quote for fitting Kelford valve springs and cams - I would like the former for a safety net at the track. Some additional top end power would be nice... something to consider for the future perhaps.

 

[Altocumulus]

I did a track day at Phillip Island on the weekend with the new suspensions setup, and everything worked well. A fantastic, flowing track.

The track was cold (11c) and I couldn't get optimal heat into the semi-slicks, but even without stiffening the damping/rebound I knocked 2 seconds off my personal best lap time.

I usually prefer Sport mode on track for a bit more rear end push through corners, but due to the cold weather I used track mode (and always expert TC setting, this helps a lot on track).

Unfortunately, the car developed a high-pitched whining noise during the day, which I don't think is a major concern (possibly transfer case?). It's booked into Toyota for an inspection.

The last lap of this session was my PB. If you listen carefully you can hear the ecutek flat-foot shifting being used for some gear changes (I wasn't using it for all gear changes).