Lotus 2ZZ-GE Clutch Upgrade

Over the past few months we have been experimenting with various clutches in our Turbocharged Lotus Elise. Throughout last year, including 3 track days at over 300whp, we used the stock clutch without any issues. In preparation for the 2011 season, we were planning on pulling the motor  for maintenance and decided to upgrade the clutch since the install would be simplified with the engine/transmission out of the vehicle.  With plans to push the engine harder, the stock clutch might reach its max holding capability and a upgrade was necessary.


This picture shows ACT (top) and South Bend (bottom) clutches.

Having success with South Bend clutches on other applications, we chose their TZ Series KTY14 clutch. This clutch is rated for 25% more ft-lb of torque compared to the stock clutch. The pedal effort was very streetable similar to the Toyota clutch.

After installing the South Bend Clutch, we put around 50 miles on the clutch and then began dyno tuning. Toward the end of our dyno session we noticed some clutch slippage.  At this point, the car was making about 220 ft-lb max torque.  We thought the clutch was overheated and did not address the issue. The following track day at Portland International Raceway, after several successful sessions, the slipping issue returned.

After contacting South Bend, they requested that we return the clutch so they could examine and determine the problem. We are waiting for their diagnosis.

In the meantime, we installed an ACT TC2-XTG6 clutch. This is a 6-puck sprung disc with an "Xtreme" pressure plate. This clutch is rated at 400 ft-lb max torque (at the flywheel). We plan to test the GTX3076R (600+hp) turbo early next year using this clutch.


The ACT clutch comes with alignment tool.  This is the first 2-piece tool we have seen for the 2ZZ-GE.


The alignment tool bushing gets pressed into the center of the flywheel as shown. This bushing remains in place even after the clutch is fully installed.


Advanced Clutch Technology (ACT) clutch completely installed.

After driving this clutch on the street we have noticed some differences. The increased pedal effort is prevalent but not unbearable. Also, there is no excessive chatter during clutch engagement. We will be putting this clutch to the test this coming weekend at the Lotus Cup USA HPDE event being held at Portland International Raceway. We will report back on its performance.

Hopefully, these experiences will allow us to make educated recommendations when discussing clutch upgrades with customers.

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Track Day with Club Lotus NW

On September 2nd, we joined Club Lotus Northwest for a track day event at Portland International Raceway. We always look forward to getting out with this group and having fun on our local track. We also seize these opportunities (and any track event) to test our products in extreme conditions in order to root out any weaknesses that would not appear with normal street driving.


There were well over a dozen modern Lotus vehicles in attendance and several vintage ones as well.


Local fabricator Kevin was on hand showing off some of his products including this new splitter. More information on this splitter can be found here.


The event also attracted a host of non-Lotus vehicles too, including this 900lb Palatov Motorsports Prototype which was by far the fastest vehicle on the track all day.


The RADIUM Elise performed excellent despite being plagued by a damaged ignition coil early in the day. The turbocharger kit and related components all performed flawlessly.


Our main issue with the Elise is the brakes. With the turbo kit,  we are reaching higher speeds and this means more work for the brakes. A couple sessions were cut short due to persistent brake fade. We use Motul RBF600 fluid, but that was not enough. We have already begun laying out a plan to address this issue. We hope to have a solution in place by mid October, which is when we will be attending LOG31 in Las Vegas.


Local Evora owner, Kris Myers, was on hand turning out lap after lap. We installed our prototype cold air intake kit on his car and he gave us excellent feedback. We could tell he was genuinely sad when we pulled it off at the end of the day and replaced it with the stock airbox.


Kris was also running our Dual Catch Can kit on his Evora. He was collecting a suprisingly large amount of oil. The photo above is after 1 session!

Additional photos from the event:

We would like to thank Club Lotus NW for organizing the event and making it fun for everyone. We look forward to coming out again!

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