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Chassis/Vehicle Dynamics Engineer
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Discussion Starter · #1 · (Edited)
Why The Hi Tech Exotic Kevlar HT350 Clutch?
  • Years of positive feedback by customers on R8Talk, LamborghiniTalk and beyond.
    • Including torque capability, pedal feel, very smooth engagement and durability in R8's and Gallardo's.
    • Specific feedback to the R8 was very important because of weights, configuration and the refinement of the R8.
      • Another company tried selling their ceramic clutch at much lower cost than my chosen HT-350 (they didn't recommend their Kevlar clutch for the track as they noted failure issues at the track), but with little understanding of their application in the R8 due to lack of testing or R8 customers.
        • Instead this competitor to Hi Tech Exotic has sold primarily to kit car customers, which are very different cars that lack the refinement of the R8, Gallardo or Huracan.
  • This is a complicated and refined system not just parts with Hi Tech Exotic clearly having the long term experience and results with our R8's and sister cars.
    • Anyone who works with these clutches knows that just 0.005" of clearance difference, for example, makes a big difference and performance and function of the clutch.
  • Straight answers to my questions by Sean of Hi Tech Exotic.
  • Labor for replacement of the clutch alone is a big and expensive endeavor on the R8 (just over 18 hours transaxle alone in and out) so I wanted a very high confidence and durable solution.
Of note - I and Ahlman Performance have no affiliation with Hi Tech Exotic. This is an important and expensive item that I thought was worth giving feedback on.

My Stock Clutch
  • The clutch pedal feel was light and smooth engaging in the middle of the throw.
  • The engagement felt very soft and had started slipping at times on full throttle.
  • The clutch was inspected because I ran into a transaxle build issue (apparently repaired prior and the 3rd gear synchro retaining nut had back off ruining the synchro and the 4th gear shift fork was missing it's set screw.
    • Upon inspection of the stock clutch it was glazed and nearly out of friction lining at 27,000 miles
    • I am sure my 6 track days so far added a lot of heat to the stock clutch and reduced its somewhat limited life further.

I purchased from Hi Tech
  • Hi TecHT350 Billet Housing Kevlar Clutch
  • Hi Tech Lighter Billet Flywheel (8 pounds vs 10 pounds stock)
  • Throw out bearing

Shout out To Audi Dealer Owings Mills in Maryland
  • Bonnie from Owings Mills parts had my 3rd Gear Synchro and 2nd Gear Bearing rushed to me (5 days) from Germany for a better price than the Graziano distributor in the USA.
    • And this Graziano distributor would not guarantee any timing after delaying for a few weeks.

My Feedback
  • HT350 Break-in
    • 500 miles of half throttle and under 4000 RPM break in with a lot of shifts per mile
      • I talked to Sean and slowly ramped up throttle and RPM through 1000 miles total of break-in because of intended track usage.
      • I always rolled in the throttle and didn't mat it during this break in period.
    • I sure wish this break-in was shorter in mileage, but it is worth it to me for the performance, feel and durability.
  • Full Throttle Since
    • I have done hundreds of hard full-throttle and redline accelerations from 1st gear since break-in and the HT350 feels extremely solid and I can feel a small improvement in hard acceleration with the lighter flywheel.
      • Of note, we run our Ohlins TTX Stage II suspension, which improves power down to allow hard full throttle 1st gear starts without wheel-spin so we are taxing the clutch and driveline more than the stock setup.
  • Normal Shifting/Driving The Same or Better
    • No difference in shift feel and function noticed at normal shifting/driving with this Hi Tech Exotic HT350 Kevlar clutch and lighter flywheel.
    • My newly rebuilt gearbox has a very smooth and positive feel in each gear.
  • Clutch Pedal Effort
    • The clutch pedal effort is a little heavier (~10-15%) than my stock R8 clutch pedal feel at 27,000 miles.
      • I thought my stock clutch pedal effort was quite low for a 530 HP engine.
      • But the throw and feel on the HT350 is as smooth as stock.
      • And frankly the extra effort reminds me to put it in neutral at stop lights instead of holding in the clutch causing a lot of unnecessary wear.
    • Further, the extra effort is worth it to me if I get the performance and typical HT350 life.
  • Clutch Engagement
    • Smooth as stock, but much more firm clutch engagement at the same point as stock.
    • The clutch engagement ramps in and out quite smoothly, but more firm than stock.
    • My stock had minimal lock up feel starting at 17,000 miles.
  • More Damped
    • The Hi Tech HT350 clutch engagement and driveline now feels more damped than stock.
  • Neutral Rollover Rattle - A Little More Noticeable - Lighter Flywheel
    • I am guessing many don't notice this phenomenon of neutral rollover rattle during idle in a stock R8 (common in manual gearboxes - an interaction between the engine firing order and the gearbox transmitting the noise) that goes away with clutch engaged.
      • We ran into neutral rollover rattle on the Ford GT - some transaxles showed it more than others.
    • Neutral Rollover Rattle is not a performance or functional issue - just noise.
    • I took a video, but need to do one with clutch engaged to show on and off to make the rattle noise much more obvious.
    • I am just noting this for those who are particular about noises (NVH), like me.
    • The acceleration gain at full throttle with the lighter flywheel is worth this noise increase to me.

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Thanks Scott. This is great (and comprehensive!) info for those who might be getting close to R&R ing their clutches. I've inquired about these clutches and have heard wonderful things about them. Some will say they're not cheap but nothing worth having, is. For the price you can and will get a much longer clutch life from my research.
 

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Chassis/Vehicle Dynamics Engineer
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436 Posts
Discussion Starter · #4 ·
Glad to post this for such a big important project that highly warrants being done right the first time.

I failed to note that we utilized Kelly Moss Racing (KMR) here in Madison, WI for this transaxle and clutch R&R. They went way beyond normal shop technicians and did a great job fixing some issues caused by others. Four of our local R8 Ohlins TTX customers have used them for install of these and other work. We highly recommend them to anyone in southern Wisconsin or Northern Illinois with a performance car, especially Porsche and R8 owners.
 

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Why The Hi Tech Exotic Kevlar HT350 Clutch?
  • Years of positive feedback by customers on R8Talk, LamborghiniTalk and beyond.
    • Including torque capability, pedal feel, very smooth engagement and durability in R8's and Gallardo's.
    • Specific feedback to the R8 was very important because of weights, configuration and the refinement of the R8.
      • Another company tried selling their ceramic clutch at much lower cost than my chosen HT-350 (they didn't recommend their Kevlar clutch for the track as they noted failure issues at the track), but with little understanding of their application in the R8 due to lack of testing or R8 customers.
        • Instead this competitor to Hi Tech Exotic has sold primarily to kit car customers, which are very different cars that lack the refinement of the R8, Gallardo or Huracan.
  • This is a complicated and refined system not just parts with Hi Tech Exotic clearly having the long term experience and results with our R8's and sister cars.
    • Anyone who works with these clutches knows that just 0.005" of clearance difference, for example, makes a big difference and performance and function of the clutch.
  • Straight answers to my questions by Sean of Hi Tech Exotic.
  • Labor for replacement of the clutch alone is a big and expensive endeavor on the R8 (just over 18 hours transaxle alone in and out) so I wanted a very high confidence and durable solution.
Of note - I and Ahlman Performance have no affiliation with Hi Tech Exotic. This is an important and expensive item that I thought was worth giving feedback on.

My Stock Clutch
  • The clutch pedal feel was light and smooth engaging in the middle of the throw.
  • The engagement felt very soft and had started slipping at times on full throttle.
  • The clutch was inspected because I ran into a transaxle build issue (apparently repaired prior and the 3rd gear synchro retaining nut had back off ruining the synchro and the 4th gear shift fork was missing it's set screw.
    • Upon inspection of the stock clutch it was glazed and nearly out of friction lining at 27,000 miles
    • I am sure my 6 track days so far added a lot of heat to the stock clutch and reduced its somewhat limited life further.

I purchased from Hi Tech
  • Hi TecHT350 Billet Housing Kevlar Clutch
  • Hi Tech Lighter Billet Flywheel (8 pounds vs 10 pounds stock)
  • Throw out bearing

Shout out To Audi Dealer Owings Mills in Maryland
  • Bonnie from Owings Mills parts had my 3rd Gear Synchro and 2nd Gear Bearing rushed to me (5 days) from Germany for a better price than the Graziano distributor in the USA.
    • And this Graziano distributor would not guarantee any timing after delaying for a few weeks.

My Feedback
  • HT350 Break-in
    • 500 miles of half throttle and under 4000 RPM break in with a lot of shifts per mile
      • I talked to Sean and slowly ramped up throttle and RPM through 1000 miles total of break-in because of intended track usage.
      • I always rolled in the throttle and didn't mat it during this break in period.
    • I sure wish this break-in was shorter in mileage, but it is worth it to me for the performance, feel and durability.
  • Full Throttle Since
    • I have done hundreds of hard full-throttle and redline accelerations from 1st gear since break-in and the HT350 feels extremely solid and I can feel a small improvement in hard acceleration with the lighter flywheel.
      • Of note, we run our Ohlins TTX Stage II suspension, which improves power down to allow hard full throttle 1st gear starts without wheel-spin so we are taxing the clutch and driveline more than the stock setup.
  • Normal Shifting/Driving The Same or Better
    • No difference in shift feel and function noticed at normal shifting/driving with this Hi Tech Exotic HT350 Kevlar clutch and lighter flywheel.
    • My newly rebuilt gearbox has a very smooth and positive feel in each gear.
  • Clutch Pedal Effort
    • The clutch pedal effort is a little heavier (~10-15%) than my stock R8 clutch pedal feel at 27,000 miles.
      • I thought my stock clutch pedal effort was quite low for a 530 HP engine.
      • But the throw and feel on the HT350 is as smooth as stock.
      • And frankly the extra effort reminds me to put it in neutral at stop lights instead of holding in the clutch causing a lot of unnecessary wear.
    • Further, the extra effort is worth it to me if I get the performance and typical HT350 life.
  • Clutch Engagement
    • Smooth as stock, but much more firm clutch engagement at the same point as stock.
    • The clutch engagement ramps in and out quite smoothly, but more firm than stock.
    • My stock had minimal lock up feel starting at 17,000 miles.
  • More Damped
    • The Hi Tech HT350 clutch engagement and driveline now feels more damped than stock.
  • Neutral Rollover Rattle - A Little More Noticeable - Lighter Flywheel
    • I am guessing many don't notice this phenomenon of neutral rollover rattle during idle in a stock R8 (common in manual gearboxes - an interaction between the engine firing order and the gearbox transmitting the noise) that goes away with clutch engaged.
      • We ran into neutral rollover rattle on the Ford GT - some transaxles showed it more than others.
    • Neutral Rollover Rattle is not a performance or functional issue - just noise.
    • I took a video, but need to do one with clutch engaged to show on and off to make the rattle noise much more obvious.
    • I am just noting this for those who are particular about noises (NVH), like me.
    • The acceleration gain at full throttle with the lighter flywheel is worth this noise increase to me.

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What a great write up!!! Only from a very experienced engineer that can tell the difference between our Kevlar clutches versus the cheaper ones.

Scott, thank you very much for your great comments. It was detailed perfectly and hopefully it answered a lot member's questions here. Thanks again!!!
 

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Chassis/Vehicle Dynamics Engineer
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436 Posts
Discussion Starter · #7 ·
Glad to give this feedback on a great product and your support of it. Keep up the great work!
 

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I also appreciate hearing this feedback from someone with the technical background that you have. A couple years ago when I was starting my search for an R8, I got to test drive a V8 that had recently had its clutch replaced. Car was at about 70,000 km and the replacement was supposedly a Kevlar clutch.

When I drove that car, the engagement/disengagement point was very early (close to the resting point of the pedal) and I couldn’t be sure if this was because of the clutch used. I had posted on the forum to see if there was a way to adjust that because it really was hard to get used to. Feedback at the time suggested no way to adjust so I passed on that car.

In hindsight, I’m not sure if it was the clutch or if it was installed incorrectly but good to know that your experience with this package is positive, especially with engagement point.


Sent from my iPad using Tapatalk
 

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Chassis/Vehicle Dynamics Engineer
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436 Posts
Discussion Starter · #9 ·
I also appreciate hearing this feedback from someone with the technical background that you have. A couple years ago when I was starting my search for an R8, I got to test drive a V8 that had recently had its clutch replaced. Car was at about 70,000 km and the replacement was supposedly a Kevlar clutch.

When I drove that car, the engagement/disengagement point was very early (close to the resting point of the pedal) and I couldn’t be sure if this was because of the clutch used. I had posted on the forum to see if there was a way to adjust that because it really was hard to get used to. Feedback at the time suggested no way to adjust so I passed on that car.

In hindsight, I’m not sure if it was the clutch or if it was installed incorrectly but good to know that your experience with this package is positive, especially with engagement point.


Sent from my iPad using Tapatalk
Great to hear my time on this Hi Tech Exotic clutch post was useful to you also.

Yes they are self adjusting clutch pedals in the R8 so something wasn't right with the one you drove so it was quite good you passed on it. Regardless of the specific cause...it would have been an expensive fix and potentially really expensive.

Hi Tech is selling a well developed system specifically for the R8 and sister cars. The engagement point, the engagement ramp in, effort, smoothness, years of testimonials including durability all motivated me enough to give this feedback. It is relatively easy to do well on one measure, but not so well on many other criteria so this is far harder than it sounds and a great example by these guys.
 

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Chassis/Vehicle Dynamics Engineer
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Discussion Starter · #10 ·
Just an update as I continue to push the car and clutch (including many 98 degree days) for another 1000 miles. If anything the Hi Tech Exotic HT350 Kevlar clutch has a little more solid lock up yet ramped in and out and damped. Smooth throughout. Impressive.

As guys continue to have trouble with the USA Graziano Distributor for transaxle parts I will once again give a shout out to Owings Mills Audi in Maryland and Audi dealerships in general regarding parts for these transaxles. You can get synchros and bearings and most internals in guaranteed timing (expedited is 5-7 days....from Germany) and for as good or a better price than these other guys.

I am awaiting feedback from another R8Talk member regarding a transaxle build source for his R8 transaxle rebuild before posting that as well.
 

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Chassis/Vehicle Dynamics Engineer
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Discussion Starter · #11 ·
We recently did nearly 8 hours of laps at APEX Motor Club in over 90 deg F weather in the Phoenix, AZ area. The HT350 Hi Tech Exotic Kevlar clutch did not change from start to finish. Still solid yet smooth engagement at the same point through out. The HT350 was a great upgrade for us and our usage of the R8 V10. Here is a link to the one lap video.

 

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We recently did nearly 8 hours of laps at APEX Motor Club in over 90 deg F weather in the Phoenix, AZ area. The HT350 Hi Tech Exotic Kevlar clutch did not change from start to finish. Still solid yet smooth engagement at the same point through out. The HT350 was a great upgrade for us and our usage of the R8 V10. Here is a link to the one lap video.

Scott, that's a great video. We knew that our HT350 is a very strong clutch but 8 hours of racing on a track, that's awesome. Keep enjoying the car!!!
 
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