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Old 10-24-2013, 02:13 AM   #1
Justin V
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Default Anyone with high torque on Exedy Stg 1 HD 6spd?

Been searching and reading and calculating, but I just wanted to see if there is any real life experience with the Exedy Stg1 HD clutch kit on a high power STI.

I am in the middle of a build and don't know what my numbers will be, but I currently have a ACT HD-SS clutch, rated for 515 at the flywheel.

I think my new setup will be at the threshold with the ACT. I'd really like something that would hold something closer or greater than 450ft/lbs to the wheels.

Exedy previously rated the 15803HD clutch at 402ft/lbs to the wheels. My ACT would hold more than that with a 20% drivetrain loss. But now exedy's latest catalog says the same clutch hold 472ft/lbs to the wheels.

Rally sport says exedys have been underrated and that's why they have released the new "corrected" numbers with no changes to the product.

I just want to see if anyone has come close to or exceeded these limits.


I really still want a streetable clutch and don't want to shell out $750 for the ACT Xtreme version. I know a $155 6 puck swap with my current setup would hold fine but I really want a full face organic or kevlar disc.
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Old 10-24-2013, 09:16 AM   #2
Aaron'z 2.5RS
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Well, you can do like I did and buy a clutch that's close and change it after a season, or you can buy a clutch that will take it and not...

Either way you're gonna spend the money one way or another.... it's a Subaru for gods sake.. hahahahaha
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Old 10-26-2013, 05:56 PM   #3
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I have the exedy 15803HD in my vf39, wrx with a 6 speed swap. At first. The chatter was absolutely insane. Now it's completely gone and great for DD. It grabs extremely hard when shifting fast. I plan to run a 20g XT on E85 when my motor gets built. I'm pretty confident it will hold
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Old 10-26-2013, 06:54 PM   #4
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Let me know when you get the 20g on and tuned. I've done the vf39 setup already and this next one will be a big step from there.

Your E85 should put you where I expect to be.
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Old 10-27-2013, 09:28 PM   #5
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i have the exedy stage1 hd on my 04 sti for about 3 years im pushing about 350whp 340wtq ,ive gone to the tracks and done launches on it and so far no problems. i dont know what your numbers are but you should be fine
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Old 10-27-2013, 09:39 PM   #6
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I'll have a 110 map that should put me somewhere close to 450 ft/lbs

I'd really like this organic clutch if someone can verify it will hold over 400 ft/lbs

Otherwise I have started looking into a comp solid disc clutch that is higher rated.
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Old 01-02-2014, 03:01 AM   #7
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Did you ever find anything out here? Interested in a clutch that will hold about 425 ft lbs at the wheels, looking at the ACT HD-SS and XT-SS but would prefer to stay with the HD-SS if possible. Plan to do a lot of street driving with some road racing, probably very minimal launching or slamming gears.
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Old 01-02-2014, 03:39 AM   #8
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The Exedy stage 1 and HD version as I've read are only a pressure plate change for the gained torque holding. The compound is the same. For the power goals you would likely be looking at the HD version if you are realistically expecting 450 ft-lbs and simply accept the stiffer clutch pedal. The non-HD version may do just fine, but it may or may not slip more than you want during engagement. Unfortunately I'm not familiar with the stage 1 clutch on the 6 speed transmission, only the 5 speed which is rated a little lower. I can tell you the oem STI clutch has been able to barely hold slightly north of 400 ft-lbs at the flywheel from my own use. The stage 1 is supposed to have about 30% more clamping force, not sure if it's the same compound as oem with a stronger pressure plate or of a different compound with higher friction coefficient. People seem to state it's more on/off than oem which should lean towards the different compound category. I can say that I'm running E85 and seeing the limits of the oem clutch on the power happy dead of winter. I can say that I think the non HD version would be fine as an upgrade, but that I am eying the HD version more heavily as a replacement.

There has been many arguments of Exedy vs ACT on the internet. The typical sway has been towards Exedy as the superior product. People have liked the ACT products, but the feedback is more hit and miss on customer satisfaction and perceived quality and operation. Then again, there isn't exactly magic happening here. A clutch is pretty much the inverse of your brakes. The flywheel is your rotor, the clutch the pad, and the pressure plate is your brake pedal, figuratively speaking. The "better" product will revolve around who has the better compound that offers improved bite and modulation as well as heat toleration against abuse. Brake pads vary a lot and so will clutches, but at the end of the day, they all will work to some degree. It may come down a little more towards personal preference or expectation of feel, bite, and chatter.

At the end of the day Exedy is oem, and very few people speak bad of their products.
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Old 01-08-2014, 04:14 PM   #9
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I never got an answer and my plans changed to a lower torque setup which make me wish I had just bit the bullet an tried this one, but now that the motor was balanced with current flywheel and Comp pressure plate I will stick with that.

Have yet to drive the comp I bought, but if it sucks I'll report back on the Exedy.
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Old 01-08-2014, 05:42 PM   #10
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Quote:
Originally Posted by Justin V View Post
I never got an answer and my plans changed to a lower torque setup which make me wish I had just bit the bullet an tried this one, but now that the motor was balanced with current flywheel and Comp pressure plate I will stick with that. Have yet to drive the comp I bought, but if it sucks I'll report back on the Exedy.
wish you had tried which one? the exedy stage 1 or HD? A little confusing on which you're talking about. seems clear that you're using an unsprung comp clutch now.

I'm looking into an ACT HDSS or exedy stage 1 HD, would love to hear feedback from someone who has used both. Wondering how much heavier the pressure plate is if any, on the HD exedy.
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Old 01-08-2014, 05:54 PM   #11
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I was only asking about one the exedy stg 1 hd. I know the stg 1 is too week so I was curious about the HD with the pressure plate with the higher clamp load.

I never said the comp I went with was unsprung either. I am using their stage 3 full face ceramic disc.

I had an ACT HDSS before, Nice clutch. I'd have kept it but I thought I'd be at it's limit.

Was originally building a GTX3076 on a 2.5L and wanted a clutch that would hold on a race gas map. I am now using a 2.34L and will probably not exceed the torque threshhold I would have with the 2.5L.
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Old 01-08-2014, 05:59 PM   #12
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Quote:
Originally Posted by Justin V View Post
I was only asking about one the exedy stg 1 hd. I know the stg 1 is too week so I was curious about the HD with the pressure plate with the higher clamp load. I never said the comp I went with was unsprung either. I am using their stage 3 full face ceramic disc. I had an ACT HDSS before, Nice clutch. I'd have kept it but I thought I'd be at it's limit. Was originally building a GTX3076 on a 2.5L and wanted a clutch that would hold on a race gas map. I am now using a 2.34L and will probably not exceed the torque threshhold I would have with the 2.5L.
my fault, I read "solid" and thought you meant unsprung.. obviously you meant full face disc. Sorry. I had another thread open and mixed up the stage 1 and stage 1 HD. Ever get definitive answer on why the newer rating in exedy HD?
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Old 01-08-2014, 06:04 PM   #13
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apparently they were just underrated so they just changed the number without any definitive testing.
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Old 01-13-2014, 05:07 PM   #14
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Not sure about the comparison between the Exedy and ACT, but I have the Exedy stage 1 HD on my STi for about 12k miles now with a conservative 305 wtq setup. Now I'm not 100% sure (yet) if it's due to improper installation or improper flywheel resurfacing (as I've installed a few clutches in my time without issue and the flywheel face was blanchard ground), but it chatters very annoyingly once warmed up. Well beyond what I think is acceptable for what it's rated at and material specification, which, again, part of me feels like it may be a defective unit, or something was skewed during installation and/or machining.

But, it's smooth when cold and doesn't chatter at all, or does so very minimally. When it's warmed up it's chatter-city. I was hoping it would go away, but it hasn't. I'm actually ready to drop the transmission and swap it out for an OEM clutch because it's that annoying (I'm getting old, have kids, and get my speed fix by other means now) and the OEM clutch lasted me 55k miles with 20k of those miles on 350wtq. Just an FYI. Not a drag racer though. Just the occasional 1/4 mile test and 2-3 HPDE track days per year.

As for holding the power I have, that's non-issue as my setup certainly isn't high-torque. Just wanted to chime in about the chatter/judder/shudder.
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Old 01-13-2014, 05:37 PM   #15
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I have one in my car now for 2 years (exedy stg1 w/ HD pressure plate). She's pretty heavy to press but still holding great. It's seen a couple dozen rips down the 1/4 and still going strong.
I have little to no chatter, only had it for the first few hundred miles while it broke in.
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Old 01-15-2014, 09:59 AM   #16
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Hey man I have the stage 3 comp segmented and still getting used to it but I love it, I think you will enjoy the full face considering it's probably slightly easier to drive then the segmented and I think it will hold power just fine!
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Old 01-30-2014, 07:54 PM   #17
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Quote:
Originally Posted by theSlothy1 View Post
I have one in my car now for 2 years (exedy stg1 w/ HD pressure plate). She's pretty heavy to press but still holding great. It's seen a couple dozen rips down the 1/4 and still going strong. I have little to no chatter, only had it for the first few hundred miles while it broke in.
Questions for you:
you've used it with the 2.5xtr and meth with no slippage? ACT just had a price increase so I'm leaning towards exedy again, did you use the exedy supplied throwout bearing? I wouldn't imagine a properly installed full face organic disc would chatter much, I've heard of a few claiming theirs did, but all were resurfaced flywheel and possibly not cut same on the step? This exedy, if it actually holds 470ft lbs at the wheels, is quite a better buy compared to ACT offerings! especially with their recent price hike!!
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Old 01-31-2014, 06:15 AM   #18
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Yup no slippage at all, even after back to back runs down the 1/4. Its a heavy clutch, but that's to be expected. I used everything that came with it, no issues at all with anything.
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Old 06-13-2014, 09:37 AM   #19
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I'm looking to use the 5 speed Exedy Stage 1 HD in a 6 speed.
The clutch fork for the 6 speed is pushed a bit further from the pivot, should help with pedal feel. Also the clamping force of the 5 speed HD plate is lower than the 6 Speed.

How many miles did you guys get out of the Stage 1 HD , so far?
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Old 06-14-2014, 07:23 AM   #20
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Mine was toast after 10-12k, went to a FX350 this time which feels light as stock
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Old 06-14-2014, 08:00 AM   #21
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Did you drag race it at all?
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Old 06-14-2014, 08:33 AM   #22
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Yea, I usually make a couple dozen passes down the track each season, nothing too extreme.
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Old 06-14-2014, 09:22 AM   #23
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I've got about 3k on mine and it still shudders a bit starting off(thought you can change your driving to make this less noticeable), I doubt I'd buy it again. Also noticed the slightest slip reversing into my garage for instance (to avoid shaking car) makes it smell very quickly. I'm not the first to say this, I've driven manual cars since I was 13-14, and I'm 30 now. It isn't a know how issue. Over revving on starts is a pet peeve of mine. I know when slip is excessive.

Fwiw, I used a brand new OEM flywheel when installing this stage 1 HD. I've heard of the shudder/chatter going away with some hard miles, maybe once I start making a few hard passes(track) it'll get better. Torque is just over 400 on a mustang. Car was trapping 116.5
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Old 06-14-2014, 09:29 AM   #24
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So you're pointing to the friction material being grippy but soft and this clutch getting it's torque rating at the expense of the material buring off much faster, potentially lasting a lot less than stock. You have a stage 1 HD 6 speed, right?
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Old 06-14-2014, 09:31 AM   #25
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Quote:
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Yea, I usually make a couple dozen passes down the track each season, nothing too extreme.
So in your case, this was the stage 1 HD 6 speed.
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