Definitely interested to hear more between the RXT and DYAD. RXT was the route I was planning, not sure now. Both sound like they have quirks, just depends on what you want to live with.
Stock -> Centerforce DYAD. My thoughts and the installation results.
- Thread starter jchristena
- Start date
So, 900 mile update.
1. Chatter is still there at low rev starts. I'd say it's gotten better over the last couple hundred miles but it is not gone. DEFINITELY worse when it's hot. In other words, smooth as glass when you first fire it up in the morning and during the first few miles. As it gets some heat in it, it chatters. Much worse on hot days too.
2. You have to give it a few more revs for smooth take offs. This at times results in burned clutch smell. Once you're moving it drives just like stock and no smell.
So, if you can live with those little annoyances, then by all means, it's a great clutch. If you want a stock performing clutch, get the stock clutch. I'm considering buying one and just leaving it in the box so that when/if this one ever dies, the stock clutch will just go back in.
1. Chatter is still there at low rev starts. I'd say it's gotten better over the last couple hundred miles but it is not gone. DEFINITELY worse when it's hot. In other words, smooth as glass when you first fire it up in the morning and during the first few miles. As it gets some heat in it, it chatters. Much worse on hot days too.
2. You have to give it a few more revs for smooth take offs. This at times results in burned clutch smell. Once you're moving it drives just like stock and no smell.
So, if you can live with those little annoyances, then by all means, it's a great clutch. If you want a stock performing clutch, get the stock clutch. I'm considering buying one and just leaving it in the box so that when/if this one ever dies, the stock clutch will just go back in.
^ thanks for the fair, honest update.
Similar long term experience with my RXT. Chatter on first gear take off isn't as bad, but still occurs. first gear reengagement will chatter. Stop and go traffic will chatter.
However.
After about 13,000 miles I made my first passes on it at the track a few months ago. Not a single instance of slip. Held the power of a launch better than I could have hoped.
You have to be honest about what these clutches are engineered for and the resulting quirks on the street. RXT and equivalent clutches are definitely race clutches.
If Im looking for increased hold over stock but intended for street driving, Im looking at an RST or equivalent clutch. If youre making a ton of power, a quirky high grip clutch is what youll have to live with.
However.
After about 13,000 miles I made my first passes on it at the track a few months ago. Not a single instance of slip. Held the power of a launch better than I could have hoped.
You have to be honest about what these clutches are engineered for and the resulting quirks on the street. RXT and equivalent clutches are definitely race clutches.
If Im looking for increased hold over stock but intended for street driving, Im looking at an RST or equivalent clutch. If youre making a ton of power, a quirky high grip clutch is what youll have to live with.
What power are you at now Lexus? If you're looking at RST, you might be better off going 13-14 OEM. I've read not so good things of the RST at 600+whp.
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Ace, I should have phrased that better! I took on the role of a prospective clutch buyer. Still have my quirky RXT, 1st gear chatter and all lol.
An owner who is looking for an upgrade over stock would be much happier with an RST than an RXT. 13/14 Clutch would be a good choice too, but not sure how I compares to an RST.
An owner who is looking for an upgrade over stock would be much happier with an RST than an RXT. 13/14 Clutch would be a good choice too, but not sure how I compares to an RST.
So I've removed the Magnum XL trans and Spec clutch and will be changing clutches also.
Had some phone issues and lost all pics from PRI and the trans removal but I'll reshoot them soon to show you the Spec clutch differences (have an SS trim in car and ST trim rebuild kit, big difference in friction discs).
For guys around 750rwhp and willing to run gears, I can't argue with the stock clutch. Mine ran several 10s passes with 3.73s-4.10s at 750rwhp and still looked new.
I'm working with a few options now, but one is through a former IHRA Pro Stock guy who consults with many of the clutch makers. That option is a rebuildable Ram billet twin with custom discs designed to perform for my street/strip goals. Another option is a new Exedy unit; my good friend works at Exedy and is taking some measurements from the Magnum trans and stock clutch to see if he can improve on their current offerings for S197s. Last is an Australian company coming into the US market with some cool ideas.
Long story short is there isn't a perfect clutch out there, like most auto applications there are compromises and you have to choose based on your goals.
Stay tuned.
-J
Had some phone issues and lost all pics from PRI and the trans removal but I'll reshoot them soon to show you the Spec clutch differences (have an SS trim in car and ST trim rebuild kit, big difference in friction discs).
For guys around 750rwhp and willing to run gears, I can't argue with the stock clutch. Mine ran several 10s passes with 3.73s-4.10s at 750rwhp and still looked new.
I'm working with a few options now, but one is through a former IHRA Pro Stock guy who consults with many of the clutch makers. That option is a rebuildable Ram billet twin with custom discs designed to perform for my street/strip goals. Another option is a new Exedy unit; my good friend works at Exedy and is taking some measurements from the Magnum trans and stock clutch to see if he can improve on their current offerings for S197s. Last is an Australian company coming into the US market with some cool ideas.
Long story short is there isn't a perfect clutch out there, like most auto applications there are compromises and you have to choose based on your goals.
Stay tuned.
-J
Yea. That pretty much sums it up. Based on what I had read, you'd never know the car wasn't stock w/ the DYAD. That is clearly bullshit and is my own fault for believing that knowing full well that it had to be capable of handling some serious abuse. Were I to do it again, knowing that the stock clutch should handle my basic mods, I'd go stock.
That being said, and solely for the interesting of letting people know what to expect w/ the DYAD, a new issue has presented itself w/ the cold weather. Maybe this is common w/ aftermarket it clutches...maybe I'm just lucky. But, especially when it's cold out, the clutch makes a squealing sound when engaged in first gear(squeal/howl/whatever). Less as the car warms up but enough such that if you have friends outside the car when the car moves, they will ask what the F* that noise was. Is that a thing w/ aftermarket clutches?
Last few posts have been VERY informative... thanks guys.
My time for a clutch is coming soon.
I had my eyes set on an RST, but now might consider going with a stock 13/14 set up.
My time for a clutch is coming soon.
I had my eyes set on an RST, but now might consider going with a stock 13/14 set up.
The squeal in first gear is my "new normal" with the RXT, especially when it's a bit chilly outside.
However, I did clean up some annoying aftermarket clutch issues fixing my transmission support brace. Two bolts fell out and 1 was loose, which caused all sorts of extra noise, vibration and slop. $20 fix for a new pack of bolts...so its worth making sure the brace is snug and torqued. Also recommend blue Loctite on the 4 bolts.
I've got that same squeal with my Dyad, I'm glad its not just me and seems to be normal.
@barspen, which brace did you get?
so - maybe a RST will be my choice too -- a bit in the middle of stock and most aftermarket clutches handling abilities.
Just using the OEM transmission crossmember brace...looks like a big dog bone.
I have the option to go with a custom triple organic deal from the Australian company, or the more proven Ram twin with custom discs.
On autopsy of the Spec out of my car, the stack height or slave cylinder weren't in spec and the flywheel side disc was wearing on the slave bearing. Clutch performed well but was very noisy due to that issue.
Now this is a base SS Spec that BIRDOC ran his 6-speed record with. I bought it with a complete rebuild/upgrade kit to ST specs, but it truly looked out, so the shop who put my car together installed it straight without rebuild. So direct from his 1200rwhp deal to my 965rwhp deal, and raced in both cars, so I guess I can't complain.
I would like to see how the higher rated (and with better driveability due to allowing slip) ST spec performs, but at this point I'll sell it with a full rebuild kit and start fresh.
I think you can get great drivability with an aftermarket clutch, but it requires a perfect install and there will usually be some NVH.
-J
On autopsy of the Spec out of my car, the stack height or slave cylinder weren't in spec and the flywheel side disc was wearing on the slave bearing. Clutch performed well but was very noisy due to that issue.
Now this is a base SS Spec that BIRDOC ran his 6-speed record with. I bought it with a complete rebuild/upgrade kit to ST specs, but it truly looked out, so the shop who put my car together installed it straight without rebuild. So direct from his 1200rwhp deal to my 965rwhp deal, and raced in both cars, so I guess I can't complain.
I would like to see how the higher rated (and with better driveability due to allowing slip) ST spec performs, but at this point I'll sell it with a full rebuild kit and start fresh.
I think you can get great drivability with an aftermarket clutch, but it requires a perfect install and there will usually be some NVH.
-J
I'm just throwing this out there, but I wonder how many of these clutch installs actually adhere to the service manual which calls for a light lubrication of the pilot shaft splines and clutch disc splines with Ford XG-8 PTFE lubricant? I can see where it might minimize some of the chatter some are complaining about. My OEM clutch chattered from time to time too.
I was under the impression that lubing the pilot shaft splines just aided in stabbing the transmission. I was also under the impression that the chatter comes from the clutch disc material "skipping" across the mating surface of the flywheel/pressure plate under certain conditions...which is why ensuring that the flywheel and pressure plate surfaces is spotlessly clean is so important. Certainly possible that I am wrong here...always looking to learn something new.
I'm at work now, but the service manual indicated that use of a different lubricant could result in clutch chatter. That indicates to me that there's more to it than just stabbing the transmission.
Admittedly, I did not use ANY lubricant when I originally installed my RXT on the back of the built 5.8, but when I swapped transmissions, I used the XG-8. Jury's out until I get it back on the road as to whether it will do anything different. It just makes sense that with dual clutch discs and all contact surfaces are dry, it would promote some sort of chatter.
Admittedly, I did not use ANY lubricant when I originally installed my RXT on the back of the built 5.8, but when I swapped transmissions, I used the XG-8. Jury's out until I get it back on the road as to whether it will do anything different. It just makes sense that with dual clutch discs and all contact surfaces are dry, it would promote some sort of chatter.
Interesting. Yea, I didn't use any either. I figured it just had to do with the input shaft dragging on the clutch splits and might allow for a little wiggle room in getting it to seat. But, I obviously don't know a whole lot about this stuff other than the basic principles...so you may be absolutely right. I appreciate the info.
Been looking in to the clutch kits, and am thinking of putting together my own setup similar to the LMR 10 replacement. Thinking of going with McLeod aluminum flywheel, stock 10 clutch with matching slave and hydraulic line, and ARP plate and flywheel bolts. From what I can found, I can get it all for $1211 shipped, which is less than the LMR kit using stock flywheel (I really like aluminum flywheels on force air cars, and the alum is SFI approved). Seems like a good way to go, should handle more power than I will make, and have a nice, light pedal.
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