I am running the spec twin p-trim

 

Jeremy told me there wasn't an issue with the hardening on my broken components, they tested the hardness in house and said they were within spec........no lie if they actually test them inside their building. i gave up on dealing with them guys, i was told there would be a refund on the original credit card for like 300 to help with my troubles, i was like wtf? 300 for removing the tranny 1 time for a freaking oversight in "quality control." how do you send the incorrect parts. then again it comes out but because the inside hub stripped. i just located a used tranny for 1100, and bought a different brand of clutch. as for this nonsense for the dowel pins, that scenario was brought up to me, and after reviewing my old tranny.....still has both the dowel pins in it, and they look perfect. if the tranny was misaligned wouldn't it wear out the input shaft bearing prematurely also?

 

I assure you that if I told you we checked the components for hardness then we checked them. As mentioned above we have a Rockwell Hardness Tester in house and use it regularly to insure consistent hardness of the components we produce. Whay would I lie about this? If you want to take a look at our facilities you are welcome to arrange an appointment with me to do so! Junk, if you will provide your name I will be more than happy to provide info relative to your RMA so others can further understand the situation and our findings. Let me know if you have any further questions.

 

600 so far on the new one. It hasn't started squealing yet on engagement from a stop, but aside from that, no news would appear to be good news.

 

Update on my car-
Had both input shafts Rockwell tested... both input shafts came back factory spec (probably because they came from mitsu). Installed exedy twin hd with fork stop (thank-you MAP). Installed a rebuilt TRE 2.5 trans ( Shifts incredibly fast and smooth - thanks TRE) 4,000 + miles and 1 trip to the drag strip later and my car is still daily driving like the day I put her back together. I see some others have had issues with input shaft damage. Glad spec brought such a well designed product to the market.

 

Didn't go reading through the whole thread, but pretty much the same thing happened to me recently with the spec 2+ for the 3/S platform. Just sheared right through the rivets on the center hub.

http://www.3si.org/forum/f1/spec-fail-part-2-a-504239/

 

Hi ladies and gents.

I've been in the market for a clutch, since getting almost 55k miles out of the stocker. Actually it had some life left, but I munched the synchros in 2nd gear and was feeling uncomfortable. Winter was coming up and it was the best time to pull the tranny, Shep it, and change the clutch all at the same time.

I originally had a Tilton Twinplate Cerametallic, sitting in a corner for 2 years waiting for my stocker to fail.

After seeing a handful of reviews I determined that the long term driving on the Tilton, although the Tilton being a great unit, was both ultra light, and potentially (if I didn't set it up right, drive it right, etc.) prone to wearing disks out before I wanted to pull the transmission out again. So I sold it.
Proof: https://www.evolutionm.net/forums/sa...ebay-item.html
This was compounded by having to drive at times in sub-zero temperatures here in sunny Utah and I've been in cars with race engagement clutches in the winter. Its not my cup of tea.

Now I was moving on to something else ... Do I choose a nice single plate and flywheel? Some of those combos could be gotten as low as 500ish quid without the flywheel or upwards of 1100 quid with a flywheel. It seemed a twin plate could still be had, and all twins come with a flywheel at least for the Mitsu.

My driving was going to center around some SCCA and Track days, thank you RallyCross at MMP. I'd like to keep the downtime in the off-race season to something reasonable, so longgevity on a clutch was a large factor.

Without debating more of my driving habits, I jumped on some more threads and narrowed my list down to three twin plate clutches.


Exedy Twin Cera - Pull Style - liked the long term reviews.
OS Giken TS2B - with Movement Alteration Kit (Push Style) - liked the design.
I had also looked at the OS Giken R2CD but there have been reports of the floating center causing tranny lockout during cornering.
Spec Super-Twin P-Spec - (Push Kit Included, I think) - liked the cost.

The Exedy was one that was very well reviewed, and after tons of years on the clutch, I'm sure they've just got a magic formula making them and I wouldn't be expecting anything magic or scary to happen. I might have the infamous TOB Popout case, but with good adjustment and a pedal stop, I could pretty much keep myself from doing even that.

The OS Giken TS2B hasn't had a lot of press in the Evo world. However getting a hold via phone to OS Giken and those that have dealt with them, this article pretty much summed up what I found out about it:
https://www.evolutionm.net/forums/se...lots-pics.html

Getting to the main point on this article; upon researching the Spec Super-Twin P-Spec I found lots of information, most of it favorable, and some key articles very very disturbing. Why did it have such back and forth reviews and experiences? Being an electrical engineer that wrenches after work, my engineering spidey sense said I was puzzled.

Now some are going to say that I'm doing an armchair review. If you believe that, take this with a grain of salt. The other side of my arguments are going to say that I try to very logically put all of the information together and try to weigh the potential outcomes. Its part of my training and experience. Also let me say that Spec has also had really good experiences in most of their Evos.

Initial Spec Pros: One thing I liked about the Spec was Spec singles had a lot of usage in my area with all of the race nuts, mostly from the muscle-car and ricer crowd. I could walk into any shop and say, "What brands of clutches should I consider?" I'd almost always hear, "Try a Spec, they seem to work well for us." So the local public and inet reviews of them seemed favorable. After a bit of research here, long term EvoHead Expert Ted B I found out was running one of the P-Specs.

Initial Spec Cons: Then I dug up these three articles:
https://www.evolutionm.net/forums/ev...ut-issues.html
https://www.evolutionm.net/forums/se...ec-clutch.html

and the second article referenced this article:
http://www.3si.org/forum/f1/spec-fail-part-2-a-504239/

and for that article you find out that there are two 3Si folks (if I read it correctly) that have had Spec issues.

I had heard in the past that since the Evo tranny to Evo motor is pilotless (and 3Si) you had to be careful and make sure that the bell housing was both clean, and within tolerance as to not put your input shaft off-center to the clutch and crankshaft. Fine. I'll make ultra sure I put things back together nice and easy. An off center under load input shaft could hog out these disks and cause these failures. However these failures usually don't end up shearing the hub rivets. Rivets are very very strong and provide an almost weld interface.

Yet I was still puzzled on why, a clutch would fail in such a manner. I've seen Tiltons with hogged out splines, and in fact I talked to a Tilton engineer that prefers to have the splines slightly softer material than the input shaft because clutch disks are easier and less expensive to replace than input shafts. But I haven't heard or seen about rivets failing and hogged holes.

I saw from some pictures that the Spec had lots of beef in the plates, carriers, and hubs, and seemed to be connected in a secure manner. Why would the rivets fail in such a way?

I was puzzled for about a 1 week trying to resolve in my mind what had happened, and if the Spec was still going to work as an option in my Evo. The Spec service guy really had a lot of good article points about what he tested: rivet installation, hardness, balance, number of clutches that haven't failed, design, etc., etc. After a while he seemed to focus on something wrong on the car setup, misalignment of the input shaft, bearing wear and preload relative to the input shaft, and so on, which are certainly issues. Also if something was indeed wrong with my car setup, how much would I want to fail and how? Some splines on a disk? fine ... an input shaft? No way. Not after a Shep build.

By the idea that I couldn't reach a failure conclusion by the sum of all things discussed, I just couldn't feel good about biting off a 1.6k dollar clutch and have it force me into potentially a 1k transmission repair. Some folks like the Exedy crowd have popoff TOBs, and you're down some time and effort getting things put back together. Some folks have hogged out Tiltons, but go get the input shaft done anyways. But an input shaft to a transmission is a whole different ball of wax. I'd probably pay an insurance cost premium if something did indeed fail. I digress.

Then it hit me, last night I was reading the articles again, and found this audio clip of 'White's first startup with the Spec here: http://www.mediafire.com/?azjj5myyejm I noted also the excessive hissing coupled with the slight high-pitched whine. Its rather hard to hear, but its there.

Then I found this article with some high-rez photos (google search, top search result): http://www.google.com/search?sourcei...xforums+photos
(Sorry about the google search link ... either I'm way behind in the evolutionm.net rules ... and I don't understand why I get evo_x_forums filtered out of the link ... if somebody posts the article and high-rez photos here, I would be very much grateful)
Here is the URL try without a link parse turned on: www.evo_x_forums/forums/showthread.php? t=20145
remove the "underscores" after copy and pasting the link. (I hope).

Holy Smokes it hit me as I saw the first really good side view of the clutch!! (BTW this is a view you don't see as part of the sales pitch on any website unless you buy a clutch, have a friend that buys a clutch, or find an article like this one.)
The pressure plate that is affixed to the spring housing is floated in three places. If you look closely at the side, power is transferred to the first pressure plate through that stackup of "bands!"

Those bands allow two forms of movement. Side to side (or in circle) movement, probably to help engagement and damping, and this is not a bad thing in theory. The second movement is up and down movement of that plate. Think of that connection point to the right in the carrier when a power pulse comes in. On the Evo firing, from the view of that side shot you'd see the clutch housing move from left to right and the bands stretch, pulling that pressure plate along. Stretching of the bands will cause a force such that the pressure plate will want to lag behind the housing. More importantly because of the stretch the bands will also want to move up to be parallel with the top most connection point. The plate probably doesn't move much or at all because of the springs, but it at least feels the force of being "pulled up." This sets up the condition of having potentially some nasty frequencies / modes all caused just by the engine firing.

The short conclusion, would be that I believe I would be seeing a potential problem with some frequencies or modes that would come through those bands into that pressure plate, couple to the friction disk, and start to hog out the rivets, and/or the splines. This was not a case of "if it can move" sort of argument, or "how much is it moving because of tolerances" type idea. More of an idea is that this could perhaps be an oversight into the modal or frequency analysis of the Spec Super Twin relative to the Evo. It is "an option" into why it might have failed.

As with the other articles, I would agree that the rivets are not failing because of material type, or manufacturing technique or tolerances.

Now if I put my frequency mode analysis glasses on: (I have to do these all of the time at work in electronics, electro-mechanical interfaces, and at times help setup and run the pure mechanical interfaces for modal analysis).

My conclusions are these as Cons to the Spec Super-Twin in an Evo:

1 - I don't like that the alumium carrier is affixed to the flywheel in only six locations. all of which a customer must use for installation, and is relatively tall with relatively "skinny" bolts.

a - The customer has to put this carrier on as one of the last steps of putting the stackup together, the type and torque needed to properly affix this carrier could have a lot of error in being properly affixed to the flywheel. Simple things such as grabbing the torque wrench head at torque time could throw off the planarity needed on the carrier, the stretch needed on the bolts for proper yield and interface to the flywheel.

b - Small skinny bolts at few locations all translate to a lower frequency mode and potentially more movement. These two points could translate into is a lower frequency mode in this regard, more movement and a potential failture.

2 - The first pressure plate is affixed in only three places "through the bands." I'm sure this was a great idea for engagement and feel as to have the bands provide some damping. As I have not seen an analysis of what those modes and movements could be I'm coming to the conclusion that those bands could significantly contribute to allowing the plates to "come loose" at some frequency and chatter, thereby increasing the likely hood of off-axis movement relative to the input shaft and rivets.

This in turn could cause the failure.

Spec is somewhat saved in that lots of clutches have worked. However changing anything in the clutch obviously changes the sympathetic modes that are seen and the clutch keeping on working without failure.

In Spec's defense I'm sure there is not a reasonable sure-fire way to model all the modes and cases except through real-world testing, and/or a really really good frequency analysis modeling program that takes significant time per car to setup.

I see machines they would have for balancing the whole assembly to the gnat's knees, but a balancing system would not be able to simulate some of the more fancy modes like sharp ignition pulses.

However not in their defense I would like to know the reasoning and relability of making such a banded interface?

Note: I contacted an older and much more experienced mechanico nut. He's been in 3D mechanical design for a lot of years as well as having done everything from muscle cars to RX7s. He mentions that the band and tab design for pressure plates is not something new. It does have an effect of allowing the pressure plate to float up when clutch disengaged. He agrees that it allows an amount of buffer on engagement. He also concurs that if he were doing a design as such, and knowing about such failures, he would try to bring forward a frequency analysis.

./flame suit on.

Does anybody have any more information, or information on the Spec Super-Twins?

Enjoy!

~j.

 

Feel your pain. I also experienced a massive spec failure that cost me my whole transmission. I didn't get a cent from them not even a replacement clutch... customer server there was also prompt but extremely unprofessional.

 

Yea as far as I'm concerned you can put a monkey in charge of Mclaren's facilities and I guarantee no good motors roll off the line...

 

SPEC clutches suck. Stick with Exedy twin or triple plate clutches.

 

I've Had a lot of kit , tilton triple carbon, rally ceramic they all sucks works great for the first 1500 miles, OS sucks they don't hold. Exedy push style is the only clutch that held the abuse and kept on ticking launch after launch it just held every time.

 

Meanwhile, my SPEC P-Trim is still holding up like new. It is confusing why individual experiences can be so vastly different. I'm sure a careful inspection time would reveal the variables. When my clutch eventually reaches its end of life, I'll disassemble and have a close look (with photos).

 

Same issue I had clutch went out six months into the change... Chattered then went out.. Throw out bearing went out launched grease all I've my clutch burned it out and now I'm out a car and $.. Worst of all both Jerermy and Chris(the gm) states if there was anything to do with my throw out Bering they would be able to warranty or help out with my trouble.. Yet all I've been getting from them is I'm pretty much screwed cause I'm out my warranty... Yet exedy clutches have lifetime warranty and will promptly assist with any problems... I will never ever buy a clutch from spec again or any product!!!

 

This was a very detailed review and I appreciate the warning.

 

man! spec is out-of-spec.