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Better upgrade/replacement Miata clutch for less then OEM.
2 Attachment(s)
First the base price. Autozone clutch kit 1.8L Miata. 10-045 $194.99
Now here's how you get a bigger better clutch for less. Order Autozone clutch kit NU31218 ('94 V6 MX6) for $109.99 then add the throwout 614079 for $28.99. $138.98 total. Saved yourself $56 bucks but it gets better. The V6 MX6 disc is 8.875" vs. 8.5" for the stock Miata replacement. The additional 3/8" of friction surface is at the outer edge of the disc and will completely cover your pressure plate and flywheel surfaces from edge to edge. The MX6 pressure plate fits the Miata's flywheel but I have no way to verify the clamping force vs. the Miata's pressure plate. I used my Exedy pressure plate when I installed mine. Being this kit is for a 2.5L V6 you can pretty much assume it'll hold more torque. A couple notes... If you set the Miata's throwout on the fingers of the MX6 pressure plate it looks as if it -just- touches the tips but once the plate is bolted down it'll look much better. ;) You may also notice the spline/hub of the MX6 disc sticks out a little further towards the trans then the stock Miata hub but I verified there's plenty of clearance left on the input shaft of the transmission. Using a stock Miata disc there's -roughly- 3/8-1/2" of unused spline before the hub would make contact with the transmission (based on the wear marks on my input shaft). The MX6 disc is only about 1/8" further out so that leaves 1/4-3/8" clearance. That's plenty of room to allow for the disc to float away from the flywheel during disengagement. Almost forgot to mention... The pilot bearing is the same. :) If I can figure out how to get pictures off my phone I'll upload them so you can see the differences. These pics are from NAPA and it's a little hard to tell but you can kinda see the difference. NAPA's MX6 kit looks like rubber bumpers for springs. The AZ one has 6 springs in it. https://www.miataturbo.net/forum/att...1&d=1269598838 https://www.miataturbo.net/forum/att...1&d=1269598841 |
So will it hold the turbo cars?
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I remember hearing about this a few years ago on another forum but I can't remember how it worked out for the testers.
I'd be interested in hearing since this would be another option for aftermarket clutches too. Mx6ers turbo their cars and make a fair it of power so their high torque clutches might help out some on this board. |
I'll use this infor for my daily with a clutch that slips at probably 70whp.
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Originally Posted by rweatherford
(Post 544965)
So will it hold the turbo cars?
"The 2.5 L (2497 cc) KL family uses an 84.5 mm bore and 74.2 mm stroke. It includes the Japan-only KL-ZE, which produced 199 hp (149 kW) and 165 ft·lbf (224 Nm). Another variant, the KL-DE (also known as the KL-03 outside the USA, and fitted to 2.5 litre Ford Probes) was the worldwide version, with 164-170 hp in various applications." So it looks like it's a 164hp engine. |
4 Attachment(s)
Here's the MX6 8.875" and Miata 1.8L 8.5" discs side by side. It's almost like looking at a 1.6 and 1.8 discs.
https://www.miataturbo.net/forum/att...1&d=1269635104 https://www.miataturbo.net/forum/att...1&d=1269635104 https://www.miataturbo.net/forum/att...1&d=1269635104 https://www.miataturbo.net/forum/att...1&d=1269635235 |
Pretty cool. Nice find lazzer. nice to have you back btw.
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Ok, a bit of a dumb question. Doesn't more surface area = less psi? That's why puck clutches are the way they are?
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Greater distance from the center = more leverage.
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Originally Posted by Bryce
(Post 545521)
Greater distance from the center = more leverage.
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Originally Posted by dgmorr
(Post 545519)
Ok, a bit of a dumb question. Doesn't more surface area = less psi? That's why puck clutches are the way they are?
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Just imagine if you cut off some of your brake shoe. Would your braking be worse? Ofcorse it would. It would take more force on the smaller shoe to create the same amount of friction. It would also create more heat in the process. The opposite is also true. More surface area is more friction area and with the friction spread over more area it should keep the disc cooler and less likely to fade. I'm going to pull numbers out of my ass here but say a pressure plate can clamp 1200lbs and the disc has 10sq-in of surface area. That's 120lbs per inch on the disc. Now say the disc has just 1sq-in more surface area at 11sq-in. That drops the force to 109lbs per inch on the disc. That should keep the disc cooler plus the fact that the disc now has more surface contact with the flywheel and pressure plate to transfer the heat away. There's also less force over more area so everything will last longer. The MX-6 was a 2.5L V6 and has much more torque then a BP so in general it's a better clutch. It's win-win-win in any case.
I posted my findings for those who may be replacing a stock clutch, need just a little more grab, or just want to save a few dollars. I didn't want to imply this is as as good as a puck disc but it's significantly better then stock for less money. I really wish I had installed the MX6's pressure plate so I could compair. My Exedy clutch hardly held 15psi on the BP. As long as it didn't get hot it was ok but launching under boost and it was instant fade. I will be able to post my opinion as to how well just the MX6 disc performs because I kept the pressure plate I had when I did the swap. |
Originally Posted by TurboTim
(Post 545511)
Pretty cool. Nice find lazzer. nice to have you back btw.
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Did some driving on the new clutch today. It's not broken in yet but the engagement is quicker which I like. It's handling boost with no problems. Pedal feels stock but it's definitly got more grip. No complaints at all.
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How much boost/power is you car running? Have you broken it in and really tried it out yet?
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Originally Posted by mfvt
(Post 565271)
How much boost/power is you car running? Have you broken it in and really tried it out yet?
We are doing a 11.1:1cr Miata build in the next month and the driver is going to try this set up. That car will have alot more torque on the launches then I do because I don't launch under boost. I'll let you know what he thinks. |
Originally Posted by lazzer408
(Post 545589)
Just imagine if you cut off some of your brake shoe. Would your braking be worse? Ofcorse it would. It would take more force on the smaller shoe to create the same amount of friction.
"Standard friction equation When a force is applied to an object, the resistive force of friction acts in the opposite direction, parallel to the surfaces. The standard equation for determining the resistive force of friction when trying to slide two solid objects together states that the force of friction equals the coefficient friction times the normal force pushing the two objects together. This equation is written as Fr = μN where: •Fr is the resistive force of friction •μ is the coefficient of friction for the two surfaces (Greek letter "mu") •N is the normal or perpendicular force pushing the two objects together •μN is μ times N Fr and N are measured in units of force, which are pounds or newtons. μ is a number between 0 (zero) and ∞ (infinity). Applies to static and kinetic This equation applies to both static and kinetic sliding friction. Static friction is the friction before an object starts to slide. Kinetic friction is the friction when the object is actually moving or sliding. Static friction and kinetic friction have different coefficient of friction values. Independent of area for sliding hard surfaces An interesting result of this equation is that in the case of sliding friction of hard surfaces, the friction is independent of the area of the surfaces. In other words, it is just as difficult to move a 1 square-cm object as a 1 square-meter object, if they both are pressed to the surface with the same amount of force. This is not intuitive. You would think that there is more friction when the surfaces are larger, but the friction equation states otherwise. You can verify this fact with experiments." I'd imagine the MX-6 clutch would work better but it would be because of its larger diameter having slightly more mechanical advantage rather than the increase in area. |
Originally Posted by Rennkafer
(Post 565719)
(discounting heat dissispation/fading).
Originally Posted by Rennkafer
(Post 565719)
I'd imagine the MX-6 clutch would work better but it would be because of its larger diameter having slightly more mechanical advantage rather than the increase in area.
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wait you guys are just figuring this out now?
ive been running KL v6 clutches on my FWD bp since like 2006 :). i wasn't the first, either! aftermarket pressure plates (like ACT) have higher clamp loads than the equivalent BP model, too. |
this is news to me... :(
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http://thegurglingcod.typepad.com/th..._you_know2.jpg
actually now i'm running a KL pressure plate with a toyota pickup truck disc but.... that's a whole 'nother story :) |
so I am guessing this does apply to aftermarket mx6 clutches as well?
random ratings comparison with prices i was seeing on ebay: f1 stage 1 clutch kit: 1.8 Miata - 227 hp, 204 ft/lbs, $117 shipped 2.5 Mx-6 - 262 hp, 246 ft/lbs $108 shipped f1 stage 3 clutch kit: 1.8 Miata - 320 hp, 297 ft/lbs $169 shipped 2.5 Mx-6 - 380 hp, 378 ft/lbs $156 shipped and mx-6 clutch kits seem to be 8% cheaper |
Just remember you will have to buy a TOB separately, the MX6 one wont work in a miata. Negates any savings you might find by buying the MX6 clutch kit.
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I guess it depends where you shop. I went with Autozone because they are everywhere and had the MX6 in stock.
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I Got a set for MX6 and did some rough measurements on the pressure plate with some weights and a dial gauge. It turned out to have an equal spring rate as the Miata. Also spring geometry measured very similar, apart from the obvious finger length. Both were Exedy/Daikin clutch (DK stampings). I do not see how I could have used the MX6 PP with the Miata TOB which falls right through. Anyway, the larger disc is a nice find!
therieldeal, you seem to be doing some interesting clutch work. I would love to hear the toyota pickup truck disc story. |
A word of caution: the MX6 center plate of the disc protrudes about 2mm more towards the pressure plate fingers than the original. Looks like they might even contact when depressing the clutch. I don't want to find out what happens if they do.
Now I'm back to considering using the MX6 pressure plate after all. I'll have to find a larger TOB to contact the fingers properly though. Toyota 1ZZFE engine (1.8 Corolla etc) should have a 33mm TOB bore which is close. Another option would be to sleeve the transmission front cover shaft to take many other bearings (such as Honda Prelude). Sadly the MX6 part I got was too wide for the fork. The seat of the fork pivot ball should also be machined a bit lower to compensate the protruding MX6 fingers. |
Originally Posted by Rennkafer
(Post 565719)
Incorrect.. if you halved the area of the pad but kept the same normal force applied to it, it would work better (discounting heat dissispation/fading). The only two things that matter are force applied and coefficient of friction. Here's a quote from a website that explains this in more detail... all you engineer/physics types need not read further.
"Standard friction equation When a force is applied to an object, the resistive force of friction acts in ;);););)the opposite direction, parallel to the surfaces. The standard equation for determining the resistive force of friction when trying to slide two solid objects together states that the force of friction equals the coefficient friction times the normal force pushing the two objects together. This equation is written as Fr = μN where: •Fr is the resistive force of friction •μ is the coefficient of friction for the two surfaces (Greek letter "mu") •N is the normal or perpendicular force pushing the two objects together •μN is μ times N Fr and N are measured in units of force, which are pounds or newtons. μ is a number between 0 (zero) and ∞ (infinity). Applies to static and kinetic This equation applies to both static and kinetic sliding friction. Static friction is the friction before an object starts to slide. Kinetic friction is the friction when the object is actually moving or sliding. Static friction and kinetic friction have different coefficient of friction values. Independent of area for sliding hard surfaces An interesting result of this equation is that in the case of sliding friction of hard surfaces, the friction is independent of the area of the surfaces. In other words, it is just as difficult to move a 1 square-cm object as a 1 square-meter object, if they both are pressed to the surface with the same amount of force. This is not intuitive. You would think that there is more friction when the surfaces are larger, but the friction equation states otherwise. You can verify this fact with experiments." I'd imagine the MX-6 clutch would work better but it would be because of its larger diameter having slightly more mechanical advantage rather than the increase in area. And furthermore, before you go spinning off on me, I'm just fucking with you.;) |
Originally Posted by j-po
(Post 617475)
I Got a set for MX6 and did some rough measurements on the pressure plate with some weights and a dial gauge. It turned out to have an equal spring rate as the Miata. Also spring geometry measured very similar, apart from the obvious finger length. Both were Exedy/Daikin clutch (DK stampings). I do not see how I could have used the MX6 PP with the Miata TOB which falls right through. Anyway, the larger disc is a nice find!
therieldeal, you seem to be doing some interesting clutch work. I would love to hear the toyota pickup truck disc story. |
Originally Posted by lazzer408
(Post 627144)
Are you using a 1.8L throwout? Mine worked just fine with plenty of contact with the fingers.
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For what it's worth all Clutch kits from NAPA, Autozone and Advance are all made by Perfection Clutch as of right now. Doesn't mean some old stuff isn't in circulation still or some may have outside sources, like independent NAPAs. Napa used to sell Exedy but every big chain is starting to sell the same stuff in different boxes. Quality is going down along with the price on some of this stuff.
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Originally Posted by shaggy13
(Post 632457)
For what it's worth all Clutch kits from NAPA, Autozone and Advance are all made by Perfection Clutch as of right now. Doesn't mean some old stuff isn't in circulation still or some may have outside sources, like independent NAPAs. Napa used to sell Exedy but every big chain is starting to sell the same stuff in different boxes. Quality is going down along with the price on some of this stuff.
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I have been playing with KL's for years and will be doing the clutch on my 2000 shortly, I am curious to hear if anyone ever went with the MX6/KL Pressure plate and how it worked out.
Having a better disc is nice but if I was going to buy a clutch kit and only use the disc that still leaves the pressure plate as a weak point. Just curious. |
Originally Posted by Cross
(Post 632959)
I have been playing with KL's for years and will be doing the clutch on my 2000 shortly, I am curious to hear if anyone ever went with the MX6/KL Pressure plate and how it worked out.
Having a better disc is nice but if I was going to buy a clutch kit and only use the disc that still leaves the pressure plate as a weak point. Just curious. I think the main advantage to the KL clutch set is mainly due to the increaded surface area of the disc. It will stay cooler, last longer, hold more torque, and with less fade based on the surface area. Being larger in diameter also put more friction surface outward from center which can transfer more torque for any given area. If your trying to upgrade all your weakest links then you will need to upgrade every weak component. That shopping list has no end. This swap is more for the owner who needs a clutch because it is worn and this is a way to get a better performing clutch for less using over the counter parts. It's not necessarily an upgrade for someone wanting the best performance. There are better options out there but they cost significantly more and it wont be in stock. I did it. It worked. It performed and felt better with much less fade then stock clutch on a turbo Miata. That's all I can say about it. Hey Cross. Why not just put a KL in the 5. =) |
I did machining work to get it to fit. Seems there are various versions out there. Take your chances.
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Trust me I already have a KLG4 sitting here, I am going to make a custom Intake Manifold and then see about putting it in.... problem is the boost bug keeps getting me and I wanna go faster right this second not in 6 months when I have finished figuring out how to make this work lol.
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If I keep my miata I will probably end up putting a KL in it. Man that'd sound fun :)
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Originally Posted by j-po
(Post 633021)
I did machining work to get it to fit. Seems there are various versions out there. Take your chances.
Originally Posted by TurboTim
(Post 633154)
If I keep my miata I will probably end up putting a KL in it. Man that'd sound fun :)
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No problem. The MX6 clutch disc with its larger diameter center stub and more outwards protruding center metal plate looked like they would not work with the Miata PP and TOB (The center stub of the Miata disc is clearly made thin enough to pass into the TOB). The Miata TOB also would not work with the MX6 PP, it fell right through. So I had to use the larger MX6 TOB which required sleeving the transmission front cover shaft to a larger diameter. Also the more protruding fingers of the MX6 PP and thicker TOB required machining the fork pivot point down as well as extending the cylindrical portion of the transmission front cover further back by machining. Also ground the fork a bit wider to fit the TOB & modified the TOB.
Anyway, parts are ready and look like they will fit now. I have not had time to install them yet. If I had to do it all over again, I wouldn't. I'd just bolt in a performance clutch designed for the Miata. Now of course I can use cheap MX6 replacement parts fairly easily which was my original intention. How knows, maybe I am wrong about the Miata PP and TOB and they would have fitted after all. I did not feel like trying and failing by having the TOB catching onto the disc center stub or the PP fingers catching onto the disc springs. It would also have been a shame to waste the new PP. Your PP looks different. I assume that may work better. As I said, take your chances. |
Which throwout did you use? 1.6L? All the 1.8L throwouts I had (all the same) contacted the KL PP fingers with no problems. The 1.6L throwout bearing won't make contact with the fingers but the body of the bearing is large enough that it wouldn't 'fall right through'. If the finger opening was large enough for a 1.6L throwout to fall through, the MX6 throwout wouldn't work either. I wish I hadn't thrown out all the parts I had. I could have taken side by side photos of the 3 throwouts. Maybe you don't have a KL PP. Wouldn't be the first time I've seen the wrong clutch parts in the box.
Originally Posted by j-po
(Post 633484)
No problem. The MX6 clutch disc with its larger diameter center stub and more outwards protruding center metal plate looked like they would not work with the Miata PP and TOB (The center stub of the Miata disc is clearly made thin enough to pass into the TOB). The Miata TOB also would not work with the MX6 PP, it fell right through. So I had to use the larger MX6 TOB which required sleeving the transmission front cover shaft to a larger diameter. Also the more protruding fingers of the MX6 PP and thicker TOB required machining the fork pivot point down as well as extending the cylindrical portion of the transmission front cover further back by machining. Also ground the fork a bit wider to fit the TOB & modified the TOB.
Anyway, parts are ready and look like they will fit now. I have not had time to install them yet. If I had to do it all over again, I wouldn't. I'd just bolt in a performance clutch designed for the Miata. Now of course I can use cheap MX6 replacement parts fairly easily which was my original intention. How knows, maybe I am wrong about the Miata PP and TOB and they would have fitted after all. I did not feel like trying and failing by having the TOB catching onto the disc center stub or the PP fingers catching onto the disc springs. It would also have been a shame to waste the new PP. Your PP looks different. I assume that may work better. As I said, take your chances. |
I didn't think anyone could understand I meant the whole body of the bearing fell right through the PP. I should have made that clear. Anyway, I used the MX6 TOB as stated in my previous post.
You are saying 1.6 and 1.8 have different TOBs? The only TOB I can find is Mazda part number B622-16-510 which fits both. Could you please show some evidence there are indeed different TOBs? Getting the wrong PP crossed my mind too but then again, there are other vendors on ebay showing pictures of the PP I have. Thus I suggested there may be variations of the theme. Search ebay for MZC 543 to see what you do not want to get. Even if you managed to get a long finger PP the thicker stub on the disc looks like it may be a problem. There must be a reason why the Miata disc stub is so slender. |
I understand you mean the bearing fit in the hole where the PP spring fingers are.
This is very interesting. o.O I also see only one bearing listed for the '89-05 Miata. The bearings 'rolling collar' (that touched the fingers) even looks small. That's very interesting. This leads me to believe there are different throw out bearings floating around autopart stores. The one I ordered for my '94 fit both the KL PP and the trans sleeve. Now I REALLY with I had all those parts to figure out what was in my car.
Originally Posted by j-po
(Post 633790)
I didn't think anyone could understand I meant the whole body of the bearing fell right through the PP. I should have made that clear. Anyway, I used the MX6 TOB as stated in my previous post.
You are saying 1.6 and 1.8 have different TOBs? The only TOB I can find is Mazda part number B622-16-510 which fits both. Could you please show some evidence there are indeed different TOBs? Getting the wrong PP crossed my mind too but then again, there are other vendors on ebay showing pictures of the PP I have. Thus I suggested there may be variations of the theme. Search ebay for MZC 543 to see what you do not want to get. Even if you managed to get a long finger PP the thicker stub on the disc looks like it may be a problem. There must be a reason why the Miata disc stub is so slender. |
OK. So it is not a PP issue at all. You were lucky to get a non-standard TOB.
As one option the Toyota Corolla TOB might fit both the MX6 PP and the Miata transmission input cover shaft, as I suggested earlier. Anyway, I think I'm done figuring this one out. I joined the transmission to the engine over the weekend, bled the clutch and it still looks like everything is working with my modified parts - grips and releases properly. Engine is not running yet though. |
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