{"id":5748,"date":"2014-05-22T16:16:45","date_gmt":"2014-05-22T23:16:45","guid":{"rendered":"http:\/\/www.racingjunk.com\/news\/?p=5748"},"modified":"2016-11-30T12:01:11","modified_gmt":"2016-11-30T20:01:11","slug":"three-pedals-on-the-floor-different-strokes-for-different-folks-part-iii","status":"publish","type":"post","link":"https:\/\/www.racingjunk.com\/news\/three-pedals-on-the-floor-different-strokes-for-different-folks-part-iii\/","title":{"rendered":"Three Pedals on the Floor: Different Strokes for Different Folks, Part III"},"content":{"rendered":"

\"Clutch<\/a><\/p>\n

To read the earlier parts of this series, go HERE:<\/em>
\nPart I<\/a><\/em>
\nPart II<\/a><\/em><\/p>\n

Double Your Pleasure<\/strong><\/p>\n

Given the single disc \u201cold school\u201d clutch package we discussed in the past two sections, we have to keep in mind that technology has relentlessly marched forward.\u00a0 In most dedicated racing applications, clutches have shrunk dramatically in size.\u00a0 Plenty of Pro drag cars function with positively tiny clutch assemblies. The truth is, it’s pretty common to find clutches with (get this) an outside diameter of 5.50-inches.\u00a0 And yes, there are some \u201cbig\u201d set-ups out there that measure anywhere from 7.00-8.00-in in diameter.\u00a0 Typically, many of these little pressure plates incorporate diaphragm springs, but real key is the use of multiple discs (two, three or more).<\/p>\n

A number of years ago, McLeod Racing picked up on the value of multi-disc clutches.\u00a0 They were fully aware of the advantages of the technology, but the big question was how to mate the technology from professional racing to something that could be used on the street. The result of their research and development is their latest series of \u201cRST\u201d clutch assemblies.\u00a0 Although \u00a0not designed as dedicated racecar clutches, the RST is a street car clutch you can take to the track. In turn, this makes for a pretty nifty combination for a dual duty street-strip machine.\u00a0 Or even for a (rare!) stick shift bracket car.<\/p>\n

McLeod has been investigating and manufacturing high performance dual disc clutch assemblies for years (pretty much ever since GM discontinued their Borg-Warner-built dual disc clutch option in the early seventies).\u00a0 One big problem that faced those earlier dual disc setups was the need for a unique (and perhaps more important \u201cexpensive\u201d) flywheel.\u00a0 McLeod\u2019s RST clutch package is actually engineered to work with a stock style flywheel (you can use an aftermarket flywheel as well and of course, for most drag race applications you\u2019ll need one due to SFI requirements \u2013 we\u2019ll get to that later).<\/p>\n

Based upon a 9-11\/16-inch diaphragm pressure plate, the RST clutch includes 2 organic discs as well as a steel floater plate.\u00a0 By reducing the overall diameter of the clutch, the moment of inertia is reduced.\u00a0 How important is this?\u00a0 More than you might think:\u00a0 You see, the rotating components found in the driveline of your car include the crankshaft, flywheel, pressure plate, clutch disc(s), the gears inside the transmission along with the driveshaft.\u00a0 Each and every one of these pieces operates at a relatively high RPM.\u00a0 Given the high operating speed, the effect of the combined rotating inertia has upon acceleration is high.\u00a0 If the weight of that rotating mass is reduced, then the basic assembly can spin faster.\u00a0 Bottom line? If the mass becomes smaller, the car in question will accelerate faster.\u00a0 But that\u2019s not the end of it:\u00a0 If the weight in the rotating mass is moved closer to center of the mass then the entire assembly can spin faster.\u00a0 Basically a double-whammy.\u00a0 That\u2019s why the Pros we mentioned previously have gone to smaller and smaller (diameter) clutch components.<\/p>\n

Next time, we\u2019ll wrap up our look at clutches (keeping in mind there\u2019s plenty of choice out there).<\/p>\n

\"This<\/a>
This is the foundation for the McLeod RST line of clutches \u2013 it\u2019s based upon two small-diameter (9-11\/16-inch), clutch discs that function by way of a custom floater ring.<\/figcaption><\/figure>\n

 <\/p>\n

\"With<\/a>
With the RST package, each disc is a solid hub disc (unsprung) pretty much like you\u2019d find in a hardcore drag race clutch. Solid hub discs such as this have the splined hub riveted directly to the disc carrier plate (the circular metal plate that carries the friction material). With a sprung, or dampened hub disc, the hub floats in a spring-loaded assembly on the carrier. When the hub is loaded (when the clutch is engaged), the springs help to absorb the load instead of transfering it directly to the carrier plate. This arrangement allows shock spikes from aggressive engagement to be dampened out to avoid possible damage to the drive train. Sounds a-ok, but how can this be streetable? We\u2019ll explain later.<\/figcaption><\/figure>\n

 <\/p>\n

\"This<\/a>
This photo shows how each disc is built with a Marcel. What\u2019s a \u201cMarcel\u201d? It\u2019s the wavy material sandwiched between each side of the lining material on each disc. The Marcel is put in place to prevent clutch chatter by providing a certain amount of \u201cmovement\u201d as the clutch is engaged. The Marcel serves another purpose: The spring effect of the Marcel helps to prevent the lining from sticking to either the flywheel or the pressure plate (or both) as the clutch is disengaged. Marcel thickness varies for the application, but it does have an effect upon pedal feel.<\/figcaption><\/figure>\n

 <\/p>\n

\"This<\/a>
This is the floater ring that keeps both discs isolated. The floater ring eliminates the chattering of discs.<\/figcaption><\/figure>\n

 <\/p>\n

\"You<\/a>
You can see how the floater ring, complete with a clutch disc on either side bolts to the flywheel and in turn, the pressure plate bolts to it (on a pair of bosses machined into the floater ring).<\/figcaption><\/figure>\n

 <\/p>\n

 <\/p>\n

 <\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

Given the single disc \u201cold school\u201d clutch package we discussed in the past two sections, we have to keep in mind that technology has relentlessly marched forward. In most dedicated racing applications, clutches have shrunk dramatically in size.<\/p>\n<\/div>","protected":false},"author":20,"featured_media":5750,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[11,9,5012],"tags":[858,825,827,669,826,828,885,321],"class_list":["post-5748","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-how-tos","category-tech-tips","category-transmission-clutch","tag-clutch","tag-clutch-package","tag-flywheel","tag-mcleod-racing","tag-pressure-plate","tag-single-disc-clutch","tag-sure-plate-levers","tag-wayne-scraba"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2014\/05\/Clutch-12Feature.jpg","jetpack_shortlink":"https:\/\/wp.me\/p42YSK-1uI","jetpack_sharing_enabled":true,"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/posts\/5748","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/users\/20"}],"replies":[{"embeddable":true,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/comments?post=5748"}],"version-history":[{"count":6,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/posts\/5748\/revisions"}],"predecessor-version":[{"id":33229,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/posts\/5748\/revisions\/33229"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/media\/5750"}],"wp:attachment":[{"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/media?parent=5748"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/categories?post=5748"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/tags?post=5748"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}