The Southbend Clutch INFO Thread

[snailD]

Ok so i noticed that Southbend had 3 different clutches for their stages and i was a bit confused so i made a call to John today and he gave me the low down.

The difference between the stages are mainly how much pressure is being forced from the pressure plate. The stage 2 is very similar to stock, very slightly stiffer in pedal feel and overall pressure. The stage 3 and 4 have a very similar pressure which is about 40% more than stock. John said that it is a very noticeable increase in pedal feel, however he doesn't believe its strong enough to really scare anyone away from it from all the feedback he has received.

The difference between the Daily, Endurance, and Drag is the friction material itself.

Daily: Made from organic materials and offers a very smooth engagement. has the least amount of tq capacity from the other 2 types.

Endurance: Either Kevlar or Ceramic depending on the stage. These are meant to handle heat a bit better while handling more tq from the Daily Clutch. John said if you were debating between the daily and endurance he would just recommend the endurance disc as there isn't a huge difference in engagement and you get a clutch that can take more abuse. The engagement is slightly more abrupt from the daily disc.

Drag: Do not buy this disc for dialy driving. This is a racing disc only and has a very abrupt engagement and will not be fun to drive often.

I personally asked what clutch he would recommend for 400wtq in a high mileage daily car that gets constantly abused on the street and the track. It was the Stage 3 Endurance Clutch. I will be purchasing this clutch in the next few days from @EdgeAutosport.com;.

He said the TQ ratings are "loosely" rated for the crank

Here is some copy and paste info from them.
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STAGE 2 DAILY:

Engineered for HP modifications. This Heavy Duty Pressure Plate has an increased clamp load with little or no increase in pedal pressure. The Organic disc material has a high metal content that increases the co-efficient of friction by two times over a stock lining and increases rotational strength up to a 12,000 RPM burst point. This clutch system maintains a stock feel while offering strength and durability.

Recommended usage is daily, street and moderate race.


STAGE 2 ENDURANCE:

An SFI approved single mass flywheel is recommended for this application to get optimal performance. This clutch system is designed for the racing climate. The pressure plate is precision balance for vibration free operation at high RPM. The pressure plate fulcrum is altered for a positive disengagement and a quick shift. The disc is engineered with a Dual Damped design to provide accurate control when accelerating through corners. The friction material is a hybrid using a full face Feramic (Sintered Iron) lining on the flywheel side and a high metal content Organic lining on the pressure plate side. Engagement is positive yet buffered due to the high graphite content unique to Feramic facings.

Recommended uses are daily and street with an emphasis on Rally and Endurance racing.


STAGE 2 DRAG:

Drag racing requires a Single Mass SFI approved Flywheel to be included with each kit when the original design is Dual Mass. This system features a Heavy Duty Pressure Plate modified for a puck style disc with no cushion between the linings to keep the clutch pedal travel short and quick. The puck design disc reduces rotational mass and total drive surface area while increasing pounds per square inch on the surface of the friction material. This combination minimizes inertia, accelerating the transfer of torque from the engine to the wheels. The friction material used for this race application is Graphite Impregnated Ceramic. This compound exceeded all other friction materials when testing for durability, reduced chatter, heat transfer and torque capacity.

Recommended uses are drag racing, drifting and limited street.


Flywheel Features

Flywheels manufactured by SBC are made from low carbon, hot rolled steel that is highly resistant to warping and perfectly suited for the friction materials mated to them. Single mount CNC machining guarantees precise tolerances and perfect balance exceeding O.E. specifications. Extensive field testing has been done to determine the proper weight for each specific vehicle and to ensure smooth operation, safety and durability under extreme operating conditions.

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STAGE 3 DAILY:

Recommended for single mass flywheel (SMF) when original design is DMF. This clutch package is designed for high HP vehicles desiring a start performance similar to O.E. The pressure plate is Race Engineered (SS) and SFI approved with significant load increase over stage 1,2 pressure plates (+600-800 lbs.). Expect a pedal effort increase of 20%-25%. Discs are assembled with heat-treated wear resistant hubs; drive plates and springs for high load transfer and dependable operation. The sprung centers on the disc in conjunction with the marcel fin between the linings create a dual dampening effect that simulates O.E. start performance. A Performance Organic friction material with a high metal content increases torque and RPM capability and maintains low operating temperatures which reduces wear and glazing.

Recommended usages are daily, spirited street and occasional track.


STAGE 3 ENDURANCE:

Recommended for single mass flywheel (SMF) when original design is DMF to achieve optimal performance. This kit uses the same Race Engineered SFI approved pressure plate as stage 3 daily package. The disc is designed for the special needs of a vehicle with circuit racing in mind. Kevlar friction material is used for its unique static to dynamic ratios of friction co-efficients at high energy levels. This translates to a perfect transition from one gear to the next. Discs are assembled with only performance components and equipped with torsion springs functioning as a damper between engine and gearbox.

Recommend usages are Rally, endurance race, clubsport, autocross, street and daily.


STAGE 3 DRAG:

Drag racing requires a Single Mass Steel Flywheel to be included with each kit when the original design is Dual Mass Flywheel. This clutch package is built to handle heavily modified cars and designed to function according to the specific needs of the 1/4 and 1/8 mile track. The pressure plate for this kit is SFI approved Race Cover engineered to disengage with less pedal travel shortening the shift time. Discs are a puck design, which reduces rotational mass and are assembled with all high carbon component pieces for maximum strength. The friction material used is Graphite impregnated Ceramic perfectly suited for drag racing because of its maximum friction co-efficient, rapid heat dissipation and abrupt engagement characteristics.

Recommended uses are drag, pulling, drifting.


Race Engineered Pressure Plates (SS) used in Stage 3 and 4 clutch kits:

These performance clutches deliver more transmittable torque and stability, longer life and superior thermal resistance. They also deliver noticeably better dynamics through higher clamp load when driving the vehicle to its limits.

Flywheel Features

Flywheels manufactured by SBC are made from low carbon, hot rolled steel that is highly resistant to warping and perfectly suited for the friction materials mated to them. Single mount CNC machining guarantees precise tolerances and perfect balance exceeding O.E. specifications. Extensive field testing has been done to determine the proper weight for each specific vehicle and to ensure smooth operation, safety and durability under extreme operating conditions.

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STAGE 4 EXTREME:

This is a "build to order" clutch kit intended for cars with HP modifications exceeding the stage 3 parameters. The Race Engineered pressure plate is modified for maximum plate load. The discs are puck design with sprung and un-sprung options. Friction material options include Sintered Iron and Graphite Impregnated Ceramic. Engagement characteristics can be abrupt. Hydraulic systems may need enhancing for proper clutch separation. Single mass steel SFI approved flywheels are required for safety. Torque ratings are calculated at time of ordering.


Race Engineered Pressure Plates (SS) used in Stage 3 and 4 clutch kits:

These performance clutches deliver more transmittable torque and stability, longer life and superior thermal resistance. They also deliver noticeably better dynamics through higher clamp load when driving the vehicle to its limits.

Flywheel Features

Flywheels manufactured by SBC are made from low carbon, hot rolled steel that is highly resistant to warping and perfectly suited for the friction materials mated to them. Single mount CNC machining guarantees precise tolerances and perfect balance exceeding O.E. specifications. Extensive field testing has been done to determine the proper weight for each specific vehicle and to ensure smooth operation, safety and durability under extreme operating conditions.

Clutch Break-in procedure per Southbend:

The purpose of “clutch break-in” is to get the friction disc to utilize the full friction surface area of the pads when pushed against the pressure plate and flywheel. This ensures that you have the maximum amount of friction possible which results in the clutch having the maximum holding capacity.
To ensure that the friction pads mate perfectly with the pressure plate and flywheel you must wear down the friction pads a very small amount (without over heating the clutch) so that you have full contact at the micro level . This is only achieved by using the clutch at normal driving RPMs. (1500-3000) The driver will have to engage the clutch many times at low RPM to properly achieve full contact, usually this takes 500-700 miles of “stop and go” or “around town” driving. Highway miles don’t count because you are not using the clutch if you are not shifting gears. Do not overheat the clutch by trying to over shift or over slip the clutch, this can cause extreme heat that will damage the clutch. High RPM shifting or launching will obviously create high heat and should be avoided during break-in. The best way to break in a clutch is to drive it normally and shift at normal RPM for the recommended 500-700 miles.

[cletusb]

Very helpful post, I had the Stage 3 Endurance Clutch in my cart at Edge so that confirms that is the clutch I want. Cheers

[Dano]

comparo from Dustin on OEM, CM and SB

southbend clutch speed6

[shaneski]

Excellent info @snailD, i had the stage 3 enduro clutch in mind a few weeks back since my OEM one is cooked.

[snailD]

awesome i was hoping this would help others decide and get rid of all the confusion. whoever gets these clutches it would we nice to see a review in here also. there were a few in the other thread but there is so much to weed through it will probably just be easier to post up in here for others

[shaneski]

Originally Posted by snailD awesome i was hoping this would help others decide and get rid of all the confusion. whoever gets these clutches it would we nice to see a review in here also. there were a few in the other thread but there is so much to weed through it will probably just be easier to post up in here for others

From what i heard from a guy i talk to he has had the CPE and the SPEC kits and is now on the Southbend stage 3 enduro and can't speak highly enough of the Southbend engagement smoothness compared to the other 2.

[jv83]

Would love to get a review for the genpu. Read so so reviews from other forums and such, but apparently they were done back in 2012 and the "OG design" and not the revised. Ill be needing a clutch soon and am leaning toward the stage 2 endurance.

[PapaSmurf]

I have decided and will be ordering the stage 4 extreme for my application, ill let everyone know how it is once I get the car back on the road.

[jv83]

have around 500 miles on my stage 2 endurance. Originally pedal was heavy but it is now back to stock feel, chatter is slowly decreasing. This break in period is killing me i wanna smash the pedal. Clutch is very responsive and feels great.

[IMASA]

Does anyone know how the stage 3 Endurance holds up for daily driving in stop and go traffic? I believe it is an 8-puck disc, which I think would wear faster than a organic disc.

Would I be better off with a Stage 2 Endurance or Stage 3 street if my concerns were clutch life in stop and go traffic?

[shaneski]

My stage 3 enduro arrived today will be a few weeks before install, here's a pic of the clutch plate..the metal bits are recessed they don't make contact.

[biggman026]

Originally Posted by IMASA Does anyone know how the stage 3 Endurance holds up for daily driving in stop and go traffic? I believe it is an 8-puck disc, which I think would wear faster than a organic disc. Would I be better off with a Stage 2 Endurance or Stage 3 street if my concerns were clutch life in stop and go traffic?

This is exactly my concern. You ever figure this out?

[shaneski]

Originally Posted by biggman026 This is exactly my concern. You ever figure this out?

My stage 3 enduro has done around 10,000 miles daily driven stop and start to work and back, dragged with hoosiers and interstate drives and copped plenty of abuse. It engages pretty much like OEM only with very slightly heavier pedal. Very happy with it.

[biggman026]

I bought a stage 3 enduro from Edge during their black Friday sale, will be getting it installed next week. Will check back here after I put some miles on it to give my impression.

[shaneski]

Around the first week or 2 the pedal feels very heavy and i thought WTF have i installed, but it comes good.

[Bob-o]

I have a stage 2 endurance w/ my setup in sig. Interested to see how she'll hold

[someguy]

Just got my Stage 3 Daily in, here's some pics for future reference:

[biggman026]

Originally Posted by shaneski Around the first week or 2 the pedal feels very heavy and i thought WTF have i installed, but it comes good.

Just got mine installed today, and that was literally the first thing I thought as well - "wtf, I'm doing leg presses!"

Haha, it isn't really all that stiff objectively though, just much more so than OEM. I've driven some trucks that had waaaay stiffer clutches. From everyone else's reviews, I expect that it will break in and some of the initial stiffness will disappear. Even now, however, the engagement is quite smooth and predictable. Much better feel than the OEM on/off switch.

Only have 30 miles on it so far, so I've still got 2-3 tanks of gas to go through before I can really test it out.

It does feel like it's engaging quite a bit lower than stock. Not at the floor per se, but probably half as far out as the OEM clutch used to engage.

[snailD]

Finally installed my Stage 3 Endurance i got from @EdgeAutosport.com; these past few days. Took her for a 40 mile cruise afterwards.

initial impressions: stiffer pedal than stock, but honestly not bad. i've felt an act 6 puck and this is much easier to push than that.

i've felt a brand new stock clutch from my old toyota celica gt and i remember that thing feeling wonky until it broke in. this thing feels nice right off the bat. Offers a really mellow engagement, very predictable. I'll update as i get some miles on it but very happy thus far

[littleloogy]

Awesome @snailD; I am looking forward to the updates. I have the same clutch sitting on my table in my garage, defiantly a quality piece.

Sent From a Galaxy, Far Far Away...

[biggman026]

Just an update. Finally put about 1000 miles on my stage 3 endurance over Christmas weekend, so first thing this morning on the way to work I filled up with E85 and flashed my fun map (been running the boring 93 map during the breakin period).

Pedal feel is now only 25-30% stiffer than stock. I actually prefer the way it feels now over OEM - less luxury, more performance. Engagement is very smooth, you can easily slip the clutch if you want to. Much easier to start from a stop than it was with the OEM clutch, no more light switch engagement. But, even though you can smoothly slip it if you want, it grips like a mother when it's engaged.

I did a couple 4th gear WOT runs and one 5th gear run on the way to work to see how it held torque, handled 383awtq like a champ (yeah, 5th gear WOT is a no-no, but I wanted to see what would happen at higher loads). No mushiness after back to back WOT runs. I haven't launched yet, but will prolly do so before the week is out.

[snailD]

Posting because i noticed a significant difference in how the clutch grabs at 150 miles now. You can tell its breaking in and really developing a good bite, reminds me when getting new brakes (i haven't had too many new clutches). Now if i pop the clutch it will grab hard and give the car a bit of a jerk, pedal still feels nice and consistent.

[shaneski]

They definitely do get more of a bite after break in period. Hows your flywheel chatter? Mine increased a fair bit compared to OEM, i am using 70 duro JBR tranny mount so that amplifies things.

[snailD]

Originally Posted by shaneski They definitely do get more of a bite after break in period. Hows your flywheel chatter? Mine increased a fair bit compared to OEM, i am using 70 duro JBR tranny mount so that amplifies things.

non existent, but I've been driving it pretty easy. I really don't notice anything negative except a little more noise on decel

[biggman026]

Originally Posted by snailD non existent, but I've been driving it pretty easy. I really don't notice anything negative except a little more noise on decel

Mine is the same, I haven't noticed any chatter whatsoever.

[shaneski]

Mine could be a shitty thrust bearing (it is new as well) with air con on it is loud as fuck..once clutch pedal is in zero noise.

[snailD]

Originally Posted by shaneski Mine could be a shitty thrust bearing (it is new as well) with air con on it is loud as fuck..once clutch pedal is in zero noise.

my throw out bearing has gotten much quieter since initial startup and is about as loud as it was stock, i now have about 350 miles on it. My TOB was new as well as the pilot bearing.

[spals]

Has everyone been torquing the flywheel to 87ft-lb per the instructions instead of the OEM spec of 115?

[someguy]

Are people just using what mazda supplies for grease on the bearings or do you add/replace the grease in them?

[snailD]

Originally Posted by spals Has everyone been torquing the flywheel to 87ft-lb per the instructions instead of the OEM spec of 115?

I honestly went in the middle lol

Originally Posted by someguy Are people just using what mazda supplies for grease on the bearings or do you add/replace the grease in them?

i left the grease on the TOB and Pilot, but i added a decent amount to the shaft it goes on

[spals]

Originally Posted by snailD I honestly went in the middle lol

I used the SBC spec of 87. Let's hope my flywheel doesn't decide it wants to meet with me in the cabin.

[Alpha]

Originally Posted by shaneski My stage 3 enduro has done around 10,000 miles daily driven stop and start to work and back, dragged with hoosiers and interstate drives and copped plenty of abuse. It engages pretty much like OEM only with very slightly heavier pedal. Very happy with it.

Same here in my MS6. It's a GREAT clutch and hasn't even had a hiccup. A nice firm pedal (Compared to stock) which I like, and just fine for light to light driving etc.

While I don't daily drive my car, I definitely could. SB FTW!

[Nel Mazdaspeed]

WARNING: WALL OF TEXT COMING..

So my initial thoughts when I got the clutch installed was "what the hell did I do! "
But after the brake-in 2 weeks, (1k miles).. Either I got used to it or it did feel a "Lil better".

The website says the pedal feels to be 25% heavier. . I say BS, as snailD mentioned in the OP, it's more like 40-50% heavier.

Today, (7mo. Later) the pedal is still rather heavy, but probably not as bad (or I'm used to it..lol) I had to change the Master and Slave Cylinders finally last week and I'm thinking more bleeding is needed :/

One thing I must add since I didn't notice others mention, is that these kits DO NOT come with a throw out bearing, so be prepared to dish out for that. I put in an exedy TOB since I've heard that they were quieter than others (I honestly can say otherwise).

I see a few others are staying that the pedal feel is "slightly" heavier than stock, I don't have that experience and am wondering why that is (would love to feel a local members STG3 with it installed after break in period to compare! )

This is my impressions and experience with my STG3 DD hope it helps some

[Nel Mazdaspeed]

Done at Rev works.. Got raped lol

[England15j]

I've had mine "STG3 Endurance" installed for about 3k so far and it's still just as heavy as day 1. I thought it had gotten better until I drove my buddy's mustang who has a very heavy clutch and it feels much lighter now that I've gotten use to my SB clutch. I think 40-50% heaver then stock is about right for this clutch.

[doctavus]

Originally Posted by Nel Mazdaspeed Done at Rev works.. Got raped lol

What happened?

[Spec]

Originally Posted by Nel Mazdaspeed WARNING: WALL OF TEXT COMING.. So my initial thoughts when I got the clutch installed was "what the hell did I do! " But after the brake-in 2 weeks, (1k miles).. Either I got used to it or it did feel a "Lil better". The website says the pedal feels to be 25% heavier. . I say BS, as snailD mentioned in the OP, it's more like 40-50% heavier. Today, (7mo. Later) the pedal is still rather heavy, but probably not as bad (or I'm used to it..lol) I had to change the Master and Slave Cylinders finally last week and I'm thinking more bleeding is needed :/ One thing I must add since I didn't notice others mention, is that these kits DO NOT come with a throw out bearing, so be prepared to dish out for that. I put in an exedy TOB since I've heard that they were quieter than others (I honestly can say otherwise). I see a few others are staying that the pedal feel is "slightly" heavier than stock, I don't have that experience and am wondering why that is (would love to feel a local members STG3 with it installed after break in period to compare! ) This is my impressions and experience with my STG3 DD hope it helps some

How many miles did you both have on your stock set up?

Originally Posted by England15j I've had mine "STG3 Endurance" installed for about 3k so far and it's still just as heavy as day 1. I thought it had gotten better until I drove my buddy's mustang who has a very heavy clutch and it feels much lighter now that I've gotten use to my SB clutch. I think 40-50% heaver then stock is about right for this clutch.

[England15j]

I had almost 40k when I did the swap

[shaneski]

Could be that it is us getting use to the clutch being heavier, would need to feel a stock one again to get an accurate feel, either way it feels great.
I'm getting an engine built so the clutch will be coming out to go on the new engine in a few weeks. Will be able to see what condition it is in after 15K miles

[Nel Mazdaspeed]

Originally Posted by Spec How many miles did you both have on your stock set up?

I had about 119k miles. . Finally started slipping in 3rd and 4th on wots or heavy pedal action.