JWT vs Southbend Clutch/flywheel set-up

forza370z · 01-03-2015, 11:22 AM

Quote:

Originally Posted by MJB

I've had both the JWT and Southbend stage 2 setup. They both pretty much felt the same, and drivability is pretty much just like stock. The only time I could really tell I had an aftermarket clutch was when I would power shift or dump the clutch, it grabbed a lot harder than the stock setup. I also had the Southbend lightened flywheel. It was 22lbs (stock is 31lbs).. it was a little noisy when sitting at idle, but while you're driving you won't be able to hear it. Plus it revs up so much faster than the stock crap.

Great info as always.

Do you know how heavy is the JWT flywheel? Is it aluminum or steel? Also are both JWT and Sounthbent stage 2 kit can hold similar amount of power?

tranceformer · 01-06-2015, 10:35 PM

Quote:

Originally Posted by forza370z

Great info as always.

Do you know how heavy is the JWT flywheel? Is it aluminum or steel? Also are both JWT and Sounthbent stage 2 kit can hold similar amount of power?

I've had the JWT aluminum flywheel, it's about 16 lb.

Now I have the Southbend steel flywheel, iirc that one is about 21 lb.

Zoren 370 · 01-06-2015, 10:54 PM

^ which one do you like most? The JWT or the southbend?
Why the switch to a light weight to a 21lbs?

wsarver · 01-07-2015, 07:45 AM

Quote:

Originally Posted by Zoren 370

^ which one do you like most? The JWT or the southbend?
Why the switch to a light weight to a 21lbs?

I'd be willing to bet its chatter. Going to something heavier has no performance benefit so I'm assuming its to quiet things down a little.

forza370z · 01-07-2015, 08:23 AM

Quote:

Originally Posted by tranceformer

I've had the JWT aluminum flywheel, it's about 16 lb.

Now I have the Southbend steel flywheel, iirc that one is about 21 lb.

Do you feel the performance differences between the two?

forza370z · 01-07-2015, 08:28 AM

Also for you guys have JWT or Southbend for years, do you have thrust bearing issue or did you guys bypass the clutch start switch as you will dry start the bearing?

MJB · 01-07-2015, 03:55 PM

Quote:

Originally Posted by forza370z

Also for you guys have JWT or Southbend for years, do you have thrust bearing issue or did you guys bypass the clutch start switch as you will dry start the bearing?

To be honest bro... I have no idea what the hell you are saying.. lol

thangcu35 · 01-07-2015, 10:01 PM

Quote:

Originally Posted by MJB

To be honest bro... I have no idea what the hell you are saying.. lol

Usually with upgraded pressure plate, there will be increased load/wear on the thrust washers in the crankshaft during the initial crank/start up because there is little oil to lubricate the washers before pressure gets a chance to build up. When thrust washers get worn out, crank walk will result. A lot of people bypass the clutch start switch when running high tq capacity clutch setup so that there is no load on the thrust washers during cranking.

Zoren 370 · 01-07-2015, 10:23 PM

^ how to bypass the clutch start switch? Whats a crank walk?

MJB · 01-07-2015, 10:57 PM

Quote:

Originally Posted by thangcu35

Usually with upgraded pressure plate, there will be increased load/wear on the thrust washers in the crankshaft during the initial crank/start up because there is little oil to lubricate the washers before pressure gets a chance to build up. When thrust washers get worn out, crank walk will result. A lot of people bypass the clutch start switch when running high tq capacity clutch setup so that there is no load on the thrust washers during cranking.

Lol... wow, that sounds really scientific for a clutch install. I've never heard anything like that before.

Joe@ZSpeed · 01-22-2015, 01:23 PM

Quote:

Originally Posted by thangcu35

Usually with upgraded pressure plate, there will be increased load/wear on the thrust washers in the crankshaft during the initial crank/start up because there is little oil to lubricate the washers before pressure gets a chance to build up. When thrust washers get worn out, crank walk will result. A lot of people bypass the clutch start switch when running high tq capacity clutch setup so that there is no load on the thrust washers during cranking.

Crank walk has never been an issue with the VQ or the older VG engines, ANY Aftermarket clutch available Z1, Southbend or JWT for the 370Z is going to be almost identical in the terms of added force it takes to release it.
We have installed them all and they all have almost identical pedal feels.

Back in the old days with really heavy poorly designed pressure plates, not nearly as good engine oils or if you owned a mitsubishi

crank walk was an issue, With the newer clutch designs and better clutch materials, better oiling systems and the great oils we have today its not an issue. Also with todays clutch designs, better clutch materials we can hold the power with less clamping force and with better designed pressure plates the "Bearing Load" is not nearly as high. Pedal effort is directly related to how much pressure your are putting on the thrust bearings and what load the crank is seeing.

You can't increase clamp load without increasing pedal effort and keep the release of the clutch the same, It's a lever, if you move the pivot point in the pressure plate to increase clamping force it has to change, no other way around it.
The Southbend Stage 1, 2 or Stage 3 are designed to have the lightest force needed to get full clutch release for the given amount of clamping force. And all the Southbend stages have about the same "Bearing Load"

How is that accomplished you may ask?

Stage 1 and 2 kits have the same clamping force, These kits feature a full marcel disk (marcel is what gives the clutch disk "Squish" which directly relates to how long your engagement window is at the pedal and also smooths engagement) which requires the plate to lift higher to fully release the clutch but since the clamping force is only about 20% more than stock it doesn't add much force needed to release the clutch fully.

Stage 3 kits feature a clamping force of about 50-60% or about 1,000lbs more clamping force than stock, Stage 3 kits either have no marcel or a modfied performance marcel (depnding on model) that does not need to have as much "lift" on the pressure plate to allow full clutch release so we can adjust the fulcrum point to lift the plate less, retain a high clamping force and still have a decently light pedal effort or "bearing load"

Clamping force is not what it takes to push the clutch in (common misconception) it is simply how much force is applied to the disk.

Is it a bad idea idea to bypass the clutch switch? No, it can only help with bearing wear, but for gods sake don't forget you did it and drive your car through the house

forza370z · 01-07-2015, 11:53 PM

Quote:

Originally Posted by MJB

To be honest bro... I have no idea what the hell you are saying.. lol

Sorry I didn't explain this well... Lol. So basically most aftermarket clutches have high spring load that will add extra force on the main thrust bearings when you depress the clutch and cause premature main thrust bearing wear. If the thrust bearings wear out it will cause the "Crank Walk" and eventually engine failure. This won't happen immediately but after 30k-40k driving. My friend's 350 had this issue. He had to rebuild the engine. My mechanic friend who worked on vqs for 12 years told me bypass the clutch start switch is a must for those clutches(that includes the JWT). However, while I am doing researches I found Z1 pointed this out and claimed their clutch has the low spring load while still keeping the high clamping force which looks pretty promising to me. That's why I want to ask you guys that have JWT or Southbend clutches on your car for a while has encountered anything like that.

Here is the quote from Z1:

The pressure plate in this kit exceeds OEM specifications and features high clamping force while maintaining a low spring load. A low spring load eases lateral force on the main thrust bearings in your engine which is especially important during "dry" start-up. (High pressure plate spring loads result in high lateral forces being exerted on the crank when the pedal is depressed and the clutch is disengaged which can cause premature thrust bearing failure resulting in "crank walk" and ultimately engine failure).

Z1 370Z / G37 Clutch and Flywheel Combo

Nick Servin · 01-08-2015, 01:09 AM

Quote:

Originally Posted by forza370z

Sorry I didn't explain this well... Lol. So basically most aftermarket clutches have high spring load that will add extra force on the main thrust bearings when you depress the clutch and cause premature main thrust bearing wear. If the thrust bearings wear out it will cause the "Crank Walk" and eventually engine failure. This won't happen immediately but after 30k-40k driving. My friend's 350 had this issue. He had to rebuild the engine. My mechanic friend who worked on vqs for 12 years told me bypass the clutch start switch is a must for those clutches(that includes the JWT). However, while I am doing researches I found Z1 pointed this out and claimed their clutch has the low spring load while still keeping the high clamping force which looks pretty promising to me. That's why I want to ask you guys that have JWT or Southbend clutches on your car for a while has encountered anything like that.

Here is the quote from Z1:

The pressure plate in this kit exceeds OEM specifications and features high clamping force while maintaining a low spring load. A low spring load eases lateral force on the main thrust bearings in your engine which is especially important during "dry" start-up. (High pressure plate spring loads result in high lateral forces being exerted on the crank when the pedal is depressed and the clutch is disengaged which can cause premature thrust bearing failure resulting in "crank walk" and ultimately engine failure).

Z1 370Z / G37 Clutch and Flywheel Combo

I got a JWT Clutch and flywheel.Love it performance wise but not the chatter sounds like im running on no oil.Plus my CMC is going out

tranceformer · 01-07-2015, 08:43 PM

Quote:

Originally Posted by Zoren 370

^ which one do you like most? The JWT or the southbend?
Why the switch to a light weight to a 21lbs?

I had the JWT flywheel with a stock clutch for about 20k miles then swapped out for a Clutchmasters stage 1. After another 30k miles I broke a flywheel bolt and the head beat up the flywheel + clutch. It sounded HORRIBLE hearing that little bolt head bouncing around.

When I ordered the southbend flywheel +clutch I wasn't sure what broke yet so I just went with a different brand clutch and more durable steel flywheel.

Southbend flywheel is a bit quieter but to be honest the noise from the JWT never bothered me.

Quote:

Originally Posted by forza370z

Do you feel the performance differences between the two?

Slight difference I guess but I hardly drive it much lately (weekend fun car) and no matter what I do, it always feels like a rocket ship compared to my daily driver.

I hope this helps.

01-07-2015, 08:28 AM	#6 (permalink)
forza370z A True Z Fanatic Join Date: Oct 2011 Location: 403 Forbidden Posts: 2,512 Drives: 2009 NISMO 370Z Rep Power: 19	Also for you guys have JWT or Southbend for years, do you have thrust bearing issue or did you guys bypass the clutch start switch as you will dry start the bearing? __________________ 09 PW 370z Nismo \| K&N Drop Ins \| HKS Hi Power \| Berk HFCs \| Work Meister S1 3P \| Project Kics R40 Neo Chrome Lug Nuts \| KW V1 \| SPC rear camber arms/toe bolts \| Southbend Stage 3 daily clutch \| Southband 19Ib Steel Flywheel \| ZSpeed CSC

01-07-2015, 10:23 PM	#9 (permalink)
Zoren 370 A True Z Fanatic Join Date: Mar 2012 Location: FL Posts: 11,018 Drives: 11 Nissan 370 M6 Rep Power: 1913654	^ how to bypass the clutch start switch? Whats a crank walk? Last edited by Zoren 370; 01-07-2015 at 10:27 PM.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
♦ Southbend Clutch/Flywheel Combos + Free Bonus Parts, $1 Shipping, NO CHATTER!! ♦	Coz@Czp	Drivetrain/Engine	20	05-25-2018 10:27 AM
Don't Be A Victim of No Clutch November - Rev Works SouthBend Clutch Specials	Marti	Drivetrain/Engine	36	12-31-2013 11:48 AM
[FOR SALE] Southbend DXD SS Feramic Stage 5 x series Clutch $400	Bernie (NoVA)	Parts for sale (Private Classifieds)	0	10-26-2012 01:55 PM
[FOR SALE] [NEW] Southbend Clutch (500tq)	Synack	Parts for sale (Private Classifieds)	11	05-15-2012 08:41 PM
[FOR SALE] SouthBend Stage 2 Clutch	Staples	Parts for sale (Private Classifieds)	3	03-11-2012 02:11 PM

01-06-2015, 10:54 PM	#3 (permalink)
Zoren 370 A True Z Fanatic Join Date: Mar 2012 Location: FL Posts: 11,018 Drives: 11 Nissan 370 M6 Rep Power: 1913654	^ which one do you like most? The JWT or the southbend? Why the switch to a light weight to a 21lbs?