JWT vs Southbend Clutch/flywheel set-up

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.

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09 Nismo #0483 sold. Viper or C7 next time around.

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?

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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

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.

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Ray
2009 370Z Base Sport 6MT / 12.860 @ 109.09mph / 1.921 60ft / street tires
official 1/4 mile track times

Zoren 370

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

wsarver

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

Do you feel the performance differences between the two?

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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

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?

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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

MJB

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

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09 Nismo #0483 sold. Viper or C7 next time around.

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.

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

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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

tranceformer

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.

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.

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Ray
2009 370Z Base Sport 6MT / 12.860 @ 109.09mph / 1.921 60ft / street tires
official 1/4 mile track times