JWT vs Southbend Clutch/flywheel set-up

forza370z · 01-21-2015, 11:12 AM

Quote:

Originally Posted by MacLean

When my stock CSC went out, I decided to replace the stock clutch and flywheel as well. I went with the JWT clutch and flywheel and the ZSpeed HD CSC. I agree with the previous posts on being able to go through the RPM's quicker and it was a noticeable difference, but there is more chatter noise while idling.

I did not know about this high spring load that will add extra force on the main thrust bearings. I appreciate the explanation about this. I was told and have heard to go with JWT over Southbend, but it really comes to personal preference.

BTW, how's your JWT holding up? How many miles on it? Any issue?

Joe@ZSpeed · 01-22-2015, 02:23 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

BC416 · 01-22-2015, 03:17 PM

Quote:

Originally Posted by Joe@ZSpeed

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

Great info Joe. Please don't bring up crank walk - my old 95 DSM doesn't appreciate it!

forza370z · 01-22-2015, 03:56 PM

Quote:

Originally Posted by Joe@ZSpeed

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

This is the answer I am looking for. Good reading! Thanks for chime in Joe!

MacLean · 01-23-2015, 09:38 AM

Quote:

Originally Posted by forza370z

I am in the same shoes as you were. CSC is on it's way out.

Decided to upgrade the clutch/FW as well. I just ordered Southbend stage 3 daily with the steel flywheel.

Sorry to hear that, but a smart move on replacing the clutch/flywheel as well. If the tranny is going to be dropped to replace the CSC, then you might as well kill two birds with one stone and upgrade the clutch/flywheel. It is well worth it.

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