13" conversion nv4500 question

Sabbath5.9

Sabbath5.9

Neato niceo airplane glue
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Jan 16, 2008
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Since I'm using a 1.375 input. Is there any real life difference between 12.25 and 13" clutches? I know it gives .75" more of grabbing area. But is their actual any need for 13"?
 
Depends on application and power levels. If you're using the truck for competition purposes or hauling with the truck yes. But if the truck is a daily driver probably not necessary.

If your upgrading the clutch for the bigger input, why not just go for the 13" any ways?

Just my $0.02.

The 13" clutch actually gives you a little more than 5 square inches of grabbing area over the 12.75" clutch.
 
I don't think you can get a 12.25" clutch with the 1.375" input. Stock, anything with the 1.375" input came with the 13".
 
Tate said:
I don't think you can get a 12.25" clutch with the 1.375" input. Stock, anything with the 1.375" input came with the 13".
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Yes you can just have to tell the clutch shop to build it that way
I have one in my 1 ton
 
If you already got the bigger input why not get the 13" too? Might as well make use of it...
 
not enoughsmoke said:
Yes you can just have to tell the clutch shop to build it that way
I have one in my 1 ton
Click to expand...

I guess the question would be, why go to a smaller, weaker clutch with the big input shaft? Seems like throwing money out the window intentionally.
 
I'm not sure the outside diameter of the clutch is directly related to the contact surface area. I know the 13" is reported to hold more HP, but I don't know that the entire 3/4" difference is contact area.

Why not do a dual disc organic?
 
Because I don't plan on going over 500hp and I don't do any towing. So I didn't see any need for a dual disc. And I also have the slightest clue on the hp/torque I have now
 
Tate said:
I guess the question would be, why go to a smaller, weaker clutch with the big input shaft? Seems like throwing money out the window intentionally.
Click to expand...

When I built my 96. Ton. I put upgraded input and upgraded main shaft and put a ceramic button clutch and stock pressure plate to beef up the trans cause I have seen stock inputs break on trucks stock
 
I have the dual drilled flywheel and have run both sizes. I never really noticed a difference between the two. the last clutch I got was from Valair. I was suggested to use the smaller one for the stiff pressure plate. IMO the larger one might have more surface are but the the pressure is spread out over that too. Where the same pressure on the smaller one would apply more force to hold IMO.
 
Sabbath5.9 said:
I'm saying I don't know what clutch I should get being I never dyno'd my truck and I plan on going more but not for a long time
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~350/800
If I were starting over I'd go with valair street dual 550hp. My southbend single is rated at 350/900 and my last dyno was 412/1018 with only pump mods, 3kgsk, #10 plate, he351 and contagious 5x12.
 
No, but I very rarely use all the pedal. I'm just saying buy more clutch than you need. I would have/ should have but dual discs were a bit more expensive 10 years ago. Valairs web site doesn't show any duals for 13" I would give them a call and discuss your options, I here customer service is impeccable.
 
They are awesome. I have talked to a couple by Dan is the one I have talked to the most. They always advised/suggested a clutch for what you have or are shooting for as far as power level/style of driving
 
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