Smarty jr. How is their HP rated?

[Motorhead]

I run a Smarty jr on my 2007, 5.9. I run it on the 70 hp setting.
Did Smarty measure HP at the rear wheels or at the crankshaft?
What about South Bend Clutch, Clutch rated for RWHP or crankshaft?

 

[Regcabguy]

Smarty and SBC are rated at the rear wheels to my knowledge.
Hi Chris!

 

[petersonj]

Not absolutely certain about this, but I have always understood that clutches and transmissions are rated for input torque and horsepower - that would be from the flywheel.

- John

 

[Ozymandias]

Rear wheel, had mine on the dyno with the Smarty in all three settings

 

[Regcabguy]

Rear wheel, had mine on the dyno with the Smarty in all three settings

That signature indicates a well thought out truck.

 

[Ozymandias]

That signature indicates a well thought out truck.

Thank you Sir, much appreciated.

 

[AH64ID]

Rear wheel, had mine on the dyno with the Smarty in all three settings

Yes, it’s all rear wheel gains for Smarty.

I dyno’d my SJR for Marco a couple times back when the SJR was fresh on the market.

As for the clutch I would call and ask SBC how they rate them. I always understood it to be flywheel power, but this article indicates it’s rwhp.

https://www.southbendclutch.com/resources/choosing-a-clutch/

 

[Hammer]

Both The Smarty and the SBC are rated at RWHP....

 

[Motorhead]

So the rating of 325 HP and 650 torque from the MFGR is RWHP or crank hp.
I am trying to get a clutch combo that is just right for my hp. I had a recent knee replacement on my LEFT knee and the clutch is a little too stiff for me now. I run a SmartyJr on the 70 HP setting

 

[Regcabguy]

You might have to go with a dual disc. I understand with the additional disc the pressure plate can be made softer. My SBC OKHD is more effort than my stocker.

 

[AH64ID]

325/610 (05-07 5.9) is flywheel power.

Call and talk to SBC. I’m not aware of any clutches with as soft of a pedal as the stock one. The SBC I’ve driven are more, as are the Valair DD’s.

 

[Motorhead]

Rear wheel, had mine on the dyno with the Smarty in all three settings

Ozy, Did you happen to write down those numbers??

 

[Motorhead]

325/610 (05-07 5.9) is flywheel power.

Call and talk to SBC. I’m not aware of any clutches with as soft of a pedal as the stock one. The SBC I’ve driven are more, as are the Valair DD’s.

I don't expect stock feel. A guy named Logan at SBC, said they have a PP that has better/different leverage. I have to call him and find out more info. The clutch that is in my truck works fine and performs as new. Just the "Operator" is getting older. My Left knee replacement was a disaster. The Dr was into the knee 5 times because it got infected. That's another story...
I was thinking of the 3250 PP and single disc. I'm ready to de-tune my truck to get a softer clutch.

 

[Ozymandias]

Ozy, Did you happen to write down those numbers??

Somewhere I've the print outs. Would have to search my files for it..

 

[jgillott]

I don't expect stock feel. A guy named Logan at SBC, said they have a PP that has better/different leverage. I have to call him and find out more info. The clutch that is in my truck works fine and performs as new. Just the "Operator" is getting older. My Left knee replacement was a disaster. The Dr was into the knee 5 times because it got infected. That's another story...
I was thinking of the 3250 PP and single disc. I'm ready to de-tune my truck to get a softer clutch.

I have the South Bend G56-OK-HD in combination with a Smarty Jr. In my opinion, the clutch has a great daily driver feel, tows excellent, and hold the Smarty Jr power perfectly.

 

[jgillott]

You might have to go with a dual disc. I understand with the additional disc the pressure plate can be made softer. My SBC OKHD is more effort than my stocker.

Are you using the South Bend hydraulics? I haven't noticed any additional pedal effort with my OK-HD with the South Bend hydraulics over my factory clutch.

 

[Motorhead]

I have the South Bend G56-OK-HD in combination with a Smarty Jr. In my opinion, the clutch has a great daily driver feel, tows excellent, and hold the Smarty Jr power perfectly.

That's the same clutch I have. I am either getting weak or the pressure plate is getting hard.

 

[AH64ID]

Ozy, Did you happen to write down those numbers??

I bet there is an old thread of my numbers somewhere. I have the printouts somewhere…

Found these numbers from my 05

All uncorrected, at 2700' and 95* ambient air temp.
Stock: 284/519
SW1 TM4 TQ2: 296/610
SW1 TM2 TQ2: 290/591
SW3 TM4 TQ2: 382/703
SW3 TM2 TQ2: 383/708

No SW2 because that was when SW2 and SW3 were putting the same power down, which is why I was dyno testing for Marco.

 

[jgillott]

That's the same clutch I have. I am either getting weak or the pressure plate is getting hard.

Interesting. How many miles on the clutch? Any other symptoms.

 

[Regcabguy]

Are you using the South Bend hydraulics? I haven't noticed any additional pedal effort with my OK-HD with the South Bend hydraulics over my factory clutch.

Well I felt my buddy's G-56 clutch. The effort is less and that trans is silent. We get used to the increased effort. it's not substantial but it is increased with the additional clamping power.