How much HP will the stock 6 speed stick trans hold up to.

 

Couldn't find the forum thread that discusses max HP (as a side issue), but here are two good points

The Crossfire N/A is the highest horsepower Chrysler to use this six-speed manual (NSG-370), although it's used in the Jeep Wrangler and Liberty with 4.0 litre V-6 with more torque. The torque limit is 272 foot/lbs. More here.

Gotbroken lists the 2004 SLK 350 (which puts out 272 horses) being paired with a standard six speed transmission (no indication whether it's the NSG-370). I would probably go to 300 myself but no further. Even then. I would beef up the clutch as far as it would go, get the best fluid possible and pull fluid samples for testing by a reliable lab frequently. Also, limit the bad boy action as much as feasible

 

As far as the clutch goes SPEC told me they could custom make me a stage 2 + clutch off the slk32o specs for agound $850. Just somthing to think about if you have not upgaded your clutch yet..

 

spec already has an application for crossfires in their catalog

and they start at 1200, which is rape for a single disc oem replacement.

and spec makes shitty clutches to begin with


no one knows the torque limit of the 6 speeds, no one has gotten there yet

 

How much can the auto trans in the limited hold???