Any dynos of with cat and cat removed? No other changes. Stock head pipe with cat and stock head pipe without. I searched and found some with other variations but nothing just with and without.

 

I would imagine pretty close to zero change, certainly nothing you can feel in "the seat of the pants"

 

I was of the understanding that the 114's at least (if not all M8's) do NOT have the CAT in the header but rather in the slip-ons. Read this on the Harley Tech Talk forum.

 

That is HD's optional high flow exhaust system. You go from having 1 cat in the stock head pipe to having one in each muffler, why anyone would spend the cash on this system is beyond me. I can't see how this would be an upgrade other than the heat of the cat being pushed back further.

 

The cat is in the headpipe, which is the same for both 114 and 107 engines. The system and pic you're deacribing is for the Screamin' Eagle Harley High Flow Exhaust with Street Cannon Mufflers - part number 64800059.

https://mstore.harley-davidson.com/s...annon-mufflers

To the OP, there have been several dyno runs showing little difference between a using the stock headpipe with cat vs a non cat headpipe on a basic stage1 configuration.

 

lol ...heat and warranty. And if one chooses the heapipe can be used, with a little welding, with non cat mufflers after the warranty has expired.

 

what about stage 2 and up?

 

I think Maxflo might have posted a dyno sheet in one of the threads. Pretty sure it showed no difference with cat in versus out.

 

All the tests I've read indicate just what others are saying. There is very minimal change in flow, the only difference seems to be in felt heat for rider comfort and nothing really for performance. The stock headpipe flows very well.

 

Removing it gave me a blatty hollow sound, probably gonna put another stock pipe with the cat back on.