Sorry Preston and Don - I've been off line for a few days.
Preston, - Seems like you are right - approx. 25k @ 10" if i did my calc's correctly.
I wasn't doubting that it ran that way or that it was that fast, (clearly it is that fast) - just went against my testing and my general thoughts on MAC's pipes.
I've run The MAC's 90 pipe that short on a K90 but found the Steve Muck 80 pipe more to my liking with that particular motor. Those Muck pipes love being set up very short. (boy they get thirsty for fuel like that!) Don't know how it would work on a CMB 90 but it made a noticable difference to the K motors. I run the Muck pipe on my K67 also. I've just started testing the "salisbury pipes" K90 proto and it is looking very promising so far. Broke the tub before I could get a true feeling for this pipe. :blink: :blink:
Most guys that know me are aware I like to shorten my pipes up a lot more than most and I spend loads of $$$ testing different pipes on each new boat. Some combinations of motors & pipes are useless when run short, and what works well on 1 motor does not always work on a different brand.
There are certain motors that have a mechanical limitation when revved very hard - an example that springs to mind is the Picco 67EXR's. Snapped cranks and rods was common and so utilising the torque was a cheaper / more reliable alternative. I switched from the Picco to the K67 for 1 reason only - I could run the pipe as short as I wanted without the fear of snapping a crankpin off the crank.
I still say the 3 piece crank design is not up to sustained high rev's on a SURFACE drive application. Seen too many twisted ones needing attention. Having said that - they are still a great engine and have many wins to their name to prove it.
40K = "the brown note"
Preston, - Seems like you are right - approx. 25k @ 10" if i did my calc's correctly.
I wasn't doubting that it ran that way or that it was that fast, (clearly it is that fast) - just went against my testing and my general thoughts on MAC's pipes.
I've run The MAC's 90 pipe that short on a K90 but found the Steve Muck 80 pipe more to my liking with that particular motor. Those Muck pipes love being set up very short. (boy they get thirsty for fuel like that!) Don't know how it would work on a CMB 90 but it made a noticable difference to the K motors. I run the Muck pipe on my K67 also. I've just started testing the "salisbury pipes" K90 proto and it is looking very promising so far. Broke the tub before I could get a true feeling for this pipe. :blink: :blink:
Most guys that know me are aware I like to shorten my pipes up a lot more than most and I spend loads of $$$ testing different pipes on each new boat. Some combinations of motors & pipes are useless when run short, and what works well on 1 motor does not always work on a different brand.
There are certain motors that have a mechanical limitation when revved very hard - an example that springs to mind is the Picco 67EXR's. Snapped cranks and rods was common and so utilising the torque was a cheaper / more reliable alternative. I switched from the Picco to the K67 for 1 reason only - I could run the pipe as short as I wanted without the fear of snapping a crankpin off the crank.
I still say the 3 piece crank design is not up to sustained high rev's on a SURFACE drive application. Seen too many twisted ones needing attention. Having said that - they are still a great engine and have many wins to their name to prove it.
40K = "the brown note"
