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This new prop really hooks up hard. Last time 94mph was at 7100rpm which was 13% slip. This prop ran almost the same at 8%. I could probably come up a 1/4" and run 95 right now but Im going to talk to Tim at Performance first. He wanted to cut the blade area down but leave the diameter to reduce the crabbing and tail lift.Quote:
Originally Posted by baja200merk
Slip is a theoretical number.... The new prop is a closer to 34 or your tach is off. The numbers hammered on the side of the prop do not tell the whole story :D
Either way that boat is very efficient, 99% of 200hp tunnels have trouble going that fast at that RPM with a 1.87. Doing it with a 2:1 is proof that thing is dialed in.
I had the prop checked by Rich Junker before I ran it. Its a 32 but it has very little progression. Most 32's are 30 at the leading edge, 32 in the middle, and 34 at trailing edge. He said this one is closer to 32 throughout the blade. Thats usually is fast and very efficient with poor holesshot which is exactly how it ran.
Little video of Dago strolling by today cruising across the harbor. I was probably only running about 60. I swear the motor sounds different with each prop I run. A lot of the unique sound of his thing is the prop. Kind of a howl and it seems to change pitch with ..... pitch! :D
https://www.youtube.com/watch?v=irUV...ature=youtu.be
So your saying your tach is on the fritz and the prop will not lay flat on a 32p block
Im saying 93mph was pretty damn fast.....but I really want that 95 :cool:
#timefora34or1.86 :DQuote:
Originally Posted by Mr. Demeanor
Would have to change gears and I might have them here. I tried a 34. Wayyy to much pitch and it didnt like it. Tried to paddle wheel that back of the boat around to the front at 90+
95 is half way through, should just be rounded up to say 100.Quote:
Originally Posted by Mr. Demeanor
Well for next year then:rolleyes:
Anyone know what the stock 115/130 compression numbers were? I know the 115 had the goofy head with different compression top and bottom. I took .050 off a stock set of 115 heads and need to take a little more to get my numbers back up. I still have .070 of squish and need about 10-15 more psi.
I want to say my stock 130 had 130+ psi which seems high but googling it I get similar numbers.
Finally tried something I have been meaning to do.
Made a wide open pass with my slow prop at 85.1. That prop always run 85 and never faster.
Took off the velocity stacks and it went 86.5.
Ray had told me to try without and I keep meaning to do it but just never did. This was back to back same load, water, weather etc.
That should get me 95+ with the big prop.
For sale: One set of Kottman velocity stacks :D
Mr. D Any idea why she runs faster without the v-stacks? Gary
Chris, can you determine how close the stacks are to the cowl? Do you have at least 1½"
Plenty of room but could be a number of things. My carbs are modified quite a bit with a "smooth bore" that is almost like a VS so maybe it was like a really long VS. I had rounded the edges of the carbs themselves when I modded them and then Ray sent me the stacks so I bolted them up. I knew there might be a slight difference but it was pretty big.
You just never know what a motor will like.
It felt better from idle up but its hard to tell seat of the pants.