formula 242 prop options
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formula 242 prop options
finally got the bugs worked out of my engine, now i'm doing some testing with my propping. its a mild 454 with about 400hp and alpha drive. i've got a 19p mirage (non-plus) on the boat now and i'm getting 4300rpms at 48mph max. i did have 4 people and about 3/4 tank of fuel, so it was a bit heavy, but i still would think it should be a bit better than that. even with just me on the boat, it still only turns 4300, but not sure of the speed. i find it odd that i can't turn the engine faster with a 19p. if i try to go up in rpms, i would have to go down to a 17p, which ive never heard of with people that run bbc's in larger boats. usually its more around a 21 or 23p. the only thing i can come up with is that the drive was swapped with another drive with a higher gear ratio (other than the 1.5:1 thats supposed to be in it). i have mild timing right now too at 8* initial with 24* tb4. at 32* total, i'm very conservative with the timing, but i still wouldn't think it would gain me 4-600 rpms or any significant speed by bumping up timing 4* or so. any ideas on what might be going on with this, or something i should test or try?
#2
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Your slip is only 7% with a 1.5gr so the prop is hooked up extremely well.
Other prop testing isn't really needed untill you figure why the engine won't pull more.
Brett
Other prop testing isn't really needed untill you figure why the engine won't pull more.
Brett
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Brett Anderson / BBLADES Professional Propellers
920-295-4435 http://www.bblades.com/
[email protected]
Brett Anderson / BBLADES Professional Propellers
920-295-4435 http://www.bblades.com/
[email protected]
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is there a way to check the drive gear ratio? the sticker vin number on the drive is long gone (mercruiser's stupidest idea ever....really....stickers?). is there a way to count teeth on the upper or something to figure out the ratio? i really am suspecting the drive is wrong, and its messing up my propping. the previous owner of this boat has hacked everything together thus far, so anything is possible. it "looked nice" and everything "functioned" and thats about it.....shame on me....i know....
would a higher ratio like a 1.65:1, 1.84:1, etc drive from another smaller engine produce the symptoms i'm seeing?
Last edited by hondahp4; 08-29-2011 at 09:56 PM.