cooltoys61

I finally got my old 29' (1990)Fever with rebuilt Vortec 454's,,450HP ea. up and running. Seems like the azzz want's to swap ends with hydromotive 4 blades if I only trim about 3 up from all the way in(it bottoms at 1.5 as is so that it reads 4.5). With the old 3 bld mirages's it was about right there. Anyway, I tried trimming 5 out from the bottom(6.5 reading) and it stabilized all the way to 78mph,,about 8 more mph than before. I think I could trim more and wait a few more seconds and hit 80,esp since it was glass smooth that day. What I need to know is, where do you guys trim with diff props,,and if you don't bottom at zero,adjust to reflect the diff. Also how do you like the speed and handling characteristics of Hydro's compared to Mirage(old style) Thanks,Throw in your your input.

jryan26

4.5 is where mine runs the best with hydros. I've never tried to trim any more than that with mirages, but if you gained 8mph I need to try it!

cooltoys61

I gained 8 from going from 365hp 454 mags to the roller Vortec. I just wonder where others are trimming with hydros and if they experience this light stern ,"bow steer?", squirrely, end swapping feeling that I felt at high 60's ,low 70's when only trimming about 3 up? Also wonder if more trim might be even better but where does it start to hurt the u-joints?

jryan26

Are you talking about chine walk?

jryan26

Have you tried a little bit of tab?

cooltoys61

Not chine walk. Feels like the back end is drifting slightly left and right. It did some better with some tab but did even better with no tab and much more trim. I guess it's lifting the back to the point where the front is starting to steer the boat,,more trim pushes the back down some and the front up some.

Jonas

are you spinnin props in or out? when testing trim untill it loses speed and then u know where it works best
my non step liked out... my twins step now likes in.. ?? why i dnt know.

cooltoys61

I'm spinnin' out. Yeah, I plan on trimming more next time and let it run for a min. or 2. I blew 2 mtrs this summer and am a little skiddish but I'm pretty sure it was just the Fram P5's that starved the oil at high RPMs. Anybody else with a twin 29' Fever that can tell me how far works best for them and mainly if sig. diff. in trimming hydros compared to mirages. I know I could just (and will) play with mine but it's crappy outside and I can bench race for now.

Lofty

Cooltoys, I have the same hull with similar power. I ran the 4 blades for a long time but they don't work as well as the Mirages. Plus the drives (TRS's) are so deep the 4 blades get too much bite and tear up the drives. I never had any problem with that boat bow steering. In fact it handles well even when I do things with it that I shouldn't. It's a forgiving hull. What RPM are you turning at WOT, 5300? Higher?

cooltoys61

My hydros are 29"s so I can only spin them to 4600 or maybe a little more with some more trim. That gives me about 78mph and still creeping
up a little. My mirage's are 27" and the boat did like them but the cruise speed diff with the hydros is huge and planes very well so I'm trying to learn what they need. I guess I have answered my own question because when I trim out more it kicks the back down and the front up and was stable at 78. Also the 3 blades did exhibit some of this same behavior but not as pronounced.