hunster

500 efi's xr and herrings. 86 all day long

upstate31sonic

Thanks for your honesty!! Now I do not feel so bad!!
Interesting that you are running 30's..My ride came with 28's from the factory and I tried to have them worked from that point..Maybe we should have tried some 30's

FuelinAround

Dyno, I find it a little ironic that they are saying your numbers don't add up... I have a 1989 sonic 30.5ss... Been talking go bblades crew and they keep saying that my gear ratio-prop-slip ratios don't make sense. I have stock 454's 330s, 1.5 gear ratio on bravos and bravo 1 props. I gps at 62 mph running 4600 rpm. I don't know what to say other than my numbers are consistent. I am replacing both tachs this winter to make sure my rpms are reading correctly. I was also told that sonics are supposed to have a 1/8in hook in the bottom and it seems this thread is suggesting to get rid of that. My biggest complaint has been pourposing issues. Any trim at all begins to cause a porpoise in my boat and I almost wonder if it's under powered or underpropped not allowing enough stern lift or forward inertia to stay out of the porpoise. I would be interested to see what all you find out.

Plum_Crazy

Bruce at Sonic instructed me NOT to remove the 1/8" hook as it's designed in to stop porpoising. I think your problem would get worse.

Have you checked your drive toe? With your power and spinning outward, you should be running close to parallel or maybe toed-out \ / about 1/16".

FuelinAround

Not sure how to check my drive toe....

Plum_Crazy

Measure between prop shaft centers and measure between the nose cone centers. They should be the same or, for toe out, the nose cones would be about 1/16 to 1/8" further apart.

FuelinAround

I will check tomorrow! Wasn't trying to jack the thread just wanted to start some informative old sonic discussion

im MartinB

I'm removing my hook this week. It's 3/16" and its fairly consistent from strake to strake. Time to make about 3 pounds of dust. Porpoising only happens at lower speeds and if you want to go slow then simply run a little tab.... These boats don't porpoise above 60mph unless you've run the trim way too high way too soon... But that mean someone had jumped the gun and we all know that never happens.

im MartinB

I've noticed I don't loose much speed until it gets super hot AND humid. Ran several times this year when it was almost 90 and was still with in 1 MPH of my record speed. And I'm carbs.

im MartinB

I removed the hook from outside strake to outside strake including the tail ends of the lower strakes. Did not affect porpoising at all, and boat require 5 trim now to get free instead of 7. BUT.... all that work and I gained about 1mph so it's not worth it and I would not do it again for sure. 1996