31ss that runs 80+????
 

anyone got one????what did it take to get there? I'm running 74-75 on GPS....I'm going to have my prop's labbed soon...whats next????

80 +
 

Dyno,

There is a 31 Sonic that runs in South Haven.
80 + I think he has around 600 HP.
I'm sure Mark / Kaama knows him.

The fellow with the 80+ sonic runs with
Larry Hollenbeck with the 41 Sonic / 104Mph.

I think Larry moved into an Ocean Express.
Anyways talk to Kaama and see what he has to
say.

Cougarman

the black one???Thriller I think its called....

>
 

Dyno,

The fellow that built his engines is
somewhere between St.Joe and Grand Haven.
I would know his name if I heard it, and it's
not Bruce at Wolfie's compition engines.

This fellow does it more as a hobby, but
is supposively real good.

Running Hot used to run with these guys
to with an active thunder. I see it's
for sale in the back of Power boat.

Cougarman

Thriller???
 

Dyno,

Your really testing my memory. :)
For some reason I'm thinking Yellow?????

Cougarman

dont know who that engine guy would be...its not Gary Garvelink is it?I want to stay with pump gas and around 5500 rpms was wondering about Imco shorties.....next time around I'll go with stroker cranks 496 Ci.....

There is a '98 in our area with Merc 525 SC's and I believe it runs over 80 mph.

Yup, I've driven it. 89 on speedo, so 80-83 real mph. That was with B1 props, would be a little faster with Mirage Plus's. My boat picks up 2 mph with the mirages.

So Goforbroke whats it take to get a 31 to 80+????I have a 1993 that runs 74-75 but am looking for 80...I'm making 480-500 hp....

Thriller is Bruce Chapman's boat. It's mostly black with yellow stripe and silver "Thriller" letters. "Doctor" Dave Lorenz did the engine work. I'm not really sure how fast Thriller is, but he's had it for a long time, back from the Running Hot days. He doesn't run it that fast anymore since they recently had a baby that's with them, so he takes it easier till she gets a little older.

Doc Dave could tell you more, but he might fluff the top end speed. He always tells you low, then spanks you:)

You don't seem to be as fast as I would expect with that much power. I know the x dimension was raised in 97 or 98 so perhaps yours is a little low. What props do you run? Your money would be better spent on 3 blades than on labbing. My bravo 1's are labbed and I gained no speed. The shortie imcos would probably be my next step. Maybe 2", if thats too much you can always use spacers to lower them again. Actually before anything else you might want to have the bottem blueprinted to be sure thats straight. All the power in the world won't help if you have a hook.

So how fast would a 2003 31ss with twin 496 HO whipplecharged run......

Broke I'm running 23 mirage 3 blades now at 5100rpm...I emailed the factory and they said I would benifit from the shorties.....but how much who knows????

I'm waiting for Maxx to start cutting lowers for customers way cheaper than Imcos.....

Guys,

I've had/have several that run over 80. The new ones with 500's do it easy. As some may know I had one built with 575sci's. (Recently installed a set of superchillers as well). Still trying to get it dialed in but that biatch should run mid 90's. It's back at the factory now and if interested I can tell you what all we do with it.

I've tried the sportmaster 2" shorties and it blew out, added the spacer and for what ya' get it isn't worth it. On older hull designs maybe...but I'd try the props first. One thing though...that hull still handles well at those speeds.

Dano my boat is a 1993 so I dont think were compairing apples to apples have you ever worked with an older hull?I'm not going to buy a new boat to run 80.....I've emailed the factory and they told me the Imco shorties would be a good idea.......but were pretty vauge about gains.....I'm making almost 500 hp????any Ideas????

Dyno,

As far as drive height have it measured as is at trim against your hull and calculate the attack angle. Take your current set-up and calculate your prop slip %.

On a 93 model shortening the drive height will probably net some gain in FW applications if the cup of the prop is to low. If your pushing that amount of ponies (I assume at crank?) do you know the HP translation at the prop? The biggest help is going to come from the attack angle and the prop. That boat was set-up for SW ocean use not neccessarily to acheive maximum speed. On the older boats I did find 3 blade props delivered better top end speed. A lot of times when dialing in those last few MPH's it's a hit and miss thing (gets rather expensive). Feel free to contact me and I'll fill ya' in on some of the things we've done.

woe.........you lost me Dude!attack angle?could you walk me through the measurments?????and give me the formula for slip....

Dude...gimme a number I'll call ya.

Working now cant get to a phone .......leave me your number or PM it to me and I'll get in touch...I'll be home after 4:00 616-786-3829

dyno...i don't understand...your running 23's @5100@ 75mph...that's making water out the other side...even with 1.36's that's a very respectable loss of <10%....

GO4 if your prop was not labed for YOUR boat i see how that could happen...my guess is that metal was removed incorrectly for the weight, X-dem, and D-rise of your boat...resulting in unwanted blade flex for your application....thus what you made up in thinner more hydrodynamicly correct blade design you lost due to the real world conditions you put it in.

Dyno, I don;t get your numbers either. Unless you are running 1.36 gears..but even then that means only about 10% slip as Audacity said.

I have 98 31 ss with 454 mag mpi's, 26p. I calculate my slip at 13%. My top end is 68 at 4800 rpm's.

Dont know what to tell you guys I just put the hammer down and read the tach and the GPS.....

forward progress can only come if you have good data!

Dyno,

I have a 1990 with a pair of 640s running low to mid 90's on a perfect day. 85+ consistantly. It takes some choppy water to get her moving! When the boat leaves the water at high speeds you can feel it lunge forward. So lots of trim and 2-3' chop and she screams.

I am also confused. I don't know how you can see 74-75mph with 23 props.

Audacity- you're probably right, it was supposedly done for my boat, but it was cheap so I don't complain. At least they look good!
Dyno, see if you can try to get you hands on some 25 mirages and see what that does. Those 23's seem awfully small, have they been tweaked?

Goforbroke not as far as I know......they came on the boat...
Ken thanks for the info thats more the infomation I was looking for......guess I should learn to read a tach and a GPS......

dyno, if you happy with what you got then cool...but if you want more?,,, then you need to base line and take good data that is repeatable...i will be more than happy to set ya up on the right track...feel free to email or phone! take care...

Dyno, sounds like we need to take my Snap On timing light w/ built in digital tach and verify your tachs next spring. Mine was off by 600 rpm when I bought my boat and 300 off this summer again. What kind of gauges do you have? I don't know anything about slip or that stuff so if your gps is reading 75 sounds like either your tachs are off or your props have been changed from their stamping. Marysville in Grandville can measure your props for you.

Bill, dave and I were talking last night about asking to barrow your light.......well I'll call you in the spring.....The gauges are some cheap **** that came in the boat!

I'm not trying to be a smartbutt here, but if a GPS says 74 or 75mph is it wrong? Myabe his tacks or props are off, but from what I have always known about GPS's, they are known for their accuracy----at least that's what I have always thought!

who knows...the data does not add up. now you need the answer why it does not if you want to make changed to the boat.

well the Numbers arent that important to me........at least the attack angle,slip,....... whatever I'm no engineer or racer just some poor smuck who likes to go fast on the weekends!....the important one is the top speed and like I said its 74.? on gps if that # is accurate thats all thats imporatant to me. the goal is to get to 80+ I need to pick up about 5mph Ken gave me a pretty good Idea about how much HP it would take to get to where He's running (85+) very simular boats ,so I'm making a guess that without changing the X demension around 600 hp would get me close....But again I'd like to keep my combination as bullet proof as possible so If I can raise the X and gain a significant ammount speed thats something I should consider....so If anyone knows of an older Sonic that has raised the X with shorter lowers please let me know!!!
Don

"well the Numbers arent that important to me"...if you want to go faster that those numers are THE MOST important thing! if going fast with reliable power was that easy everyone would have a 93mph 30 foot plus boat with 500's in it!

OLD 1990 31' Sonic???????
 

Audacity,

I don't quite under stand what you mean
by making water out the otherside of the
prop. But I respectfully believe you
know allot more than allot of us
pleasure boaters.

Now to add to the confusion, I don't
understand why dyno isn't running faster
with the said power. I realize it takes
allot for a few mph, just seems he should
be faster.

A few years back I used to run a
1990 31' Sonic (OLD SONIC) :)
23 pitch Mirage aswell
74mph at 5200rpm on Sonic's Faria gauges.
I never had GPS so I figured 3mph to 4mph
slower.

My friend that I run with has a
36'ss Sonic with 468's that were
run on the dyno at 500hp.
Not sure of his prop size or pitch,
but they are mecury's and merury
labbed finished them for his set up.

The 36'ss runs a 25 degree deadrise
and I believe the 31' runs a 23 degree
deadrise with a pad. He uses gaffrigs
liquid filled speedo with a tattle tail.
Best speed ever recorded is 68mph at 5100rpm.

On calm Lake Michigan water I could run
by him with ease. Quite frankly pissed him
off. Nothing mind blowing, but a desent clip.

In 3 to 4 footer's we were dead even.
neither one of us could ever shake each
other. Just dead even running HARD.

I had a few ask me here or there if it was
ever worked over, answer is NO. For
365 magnums it ran well. So Old 31' or
new 31' I don't believe Sonic made new plugs.

They may have corrected there existing molds,
if there was anything to correct. I guess
Jay Ross would be the best one to ask.
X-dimension changed since 1990, I don't know
she ran pretty good with 365 magnums.

So Dyno, I don't know if any of this helps
or makes sence, But I feel you should be
running faster. I agree with Audacity
that if you want to do anything the numbers
are very important.

I didn't take the time to go back and re-read
these post. But Didn't Audacity offer to call
and help? Could Quite possibly be the best
Nickle ever spent. He has more exposer than
any of us on a daily basis. And how many
racers are willing to lend a hand.

Good luck with your project, Take your
time and spend your money Once.

Cougarman

ok brother...here we go...the numbers game...if you have X RPM going into a gear box...with a given gear ratio you can calculate a rpm out...every time...your prop,,,,lets say a 23 will pull(not push) 23" forward for every RPM . thus giving you a speed for X engine rpm,,,,but then you have to calculate losses...kinda like spin'n your tires....the math can never be so that the prop is pulling you forward 25" with the same given rpms...it like saying the engine has 500hp at the crank and 525 at the wheels...that would require out side forces or inccorect math...it's all math you know! as you know energy can not be created nor destroyed!

Cougar according to Jay at the factory the X is higher (about 2") on the Sonics that they are building now then when my boat was built.....the mold is the same.

Cougarman,

My 1990 30SS with stock power, 365s, ran 67 on GPS in 4' ers

Cougar that sound about right mine ran 64 with 330's....