Average speed in mid/late 80's Sunsport

[bmtsupra]

I did a search of the forum for "sunsport average speed" and didn't get an results, so....Wondering what the average running speed is for Sunsports from the mid-late 80's. 351w, 1:1 trans and 13x13 prop? Is the 3-blade 13x13 prop the factory size for that time frame? My friend has an 1986 Sunsport and tops out around 30-33mph. If the river is glass, he can sometimes get 35mph out of her. Only time he runs that speed is when we're going from sandbar to sandbar.Since his is the only Sunsport on the river (until mine finally gets on the water :)) we've been assuming that is about the average speed for this model and year Supra.

[cadunkle]

I would expect more like 40-45 top speed. There boats were presumably made for slalom skiers (granted, the casual type in a larger open bow) Means you should not have to go WOT to do 36 MPH. If you haven't already, check speed with GPS and see what RPM you're at. If you're below 4400-4800 RPM you have a problem. Likely issues may be carb, timing, or too much prop pitch. I don't own a Sunsport and have never been in one, but I would not expect such a slow top speed from an inboard unless it's set up strictly for wakeboarding and riding heavy. 13x13 sounds about like factory prop.

[michael hunter]

My 89 Sunsport 351 1.23 to1 trans tops out at 41mph maybe 42 on a good day . The only thing that speed is good for is bare footing?

[Jetlink]

And outrunning a storm a time or two.That and getting back in time for dinner and brews.

[kvand347]

"My '93 Sunsport goes 42-43mph w/ 351w 1:23 trans 13x13 OJ Legend Prop."

CORRECTION: Had it out last night and speedo read 45mph @ 4800rpms. Would have to take a gps to verify if speedo is on, though!

[DAFF]

My Comp and Sunsport both ran 42MPH. But not for very long. Its a GPH thing.

[Jetlink]

My comp will run out at 44MPH on the water if needed and 70 on the highway...:D

[86 century]

Bravura 351w 1.23-1 dont know on the prop 4600rpm at 43mph with 2.5 people on crap water.

[jet]

With my new 5-blade prop..I know I can get 13 mph out of her!

http://www.youtube.com/watch?v=57p2uOK4g6Q

[bmtsupra]

And outrunning a storm a time or two.

ngavba, does your RIDER top out around 40mph?

[bmtsupra]

17-23mph is what he usually runs depending on if we're wakeskating or wakeboarding. Was just wondering about the top speed on a set up like his. Looks like we'll be looking into some carb and timing adjustment.

[bmtsupra]

With my new 5-blade prop..I know I can get 13 mph out of her!

http://www.youtube.com/watch?v=57p2uOK4g6Q

LMFAO...Ya know JET, just when I think you couldn't possibly post anything better you go and do this, and TOTALLY REDEEM YOURSELF!!! That was a perfect time to add that vid in JET.

[jet]

LMAO, yours was pretty good too! lol. Its friday!!

[mapleleaf]

Mr. Hunter is right about a 41 mph topspeed being good for mainly barefooting....when my Conbrio's at WOT +/-40 mph all I can think is how great it sounds and how much fun it is to drive!!!!

[jet]

maple, is your boat still apart??

[mapleleaf]

not at all, just stuck behind my toyota dealers last delivery......

[kvand347]

I edited my reply...had the boat out yesterday and went 45mph @ 4800rpm's.

[TitanTn]

not at all, just stuck behind my toyota dealers last delivery......

Are you saying you got a new truck?

[mapleleaf]

used '08, and i keep the Conbrio over there....He needs to sell some friggin Corrolla's soon, gotta get the old girl out and shake her down.....

[Jetlink]

used '08, and i keep the Conbrio over there....He needs to sell some friggin Corrolla's soon, gotta get the old girl out and shake her down.....Just get a bunch of your hockey buddies to go test drive a bunch of Corrola's. Then while they are out, drag your boat home.

[csuggs]

86 Sunsport, 351W, 1:1 trans
With original 13 x 13 3-blade top speed about 44 @ 4400
With 13 x 13 4- blade OJ Legend top speed about 41 @ 4400
With Acme 13 x 11.5 3-blade top speed about 43 @ 4400 with the hole-shot like the OJ 4-blade. Best of both worlds!

[chrisk]

csuggs, I'm running the exact same set up as you. 351W, 1:1 Trans, and the Acme 13x11.5. However, I'm only seeing upper 30's at top speed. Wonder what the difference is?

[csuggs]

csuggs, I'm running the exact same set up as you. 351W, 1:1 Trans, and the Acme 13x11.5. However, I'm only seeing upper 30's at top speed. Wonder what the difference is?

Are you running with ballast? Also, is your prop a 3 or 4 blade? Mine is 3-blade. AND, are your speedos right?

[chrisk]

That's with no ballast, I do quite a bit of slalom skiing and would like to do more barefooting so that's why this concerns me. It's the 3 blade, I'm pretty sure we have the same prop, I just bought it new last year. The upper 30's I see is when I use a GPS app on my phone.

[csuggs]

Chris, what rpm are you getting out of that motor?

[chrisk]

Man that's a good question, last August, September, or October I could have told you. I haven't driven it in a long time so I'm unsure now. I want to say somewhere around 4000 or less. I seeeeeem to remember running at about 3000 rpm or maybe a little higher for my slalom speed, which is about 30-32 mph. Now that you mention it, the RPM's seem low, compared to your 4400...

[csuggs]

One thing I've noticed about our boats . . . with a 13x13 and BW 1:1 trans the rpm nearly equals the speed. In other words, 2000rpm equals 20mph and 3000rpm = 30mph. And I've noticed it's real close to the same with my 13x11.5 Acme prop. Being 11.5 pitch, I'm getting a better hole-shot than with the 13x13, but my top-end is just as good as the 13x13 since the Acme is a more efficient prop.

If you're getting 32mph at 3200rpm or so, I'd say that's right. You should be able to get more than 4000 out of your motor though.

[chrisk]

Yeah it's frustrating, I remember purchasing the prop last summer and being all excited about getting better whole shot but still maintaining the same top end. I did get that whole shot I was looking for, but top end is honestly usually at like 37 or so. Sometimes it's higher on "good" days.

[csuggs]

Yeah it's frustrating, I remember purchasing the prop last summer and being all excited about getting better whole shot but still maintaining the same top end. I did get that whole shot I was looking for, but top end is honestly usually at like 37 or so. Sometimes it's higher on "good" days.

I'm not sure what to tell you. Our boats were set-up to run at 36 all-day long at 3600 with intermittent 4400. If you're not getting the rpms then you might look at your throttle cable to be sure there's nothing funny going on there either where the cable-stay is attached to the intake manifold, or anywhere along the cable run where there could be a kink or something. Be sure you're getting cable movement with the full stroke of the throttle lever. Also, your carb could be out of adjustment. Just thoughts . . .

[chrisk]

Yeah, when I'm finally able to mess with it I think I'll run it on the water just by pulling the lever on the carb manually, rather than using the throttle cable, and see what top end I can get. Maybe there's a nut that is too tight or too loose, depending on how it's set up. I never really thought that there might be something wrong with it, because it runs so well otherwise.. just thought the top end was normal.

[86 century]

You might give the eng a once over. I worked on a mercruiser 351w at that started great ran smooth but was about 1000rpm short on topend ended up being a stuck lifter.

A compretion test would confirm if you havnt done that yet.

[chrisk]

Thanks for the heads up, I'll be looking into this in about a month : (