Top speed too low?

[nola mike]

Still seems low.I don't think I should have almost 10 mph on you with the same hp. Any idea of the weight of the boat?

 

[Chuckles88]

Jd website says 2k

 

[Chuckles88]

It made no difference in top end with 450 extra pounds. I also checked the foam in the hull and it was dry in both sides.

 

[nola mike]

I found a great site that listed specs for all the late '80s glastrons, from glastron, including fuel use, top end, 0-30, etc. Can't believe I can't find it now . Mine had a listed top speed of 50 mph, and I'm still within 3mph, 1700#. I still think you should be mid 40's easy, but who knows I guess

 

[achris]

.... My estimations have me thinking I could go to a 14.5 x 19 to get me right in the middle of the 4400-4800 and bring my top end up a bit. Does this sound correct? Thanks!

No, stay at the top of the range. 19" will take you down to the bottom end, and that's a BAD place to be (each inch of pitch is worth about 200rpm)....

I'm currently running a 17", and I get a tad of 5000, 19" puts me right in the middle of the range at 4600, but my acceleration suffers, the boat feels 'heavier', and I have no increase in top speed. Where I am now (and where you are) the engine isn't working as hard, so less wear, and it's more 'driveable'...

Chris......

 

[scoflaw]

I prop for midrange, where I spend 90% of my cruising. WOT and holeshot are not important to me. The difference may be 5 mph at 3200 rpm between the 17 and 19 in favor of the 19

 

[achris]

I prop for midrange, where I spend 90% of my cruising. WOT and holeshot are not important to me. The difference may be 5 mph at 3200 rpm between the 17 and 19 in favor of the 19

It's not about having great holeshot and WOT speed. It's about not making your engine work so hard. Think driving around a gear too high all day... Your engine will not love you for that!

 

[Chuckles88]

Thanks for the replies. I'll stick with the 17 and see if someone can lend me a 19. I might just have a tired engine.

 

[achris]

Thanks for the replies. I'll stick with the 17 and see if someone can lend me a 19. I might just have a tired engine.

Have you done a compression test?

 

[Scott Danforth]

at 5000', your down 15% in power than you would be at sea level. (no getting around that unless you have a turbo or supercharger)

so if you were at 185hp, you are now at 157hp, and your top speed is about right

 

[nola mike]

at 5000', your down 15% in power than you would be at sea level. (no getting around that unless you have a turbo or supercharger)

so if you were at 185hp, you are now at 157hp, and your top speed is about right

That was what I was wondering earlier... And he should be at 175hp with his year, right?

 

[Chuckles88]

It is a 175hp. I saw the sticker on the valve cover. I'm dreading a compression test but It needs done just in case. The prop is a little chewed up so that will be first.

 

[Scott Danforth]

Well, if the OP was at 175 and at 5000' his power is closer to 147 hp then. And his speed matches what i would expect

 

[achris]

Well, if the OP was at 175 and at 5000' his power is closer to 147 hp then. And his speed matches what i would expect

And it's a 29 year old engine, so it's probably lost a pony or 3 over the years. Possibly down to around 130 now?

Chris....

 

[nola mike]

Yeah, probably not that far off with those factors. I only hit 40 today @ 4100rpm wot, though with 1200# of passengers fwiw. Fatasses make a big difference.

 

[Chuckles88]

Haha. I guess I'm lucky with weight only dropping mine down 2-3 mph. I shouldn't complain with a 30 year old engine. It pulls hard and plains in about 3 seconds

 

[Rick Stephens]

Chuckles, in Idaho? Mee too. Up Grangeville way.

 

[Chuckles88]

I'm in the uglier part. Pocatello, but it's still Idaho.

 

[Rick Stephens]

I'm in the uglier part. Pocatello, but it's still Idaho.

My kid is a freshmen at ISU. I loved the visit down there at registration. Was thinking of dragging the boat down when the wife and I visit. There's an upcoming parent invited event in 5-6 weeks or so from now. Any fishing to be had?

 

[Chuckles88]

This time of year a lot of great river fishing. The reservoirs are getting pretty low for the boats.