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-   -   How fast MTI 40 with 525's ? (https://www.offshoreonly.com/forums/general-boating-discussion/272732-how-fast-mti-40-525s.html)

36Tango 03-19-2012 09:43 PM

Very, very few boats have the recognition of Speed Racer. I can't imagine what it would be like to pull that boat down the road, let alone to have it on the water. The 525's seems to be a great mix of speed, reliability, and fuel economy. The dirtiest spot on this boat is cleaner than anyplace on my boat. I'd hate to see it leave LOTO, but I sure don't have the checkbook to keep it there.

Philm 03-20-2012 01:45 AM

So here is a question. Why are the big cats, i.e. 368's, 388's, 40's, faster with 525's than a 30 or 32?

I understand that they have a lot more tunnel surface area, but they also have more weight and loads more aerodynamic drag. Does the tunnel size really make that much of a difference? What is the fastest 30, or 32 cat with 525's? I certainly cant say that I have ever read about any of them approaching 140mph.

boatme 03-20-2012 04:56 AM

[youtube]http://www.youtube.com/watch?v=RGDNYdVhuZk[/youtube]

MTI running at Smoke On The Water Poker Run

Music sucks on this

I had used somthing more appropriate but You tube changed it

We did not have any engine sounds for this but you can see this boat hauling the mail. Got a little scarry for a minute

byrideroffshore 03-20-2012 05:21 AM

Do they want $250k with power, no trailer? thats a great deal

skaterboy 03-20-2012 11:49 AM

Possibly someone can shed some light on me. When you use a "Prop Slip Calculator" and plug in the following values for calculating THEORETICAL SPEED of a boat running 525EFI and #6 drives:

Gear ratio - 1:50 (highest allowed ratio for racing orgs)
Prop pitch - 40P (maxium size pitch prop allowed)
engine rpm - 5600 rpm (rev limiter set on stock 525EFI)

In theory you get a top speed of 141 mph, with a 7% slip you would see an actual 131 mph. (if the boat was set up right on the money and ran perfect)

I don't understand how all these other " higher mph numbers" come out without changing one or more of the above variables.

I am willing to learn.

Wild 03-20-2012 12:48 PM

gear ratio and props wiill change with higher HP

Strip Poker 388 03-20-2012 01:10 PM


Originally Posted by cdowns (Post 3644477)
125+

Would that hull be the same as Richie Prince's?


I would Whipple it:D

tomcat 03-20-2012 01:18 PM

Hi Wild:

This boat holds a LOTO record doesn't it?. What RPM/ratio/props were used for that?

Thanks,

Tom

gofastlvr 03-20-2012 01:21 PM

Change in gear ratio is the usual culprit. I am pretty sure the ratios are as follows: 1.49:1, 1.35:1, 1.24:1 and 1.15:1 so you can see how it can be changed but as you go up in gears you will lose a lot of the punch. My boat has been 153 with 1.35's but with the 1.49's it's 10-15 mph slower but doesn't take 10 miles to get there.



Originally Posted by skaterboy (Post 3645337)
Possibly someone can shed some light on me. When you use a "Prop Slip Calculator" and plug in the following values for calculating THEORETICAL SPEED of a boat running 525EFI and #6 drives:

Gear ratio - 1:50 (highest allowed ratio for racing orgs)
Prop pitch - 40P (maxium size pitch prop allowed)
engine rpm - 5600 rpm (rev limiter set on stock 525EFI)

In theory you get a top speed of 141 mph, with a 7% slip you would see an actual 131 mph. (if the boat was set up right on the money and ran perfect)

I don't understand how all these other " higher mph numbers" come out without changing one or more of the above variables.

I am willing to learn.


Reggie Fountain 03-20-2012 01:59 PM

Gofastlvr your boat has been over 160 MPH. I've played with alit of different ratios on your boat & it was a fast one.


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