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-   -   Considering channging my 242SS to a 271 Sr1 (https://www.offshoreonly.com/forums/formula/317197-considering-channging-my-242ss-271-sr1.html)

TomZ 01-05-2015 03:02 PM

Nice going!

Everything looks great. Sounds great too!

Monaco20 01-07-2015 04:13 PM

Interesting article about 271 SR1 502 415 Bravo1 Top speed 63 mph :-) Fantastic numbers after rebuilt, I did not know the 271 had that speed potential :-) Look forward to summer to test my boat with 560 Hp

enjoy:-) :-)




https://books.google.no/books?id=R0P...epage&q&f=true

Monaco20 01-15-2015 07:54 AM


Originally Posted by Monaco20 (Post 4245788)
Interesting article about 271 SR1 502 415 Bravo1 Top speed 63 mph :-) Fantastic numbers after rebuilt, I did not know the 271 had that speed potential :-) Look forward to summer to test my boat with 560 Hp

enjoy:-) :-)




https://books.google.no/books?id=R0P...epage&q&f=true

Any comments on this article? seems fantastic 75,9 mph with 540 HP ??

That Hydromotive propeller must do magic to this boat ;-)

TomZ 01-15-2015 08:11 AM

Pretty okay read, but I could have done without the author's commentary.

Would have been nice to know what they used for parts, but I guess that's their secret.

Monaco20 01-15-2015 08:58 AM


Originally Posted by TomZ (Post 4249950)
Pretty okay read, but I could have done without the author's commentary.

Would have been nice to know what they used for parts, but I guess that's their secret.

It is a short description of some of the engine work, I noticed that the rpm was very high 5600 at top speed (with out blower)

Never saw any speed close 76 - 77 with that 540 HP

I have seen some 271 Fastec done 72 - 72 mph with Merc Racing 525 ...:-)

TomZ 01-15-2015 09:45 AM

Nothing wrong at all with spinning the 502 that high. The bottom-end is certainly strong enough to handle it.

I can't really say too much in regard to the setup. I don't know the 271 at all, and being fairly new to Formula it's hard for me to say what it would take to run "xx" mph. It was definitely moving though! I know I have my work cutout for me with my 242, but that's what superchargers are for!

Mr Maine 01-15-2015 10:08 AM

I noticed the author got the pitch and diameter backwards in the article, haha. Definitely a healthy motor to push it to 76, although its an old article and they were talking about the speedometer so I assume it's not GPS speed. If so, may have been closer to 70mph GPS?

Monaco20 01-15-2015 12:52 PM


Originally Posted by Mr Maine (Post 4250041)
I noticed the author got the pitch and diameter backwards in the article, haha. Definitely a healthy motor to push it to 76, although its an old article and they were talking about the speedometer so I assume it's not GPS speed. If so, may have been closer to 70mph GPS?

Maybe I am wrong, but I think that they used mostly radar to measure speed in mid 90 s ???

bj1464 01-15-2015 04:43 PM

I use hydromotive p5x prop 24p with 525 efi ,helped with getting on plane and staying on plane at slow speed.Top end speed still good 68 gps carrying lots of fuel and cargo.

Monaco20 01-15-2015 05:05 PM


Originally Posted by bj1464 (Post 4250275)
I use hydromotive p5x prop 24p with 525 efi ,helped with getting on plane and staying on plane at slow speed.Top end speed still good 68 gps carrying lots of fuel and cargo.

What's your all time high Speed with 525 ? What prop did u use then ??


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