Posted: October 04 2005 at 00:00 | IP Logged

I have been using my new 31PC for the pas couple of weeks. It has a twin 6.2MX 320HP with Bravo III, I am able to cruise at 3800RPM with 31MPH and burning 29GPH or .9GPM, is that about right? I was reading the review on boattest.com and they have it burning 18.6GPH at 3500RPM with 31MPH, granted I might have more of a load than the test boat was.

What are you getting GPH or GPM on a similar size boat?

Posted: October 05 2005 at 00:00 | IP Logged

That sounds about right.

At 1GPNM we can typically do about 32knots or 37mph at 4000RPM if its trimmed just right. The way the boat is trimmed makes a difference. I try to keep the I/O's trimmed up as high as possible with as little tabs as possible. We have the same engines as you do but your boat's about 2000lbs heavier than ours so 1.06mpg at 3800RPM is right in line.

Is your bottom painted? I found that after we had our bottom painted we lost about 2knots at WOT. Test boats typically don't have their bottom's painted and they're not loaded with food, drinks, cloths, extra anchor, dinghy, dinghy motor, etc. Perhaps once your engines are completely broken in they may get slightly better MPG, but I wouldn't expect much better. 

Do you have a GPS? GPS's are much more accurate than the Speedo that comes on the boat. 

Posted: October 05 2005 at 00:00 | IP Logged

First compare apples to apples.  Run your cruise at the same rpm as they did, then see what your fuel burn and speed is.  I wouldn't expect it to be better, but your info will be more accurate.

I have a 29PC w/twin 454 carbed.  I run a cruise at 3200 RPM at 32MPH and burn 17-18GPH total.  I have bottom paint, but slightly different boat.

Posted: October 05 2005 at 00:00 | IP Logged

DavidK, I have tried that but was not able to come to the test boat numbers. Actually what you have for numbers is what I expected, I guess I will have to play with it for a while to get the best performance. Don't get me wrong, I am more concerned about running it right in the first place and having the best ride performance.

Thanks for all the input.

Posted: October 05 2005 at 00:00 | IP Logged

I received this reply from Formula, although the speed they are quoting at 3500RPM is less than what i am getting with a full load but it is close:

__________________

LBI4fun, 2005 Formula 31PC T-Merc 6.2MX 320HP

Posted: October 26 2005 at 00:00 | IP Logged

always4sale wrote: First of all you should not get the 6.2L they are stroked 5.7L and are not good motors either go with the 5.7l 350 Mag or the 496 have seen a ton of problems W/the 6.2L stay away!!!!!!!!!!!!!!!!!!!!!!

Bull!, I have not heard nothing that make this engine that bad, just minor everyday items

However, I always feel that more power is better

Posted: October 26 2005 at 00:00 | IP Logged

I have done a lot of research and have not seen any major problems with this engine out there. I put about 15 hpurs on the boat in about 3 weeks and every thing is top notch on this boat from fit to finish to performance.

always4sale, can you tell what did you base your statement on?

Posted: October 27 2005 at 00:00 | IP Logged

Interesting that always4sale's first post is to blast the 6.2L (377cid) engines. They've been stroking 350's for years, there's alot of hot-rodders running 383's and 408's. Both the 383 and 408 are stroked and milled/bored 350's.

I've got 175 hours on my twin 6.2Ls and besides IACs and impellers have never had a problem.

Just talk to Chevy, the new Corvette Z06 is a 350 bored and stroked to a 427 putting out 505hp. If Chevy believes they can manufacture a small block 427 making 505hp with a warranty, I trust a 377 making 320hp is being a bit on the conservative side. 

Posted: October 29 2005 at 00:00 | IP Logged

Check it out (the LS7):

http://www.corvettemuseum.com/specs/2006/LS7.shtml

Posted: October 29 2005 at 00:00 | IP Logged

lbi4fun wrote: Talk is cheap, I guess.

Talk may be cheap, but Formula's sure ain't.