AWELSH

Hello everyone, this is my first post on this site. I hope you guys/girls can help. I have a Convincor 270 with a 496Mag(375hp)/Bravo 1. The boat came with a Mirage Plus 48-13704 23 pitch prop. The boat will hit about 60 to 62 mph on the speedometer at 4800 rpms. I don't seem to have any blowout problems, although I never floor it out of the hole so I guess I wouldn't now for sure. I would like to get a few more mph out of the boat and was thinking of going to a 25 pitch Mirage Plus and getting it lab finished so I wouldn't lose any rpms. Does this sound like a good idea? I would also like to buy used. If anyone has any ideas I'm all ears. Thanks

mxz800

i think you need to play with what you have a little more first. i have a 99 270 with a 454/385hp and have seen 75 on my speedo which translates to 67 on gps!! you need to get gps speeds before you can do any testing upgrades. i feel you should be seeing much better spedds on your speedo than that with the 496. i trim my boat up alot to get max spedd are you doing this or being conservative with the trim??other than the speed how do you like your 270(259)??

toonatime

Agree with 800.. You should see better with your setup.. Be sure you have no prop nicks,,practice with trim..get rid of weight..

AWELSH

I typically go boating with just me and my son, although sometimes the wife comes along. I usually have anywhere from 1/2 to a full tank of gas, and a cooler with food and drinks and a bag with cloths, suntan lotion,etc.... It doesn't seem to matter very much how loaded the boat is, we still seem to hit about the same top speed (60-62 mph). I trim the boat until the front end seems like it is floating and I start losing stability. I don't want to have to remove all cushions, have 2 gallons off gas in the tank and no supplies on board to increase speed. I don't know how I can play with this setup anymore. The prop is in excellent shape, no nicks or scratches. I love the boat, I'd just like to see mid to upper sixties if possible (so would my son!!).

wild willy

hey guy; you should be running better than that!! e-mail checkmatepowerboats.net and ask kipp or mike what speed and prop set up you should be using!! BILL

dyno

Get a gps take the boat out and run balls out and start trimming out the boat until you see the speed start dropping off, then go the other way until it recovers then you know if your getting the best out of the prop you have now. The speedo isnt very accurate but a hand held gps works great for testing and tuning...my .02

AWELSH

Thanks for the responses. Since everyone seems to think I should be seeing higher speeds on the speedo I'm going to E-mail Checkmate and see what they say. Is it possible to buy a used hand held GPS?
Thanks

dyno

check Ebay!!!!

mxz800

how much are you looking to spend on gps you can buy a handheld for just over a hundred bucks brand new! i always worry about buying electronic stuff used you never know. my speeds were taken with two people on board and 1/4 tank of fuel and cooler of food. boat full of gas and people is probably worth about 4 mph in my boat. biggest affect on speed is water, smooth water speed sucks, two foot chop speed is great! i have watched speed jump 5 mph when i leave river and enter bay and get into some chop where the air gets under it a little bit;.

AWELSH

Thank you for the inputs. Looks like I should be able to handle buying a new hand held GPS.
I don't want to beat a dead horse, but what if a GPS calculated speed shows below 60 mph and the manufacturer says the boat is propped correctly (this will happen with my luck). What would my next step be?