More HP or Torque
09-22-2010, 06:42 PM
#12
Charter Member # 55
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Probably should have mentioned my WOT use to be 4800 RPM but forgot about some of the slime that builds up. I have four sets of props and tried verious things just to get it up quicker, different rakes and cupping. Matter of fact I mis spoke I currently have 24 pitch props on it. When I run 22's it creeps to close to 5000 and I'm turning 3700 to 3800 to stay on plane. When I'm up that high I start getting in to the major fule burn issue. The 3600 RPM range gets me about 1 MPG. With the wife and I it does OK and I know it's not a runabout but I'm looking for what is the best choice. I do have trim tabs and they are all the way down, without them I don't stand a chance of getting up unless by ourself. If I can just figure out the right way to go.
09-22-2010, 06:59 PM
#13
There should be very little, if any, difference in fuel usage between 3600rpms with a 24" prop vs 3800rpms with a 22" prop. Unless you have a flow scan, and have figured out your exact mpg, you are just guessing at that. Chances are the throttle is pushed to the same exact position. The engine just has to work harder to spin the 24.
Maybe a 540 and an XR drive is the way to go but would sure like to find someone who has gone down the same road.
09-22-2010, 07:51 PM
#14
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Fixx
How are your props timed? looking at the skeg the lower part of the props are not soppose to be aleigned, inner prop @ 6:00 and the outter prop @ 12:00
09-24-2010, 01:57 AM
#17
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You may be right but I do the same thing most every trip. Get up on plane go out 9 miles anchor. 4 to 5 hours later come back the nine miles. When I'm turning the 3800 plus I have to get gas every other trip (never fill up I don't like carrying all the weight, about 40 gal each time), if I turn less RPM I get gas every three some times four trips.
Maybe a 540 and an XR drive is the way to go but would sure like to find someone who has gone down the same road.
Maybe a 540 and an XR drive is the way to go but would sure like to find someone who has gone down the same road.
Not to mention, it makes no sense to spend 20k on 25k boat.
You'd be better off to buy something different with twin small blocks.
09-24-2010, 08:07 AM
#18
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Like everyone has said , a 27ft cruiser weighing 10K is seriously underpowered with only a single 502 ....
45mph for that setup is not bad at all..
45mph for that setup is not bad at all..
Last edited by HTRDLNCN; 09-24-2010 at 08:10 AM.
09-24-2010, 06:11 PM
#19
If you are at all worried about fuel economy, this is not the answer. It will probably use twice the fuel and be even harder to get on plane. A Bravo 3 is about as good as its going to get. Any significant power increase is going to break the drive.
Not to mention, it makes no sense to spend 20k on 25k boat.
You'd be better off to buy something different with twin small blocks.
Not to mention, it makes no sense to spend 20k on 25k boat.
You'd be better off to buy something different with twin small blocks.
I've made two calls to Bblades and have not connected yet, but will keep trying. Willing to spend some money to get the boat running like I want but do understand to differences.
May wind up with another boat but have to make sure it's worth the funds. There is a 2008 370SS at a local Formula dealer with twin 525 but he wants 299K.
09-24-2010, 06:27 PM
#20
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Fixx
Not to worried about fuel but still don't want to throw it away money away either. Formula screwed up in 94 because they don't sell the boat without twins anymore. Twin 350 would put out 260HP each yet weight about 1000 each equaling 2000 pounds and 520HP. One 502 puts out 415HP and weights 1210. 800 pounds more for 105hp and more drag. Net sum gain might be a bit more but not a lot. Spend 20K on a 25K boat may be worth it if it cost 100K to replace it with a few year old used one, new one is 206K.
I've made two calls to Bblades and have not connected yet, but will keep trying. Willing to spend some money to get the boat running like I want but do understand to differences.
May wind up with another boat but have to make sure it's worth the funds. There is a 2008 370SS at a local Formula dealer with twin 525 but he wants 299K.
I've made two calls to Bblades and have not connected yet, but will keep trying. Willing to spend some money to get the boat running like I want but do understand to differences.
May wind up with another boat but have to make sure it's worth the funds. There is a 2008 370SS at a local Formula dealer with twin 525 but he wants 299K.
Read his background before you decide..
http://www.dahpropellers.com/
