Probably beating a dead horse, but I haven't had much luck finding very many performance sites for the 3.0l. Are there any ways to reliably put a 3.0l on a diet to at least get down to 440lbs? 15" mid maybe or possibly a different cowlings?
Merc 250XS looking for a Slimfast diet
- Thread starter 99hawk
- Start date
whipper
Well-Known Member
Nope K kraft on S&F has done all you can do from a 15 inch mid carbon cowl and all the DBR mods. still over 480. The only way is a 3.0lt 300pm. They are lighter and a cowl and 15 inch mid {though the mid isnt going to save you anything it at least brings down the CG} plus ratcheting gearcase.The cowl will save you some and a lighter flywheel also. Thats your best bet to get over 300hp with mods or a 300X has 335 out of the box. I think they were both 465 stock with out checking? Your fuel economy goes out the window with these motors but they have better load carrying ability than a 2.5.
The main 2 reasons to go to a 3.2 or 3.3 LT is better fuel economy than a 2.5 and better load carrying ability say always have 5 in the boat doing water sports all the time. they would be great for that. You just have to be real careful letting of the gas because more weight at the stern. Darris refers to Allisons having a teeter totter effect all the time. Well having over his recommended design engine weight is like a fat guy jumping off the teeter totter when ya let off. The poor guy on the other sides that hits the grounds name is bow.:wink
The main 2 reasons to go to a 3.2 or 3.3 LT is better fuel economy than a 2.5 and better load carrying ability say always have 5 in the boat doing water sports all the time. they would be great for that. You just have to be real careful letting of the gas because more weight at the stern. Darris refers to Allisons having a teeter totter effect all the time. Well having over his recommended design engine weight is like a fat guy jumping off the teeter totter when ya let off. The poor guy on the other sides that hits the grounds name is bow.:wink
h2oskiier30
Well-Known Member
Not sure about the 300x, but the 300 Promax motors were 467 lbs.
GotMyAlly
Well-Known Member
505 down to 440 is a lot of weight to shave off!
whipper
Well-Known Member
Be sure to post your motors weight i for one would be very interested in what you ended up with.:beer: Sounds awesome!! Was there much tinkering to get the 3.0 to fit on the pan and line up with the shift shaft and drive line? You mean 2.5 gearcase or 2.5 15 inch mid?
Darth VMAX
Well-Known Member
300x were listed at 480 lbs from Mercury
GotMyAlly
Well-Known Member
I think the carbon fiber cowl is a 10 lb savings......but expensive at $1k.
And IIRC, the simon flywheel will cut another 10 lbs.
And IIRC, the simon flywheel will cut another 10 lbs.
whipper
Well-Known Member
20 lbs for a 300 PM pluss premix is getting very close. Would be the best beast to dawn an Allison 20ft if one was inclined with the taylor mid to 2.5 gearcase. Simon can get them spinning 7000 rpm+ also.
2.5 gearcase. The Taylor mid is about 1 1/2" wider for the 3.0 adaptor plate. I have a custom
pan to use a 2.5 alien cowl. I'm using the same clamp and swivel. Really the only weight difference is the powerhead.
whipper
Well-Known Member
Sounds sweet! If i were a guessing guy witch i am with a lighten fly wheel without cowl on it will be right around 445-450. Carbon cowl saves a few lbs also. Can you pre mix the 300 promax? Should be a monster out of the hole with the right prop!!
I was over at a friends place who was setting up a STV Euro to run with a 300xs. After he did some changes to the weight distribution he said it flew very close to the same as with a 2.5 on the back. He moved the motor in and played around with the gas tank position and batteries until he achieved the same center of balance as the 2.5. the gas tank was moved ahead 1.5 inches half full I think it was. The easy way first off was other than lots of testing he did was to start with using the tongue weight with the well setup boat while it still had the 300drag on it. Then when rigging the new 300xs move things to match the same tongue weight as before. Then go test. He moved the tank ahead another 1/2 inch after 1 inch matching tongue weight. Mostly because to compensate for the taller wheel and its effect on trim. She was setup so a 5 year old could fly her to 100 after he was done with no ill effects. Just a FYI from talking to different people.
I was over at a friends place who was setting up a STV Euro to run with a 300xs. After he did some changes to the weight distribution he said it flew very close to the same as with a 2.5 on the back. He moved the motor in and played around with the gas tank position and batteries until he achieved the same center of balance as the 2.5. the gas tank was moved ahead 1.5 inches half full I think it was. The easy way first off was other than lots of testing he did was to start with using the tongue weight with the well setup boat while it still had the 300drag on it. Then when rigging the new 300xs move things to match the same tongue weight as before. Then go test. He moved the tank ahead another 1/2 inch after 1 inch matching tongue weight. Mostly because to compensate for the taller wheel and its effect on trim. She was setup so a 5 year old could fly her to 100 after he was done with no ill effects. Just a FYI from talking to different people.
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whipper
Well-Known Member
OMG that looks sweet!! Nice nice nice!!:big grin
whipper
Well-Known Member
Snap that's the the ticket right there!! Great work on making such a sick motor Ill bet it runs sweet.:beer:
90 5.0
Active Member
Yep, hope to have it in the water next weekend.