Engine Rebuilt Nightmare
09-07-2011, 08:11 AM
#11
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09-07-2011, 10:14 AM
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Good question, Baja's generally go fastest with bow lift and trimmed out, might not be carrying the bow enough. I think with the right prop, probably a 5 blade you can achieve this without going back to your original set-up but it will take some testing, Smitty
09-07-2011, 02:06 PM
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Questions-was your 555 ecu re-programmed or did you switch everything over to mefi-4? If your motor was tuned at 45 psi at part throttle and 42 psi at wot, what were your afr's?? If you now have it set at 52 psi that is a good 10% richer than before, could be at 11.5-1 afr vs 12.5 on dyno at wot, not suggesting that you turn the press down and see what happens but it really sounds like your engine builder needs to ride in your boat with a 02 meter installed in your exhaust to see where you are at. Motors seem to richen up in the boat vs the dyno too, mine always has. I would expect to see you in the low 70's/high 60's depending on load. once you have afrs set right in the boat/fuel pressure right you then need to see where your at with the prop, a 26 might end up being too big, my 272 normally aspirated made 650 gross hp and it can only turn a 26 labbed 5400 at 75 mph or so, a 24 labbed might be in your future. Get your fuel correct and see where you are, Smitty
When you ask what else changed during the engine swap what exactly are you asking about?
Yes, it is fuel injected and yes the ecu was sent out for reprogramming. I just simply plugged it in.
09-07-2011, 02:13 PM
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I just did a repower myself....had a 496 and researched it quite a bit before selling it and going with brand new horses. I've heard good and very bad stories about trying to beef up the 496. It has cast internals and needs to be completely replaced to make any kind of difference with maintaining reliability. I've got the 25 OL(not the 26) and it's 150 lbs less...and my 496 mag(375 HP) pushed it to 63-65mph at 5000 rpm depending on temp. If you are turning a 26p B1 at 4900 rpm, you should be seeing 70 at least. I'm not a fan of the B1 as it creates azz lift instead of bow lift like the baja hulls require. The B1 is made for a heavier boat. My opinion is if you find the HP and start getting 75-80 mph out of this setup...the B1 will create some issues in handling vs going to a 3 blade Mirage. I'm turning a 27 M+ on my 25' but am also putting out 700+ HP.
Artic, i'm curious about your comment on a 5 blade prop? You think the 5 blade will help in bow lift? Wouldn't it be hard to turn that thing to any rpm's with this setup? If you're getting 560 HP....IMO it should be turning a 25 Mirage. BBlades can offer a more professional than mine.
Artic, i'm curious about your comment on a 5 blade prop? You think the 5 blade will help in bow lift? Wouldn't it be hard to turn that thing to any rpm's with this setup? If you're getting 560 HP....IMO it should be turning a 25 Mirage. BBlades can offer a more professional than mine.
09-07-2011, 02:19 PM
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Dave, I do not have an answer for you. This was with the prop shaft centered with the keel on the driveway. Kind of ball park. I also have a X-dim of 15.5" that is off the Performance Sheet from Fountain. But then there was the discussion of whether or not the transom angle moved the X-dim when it went back a foot off the transom. So, I am not 100% clear on this either.
2 pulls @ 5200 RPM first 529HP then 532HP
2 pulls @ 5400 RPM first 537HP then 560HP
There is no notation of whether it is was dry or wet.
Last edited by TW720HVY; 09-07-2011 at 05:07 PM. Reason: Accurate X-Dim
09-07-2011, 02:23 PM
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I just did a repower myself....had a 496 and researched it quite a bit before selling it and going with brand new horses. I've heard good and very bad stories about trying to beef up the 496. It has cast internals and needs to be completely replaced to make any kind of difference with maintaining reliability. I've got the 25 OL(not the 26) and it's 150 lbs less...and my 496 mag(375 HP) pushed it to 63-65mph at 5000 rpm depending on temp. If you are turning a 26p B1 at 4900 rpm, you should be seeing 70 at least. I'm not a fan of the B1 as it creates azz lift instead of bow lift like the baja hulls require. The B1 is made for a heavier boat. My opinion is if you find the HP and start getting 75-80 mph out of this setup...the B1 will create some issues in handling vs going to a 3 blade Mirage. I'm turning a 27 M+ on my 25' but am also putting out 700+ HP.
09-07-2011, 02:53 PM
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Stock intake? I would think that would be the first thing to scrap if your goal was 575HP.
