opeliac

It is an 89 model with a big block and a B1...I have gotten so many conflicting numbers about what these boats generally run...It currently has a basic 330 merc with 10:1 compression, and a magnum cam...It has gone 69.4 GPS with a Mirage Plus 23P, but the boat seems to be wanting more prop. To get to that speed, I had to go to the trailer trim button and the boat felt hairy at that speed...I have talked to several people that claim to have ran high 70's to low 80's with these boats in close to stock form...Any info would be appreciated...

bajabob

thats a good speed .you need more ponys to go past 70!

AIR TIME

what rpms, if can turn a 25 mirage try that. but you should not go to trailer trim. maybe a rev4 25 p by merc.

A.O. Razor

If more bite and bow lift is needed over the stock Mirage+, there are a couple of things to do. But yes, as AIR TIME pointed out, the trailer switch is not needed. Timming that high, will ruin your u-joint and gimbal bearing. The Revolution is indeed a great choice, but another way, would be to have a "Baja cup" or double cup done to the prop at Bblades. If you are at about 375-400 hp, your speed is about right. Granted, getting the hull aired out will help. Besides adding cup to your current prop, it could also be re pitched. Give Brett a call, the double Baja cup works very well. Getting a Rev4 and labbing the one you have now, could be a really great way to get the best of both worlds. 23" or 25" Rev4 for cruising and labbed M+ 23"/24" for speeding.

Good luck with it.

XT-Innovator

iTrader: (1)

The 89' 330hp engine was rated at the crank, and Mercury Marine later started rating that same engine at the prop (300hp) so 70 mph is about right. The 210 Sport has a very narrow chine beam so I think I would avoid a 4 blade prop that may torq the boat on its side. I tend to agree with cupping the crap out of a 23, or a (labbed) 25 Mirage "plus/plus".

Another thing you could consider was the early 88'& 89' Bravo drives had a shorter "blunt nose" design, and many people put add-on "nose cones" on that drive with success. A nose cone might also help if you were to try smaller dia. props like a Turbo 24.

Just my .02

XT

opeliac

Mine already has a nose cone added to the drive...I have talked to people that say they have gps'd in the upper 70's with the 210 with no mods done...As soon as I can catch a wind-less day, i'm gonna try a 25P Mirage...

A.O. Razor

You say your motor is modded somewhat. At what rpms did you spin with the 23" @ 69. 5200+? Is the 25" a Mirage+?

Are you saying upper 70's to low 80's with a bone stock 454/330? Never in a million years. Remember that you sometimes need to subtract a little untill you see the boat run the speed, and on the trailer does not count. Ask them at what rpms and with what prop they did it. A stock 454/330 revs between 4200-4600, so with 10% slip @ 4600 rpm's you would need a 29" prop to run 77 mph.

opeliac

So where does gear ratios and hull designs play into all of this? I come from the drag racing world, and there sure does seem to be alot of voo-doo when discussing boats...Dont take that the wrong way, I am asking these questions because I do not know the facts...

My boat was in the 5200 range and I know it wasnt making its peak power that high...I'm going to say it will make peak around 4600-4800...

A.O. Razor

No offense taken at all. Yep lots of voo-doo, boats are always faster at the marina

The number I quoted, is with a 1.5 ratio. I highly doubt any boats came stock with the 1.36. If you are indeed spinning in the 5200 rpm band with the 454 mag cam, yes you are somewhat high, but your prop slip is good. The mag likes to be between 4800-5000 rpms for max power. I've been looking around the web a bit, and from what I can find, the general concensus is that with a 454/330, 65 is the norm and 69ish with the 454MAG. There is a thread about a 210ESS (same boat) on here somewhere, with a 330 and that ran about 65-66. So if you are making a little more than a 454Mag with the higher compression, a 25" @ 4900-5000 should put you somewhere around 71-72. As mentioned earlier, it will also run faster if you get better bite and can air it out. See what the 25" M+ gives you. No matter what, I don't think you'll need much more than the 25". My guess is that it'll take you down to about 4900 rpm in stock form. After that, you can look into labbing - especially if you still need bite to get the bow up. The Baja's love cup.

opeliac

Thanks for the info...If things work out this weekend, i'll try it with the 25P to see if it runs like I think it will...