Virage Turbo/Merc 2.5 260
I have a 1989 Virage turbo that needs help
getting "over the hump". The boat is pristine with not even a
scratch on the bottom. I'm running a '94 2.5 260 with 7 1/2" of setback.
like your Virage is running pretty good already! My reply is going to be
filled with my opinion so don't take anything personal if it sounds that
way. Now, for what I think. I'll do this in two parts, first the stuff
I've found over the years and then how we could go faster.
used to have a Virage Turbo and have had my hands on a half dozen more.
The Virage is a fairly heavy boat but it does have tunnel compression,
so that helps. I've heard of these big speed numbers and have to believe
they are only obtained by super high gearcases. Big props and several
miles to get it there. to me that last part sucks. Why would I want a
boat that takes miles to go fast? With 260 2.5's the speeds you are
running is about what I found with a set-up that takes a half-mile to
do. If that is the way your boat is performing now thatís good. If it
takes a long time to get to 100 then we have some work to do. The CLE
gearcase runs fast if it is above the bottom. Roark Summerford found at
Lake X that if you fill the outside water inlets they were worth 1 mph
each. If you close off the center on the sportmaster, the same 1 mph
appears. On my old STV Euro I put a sportmaster on (had a CLE) and lost
2 to 3 mph. I did some creative grinding and I got them back luckily. On
set-ups with the gearcase above the bottom you probably won't see much.
But I could be wrong! Your set back is what I ran and I tried them all.
Your motor has mods in it that like to run 8000 plus to get the maximum
effect so I'd keep the R's up. The Japanese pistons you mention should
be for the 225X. I'm not aware of any new 2.5 casting not made by
Wieseco. If the part number ends in T6 then you have the new Malhe
replacement. If T9, that is the 280 piston. Both are Wieseco. No matter
as long as they work. Me and several other people have found the bored
airhorn does nothing to speak of; unless you are in the 10,000 rpm plus
club. Just about any airhorn mod is for naught as the drag guys found
out. (Removing the front of the hood for "ram" air) It makes
more noise but thatís about it. Everybody thinks that the air flow
thru the airhorn is supersonic or something. It is pathetically slow.
am I going with this? If the sportmaster change works I would expect the
rpm to go down and the speed to go up. If not much change then the Cle
was ok. I'll admit I'm leaning to the first scenario. Next I think you
need to get the rpm to the mid 8's to take advantage of all that motor
work. Bad news is usually when you go down in pitch efficiency suffers.
If we're lucky the added speed will compensate and give us our rpm back
but it will most likely take a good 28 to turn 8500 and have a good
performing boat overall. A 28 at 85 would put you in the low 100's and I
think you punch would scare the "big mph" Virages.
this helps. Feel free to contact me if you think this is making sense.
Sometimes I can be kind of winded.
Please submit whatever questions you have to IHRTechTalk@yahoo.com. All questions and answers selected will be displayed on this page as they come in. Note: though all boaters are welcome, priority may be given to I.H.R. members. Randy can not be held responsible for any advice given. Though his information and expertise is second to none, he has no control over what you do with your boat. It is up to you to boat safely and act responsibly, and his advice is only to be used as a guidance for your high performance boat/motor of which you are the one responsible for the risks involved.
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