Question on Low Water Pickup vs. Standard?
 

Guys,

Help me out, what are the pro's and con's of LWP vs. Standard water pickup on an XR lower? I am already aware of the mud sucking problems with LWP. Is there a speed differance? Can a LWP be converted to side water? Is there any problem with increased water pressure if you are running a crossover setup? Add anything you feel is worthwhile. I will be using the lower on a non-stepped hull up to 80mph.

Tim T.

Tim,
Teague in a past PBM reported that,
at if your boat runs over 80 and your
x dimension is conservative, the
low water pick up's cost you 2 mph.

I think I remember Treadwell posting
something on this too, maybe he will
chime in on this one.

Someone had posted the water pressure
issues at one time, but I can't recall who.

Later this week, since I have most of
my side jobs done, I plan on doing
a test.
mine has LWP's, a friend of
mine has SWP's, I'm going to pull his drives,
go out and run mine, verify speed GPS,
go back to shop, put his drives on,
run again.
I will post results later next week ( weather cooperating)

jt

WHEN I RAN BRAVO 1'S ON MY OL AND BLEW A DRIVE I WOULD PUT A DRIVE OFF OF MY SEA RAY ON THAT HAD A STANDARD WATER PICKUP.WHEN I GOT TO HIGH SPEEDS I LOST WATER PRESSURE BECAUSE THE DRIVE WAS TOO FAR OUT OF THE WATER. SO X DIM. MEANS ALOT TO PICK UP WATER. RB

I am currently running side pickups and can trim to quite high without water pressure issues. I did a search and found rumors of speed loss with the LWP. Any verification? Waterfoul had investigated drilling holes in the side and covering the LWP holes. Is this feasible? Would that be a PITA job?

.............And the results are in !




As I mentioned previously, going to
test this theory out, here's what my results were,

The time between runs was 1 1/2 hours,
everything (water conditions, temp, weight)
else was as equal as possible.

...........The side water pickup drives were
1.4 MPH faster ! ( GPS speed's)

Now I need to find a home for these
mud suckers :D

Quick............ someone else find me a comparison
test to do.
Everybody's boats that I've been working on
are fixed, If I don't find another project soon,
I will be forced to fix stuff around the house :(

God help ya, fixing house stuff is strickly for winter. Interesting test you did.

Is your Cap key broken ?? stuck or what ,proper to use caps when yelling and we can all hear fine ???

jt29olhp500 How did boat handle between the to drives. And what was top speed ?

I have not had a chance to do anythying to my drive. Too busy trying to get my motor together and in the boat before Mem. Day.

BUT, if it were me, I'd avoid the LWP drive if given the chance all over again. Been nothing but a sandy, muddy mess for me since I put it on my boat. Unless you are running a car or a high x dimension v-bottom, the LWP is more trouble than it's worth.

There was a post about plugging two of the four holes to improve mph. I think it was one of the F2 racers that posted it.

I lost around 1 1/2 to 2 mph going from a standard bravo with side pick ups to an X drive with dual pick ups. Not sure if the loss was from the pick ups or the upper gears. I changed drives because I was getting air into the system with the side pick ups.

Dan

FFO,
the handling didn't change,
water was glass smooth,
so anything would have been
noticeable.

Top speed ?
Since my class competitors at the
LOTO shootout may be "lurking"
( you know who you are )
I'll give you the answer my
brother-in-law thats in the
navy gives me when I asked
him what the top speed of
the boomer he was stationed on,
his answer: "Its classified" :D :D

No, seriously, let's just say it
was low, to mid 80's, with "x"
amount of people on board
and "x" amount of fuel on board.
( that should keep them guessing)

Come to the Shootout,
thats when the next results will
be announced :D :D

jt

jt29olhp500s,

I have a test for ya - compare a set of 1.5's to a set of 1.36's and see if it makes a difference! Of course, you will need to prop accordingly - probably about 2" less pitch with the 1.36. I have a set of 1.36's in my boat, and I have been wanting to do this experiment myself to see if there is any meat to the theory (put forth by others) that my 1.36's are costing me top end speed. I just haven't been able to get my ducks in a row to perform this test.

Budman,
I actually did this about
7 years ago on my 24 footer,
I didn't have a GPS back then,
so I don't have any " factual"
results.
acceleration was definetly
better with the 1.5,
2" increase in prop size
was about right, but RPM's
were slightly higher with the
1.5.
I know a guy with 1.36's,
he has Imco external steering,
I have latham, I don't know
if the pins are compatable,
may have to change end caps.
I could borrow the props off the
boat I borrowed the SWP's from,
there 2' less.

I'll have to see if I can pull this
one off, the guy with the 1.36's
is "paid up", and doesn't owe
me any more favors at the moment;)

jt

Looks like you might have to go "in debt"
 

JT,

What kind of boat is it? What kind of 24' boat were you running 7 years ago when you did the test. Mine is a Baja Force 235 - basically a 24' deep vee - 4500 lbs or so.

Budman,
it was a 91' Baja Bandit,
hull lenght was 22'3"
weight was 3600#'s

Things are kind of blury,
trying to remember back then,
as I recall the 1.36 would
spin a 24" turbo to 5k,
the 1.5 would spin a 26"
turbo 5200 +
Using the prop slip
equation;
1.36 theoretical top speed: 83.55

1.5 theoretical top speed: 85.35

That looks pretty close to
2 mph to me ;)

jt