OUTLAW EAGLE MANUFACTURING

Xerophobic · Posted: Tue Sep 06, 2005 5:17 pm Post subject: Speed/power with tunnel..

Had another great party weekend with the tunnel. I drove the boat quite a bit, took a bunch of people out for rides etc I'm a bit baffled at something tho..
First time I GPS'd the boat was way back when I had the trim somewhat neutral and the boat was seriously stuck to the water. Since then its been trimmed to full up and locked that way(its not adjustable while driving) Ive done all this river stuff since and haven't paid much attention to top speed(till the new motor comes)
Anyway on Sat nite we were heading into the marina and a guy with a big crusier wanted me to do some flyby's on video. I did a bunch and noticed that the seat-o-the-pants meter was running pretty high. The water was maybe 10" chop and the boat felt extremely loose but was not bouncing enough to starve the pump at all. I pulled out the GPS and ran the lake and low and behold it showed 70.3!!!
Now that may not sound very impressive but Im still running a '78 van 460! (internally stock with a stealth intake, full msd and headers)
Is that even possible? I don't think the motor makes much over 300 HP if even that. Best I recall its spinning my AA at like 4000-ish
The boat felt like it was doing more than the 60-ish we'd seen before
but im not sure what was going on.
I am wondering if a rock I found stuck in the bowl has been there for sometime and finally cleared??

Baffled here

thoughts? what ppwer does it take to push a tunnel to 70?

G-force · Joined: 05 Jul 2005 Posts: 105 Location: no-po, OREGON

i can get 70 out of mine with just me and chop doesnt seem to make a diff. that is impressive i think since i have a sbc and it must weigh a bunch less. plus i have a steel race nozzle. maybe your pump is a hotrod? are you sure it wasnt KPH?

Xerophobic · Posted: Tue Sep 06, 2005 6:29 pm Post subject:

if anything the leading edges of my impellors are chewed pretty good from rocks etc(its alum)
It definatly wasn't kph cause thats real slow and the bug hitting my face told me it was above 60. the roll bar was caked the next morning as this was right at dusk. Chop always makes my hull feel way looser, calm water it feels just stuck to the surface. The air was cooler but I dunno it seems odd I could pull 70 with that motor. The new motor I'm hopin for 80's but its got porting, cam, comp etc
What power your SB makin G?
Any other oppinions?

G-force · Joined: 05 Jul 2005 Posts: 105 Location: no-po, OREGON

i dunno i didnt dyno, but the machinist said about 400, but that doesnt jive with the berkeley chart, since i twist the A 4600 rpm. maybe i got a big prob with the hull but i thought 70 with a sbc was pretty good, but 70 with an old van bbf seems even better! i guess there really isnt any replacement for displacement!

SouthIdahoGary · Joined: 15 Jun 2005 Posts: 295 Location: Wilder, ID, USA

Need more info--
Was 10"chop from current or wind? (chop is always good for 1-2 mph)
If wind were you running with or against the wind? (Into the wind the tunnels help lift the hull free of the water)
How much fuel? (Fuel weighs about 6 # / gallon-rule of thumb-every 50 # reduction is about 1 mph)
Alone or with passenger? (Weight factor again)
How much extra stuff in the boat? (weight wise)
A tunnel in race trim will do 75 against a river current-85 with current with a crew, a light load of fuel and 375 hp. 550hp low to mid 90's. 600 hp mid 90's. 650hp mid to high 90's. 700hp low 100's

Jet pumps respond to torque. Would not surprise me to see 70 with your setup. The difference between 90 degree midday heat and 70 degree evening air could easily translate into 30-50 hp

WILSON · Joined: 17 Jun 2005 Posts: 352 Location: Mexico City

A rock in the bowl; a dented impeller; or too much clearance between impeller and wear ring can definitively reduce more than 3 MPH top speed.

According to the Berkeley chart, the AA impeller @ 4000 RPM demands 240 HP; and @ 4400 RPM, it demands 320 HP.

But usually, worn impellers result in higher RPMs and less speed.

Poor timing and/or carburetor jetting can make you loose a lot of power. Even if it sounds strange: Timing do changes over time, even If you don´t move the distributor at all.

That´s my two cents.

Bald Man · Posted: Wed Sep 07, 2005 10:42 am Post subject:

The best I got out of my boat was 100 mph with the 434 ci / 560 hp; aired out and scary. Shocked

mid ninety all day long, though.

Xerophobic · Posted: Wed Sep 07, 2005 2:31 pm Post subject:

Good info guys

I don't know which pass I pulled the 70.3 on as I was busy driving the boat not lookin at the gps lol I was alone and it may have been up or down wind
The chop was wind not current as it was on a sizable lake.
I figured the cooler air was helpin me but by how much I don't know.

I guess im most surprised because I have hardly been attempting to pull every last HP out of the motor since well ...its a van motor lol I haven't done a thing other than set the timing at 12 initial. It has a 750 carb and a 2" spacer
I would have to check how much fuel is left, I haven't run much since but it would easily be less than half tanks. I don't like running with full tanks since i rarely run that far from pumps.
I have never done much to my pump but know it had very few hours on it when I got it used. Ive never really run anything shallow or silty till this hull so I'd assume its fairly tight(??) The leading edges of the blades don't look good at all at the moment but would that not more affect holeshoot than top speed? (it sure seems to) That damage is all recent from my river runnings

I also had very little gear in the boat and I haven't weighed the hull but I'm guessing my 4 buckets are reasonably light since I have no other interior to speak of. I did remove the inner bulkhead/bar too so thats a little weight gone. I will try to get a hull weight when I swap motors next week. There is a weigh station a km from my house I can use at night.

I guess it is "possible" so I'll go with it. Its nicer saying it does 70 than 60! haha
Things should be diff with the motor i pick up tomorrow

Cheers

(p.s. I will try to post the video shot minutes before my gps run, maybe you guys will recognise 70????)

ntjetboater · Posted: Wed Sep 07, 2005 2:39 pm Post subject:

I don't know if I would recognize 70 mph but here is a shot at close to 170...kph of course
sorry to hijack yer post..just having some fun
Bald man check your pm's or drop me an email

Cavefish · Joined: 18 Jun 2005 Posts: 130 Location: Klamath, CA, USA

I am impressed at 70 out of a full size Eagle tunnel with what probably is about 300 hp. Considering the weight of the motor (600 or 700 pounds?) and all, it gets more impressive, or maybe the BBF doesn't weigh as much as I think?
You keep on having adentures with that boat and telling us about it, we will keep egging you on! Wait'll you get to drive it with some serious hp and get it really flying, it'll feel like a completely different boat when you get it to where it likes to work.

Xerophobic · Posted: Thu Sep 08, 2005 10:46 pm Post subject:

Im gonna tyr the video attachment. This isn't the best clip, but the good one is over 2Meg so ????

boat was running pretty good in this one too tho

Cheers

AR · Joined: 23 Jun 2005 Posts: 181 Location: Iowa, USA

I like the Fly-by !

I have watched your project come together, and at the same time I was doing the same thing. I almost painted my boat Red and White, but at the last minute decided on the Aluminum and Red look.

Our speeds are even close. I've had mine to 72.6 with dry headers and a race nozzle with a 2" spacer.

Xerophobic · Posted: Fri Sep 09, 2005 5:27 am Post subject:

Here's the "good" clip. Too big to post here........

http://www.nzjetboating.com/yabbse/index.php?topic=5523.0

Cheers

WILSON · Joined: 17 Jun 2005 Posts: 352 Location: Mexico City

That boat is running very nice.

After watching the clip I suggest you try with one degree more on the nozzle.

Xerophobic · Posted: Fri Sep 09, 2005 12:45 pm Post subject:

Tks Wilson
Im at the limit of the stock Berk trim but I intend to make a steel nozzle shortly. I am going to fab one in a little different way which should be easy(faster) and allow more tests of size/angles. It may not be as pretty but it will also be cheap! I was going to make some wedges but for now I think its easier to make different nozzles
Goin boating this weekend but will put the new motor in starting Mon nite
Im sure an additional 150-200Hp should be quit noticable!

Cheers

( I can't watch the bigger clip on the NZ forum enough, should come in handy over the winter haha)