more v8 horses

[jerry1865]

hello, im thinking i might find some room in a budget soon. where would i send a v8 johnny to find a bit more hp (like maybe another 100 or so). i want good old fashioned lake motor performance and reliability.
it has been freshened up a couple years ago but is all still stock except for the fuel system.
what would be a good ball-park number for how much room im looking for in my budget?
id want the whole thing done, powerhead to lu.
really luv that old 4.0, the only way i could luv it more would be if it had a twin beside it. or maybe if they made the e-tech in a v8.
ive never had a fuel injected outboard but if it was going to a large gain i wouldnt mind

[jerry1865]

also, where is the best shop to get it done?

[Action Dave]

also, where is the best shop to get it done?

www.montyracing.com (http://www.montyracing.com)

[STV_Keith]

Monty did the two on my Scarab. 380hp/340tq on the dyno, pump gas lake motors for a 30' open fish. 6500rpm (about stock) rev range. I stuck with mid-bore carbs for fuel economy too. Might have made more power on top with big-bores.

I did convert to Merc CLE's at the same time. That was a bit spendy for two setups, but they've been more reliable than even modified V8 cases. I will say the Merc water pumps aren't as good as the OMC's as far as volume goes...I'm looking for a solution to that now.

[jerry1865]

i called him today, he told me roughly 5 k for top to bottom 370-380, as soon as im done with a patent im going to look into that. it will be a strange thing for me tho, i use to build john-rudes for folks and ive always done my own work a (on everythin)
back when i had time...lol
ive actually been thinking about the water pump. if i put a jabsco on it i could have a much better eye on whats going on with the engine, as well as have more volume...
would be pretty easy to do.

[jerry1865]

the pump i was lookig at is rated for 12 gallons per minute. would be pretty kool to put in.

[racer]

Factory pump on your V8 is much better than adding a jabsco as they will supply more than enough water.

[STV_Keith]

Al, got any spec on the stock V8 pump? The stock Merc V6 pump ain't good enough...I need to supplement with electric.

[jerry1865]

i dont have the spec, but i can say that i cant tell a differece between that particular jabsco impeller and the v8 impeller. i didnt measure it out, bur it sure looks same to to a machinist of 20 yrs.
just curious, what sort of top end do you get with the scarab?

[markt111]

ya Keith how does she go now? I assume it's mostly dialed in? still running Bravo props?

[STV_Keith]

Jerry, I'd be interested in that part number. I want to figure out something before this season.

Mark, no more dialing. Just haven't had the funds to build a bracket, which is what it needs. 72 and change loaded with 5 people, two coolers, 100gals and scuba gear + stardard stuff (3 anchors, bumpers, tool box, stereo, etc).

Kevin @ R&R Prop Shop just finished a pair of 28 Bravos for me too...have yet to try those. The 26's ran good, but I'm hoping for a few more MPH cruise. Best I saw before at 4000rpm was ~43mph. Shooting for 46-48.

[jerry1865]

keith, i couldnt find the impeller. so i went to ebay and found the pump that i had been looking at. jabsco # 18220-1127.
theres one on ebay with a buy button for 2 bills...#400103272404
11 gallons per minute on that one. i believe thats the one that mercruiser used (front half)
btw, those particular pumps are nearly bullet-proof so-to-speak. gl
glad to help, i owed u 1 for turning me on to r&r for a prop.

[jerry1865]

here is the bracket and pods i just finished on mine. the pods were to help float it when its sitting still.

[markt111]

damn Keith sounds awesome for a heavy load!! your looking for more setback from a bracket? or to raise the engines?

i have to get my hands on some 24 Bravos to try or labbed 26s, still running the mirage plus...

are those 26s modified?

[STV_Keith]

Jerry, thanks for the info on the pump. I'll look into that!

Mark, I had 24" of setback and then added 4" jackplates. The extra 4" HURT the performance, and makes the boat porpoise, but I need the jacks. Eventually I'll build a bracket at 20", then bolt on the jacks and have the correct setback.

I've run 24's, 26's and now have 28's. The Bravos were all stock except for PVS sized vent holes CNC'd in for ventillation out of the hole. Remember though, I have Merc gearcases with 1.87:1 gearing. With the stock OMC 1.76:1 ratio, you'd run 2" less pitch than I am.

[jerry1865]

keith, my job takes me all over this country and others. next time im in your area id like to check out your rig.
the last time i was in vegas i had an extra day to play with ,but i was just spent and chose to sleep till my flight time. why would i do that ,huh? well sometimes i have to work as long as it takes. so far ive had to 27 hrs straight several times.
those dont happen very often tho.
jerry

[STV_Keith]

Sure Jerry. I'll PM you my number.

[STV_Keith]

Jerry, do you think a pump like this would work in this application? 4.5gpm at 35psi regulated...wonder how much it would move at 10psi?

http://www.jabsco-pumps.net/31755-0000.html

Or how about this Flojet pump...5gpm at 10psi?

http://www.flojet.com/files/4125_series_81000-083.pdf

[jerry1865]

flo jet .those numbers are right in line
jerry

[jerry1865]

keith, im thinking about the water bypass thats attached to the throttle. it may be a good idea to look closely at it. might need to open up the bypass orifice/hose dia. for the sake of idle and low rpm.
be sure and let me know the numbers you get at low/high rpm,
BTW, its really kool to have some-one else doing the leg-work on a project i was soon to undertake.
maybe i can return the favor one day.

[STV_Keith]

No problem Jerry. I need to "fix" this issue before the season gets going...it's a PITA having to rev the motors up for 30 seconds to get water in the blocks. I just don't have the money to buy 3 different pumps to figure out what works. I want to buy it once and be done.

[STV_Keith]

Just a heads up Jerry...I ended up calling ITT/Jabsco about a pump. Turns out the ones we were looking at were not rated for 100% duty cycle (continuous use). They pointed me at this pump instead: http://www.jabsco.com/products/marine/circulation_pumps/low_pressure_centrifugal_pump_50840_series/iid_2098-item2098/index.htm

29GPM free flow, ~10GPM at 6psi which should be fine. Found it here and got it for $165 shipped: http://www.northeastmarineelectronics.com/jabsco-low-pressure-cyclon-centrifugal-pump-12v.aspx

Should have some empirical data on how it works shortly.

[STV_Keith]

Well, I got the pump...but it won't self prime...so now I'm buying a thru-hull fitting in -12an (3/4") and plumbing it from the same location - a water pickup in the trim tabs. Then the pump will be below the water line while at idle, and get forced water while under way.

Had to have the thru-hull made...Teague is doing that for me damn reasonable. Hope to have all this stuff in and working before the 20/21 weekend. We'll see.

In doing so, I have been looking at check valves too. I have some 1/2" NPT fitting ones, but no flow rating. I'm sure they're not up to the task of 29GPM, so I found these at McMaster-Carr... 5492K14 (http://www.mcmaster.com/#5492k14/=65eqbl), the 3/4" NPT one is rated at 111GPM, which is WAY more than I need, but it's the only one that's of the flow. I'm crossing my fingers and ordering later this week.

[STV_Keith]

Hmmm, am I talking to myself in here? :)

Made some headway this weekend. Besides the new speaker grilles and another stereo battery, I did get the water pickup and thru-hull fitting mounted. This is just for one motor for now, until I prove it works.

http://www.speedcraving.com/scarab/waterpumps/pickup2.jpg

http://www.speedcraving.com/scarab/waterpumps/pickup3.jpg

http://www.speedcraving.com/scarab/waterpumps/thru-hull.jpg

[JrCRXHF]

looks good man if my new water pump in in the lower unit does not do the trick i am going to do the same thing. Let me know how you hook it up to the motor.

I was thinking about one of these pumps for a BBC they pump 35gpm.

http://cgi.ebay.com/ebaymotors/WATER-PUMP-KIT-CHEVY-BIG-BLOCK-ELECTRIC-CHROMED-NEW_W0QQcmdZViewItemQQhashZitem3efdaf2071QQitemZ270544085105QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAcce ssories#ht_2336wt_958

[jerry1865]

looks good. that pick-up looks pretty aggressive. are you going to y into the water tube or go all elec?
i just finished making sweep 90's and welding larger ports (5/8 pick up) with 1/2 fuel line for all 3 fuel tanks.
anyway ...good luck and thanks for blazing the trail for me.

[STV_Keith]

The pickup will send the water through the transom to the pump which is mounted in the boat below the water line. This pump has to be "wet" meaning that it has water to it. It will not suck water up.

From there, it will go out, through the transom, through the cowl (bulkhead fitting) and with a check valve in place, will get tapped into the exhaust adapter on the port side, into the cold water jacket. 3/4" NPT.

[jerry1865]

how does the new water system perform?

[STV_Keith]

Still not done. It's in, wired and plumbed, but I'm missing 3 fittings that I ordered today. It WILL be in and I will test it Desert Storm poker run weekend in Havasu...2 weeks from now.

[kimswang]

Looking good Keith, happy to see it all coming together. I just got a 30" midsection in the garage and is taking it apart for prep and paint. Next step is to get the boat over to Tom for a 5" extra lip on the bracket. Then save up the $$$ to go to Gordon...

[STV_Keith]

Thanks Kim. I got the fittings in the mail yesterday. Install Thursday night when I get to Havasu and test on Friday/Saturday. :)

[STV_Keith]

Get the rest of the hose and fittings installed. The system works great too!

Now, after about 30 seconds of running only the electric pump, the motor will start spitting water and make about 2-3psi. When I start the motor, it will go up to a solid 4psi. I was able to idle around indefinitely and the motor never saw over 110* of head temp.

Before the pump, it would climb to 180* and keep going if I didn't pull them out of gear and rev it up to about 1500rpm for a minute or more. Even then, it would only get back to about 150*.

Due to the pickup location, with the pump off the motor went up from 5psi to 7psi, and with the pump on was just shy of 10psi. This motor now cruises 20* + cooler. At WOT, about 70mph, water pressure rose to ~25psi.

Now I just have to replicate the system on the other side for the other motor. :)

[jerry1865]

kieth, i just have to say that the results are really quite impressive.
sounds like a system that would help a number of folks.
if im not mistaken i think the 20 degrees cooler is also worth just a fuzz more power that can be had as well.
jerry

[jerry1865]

25 psi at wot, it does seem a might high. it may be worth checking with someone about putting in a pressure relief, somewhere around 15 psi might be a good number for a relief valve. it would be pretty easy to add.
i just hope that my winter project gives me results kool as those.

[STV_Keith]

Jerry, I was thinking about that too. I think I'll be cutting the pickup down (or up) some. Right now, it sticks down about 1-1/4" at the back and 3/4 at the front. I can shorten it or cut down the angle of the scoop to tailor it for less pressure at speed. Since it is always submerged at idle, that won't be affected.

[STV_Keith]

A few more pics of the finished setup for you guys...

[kimswang]

That is cool (literally...)..