Fast Fred's OMC Mod 50 secrets Thread #2

[Tim Kurcz]

What the MOD 50/M31 needs is to have E Tec injectors

Not sure: What do you see as pro's and con's?

[Powerabout]

Waiting for Dave Bush to be able to mod e-tec paks..
Get computer control of your fuel curve
engine might pass EPA - green racing engine
Slight boost to volumetric efficiency as no fuel coming in the front

Not sure what to do with the oil though, drop in in the front I guess
Will require oil pump
Might need customs pistons
Will need custom head

ok just put e tec 90 on race mid and lower

[Mark75H]

Fuel coming in the front increases volumetric efficiency by evaporating and cooling the air causing the air to contract.

[Tim Kurcz]

Yesterday's test session was scratched in favor of demo rides as Virgo performed almost perfectly from the start. Weather was 70F+/- with a heavy overcast and mist, but no wind. All were impressed with the incredible power and relative quiet. Racers Eric Vanover, Rich Welch, and Jimmy Robb (Jr.) all drove. From memory, initial comments included: OMG! Holy SH&%!, Vicious, etc. If the boat was top ended, Eric made it happen as you’ll see in a video (or two) to be loaded soon to YouTube.

On the subject, friend John Mitchell shot well framed video with my pocket camera. Unfortunately quality is lacking compared to prior work by Vic Banta, but the sound is great: You’ll get a good feel for performance. Not to worry, though. There’s one more opportunity to secure a quality shoot at Dixon Smith’s where it will run side-by-side with his 2.5 Merc drag hydro.

Observers on the beach included Mark Suter, Dave Brill, Ed Weinert, Brian Cafarelli, Jim Robb (Sr.), Bob Dunlap, Mark Wheeler, Jason Hay, Steve Hueninck, and many others. All recognized the engine as nicely built, and were stunned by its performance. Perhaps you’ll see a comment or two posted.

During the demo rides, a handful of technical issues were observed:

1) The engine starts easily cold and idles nicely. Unfortunately, the additional fuel bleed caused a rich off-boost condition. It four-strokes heavily, and had difficulty with one hot restart (flooded).
2) The revised oil reservoir is still inadequate. Oil vapors/drips still escape the vent.
3) The Methanol enrichment system works great, except the reservoir size allows only 10-15 minutes of spirited driving – actually might be about right.

Post test inspection found:

4) Gear oil is clean and backlash is good: No external signs of overstress - yet.
5) Cranking compression was appx. 135 PSI for all cylinders – unchanged.
6) Plug reads were dark coffee with black in the recesses - clearly over-rich.

That’s all for this report. Idle re-jetting will be take place tomorrow. More information and hopefully better video will be posted after the next outing.

For those that would like to see/discuss the engine, it will be on display October 22 at Mark Suter’s AOMCI antique meet in Byron, MI (about halfway between Brighton and Lansing). In case you don’t know: Mark and his wife Elaine created a fabulous museum of including appx. 350 outboards, of which 150 or so are racing engines – Alkys, Mods, and Stocks. Google AOMCI and click on “upcoming events” for more information.


Video links:
http://www.youtube.com/watch?v=dMpwqn10czE
http://www.youtube.com/watch?v=OeJltlXMN8I

[Dixon263]

[QUOTE=Tim Kurcz;110680] Not to worry, though. There’s one more opportunity to secure a quality shoot at Dixon Smith’s where it will run side-by-side with his 2.5 Merc drag hydro.

Tim, I'm looking into my cyrstal ball and I see us side by side right up until you knod your head and reality sets in. Must be the long snowy winter combined with AV gas fumes erased some memory of your ride last fall in the 2.5 V-6 Merc. This reminds me of the time I decieded to take on the school bully after school and wound up in the hospital!
I weighed my hydro today and it was 567# ready to go with motor, 3/4 tank of 110 octane gas, and battery with 330-350 HP, so you better make sure your spray shield is down before we hit it!
Although I have never offically draged it through timers, the previous owner claimed it went 140 in 8.3 sec with a stock 260 HP Merc.

http://www.youtube.com/watch?v=8eGFumvGujo

[Tim Kurcz]

Hey Dixon,

Hmmmm; the math says you've got about 2.5:1 power to weight on me - yikes! So, you should be happy to spot me a few boat lengths! On thing for sure, the turbo adds enormous punch to the ride. It'll be fun to see how it all works out. Let's hope for better weather next weekend.

Tim

How about that sweet V6 sound!

[Dixon263]

Tim, I'm glad you brought it to my attention about the 2 1/2 to one HP advantage I have over you. IMO, that's cutting it a bit close, I prefer at least a three to one HP advantage over anyone I line up with so I'll be running the expansion chambers this weekend which should put me in a solid four to one HP over you to avoid any controversial results.

[Tim Kurcz]

Tim, I'm glad you brought it to my attention about the 2 1/2 to one HP advantage I have over you. IMO, that's cutting it a bit close, I prefer at least a three to one HP advantage over anyone I line up with so I'll be running the expansion chambers this weekend which should put me in a solid four to one HP over you to avoid any controversial results.

Hmmmmm...... Better bring 5 gal of Methanol and 25% Nitro-methane just in case. That should even the playing field, if only for a run or two! All the horses and men are lined up for Sunday 1PM at Riverside Park......

Tim

[Dixon263]

Tim, Sunday is way better for me because I won't be getting my nitrous tanks back from filling until Saturday afternoon. Have you ever tried the direct port mega-fogger super blast nitrous system on any of your motors? It works great, but the downside is you only get a couple of short runs out of a motor and it uses an entire tank of premium nitrous for a six second run, but I guess that's the price of tripling your HP.
Dixon

[Tim Kurcz]

You're going through alot of trouble to wax my little OMC - it must make you nervous! Just took delivery of a 14 pitch Dewald that will carry 115+ 15 PSI boost and the nitromethane shoud narrow the range, nitrous or not........ It will be interesting and fun!

Tim