Thanks Thanks:  0
Likes Likes:  0
Page 11 of 19 FirstFirst 12345678910111213141516171819 LastLast
Results 101 to 110 of 190

Thread: Gt Pro -- New Class For Region 8

  1. #101
    Team Member Smokin' Joe's Avatar
    Join Date
    Mar 2007
    Location
    Texas and Tirol
    Posts
    657
    Post Thanks / Like

    Question

    Quote Originally Posted by Chairman View Post
    Transom height is 20". With a jackplate (6" setback) you can run it up about another inch.
    I also don't understand why, when your Vs are running a 20-21" transom height while your tunnels are running with the gearcase bullet above the sponsons, and you're both running essentially the same props, that the tunnels don't run off and leave you. In the 'good ol' days' of OPC, most SE boats could not outrun a good EP boat with their gearcases submerged like ours (same was true in Mod VP!), but once their gearcases came above the sponsons they ran 73-78 mph while we ran 63-67 mph (and the Mod V tunnels went from 85 mph to about 100 mph).

    ... unless the power curve on the 35 is so bad that the motor won't turn 8000 RPM ... . Mine turns 6050 RPM@41.5 mph. Actually, i have the power curve in my 1980 manual: hp peaks sharply around 6000 RPM and drops by over 30% at 7000 RPM. So maybe the answer is that the tunnels need to run a much higher pitch than 16-17".

  2. #102
    Team Member JohnsonM50's Avatar
    Join Date
    Apr 2005
    Location
    Jersey
    Posts
    1,030
    Post Thanks / Like

    Default

    Quote Originally Posted by Smokin' Joe View Post
    I also don't understand why, when your Vs are running a 20-21" transom height while your tunnels are running with the gearcase bullet above the sponsons, and you're both running essentially the same props, that the tunnels don't run off and leave you. In the 'good ol' days' of OPC, most SE boats could not outrun a good EP boat with their gearcases submerged like ours (same was true in Mod VP!), but once their gearcases came above the sponsons they ran 73-78 mph while we ran 63-67 mph (and the Mod V tunnels went from 85 mph to about 100 mph).

    ... unless the power curve on the 35 is so bad that the motor won't turn 8000 RPM ... . Mine turns 6050 RPM@41.5 mph.
    When somebody runs an OMC 35 at 8G's under load & those 3"ers are still attached .. Please tell me .. Id love to hear LoLs. Ive been running the heck out of them for years trying all kinds of go fast ideas. Low 7s is the most Ive seen, thats also waaay beyond the torque max, dosent matter much in light load mode tho.. when you back down to 5800 or so you actually feel the torque re- emerge & bounce the boat a little. As Ron said, better props will be available, thats where youll probably see most difference on the stock motor.

  3. #103
    Team Member Smokin' Joe's Avatar
    Join Date
    Mar 2007
    Location
    Texas and Tirol
    Posts
    657
    Post Thanks / Like

    Talking

    Quote Originally Posted by JohnsonM50 View Post
    When somebody runs an OMC 35 at 8G's under load & those 3"ers are still attached .. Please tell me .. Id love to hear LoLs. Ive been running the heck out of them for years trying all kinds of go fast ideas. Low 7s is the most Ive seen, thats also waaay beyond the torque max, dosent matter much in light load mode tho.. when you back down to 5800 or so you actually feel the torque re- emerge & bounce the boat a little. As Ron said, better props will be available, thats where youll probably see most difference on the stock motor.
    Here's the power curve below. Jim Nerstrom pointed out to me that you can't get much power out of the 2 cyl. 35 because of the intake system. That's easy to understand: like the shock mounts, the flat leaf plate is straight from a 1954 Johnson 25. Think of air entering: any flat surface is a big obstruction. That's why high-winding Mercurys in 1949 and later had a reed cage on the crank, less restriction of air flow. the high winding 3 cyl. loop charged 75 had no flat leaf plate, nor did the larger OMC motors made (at least) after 1975. The 1930s era OMCs had rotary valves (like the König), not flat leaf plates.

    Still, I like the 1976-1993 OMC 35, it's reliable and fun to play with. I guess it represents the limit of what Mercury engineers like Strang and Rose could do with an old OMC design. I.e., it's not a Mark 55 .... .
    Attached Images Attached Images   

  4. #104
    Team Member JohnsonM50's Avatar
    Join Date
    Apr 2005
    Location
    Jersey
    Posts
    1,030
    Post Thanks / Like

    Default

    Quote Originally Posted by Smokin' Joe View Post
    Here's the power curve below. Jim Nerstrom pointed out to me that you can't get much power out of the 2 cyl. 35 because of the intake system. That's easy to understand: like the shock mounts, the flat leaf plate is straight from a 1954 Johnson 25. Think of air entering: any flat surface is a big obstruction. That's why high-winding Mercurys in 1949 and later had a reed cage on the crank, less restriction of air flow. the high winding 3 cyl. loop charged 75 had no flat leaf plate, nor did the larger OMC motors made (at least) after 1975. The 1930s era OMCs had rotary valves (like the König), not flat leaf plates.

    Still, I like the 1976-1993 OMC 35, it's reliable and fun to play with. I guess it represents the limit of what Mercury engineers like Strang and Rose could do with an old OMC design. I.e., it's not a Mark 55 .... .
    The graph corresponds with experience no doubt but I like them too. I considered changing the reeds to a V block type but there- alot to overcome & play only. I have opened the dampers on a few, One of them really moved out! [compared to itself] the day before. That cost me a re-assemble & piston tho I have a reed plate set up with Boyesens & mildly tweeked dampers ready to install.. Ill be bringing the steel ones as a back-up.

  5. #105
    Team Member Smokin' Joe's Avatar
    Join Date
    Mar 2007
    Location
    Texas and Tirol
    Posts
    657
    Post Thanks / Like

    Talking

    Quote Originally Posted by JohnsonM50 View Post
    The graph corresponds with experience no doubt but I like them too. I considered changing the reeds to a V block type but there- alot to overcome & play only. I have opened the dampers on a few, One of them really moved out! [compared to itself] the day before. That cost me a re-assemble & piston tho I have a reed plate set up with Boyesens & mildly tweeked dampers ready to install.. Ill be bringing the steel ones as a back-up.
    PS Nerstrom recommends his 3 cyl looper 35, but I have yet to see one for sale. Next choice: a Mark 55 with a tiller handle, but they're rare and expensive as well. Plus, I'll never find a tiller handle ... . I've forgotten what dia. prop they ran (same as Mark 58), but 14" (or maybe 15") pitch was correct at about 45 mph.

  6. #106
    Team Member JohnsonM50's Avatar
    Join Date
    Apr 2005
    Location
    Jersey
    Posts
    1,030
    Post Thanks / Like

    Default

    Quote Originally Posted by Smokin' Joe View Post
    PS Nerstrom recommends his 3 cyl looper 35, but I have yet to see one for sale. Next choice: a Mark 55 with a tiller handle, but they're rare and expensive as well. Plus, I'll never find a tiller handle ... . I've forgotten what dia. prop they ran (same as Mark 58), but 14" (or maybe 15") pitch was correct at about 45 mph.
    Ive got one, 35/3 its a basket case that needs intake, carbs & pistons etc..etc. Its on the someday list.. I heard its a hot one & heard Canada's the place to look.
    With these RaT lower units I put together most anythings pretty fast, a stock 25hp on my hydro will do 60+ on the Yamato foot but of course I cant race that. 31.8s [stock power head with megaphone allowed] are legal in C-mod in the NBRA. Bet the cone makes em lite up! You would have to be P.D.F. to compete.

  7. #107
    Team Member Smokin' Joe's Avatar
    Join Date
    Mar 2007
    Location
    Texas and Tirol
    Posts
    657
    Post Thanks / Like

    Default

    Quote Originally Posted by JohnsonM50 View Post
    Ive got one, 35/3 its a basket case that needs intake, carbs & pistons etc..etc. Its on the someday list.. I heard its a hot one & heard Canada's the place to look.
    With these RaT lower units I put together most anythings pretty fast, a stock 25hp on my hydro will do 60+ on the Yamato foot but of course I cant race that. 31.8s [stock power head with megaphone allowed] are legal in C-mod in the NBRA. Bet the cone makes em lite up! You would have to be P.D.F. to compete.
    What's p.d.f.?

  8. #108
    Team Member JohnsonM50's Avatar
    Join Date
    Apr 2005
    Location
    Jersey
    Posts
    1,030
    Post Thanks / Like

    Default

    Quote Originally Posted by Smokin' Joe View Post
    What's p.d.f.?
    pretty darn fast

  9. #109
    Team Member Smokin' Joe's Avatar
    Join Date
    Mar 2007
    Location
    Texas and Tirol
    Posts
    657
    Post Thanks / Like

    Talking

    Quote Originally Posted by Mark Poole View Post
    Here's my mini boat. If you call 15' mini! Only a few of these were built in Florida and they were center console fishing boats. Never sold well, too small for a fishing boat. I decked it over and made it a sport boat. With me in it and all coast guard stuff, battery, bilge, lights, anchor, etc. it runs 39. Check out the transom pic. It is a 15" motor on a 20" transom. Simple solution, turn jack plate over (I guess it would be called a jack down plate now!) Cav plate is about 2 inches above pad.
    You didn't tell us the prop size and brand. RPM?

  10. #110
    Team Member Chairman's Avatar
    Join Date
    Nov 2005
    Location
    Hackensack, MN
    Posts
    221
    Post Thanks / Like

    Default

    Quote Originally Posted by Ron Hill View Post
    Can anyone give us a re-cap of the 2009 season?

    Or tell us where to find it?
    We had another good season for GT Pro. Mostly the same drivers and boats, but also several "guest" drivers getting the chance to drive a race or two. Numbers ranged from six to eight per race, and fourteen drivers participated overall.

    One boat barrel rolled; two developed "bottom failures" and one of those sunk; one boat was rear-ended on the highway on the way home on a sunday night. No one hurt, all boats repaired and back on the racecourse with hardly a race missed.

    Ron generously donated four propellers to the class last spring. Three of them got a lot of use (the fourth was too small). Then late in the season we sent three props down to TX where "Smokin' Joe" Prof. Joe McCauley tweaked them, at no charge. The jury is still out on the outcome as we got them back just in time to race in late September, then October weather was horrible, and then winter closed in. Not to worry, the ice is usually out around here by the end of April.

    There are two new guys busy building boats right now, and they will hopefully be ready to race in 2010. Also, I'll be driving a new tunnel boat next season, so my two-time highpoints champion v-bottom is for sale. Hopefully someone will scoop it up so it will be back out there next summer. We've got another driver in Sault Ste. Marie, Ontario, which is waayyy far away, but he hopes to come race a couple of times. I'm hoping we can average nine or ten boats per race in 2010.

    Also, Mike Weinendt has invited GT Pro to run at the Nationals in 2010 as a demonstration class. We need eight boats/drivers to commit, so we're hoping we can make that happen.

    Tunnelboat and V-bottom Plans for 15-35 hp, 40-60 hp, 60-80 hp

    Dillon-Racing.com also on YouTube, on Facebook, on Twitter

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Who's Who in Boat Racing
    By Mark75H in forum Boat Racing Encyclopedia
    Replies: 395
    Last Post: 09-30-2017, 08:50 PM
  2. A Howard Pipkorn Class???
    By Ron Hill in forum Tunnel Outboards and Tri Hulls
    Replies: 10
    Last Post: 01-12-2007, 10:15 AM
  3. New SE Circleboat Racing class proposal
    By Norseman in forum Mini Boats and Mini Boats History
    Replies: 5
    Last Post: 03-16-2006, 04:55 PM
  4. Entry level class info!!!
    By T-REX in forum BRF Open Discussion
    Replies: 1
    Last Post: 08-20-2005, 03:27 PM
  5. Australian Junior Racing
    By Drats in forum BRF Open Discussion
    Replies: 5
    Last Post: 03-20-2005, 11:53 AM

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •