To all IMPBA Outboard Racers.

[Grimracer]

then.. with this news.. as long as the "size" (Volume?) is met.. AND you use one of the hole sizes listed.. one "COULD" make there own muffler from Carbon fiber, aluminum or whatever... Could one bolt on a airplane muffler?

Carl, whats the going price for the thunder tiger muffler and the K+B.. I cannot find those.. the OS is 83 bucks.

Grim

 

[Marty Slater]

sounds like a pipe to me or a mod
not a sport

 

[Carl Van Houten]

then.. with this news.. as long as the "size" (Volume?) is met.. AND you use one of the hole sizes listed.. one "COULD" make there own muffler from Carbon fiber, aluminum or whatever... Yes, you can make your muffler out of any material you want. It's a muffler not a tuned pipe. If you do make your own muffler it had better meet the specs or your boat will not race in the class. Could one bolt on a airplane muffler? No airplane mufflers that I have ever seen will qualify for this class.

Carl, whats the going price for the thunder tiger muffler The Thunder Tiger Muffler is made or Cast-into their lower unit. It's max exhaust outlets are given if someone chooses to run one. As you know that engine would struggle to keep up with the other RTR outboards.

and the K+B.. I cannot find those.. The K&B 7.5cc canister muffler is listed as available status and is P/N 30-8721 for $38.60, Adaptor P/N 30-8722 for $12.00 . The 3.5cc Canister Muffler P/N 30-8921 is showing available status and is $39.90 with the adaptor P/N 30-8922 for $12.85. Looks like the other 3.5cc canister muffler P/N 30-8923 is out of stock right now. These can be found at the K&B / MECOA website. the OS is 83 bucks. I have not priced them.



Grim

 

[Carl Van Houten]

sounds like a pipe to me or a mod ??? Okay how?
not a sport Not sure what has been said in this post that would make you believe that a canister muffler was remotely similar to a tuned pipe. A premanufactured or custom built canister muffler that meets the dimensional requirements for the class offers you no resonant advantage.

 

[Kris Flynn]

Simple questions here also...since there is talk of very old motors...

How competative is an 8907 Vs an OS in the current Sport Rules?

How many people currently RACE a K&B 8907?

I dont think anyone ran an 8907 k&b at the 2014 tunnel race i was at, certainly no one in the top 10 maybe even top 20 (from memory). Why? Because they are not as competitive I would think. Therfor these new rules surely wont make them any less competitive...it should actually make them MORE competitive as you can adapt an OS or SS muffler to them.

Anyway...just my .02c

LETS RACE!!

 

[Carl Van Houten]

Simple questions here also...since there is talk of very old motors...

How competative is an 8907 Vs an OS in the current Sport Rules? About 10 years ago I made a print for a simple adaptor plate that would allow you to bolt the O/S 3.5cc muffler to a 3.5cc K&B. I sent one to Kevin Lee and one to Joe Monohan. Both made the adaptor from the print. The performance improvement was apparent right away with both engines. Joe has since passed but as far as I know Kevin Lee still has this combo. He called it his K&S. Even though this engine was greatly improved, he had to put it away because it was not legal to put in the Sport 3.5cc class.

How many people currently RACE a K&B 8907? Right now probably none. There are thousands of them sitting in racers old engine boxes not being used.

I dont think anyone ran an 8907 k&b at the 2014 tunnel race i was at, certainly no one in the top 10 maybe even top 20 (from memory). Why? Because they are not as competitive I would think. Therfor these new rules surely wont make them any less competitive...it should actually make them MORE competitive as you can adapt an OS or SS muffler to them. This is true and has already been proven.

Anyway...just my .02c GREAT POINT!

LETS RACE!!

 

[Carl Van Houten]

If anyone has a bag full of K&B 3.5cc powerheads and wants to play around with adding an O/S muffler to it and just play around, I have attached a print of the adaptor that you will need to do it. I will draw more if others are interested in putting canisters on there 7.5 or 11cc engines. Just let me know and I will make the prints for them as well. If you build a 3.5cc SS Out Board using this adaptor, upload a picture of it.

Okay I made a drawing of a split flange for the Nova Rossi 7.5cc. Joey, this is what you will need to build your Super Sport 7.5 O/B. You can lay it out and build it yourself or you can send this print to your favorite machine shop and get them to build it for you. Maybe the machine shop suppliers that visit this site can build some and have them ready when people need them.

If anyone else needs a print made for a custom flange configuration just let me know and I will work it in for you. The print for the Nova Rossi Split Flange is the one in this picture.

Please measure to be sure that the dimensions given will work for your application before building from these prints. Always have to throw that disclaimer in there... For NR 7.5 Split Flange (See Rev2)
-Carl

 

[Carl Van Houten]

Most if not all of the outboard engines shown in the "Car Engine Conversion Mounts" Post will qualify as a Super Sport if you put an approved muffler on them.

 

[Grimracer]

Most.. can you elaborate?

Grim

 

[Carl Van Houten]

"All" sorry. It's been a busy day today. After doing some research I found out today that the 7.5cc Super Sport Class has been raced in the South East since 2005 (17 years).

 

[Grimracer]

so.. all B class motors (power heads) are OK for the B Super Sport Tunnel class.. very good... thats all I was thinking about.

Grim

 

[Carl Van Houten]

Yes. All 3.5cc Power Heads of any manufacturer LH or RH rotation will be legal to compete in the IMPBA "B" Super Sport Class with a legal S.S. muffler.

 

[Mark Poole ModVP]

After reading through this I like the idea. Any powerhead and lower unit with a non tuned exhaust makes for a very interesting choice of power plants. We all know what people were doing with the OS engines in Sport B that set them on fire. And with no engine tear down you could not see it. So basically Super Sport is run whatcha brung without tuned exhaust. I think that is a better plan than running it as Sport B only.
You want to revive outboards I will tell you what will help. Some will disagree. The stigma with outboards it that is a one hull class....tunnel hull. Put some fun back in it by running boats other than tunnels. Personally I think a 'Nitro Outboard Challenge' class would be a hoot. Any hull and any size nitro engine. The Sundowner was a fast boat. The MRP OB canard was a fast boat. And....shameless plug for the Mod-VP's. What will save the outboards is finding ways to make it fun.

I am glad to see someone being proactive. Better than silence.

 

[Carl Van Houten]

Thanks for the support Mark. There are a few Pre-S.S. projects being worked on already. I have gotten a lot of request for the print I am attaching to this post. This one is going to be a very popular part. This S.S. Cup Flange will definitely put some heat on the long standing superior O/S Sport engines. We have all known from day one that the muffler on the O/S was 90% of what was lighting up that powerhead. It will be fun to see what happens when finally after all these years there will be a fair fight back on the table in this class. Note: these are all first draft revision #1 prints. Look them over and check my dimensions before building one.

Next I will make a print for a cup style flange for the 7.5cc Nova Rossi. It will mount with springs just like this one but will provide the matching hole pattern for the K&B 7.5cc Canister Muffler.

 

[Kris Flynn]

Sorry if this is answered already, but I cannot remember seeing this...but are geared setups allowed in this new/updated class?

 

[Carl Van Houten]

Hello Kris,

Geared outboards are allowed in the Super Sport Classes. Geared drives are legal right now because the Thunder Tiger is a legal Sport engine and it is gear driven.

 

[Kris Flynn]

Excellent Carl, that is great news and will definitely get people cogs turning (so to speak haha) on some different setups!

 

[Jeremyhines]

Im glad to hear people want out boards back, mine are all ready to go . I can assure you that I’m a newbie who is excited about going racing. Outboards was a cheaper alternative for me than inboards. I was able to craft my fleet without too much trouble. The parts are out there you just have to look.

 

[Wasted wages]

Nice fleet you have there Jeremy!

I tried an outboard mono many years ago...
couldn't get it to turn very well... I think it was too much boat for the motor..

was fun to play with and let spectators and kids take a try at driving a rc boat.

 

[Carl Van Houten]

Im glad to hear people want out boards back, mine are all ready to go . I can assure you that I’m a newbie who is excited about going racing. Outboards was a cheaper alternative for me than inboards. I was able to craft my fleet without too much trouble. The parts are out there you just have to look.

The O/B hydro's are fun. You can run that O/B mono in the Mod VP class. Where are you located?