IMPBA gas outboard tunnel class

[Bob Kensill]

Just got off the phone with a well known tunnel designer/ builder. We were talking about making a set of rules for the class. We discussed some basic rules to get things going. We agreed on a maximum engine size of 32cc, and a minimum boat length of 40 inches. Obviously there many other specs that need to be discussed. So here is your chance to be a part of the rules group. What I would like to see in your posts is, if you are currently running the class, where you are from, what boat/ engine combo, and etc. please, no arguing or complaining about what happened in the past. I will try to get a voting board member to bring the proposal before the board. Ready Set Go

 

[rumrunner]

Thor with a 30.5 . But I think some of the guys in other places of the world are using quick draw 35 , if they deside to come to one of the races in USA they would have to change motors ,so maybe you should go to 35cc just a thought .

 

[Bob Kensill]

Thanks for your input, let's see who else has some ideas.

 

[michael faszcza]

Why not 40 inch min but 27cc max ? The cost to get into the class is expensive enough

 

[michael faszcza]

Im in virginia .i have a ml boat works gx480. I'm just getting it together but have a 26 full mod or a 29.5 promod

 

[jaxracer]

Why not 40 inch min but 27cc max ? The cost to get into the class is expensive enough

Most guys are running at least 29s so that wouldn't work. I agree with the 35cc max for now just to get the numbers up for the class. Btw Bob, my dad is running a Thor 470 with a 29.5 Zenoah. I don't see a point in running a hull minimum. If you can squeeze a gas motor on a 38" boat and make it run competitively then go for it but good luck. I do see a need for a max though because at some point you're just throwing a barge out there and makes it difficult on the pitman and the retrieve guys. Say 53" max because I think that's how long the Ossi hulls are that people were running for a while.

-Mitch

 

[dave roach]

Bob

The 470 THOR is 47 inchs long.

Dave Roach

 

[RonShaw]

I would like to see us follow the standard LSG Rules. We have either the LSG 27 or LSG 36 Engine Classification Rules. Most all IMPBA LSG Classes follow LSG 36. All NAMBA Classes follow LGS 27 rules. I know 90% of the Gas Tunnels I have seen to date (IMPBA races) are between 27-32cc (LSG 36 specs). With this in mind, my suggestion would be for the IMPBA Gas Tunnel Class to be LSG 36 Gas Tunnel. Once this class is established in IMPBA, I would like to follow suit and suggest that NAMBA follows the same LSG 36 specifications for NAMBA OPC Gas Tunnel class so the same entries would be accepted in both organizations races.

IMPBA Rule Book

IV - ENGINE CLASSIFICATION

The gasoline LSG engine classes shall be divided into classes, distinguished by maximum displacement.

(Formulas CC x .061 = CID or CID divided by .061 = CC)

A. General Engine Rules for the LSG 27 Engine Classes

LSG27 Up to 1.647 cid maximum (27.0 cc maximum)

1. Maximum displacement will not exceed 27.0 cc.

2. All engines must have a canister muffler, tuned pipe, or custom exhaust that meets the

current IMPBA db levels (as per section K-4 of the IMPBA Technical Standards).

3. All 2 cycle engines must be naturally aspirated.

4. All 4 cycle engines must be naturally aspirated.

5. Internal and external modifications may be made to the engines major and minor

components.

6. Single piece cylinders or cylinders with removable head buttons are allowed.

7. Major and minor parts from secondary manufacturers may be used.

8. The engine must use spark ignition. No glow plug or compression induced combustion

allowed.

9. Each engine must have a working throttle control and the engine must be set up to be

completely stopped with the transmitter controls.

10. Any size or brand name carburetor may be used.

11. Pull start or belt/pulley start are acceptable methods of starting the engine.

B. General Engine Rules for the LSG 36 Engine Classes

LSG36 1.648 cid thru 2.196 cid maximum (36.0 cc maximum)

1. Maximum displacement will not exceed 36.0 cc.

2. All engines must have a canister muffler, tuned pipe, or custom exhaust that meets the

current IMPBA db levels (as per section K-4 of the IMPBA Technical Standards).

3. All 2 cycle engines must be naturally aspirated.

4. All 4 cycle engines must be naturally aspirated.

5. Internal and external modifications may be made to the engines major and minor

components.

6. Single piece cylinders or cylinders with removable head buttons are allowed.

7. Major and minor parts from secondary manufacturers may be used.

8. The engine must use spark ignition. No glow plug or compression induced combustion

allowed.

9. Each engine must have a working throttle control and the engine must be set up to be

completely stopped with the transmitter controls.

10. Any size or brand name carburetor may be used.

11. Pull start or belt/pulley start are acceptable methods of starting the engine.

 

[Bob Kensill]

Keep the ideas coming.

 

[HTV Boats]

I think Ron has it spot on. 27 & 36 cc limitations are established in both NAMBA and IMPBA. Clubs can choose which designation works in their area or to accommodate traveling racers. I ran gas and have obsolete 26's I paid good money for cause everyone had to have a 2-4cc edge. Sold half of my gas fleet and the rest is gathering dust. No need for a minimum length just to have something to enforce.(and protest) If someone figures out a better smaller mouse trap it's a positive for the hobby.

Mic

 

[Ronald L Cook]

Minimun boat length of 40" sounds good, what would the max be 50"

Ron

I was just thinking hull length, just getting use to adding the outboard unit to over all length.

Ron

 

[Bob Kensill]

IMPBA limits boats to 60" max overall length, including hardware and 25# max weight. Do you guys think it will work?

 

[Bruce Clark]

Just a thought and don't know if anyone is running a 4 stroke engine. In Moto-X they allow twice the engine size for the 4 stroke engines. 125cc two strokes run against 250cc four strokes. Is this something to consider down the road that may need addressing now? I see a lot of 4 stroke motors in the r/c airplane group. I don't run gas but I'm sure I will someday.

 

[rumrunner]

IMPBA limits boats to 60" max overall length, including hardware and 25# max weight. Do you guys think it will work?

You d have to weigh one of the ossi glass boat fully rigged to come up with a weight because they where the heaviest , that would give people with them a chance to race them. I would say all of us at the WTC fell under lsg36.

 

[Greg Rowe]

Brandon Club Florida Insane with a 29.5 at 20 pounds, but why change the 26 to 30cc ? when is this going to stop with the increase engine displacement.

in the last 3 years the classes keep changing,I started with $600.00 26 mod motors and now $700 .00, 29.5.(all gas classes)

So lets keep it simple and in a cost range people will stay in the game.

there is only a hand full of gas tunnells because of the cost. or just leave it wide open and deep pockets can show up with 60cc twin cylinder.

Greg

 

[MarkScott]

#11: Need to include the "cone" start also. When I ran my gas tunnel, I changed out the pull starter and placed a cone on top. The starter I use for all my tunnels then started my gas motor. No belt or pull start for me.

 

[Carl Van Houten]

I have enjoyed the Gas Outboard Tunnel project. I watched the class for a while before I got involved with it. I hope that it can become an official class soon and is the reason this thread was put up. The Gas rules that Ron Shaw put on here are already being used to govern the other gas classes and seems to be working for them. If not, speak up and let's hear what you think should be changed so we can get our O/B rules as close to right as possible from the start.

We could tweak them to suit our O/B initial needs such as the cone start option that was mentioned then get them on the books.

Everybody has their own ideas and rules can't please everybody but we need to put something in place to get things started and if the wording needs to be tweaked we can go back to it and get it changed to suit the racing class majority.

I only build into the class so what I think doesn't really count. I think Bob wants to hear what the actual racers of this class think. It is about what they want. If I did race the class, my vote would be to use the LSG rules as a baseline, tweak them to suit O/B's and get them approved.

-Carl

 

[RonShaw]

Greg,

The current LSG 36 class covers us all. Basically anything above 27cc is included in this class. Most everyone I have seen enter the Gas Tunnel class since I started running falls into this classification. What makes it easy is it has already been established within IMPBA and NAMBA, which makes this part of establishing the new class very easy.

 

[RonShaw]

#11: Need to include the "cone" start also. When I ran my gas tunnel, I changed out the pull starter and placed a cone on top. The starter I use for all my tunnels then started my gas motor. No belt or pull start for me.

Mark,

I have been using the cone start on my outboard for two years also will a lot of success. Using a cone, pull start, or pulley are all boater preference in the Gas classes.

 

[jaxracer]

I have enjoyed the Gas Outboard Tunnel project. I watched the class for a while before I got involved with it. I hope that it can become an official class soon and is the reason this thread was put up. The Gas rules that Ron Shaw put on here are already being used to govern the other gas classes and seems to be working for them. If not, speak up and let's hear what you think should be changed so we can get our O/B rules as close to right as possible from the start.

We could tweak them to suit our O/B initial needs such as the cone start option that was mentioned then get them on the books.

Everybody has their own ideas and rules can't please everybody but we need to put something in place to get things started and if the wording needs to be tweaked we can go back to it and get it changed to suit the racing class majority.

I only build into the class so what I think doesn't really count. I think Bob wants to hear what the actual racers of this class think. It is about what they want. If I did race the class, my vote would be to use the LSG rules as a baseline, tweak them to suit O/B's and get them approved.

-Carl

I agree with Carl. Roll with the LSG 36 rules as that will incorporate everyone who has already built a gas tunnel, but tweak them slightly to read a minimum displacement that will also include the handful of guys that are running the Zenoah 260s. Don't worry about hull mins or maxs (just roll with the IMPBA 60" max). Throw in the rule about the cone start, coupled with the rules of a tunnel and what constitutes as an outboard (let the turn table vs. transom mount debate begin). If it's mounted on a transom and the engine turns with the lower to steer the hull, then it's an outboard. I'm sure you guys can clean up the wording, but you get the gist. Other than that, let's get this thing drafted and put her in the books fellas.
-Mitch