Tunnel Hull Speed

[Greg Ballard]

I just got into this awesome hobby about 4 months ago and think it is the greatest thing sense pocket on a shirt. The problem is there is no racing or clubs close around so I would like to know what a good speed to shoot for on my boat. I have a Mike Starrett tunnel hull with a Thunder Tiger 3.5 and a octura x637 3 blade detounghed bar cut balanced and polished prop. I have gps at 39.8 mph and would like to know if I am at top speed or is there some left.

 

[bzubee]

there is always something left just a lot harder to find it as the speed goes up. Some hulls and sport engines are capable of speeds over 50mph I would say you should be able to up to at least the low 40's.

 

[Greg Ballard]

Thank you,I looked at the wrong notes the prop was a Grimm Racer 40x52 3 blade not a octura sorry.

 

[Grimracer]

Greg,



The fastest of the fast are in the 50MPH and a tick above that range. DONT LET THAT get in your way however.

In time.. you will get your "tunnel hull program" into the mid 40s and beyond.

The hull is VERY important to faster numbers as well as the motor and prop. If you choose the MS hull as your weapon know with any hull there are limits. Know that with any motor there are limits. Understand that with props.. there are VERY few limits.

Hence.... learn props.....and good news is they are cheaper then new motors...or hulls for that matter.

Then.. when you feel you have it figured out let us know.. we all need and want MORE SPEED!



Stick with it!



Grimracer

 

[RodneyPierce]

Also remember the faster you go the harder it is to keep the boat on the water. I'm dealing with that right now. I currently have my tunnel in the upper 40's low 50's but am having trouble keeping it on the water. More time and small tweaks and she will get there.

The man above gives some of the beat advise out there. Stick with it!

 

[Rhonda Pickard]

Get one of Grims 40/53 2 blade had that on a cobra 20 with a o.s. i was hitting 50 mph, you should pick up more with that prop Robert

 

[RodneyPierce]

Robert the TT is a bit of a different animal. I found an x637 to be the best prop on that motor. The key is getting it to spool up. Cut the water down to nearly nothing and it will go.

 

[Steven Bryant]

What fuel are you guys running?

 

[RodneyPierce]

Im running 66% Torco.

 

[Tim_Duggan]

Robert the TT is a bit of a different animal. I found an x637 to be the best prop on that motor. The key is getting it to spool up. Cut the water down to nearly nothing and it will go.

Exactly right. Plus dig out the head shim thats pressed into the head button and use a MC59 Mccoy or K&B 1L or ODO 77 plug.

My Sport 3.5 only does a real 44mph in heat race trim and wins plenty of races. There's more to racing than just top end speed (it helps though!)

 

[Rhonda Pickard]

Very true Tim it isnt how fast it is if you finish and be consistent, i run 50% in all my boats and Odonnel blue plugs Robert

 

[John Knight]

There is an absolute truism in boat racing - the boat that runs the fastest LAP will win the race and not the boat that runs the fastest. The fastest lap time brings all aspects into the equation, boat trim, prop, engine trim, pipe and driver ALL must work in sync. The % of nitro is the very least aspect needed. A boat running 70% running in a poorly trimmed boat will be like a brick pushing around the lake. Mic has spoken on this subject many times and few just seems like they have caught on. If a boat is flying off the water at the 50 mph mark more set up is needed, big time. My Vision is running in the mid 50's, absolutely planted on the water regardless of water and wind conditions, and I can run the corners at any throttle position and speed that I want. And there are a bunch of other drivers that can do the same thing. It takes a lot of work to get there for a tunnel, which is the most challenging of all hulls IMHO, and high nitro is not required to get there.

 

[RonShaw]

Ditto John!!!...

Mod tunnel for clarification, not Sport....

Only seen a couple sport tunnels get this much speed but were IMPBA modded motors inside!!!...

 

[RodneyPierce]

Mid 50's isnt easy to achieve. (in a .21 sport tunnel) I have a very hard time believing that a mid 50's boat can run tight to the water. Perhaps it can, but I havent seen it.

 

[Grimracer]

RP...After years of this me either man.. But he said it so it must be true.. its on the internet! lol.. just kidding John..

Grimracer 50% for me!

Grim

 

[Andy Greene]

To Finish First- First You Must Finish

 

[HTV Boats]

Unless your going to record trials for SAW runs the GPS and Radar gun are nothing but "False Gods". Even two bouys 300' apart and a stop watch will improve your setup. Add bouys or a regular course and the bonus of a watch is you WILL become a better driver. If and when you actually run heats all that's left is trim for conditions and traffic. If you don't know your lap times your leaving "money" on the table. Racing is about leaving as little to chance as possible. Control what you can, prepare for what you can't.

Mic

 

[Rene Danner]

To Finish First- First You Must Finish

So true...

 

[Andy Greene]

Unless your going to record trials for SAW runs the GPS and Radar gun are nothing but "False Gods". Even two bouys 300' apart and a stop watch will improve your setup. Add bouys or a regular course and the bonus of a watch is you WILL become a better driver. If and when you actually run heats all that's left is trim for conditions and traffic. If you don't know your lap times your leaving "money" on the table. Racing is about leaving as little to chance as possible.

Mic

Even MORE true, lot to be said there B)

 

[RodneyPierce]

Agreed Mic. But one cant argue with fast speed, and fast lap times....