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The Unofficial 7.5cc Tunnel Thread

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Old 08-25-2007, 10:25 PM
  #1
ryan_t888
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Default The Unofficial 7.5cc Tunnel Thread

I would like to turn this thread in to something that can be very useful for anyone with a 7.5 Tunnel. Information on stock or modified 7.5cc engines can be shared here as well as all the tunnels available on the market.

I'll start with my DPI 33" Tunnel that I have owned for a little over 4 years after purchasing it used, and it is still my absolute favourite boat.

It sports a K&B with a Silver Bullet pipe from HTBboats, muffler and prop shaft rebuild kit from www.ovalexpressracing.com , Hitec 5645 steering servo, futaba S3004 throttle servo, 4+8oz tank, failsafe and 4 cell 4.8v receiver battery. I'm pretty happy with this setup. Using 25% nitro and a Prather 230, I'm in the low 40's. I'll have an accurate GPS figure soon to come.

Here are a couple photos. I hope together we will come up with a very valuable thread and shed some more light on the 7.5 OB class.

Thanks
Ryan


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Old 08-25-2007, 10:55 PM
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Default RE: The Unofficial 7.5cc Tunnel Thread

Good idea Ryan[sm=thumbup.gif],

this is an HTB-360-2, 36" in length, .45 Rossi, lawless lower unit, carbon fiber salisbury pipe but now i'm using the Silent pipe by Irwin, likes x447 prop, 1/4 scale steering futaba servo, futaba micro for throttle,nomadio 2.4Ghz radio.
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Old 08-25-2007, 11:50 PM
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Default RE: The Unofficial 7.5cc Tunnel Thread

very good idea! Now we need a 3.5 tunnel thread also! As I dont have a 7.5 boat
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Old 08-26-2007, 10:11 AM
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Default RE: The Unofficial 7.5cc Tunnel Thread

Its kinda funny I happened to come across this I have a 32" prather lap cat II that I have had since I was a teenager. I have not driven it in about 3 years last year I figured it was time to rip it apart and repaint & rebuild it. With young kids It has taken alot longer than wanted. Anyway I've only painted one boat in my life and I want to do it nice. Just wondering if any one has some ideas on themes. Im also not sure if I want to go with decals or not. I also wondered if the flames on most boats that I see on this site are decals or decals used to paint the flames. Any help, ideas or pics would be great thanks.
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Old 08-26-2007, 11:15 AM
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Default RE: The Unofficial 7.5cc Tunnel Thread

You can check out the tunnels on this site www.HandRcustoms.com He is the guy who paints all of my and most of my teams boats. You may not want to spend the money to get him to do it, (although its not too expensive), but it will give you an idea of some paint schemes.

~James

PS, good thread, somebody go ahead and start a 3.5 tunnel thread too!

PPS, so who is bringing a 7.5 tunnel to the World Tunnel Champs next year? I am!
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Old 08-26-2007, 04:14 PM
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Default RE: The Unofficial 7.5cc Tunnel Thread

James, I will start a 3.5 tunnel thread right now Rodney Pierce
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Old 08-27-2007, 02:10 AM
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Default RE: The Unofficial 7.5cc Tunnel Thread

Thanks for the great thread, I know I'll be using it allot. Lot of pro's in here to ask for help.

My Rossi powered tunnel finally started to run consistantly this weekend. I got some great practice laps in for next weekend's club race. I really looking forward to my first race. Allthough my boat is not the fastest out there yet , I'm confident she will get there although I must say that allot of our races have been won by consistancy and not speed. Allthough speed makes it a lot more fun.

Check out my "fan" in the pic.
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Old 08-27-2007, 04:31 AM
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Default RE: The Unofficial 7.5cc Tunnel Thread

NICE THREAD!!

Ive got a super pro K&B and im having a WOF built soon. might get a different motor though.
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Old 08-27-2007, 07:31 AM
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Default RE: The Unofficial 7.5cc Tunnel Thread

Wave waker, that a pretty sweet setup. I wanted to go ROSSI last year but from what I've heard, I'm not sure if it is worth it. How fast has your Rossi pushed that hull?

Ryan
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Old 08-27-2007, 07:45 AM
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Default RE: The Unofficial 7.5cc Tunnel Thread

Rossi 7.5's are great engines. They run better than, and are of better quality than a K&B. On top of that, you can actually get Rossi's, unlike K&B's We run Rossi's on our 7.5's with great success, stock or modified. They just need a little tweak here and there, as with darn near any engine.

Just my $.02 ~James
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Old 08-27-2007, 08:39 AM
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Default RE: The Unofficial 7.5cc Tunnel Thread

anyone have any idea on when the TS3 is coming out?????
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Old 08-27-2007, 09:09 AM
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Default RE: The Unofficial 7.5cc Tunnel Thread

I doubt it will be for a 7.5 engine.

Ryan
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Old 08-27-2007, 07:57 PM
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Default RE: The Unofficial 7.5cc Tunnel Thread


Hey Jan the Man where is your venue in Cape Town that looks like TweeWaters kloof!!!!
Cheers Ou Boetie
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Old 08-27-2007, 10:53 PM
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Default RE: The Unofficial 7.5cc Tunnel Thread


Quote:
ORIGINAL: Jan_the_man

Thanks for the great thread, I know I'll be using it allot. Lot of pro's in here to ask for help.

My Rossi powered tunnel finally started to run consistantly this weekend. I got some great practice laps in for next weekend's club race. I really looking forward to my first race. Allthough my boat is not the fastest out there yet , I'm confident she will get there although I must say that allot of our races have been won by consistancy and not speed. Allthough speed makes it a lot more fun.

Check out my "fan" in the pic.

how cool it could be running boat with chopper hovering above[sm=thumbup.gif]
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Old 08-28-2007, 12:19 AM
  #15
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Default RE: The Unofficial 7.5cc Tunnel Thread

No Peter we are Cape Town side of Paarl. At the turnoff to Wellington. Our dam is about 1% of t-waters.
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Old 08-28-2007, 12:42 AM
  #16
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Default RE: The Unofficial 7.5cc Tunnel Thread

It's a great venue to race at , I would just like to be able to spend more time there , but we are a bit restricted by the farmer who owns the dam. I can definately use the practice and setup time on the water.

We just finished modifying the stock rossi carb last night and will be testing it soon. Just waiting for the remote needles to arive from OER.

I haven't done a speed test yet and will rather wait and play a bit before I do that. Like I said she still isn't the fastest out there...
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Old 08-28-2007, 10:38 AM
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Default RE: The Unofficial 7.5cc Tunnel Thread

Hey All,

I have had a 7.5 tunnel since 1994 (K&B). it was a gift from my father. It has collected dust over the years but I'm dragging it out for a refit.

The one obvious fact I notice is it has no exhaust or muffler, if nothing else it is incredibly noisy. Does anyone know where i could get them from?

Second was on the KB site and saw they have a 16.4cc outboard now. Anyone using that on a tunnel or is it too heavy/powerful.

Thanks for the Help

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Old 08-28-2007, 12:10 PM
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Default RE: The Unofficial 7.5cc Tunnel Thread

Try www.ovalexpressracing.com.

He has a header, pipe and muffler that will work very well for your K&B.

- HTB Silver Bullet 7.5cc Tuned Pipe
- HTB 3.5cc/7.5cc/11cc Aluminum K&B Header
- OER 7.5cc Add-On Muffler. Custom Fit

Post a photo of your Tunnel. I wouldn't recommend going any larger than 7.5cc for a 33-37" hull. A 7.5 will be fast enough!

Ryan
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Old 08-28-2007, 02:05 PM
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Default RE: The Unofficial 7.5cc Tunnel Thread

Thanks Ryan,

Will have a look at the site now.
At present theboat completly sanded to the base coat, but will dig of photo from its prime and add it on..

L8r
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Old 08-28-2007, 03:57 PM
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Default RE: The Unofficial 7.5cc Tunnel Thread

Hi Rowley15

Cobus Fourie here from South African Model Powerboat Association. We have a representative of OER in Cape Town. Their is guys racing in Gauteng and the club is growing quite nicely. Please feel free to contact me at 021 558 1301 or 084 558 1301 for contact details.
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Old 08-29-2007, 02:03 AM
  #21
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Default RE: The Unofficial 7.5cc Tunnel Thread

Hey Cobus,

Many thanks for the info, I will do that.

Go the Bokke!

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Old 08-29-2007, 05:47 AM
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Peter T
 
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Default RE: The Unofficial 7.5cc Tunnel Thread


Hey Rowley, the Bokke going to win the world cup, 7 days till the whistle blows.
Go the ALL BLACKS !!!!
Cheers Peter
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Old 08-29-2007, 09:33 AM
  #23
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Default RE: The Unofficial 7.5cc Tunnel Thread

How can you say in one sentence the Bokke's going to win and in the next sentence cheer for the Down under boys. Might I asume you might be from down under Peter T
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Old 08-29-2007, 12:29 PM
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Default RE: The Unofficial 7.5cc Tunnel Thread


From Zim Cobus, !! so I suppose I should support the Bokke hey looking forward to the World Cup
Cheers
Peter
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Old 08-29-2007, 02:02 PM
  #25
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Default RE: The Unofficial 7.5cc Tunnel Thread

Ya, World cup gonna be a cracker..

Back to the Boats, anyone tried to use a third channel to change the engine trim while running?

Should not be too dificult..
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