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The UNOFFICIAL 3.5/.21 Tunnel thread

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The UNOFFICIAL 3.5/.21 Tunnel thread

Old 08-26-2007, 04:21 PM
  #1  
iowapiper_rcp
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Default The UNOFFICIAL 3.5/.21 Tunnel thread

Well guys, I see we have a 7.5 cc tunnel thread, so we also need a 3.5 cc tunnel thread. Well hopefully RCU will let it stay. Post all your 3.5 tunnel questions here, from props, to setup, any hulls, scratch built, fiberglass, you name it! I will start off by posting my boat. its an HTB290 with a Thunder Tiger. Yes, you heard right, a junky old thunder tiger, that Jerry Wyss has done up for me. Pretty hot motor, but havnt gotten the setup figured out yet. Balance point is currently at Approx 28%, X637 prop, bag stock, just S/B. Irwin QP at Approx 8 1/2 inches. Water pinched down to near nothing. Motor was a proven hard runner before, but it now has a different piston/sleeve, head space and timing then the last mod, along with a deeper head button, and angles squish. So as you see, it takes some time to get this beast setup
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Old 08-26-2007, 07:16 PM
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RaysonCraft
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Default RE: The UNOFFICIAL 3.5/.21 Tunnel thread

MRP ABS bud lite tunnel. Custom radio box. Sharpned up all the running surfaces. First time out the engine height and angle were just about perfect.

Had a bone stock K&B 3.5 run 32mph. a very slightly moded K&B run 35mph. Had some fuel tank issues with a single tank.

Now I've put on a Frankenstein K&B. Gold carb, single bubble head SX muffler, SX lower, thined and cut skegg. and a hopper tank setup that has yet to be tested. The new engine screems but I haven't got the setup down yet. I was fighting with fuel draw issues that I hope the new hopper tank should fix.

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Old 08-26-2007, 09:21 PM
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terry kelly
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Default RE: The UNOFFICIAL 3.5/.21 Tunnel thread

rodney i seen you run a thunder tiger as well.. i have one and really want a setup on my exhaust like yours how did you do it and what part numbers if you have them, that would be really helpful . also i have another top speed 2 with the os 21 xm and would like to tune pipe that one as well. any help would be great and i need to run wiht you guys sometime, gettin my butt kicked by woody "chris wood" all the time at everything we have ever raced together stinks..lol
Old 08-26-2007, 09:39 PM
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wave waker
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Default RE: The UNOFFICIAL 3.5/.21 Tunnel thread

there u go!this will be an interesing thread too[sm=thumbup.gif]..soon to post mine.
Old 08-27-2007, 05:15 AM
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ozbryan
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Default RE: The UNOFFICIAL 3.5/.21 Tunnel thread

Again NICE THREAD!!

Ive got a couple of these ones

2x ts2 one with an OER OS full mod ( just won our winter spectacular) and one with a cmb green head and a villian with a K&B but could become electric.
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Old 08-27-2007, 06:37 AM
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topfuel4430
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Default RE: The UNOFFICIAL 3.5/.21 Tunnel thread

OK, I will throw my 3.5's on here. This is my fleet from 2007, I will be building 3 new HTB's for next years World Tunnel Champs.




A picture of the boats in my shop. Very top (barely see it) is my 3.5cc SAW boat. Next one down is my Nemesis running twin OS outboards, runs in either the Mod 7.5 class, or the Sport 7.5 class., next down is the villain extreme, Next Is Grimracers old boat for Mod .21 class, and lastly is another Villain that has been converted to FE power, running a NEU Brushless, and Barracuda Speedo on 12 cells.




Back view of the modified sponsons on the villain, it has been dubbed "Villain Extreme". This is my sport .21 class boat, and runs a OER OS sport motor.




Back side view of the Villain Extreme.




This is Mike Zaborowski's old boat, a Power Surge Racing Producst (his old business) Nemesis. I am running a OER Mod Rossi 3.5 on it.


I have a few more .21's, and honestly am not sure why! I just love the little 3.5's.

~James
Old 08-27-2007, 07:20 AM
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Default RE: The UNOFFICIAL 3.5/.21 Tunnel thread

James, now I understand why your store is packed with all the goodies for the 3.5 class. A very nice fleet you have there!

Great thread. The 3.5 class has always been more popular.

Ryan
Old 08-27-2007, 11:25 AM
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Default RE: The UNOFFICIAL 3.5/.21 Tunnel thread

cCool Guys will be posting mine up shortly...OZBRYAN mate whats the top spped you are getting out of your two Top Speed Two Boats and do you have a problem with Porpising when slowly down and going into a corner....Hey James NICE fleet mate...Why arent you running a pipe on that HTB290 buddy..Any reason why???? and what props are you using...
Old 08-27-2007, 11:54 AM
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topfuel4430
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Default RE: The UNOFFICIAL 3.5/.21 Tunnel thread

Barry, what are you refering to? There isnt a HTB290 in the pictures....

~James
Old 08-27-2007, 12:18 PM
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Default RE: The UNOFFICIAL 3.5/.21 Tunnel thread

Oh my mistake James I thought the 2nd one down was a 290...I see anyway you not running pipes on those engines.
Old 08-27-2007, 12:34 PM
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Hesco Racing
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Default RE: The UNOFFICIAL 3.5/.21 Tunnel thread

James here's a question. Have you tried to fit a OS .21vz-m onto a OS leg and what could that turn up seeing that the motor makes so much more power?
Old 08-27-2007, 12:45 PM
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topfuel4430
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Default RE: The UNOFFICIAL 3.5/.21 Tunnel thread

Hesco, there are a couple guys running VZ's, but you have to have a new crank machined, as the inboard version wont work. They run ok, but certainly no better than whats currently available. I thought about it, but just not worth it in my opinion.

Barry, the OS's dont have pipes because the boats are run in the IMPBA "Sport" class. You cant run tuned pipes in that class. The OS with a Stock muffler will run just as good as one with a pipe, if eveything is where it needs to be. The OS XM is a great little engine, with only few things needing change. The boat you are refering to runs just as fast as my Mod tunnel.
Old 08-27-2007, 12:47 PM
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Default RE: The UNOFFICIAL 3.5/.21 Tunnel thread

To my understanding, both engines rotate in different directions. Outboards always rotate clockwise when looking down on to the engine's flywheel.

Ryan
Old 08-27-2007, 12:54 PM
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topfuel4430
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Default RE: The UNOFFICIAL 3.5/.21 Tunnel thread

Here is another shot of the business end of the Twin.



It was rediculously fast in a straight line, but was too much power, and not enough boat, so everything is going on a 7.5 hull.

~James
Old 08-27-2007, 01:37 PM
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Default RE: The UNOFFICIAL 3.5/.21 Tunnel thread

Wow what a great set up...Have never seen a twin installation before...GO OVAL EXPRESS...TOP TEAM
Old 08-27-2007, 02:01 PM
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Hesco Racing
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Default RE: The UNOFFICIAL 3.5/.21 Tunnel thread

And those few things would be what James.
Old 08-27-2007, 02:16 PM
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topfuel4430
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Default RE: The UNOFFICIAL 3.5/.21 Tunnel thread

Aw come on Cobus, you know, a little tweak here a little tweak there Its more about the prop and setup than anything, but our Sport Mod motors run well. Flow is the key. Id be glad to do one for ya. Hopefully I can make it to South Africa next year to run with you guys, and that is the boat I would probably bring.

~James
Old 08-27-2007, 02:44 PM
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Default RE: The UNOFFICIAL 3.5/.21 Tunnel thread

Ok, I just bought this TS2, I ordered this boat from tower Hobbies, and a day later they called and said it wasnt shipped for some reason months bak, well, up to now, I had recieved the boat, and didnt exspect it to arrive. Im not a tunnel guy, but when the boat came in, I really liked the hull, so i figured id go ahead and deck the boat out, so i went with the .21 Rossi w/ rap around tuned exhaust, and it can with an octura prop, not sure what size. This boat is running in the mid 50's, fastest boat (nitro) that i own. heres some pics, enjoy.


Old 08-27-2007, 02:57 PM
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topfuel4430
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Default RE: The UNOFFICIAL 3.5/.21 Tunnel thread

Mid 50's huh? Do you have videos of her running? Sounds like its going good. Intersting car pipe set-up, I tried that years ago, but could get much out of them, they were pretty quiet though. Boat looks good.

~James
Old 08-27-2007, 03:33 PM
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Hesco Racing
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Default RE: The UNOFFICIAL 3.5/.21 Tunnel thread

Your very sneaky Mr Clegg. Now tell me this. OS 21 - 2 liters of feul through her - Head shim removed - cooling removed - 50% Nitro feul, 15% oil (12 Morgan 3 Castor) - OS R5 plug - mild day and the cow wont make temp?????[>:]
Old 08-27-2007, 03:35 PM
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Default RE: The UNOFFICIAL 3.5/.21 Tunnel thread

Ok, mid 50's, around 52 if gps was right, this motor is pretty quiet, but when it was broke in, running 65%, it was screaming, i had actually flipped it in a turn and did a couple of rolls lol these pics were took b4 it was ever ran. Yea ill get a video pretty soon, thanks.
Old 08-27-2007, 05:25 PM
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Default RE: The UNOFFICIAL 3.5/.21 Tunnel thread

Hi all here are some Pic's of my 3.5.
Old 08-27-2007, 05:42 PM
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Default RE: The UNOFFICIAL 3.5/.21 Tunnel thread

Sorry here they are.
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Old 08-27-2007, 08:55 PM
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agentorangeracer
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Default RE: The UNOFFICIAL 3.5/.21 Tunnel thread

Wow,what hull is this and who makes it, kinnda fat lol. but pretty cool.
Old 08-27-2007, 10:03 PM
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Default RE: The UNOFFICIAL 3.5/.21 Tunnel thread

That I believe is an F1 tunnel.

Dan.

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