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Hot rodding a Zenoah GT80??

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Old 04-06-2011, 06:39 AM
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sodbuster 1
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Default Hot rodding a Zenoah GT80??

Can it be done ? If so is there any horsepower gain?
Is it worth it?

My dillema is this.
Looking to buy a plane that is fitted with one but want a little more power than the 80 provides.
Looked at a few 100 c.c. twins and they won't fit in the cowl.
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Old 04-06-2011, 06:54 AM
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Default RE: Hot rodding a Zenoah GT80??

This is a Ralph Cunningham specialty. He builds racing engines from GT80's and I am sure he will weight in on it soon.
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Old 04-06-2011, 07:13 AM
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Default RE: Hot rodding a Zenoah GT80??

I had a feeling that might be the case.
Was hoping he would.
I lost his contact info....
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Old 04-06-2011, 07:34 AM
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Default RE: Hot rodding a Zenoah GT80??

Ralph would be the man for sure. FYI, the BME 116 is sized not all that much larger than the GT 80, and weighs the same or less.
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Old 04-06-2011, 09:02 AM
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Default RE: Hot rodding a Zenoah GT80??


Quote:
ORIGINAL: Tired Old Man

FYI, the BME 116 is sized not all that much larger than the GT 80, and weighs the same or less.

But at 1.5 times the price. Not realy worth it in this ship.'Specially since it already comes with the Zenoah.
Do you guys know if there's a thread detailing what kind of gains are gotten from Ralphs mods?
Didn't have much luck on my own finding anything on the threads.
OR do you know Ralphs current contact info on here?
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Old 04-06-2011, 09:43 AM
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Default RE: Hot rodding a Zenoah GT80??

He goes by Antique here in the forum. Sometimes he is away at races and such if you don't get an answer.

AV8TOR
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Old 04-06-2011, 09:44 AM
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Default RE: Hot rodding a Zenoah GT80??

Thanks
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Old 04-06-2011, 12:56 PM
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Default RE: Hot rodding a Zenoah GT80??

Slap one, or two, tuned pipes on your GT-80. That really wakes it up.
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Old 04-06-2011, 01:27 PM
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Default RE: Hot rodding a Zenoah GT80??

GT80s are made to run at LEAST 7000 on the ground so they can get into the torque band..Check out the Toni Clark website for the reason there is no power at lower speeds, the engines are made that way....Our stock GT80 race engines turn 7500 on the ground and about 9000 in the air....28 lb GR7 and other Reno style formula one airplanes, 140+ mph...No mufflers, just short stacks...The prop is a special 2 blade APC.....
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Old 04-06-2011, 01:42 PM
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Default RE: Hot rodding a Zenoah GT80??

yeah, but wait and see what happens if you fit a tuned pipe to each of them stacks, and tune for sweet spot  between 9,000 and 10,000 rpm! Power in a good setup almost doubles!
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Old 04-06-2011, 01:43 PM
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Default RE: Hot rodding a Zenoah GT80??

The Toni Clark web site has information on various combinations of the the GT80 www.toni-clark.com/index_en.htm.
I changed my carb to a Walbro SDC 80, added electronic ingnition, cut the rear crankshaft stub off, & converted to CM6 plugs. I don't expect much performance improvement but it will do what I want it to do. If you're looking for 3D performance, better look elsewhere.This engine makes it power above 7000 rpm. Looks like I'm typing too slow!!!!
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Old 04-06-2011, 02:14 PM
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Default RE: Hot rodding a Zenoah GT80??

not looking for 3D performance, but it's powering a 33 lb warbird that only has ground clearance for a 23" prop.
plane at best does a loop with no umph at the top
no room for a 100c.c. size motor in the cowl so was hoping I might be able to gain enough performance to at least drive a 23"
3 blade in the mid 7,000's

any thoughts?

trying to decide whether to bother buying this plane or not
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Old 04-06-2011, 02:25 PM
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Default RE: Hot rodding a Zenoah GT80??


Quote:
ORIGINAL: Tony Hallo

The Toni Clark web site has information on various combinations of the the GT80 www.toni-clark.com/index_en.htm.
I changed my carb to a Walbro SDC 80, added electronic ingnition, cut the rear crankshaft stub off, & converted to CM6 plugs. I don't expect much performance improvement but it will do what I want it to do. If you're looking for 3D performance, better look elsewhere. This engine makes it power above 7000 rpm. Looks like I'm typing too slow!!!!

all I could see is that they sell both the magneto and electronic versions.
You can buy all kinds of exhaust options and a different intake it seems but that's about all I saw relating to performance.Am I missing something?
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Old 04-06-2011, 02:37 PM
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Default RE: Hot rodding a Zenoah GT80??

Click on power curve on the left had side.....
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Old 04-06-2011, 03:26 PM
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Default RE: Hot rodding a Zenoah GT80??

Tony, I sent you a PM. Dan.
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Old 04-06-2011, 03:42 PM
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Default RE: Hot rodding a Zenoah GT80??

The GT80 Manual from Zenoah of Japan
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Old 04-06-2011, 04:14 PM
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Default RE: Hot rodding a Zenoah GT80??


Quote:
ORIGINAL: Antique

Click on power curve on the left had side.....
Ralph,
Please help me out.
What does this mean?
I'm a total layman as far as this chart goes.
PLUS I don't understand German!
Are you still doing any work on these?
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Old 04-06-2011, 04:20 PM
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Default RE: Hot rodding a Zenoah GT80??

The same power graph is in the Zenoah catalog. Scroll down to where the GT-80 is to see the graph. If you zoom in on the graph, you can read the numbers in English.

http://www.husqvarna.com/files/Zenoa...bby_Engine.pdf
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Old 04-07-2011, 02:19 AM
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Default RE: Hot rodding a Zenoah GT80??

My friend has 32 pound Iron Bay Texan, the G62 is more than it needs. He's spinning a 22-10. I would tend to believe the GT 80 would easly fly a 35 pound warbird in stock form.
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Old 04-07-2011, 02:40 AM
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Default RE: Hot rodding a Zenoah GT80??

Hi,

I have a fleet of research planes which have a takeoff wt of 45 lbs and they are powered with a 3W-50 single using a 22 x 8 bolly. At 45 lbs, they will loop continuously (large loops). They are also equipped with very draggy samplers. These planes have flown hundreds of hours.

I agree that a 35 lb warbird would be overpowed with a zt-80. Prop the engine as Ralph says and you will be fine.

Elson
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Old 04-07-2011, 07:40 AM
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Default RE: Hot rodding a Zenoah GT80??

What kind of warbird are you talking about. 23" clearance is way to little for any warbird with a gt80. Sounds like you are way under propping the engine. I would expect that engine to use at least a 24X10 or 26X8 prop. I have seen 45lb warbirds fly quite well with the gt80 swinging big props.
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Old 04-07-2011, 10:08 AM
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Default RE: Hot rodding a Zenoah GT80??

a 3-blade prop in the mid 7000 rpm range needs at least 8 hp to spin. I would dare say that the 80 is no way underpropped. It will have a hard time obtaining these rpm. A two-blade would be OK though, and have no problem with a 33 lbs warbird that needs energy management to loop.
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Old 04-07-2011, 11:34 AM
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Default RE: Hot rodding a Zenoah GT80??

That engine is HEAVY! Sell it and get something else!
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Old 04-07-2011, 12:16 PM
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Default RE: Hot rodding a Zenoah GT80??


Quote:
ORIGINAL: AraTidwell

That engine is HEAVY! Sell it and get something else!
Yea that is real good advice, put a lighter engine in a warbird so you will just have to go back and add 2 lbs to get back the weight you needed in the first place. Brilliant.....
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Old 04-07-2011, 12:48 PM
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Default RE: Hot rodding a Zenoah GT80??

Quote:
ORIGINAL: Whistling Death


Quote:
ORIGINAL: AraTidwell

That engine is HEAVY! Sell it and get something else!
Yea that is real good advice, put a lighter engine in a warbird so you will just have to go back and add 2 lbs to get back the weight you needed in the first place. Brilliant.....
Not to mention a cheap-sh*t clone that weighs less, costs less but also lasts less
Once that engine is dead, the block of lead will still be there as a reminder of the brilliant decision but the other guy's GT80 will still be running for many years.......
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