HOTSAW! Not and audi, but still cool

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dana
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HOTSAW! Not and audi, but still cool

Post by dana »

My good friend is a professional lumberjack competitor. He qualified for the Stihl series finals next weekend and I was helping him get his hotsaw tuned up. Doing some experiments with exhaust pipe setup and timing.

Strangely it makes the most top end power with the ignition timing retarded to the max adjustment of the range. Two stroke pipe design and scavenging effect definitely comes into play here, but i barely understand it, and surely not enough to really explain it.

With timing more advanced it was more responsive to throttle input, but that doesn't really matter since top end power is really all that matters.

Hes been competing with this saw for several years, and is actually to the point where he needs more power. He is stalling it out on the upcuts when going for time. It actually cuts faster with less pressure on it.

The current setup is a 2001 rm250 motocross bike engine with a 265 big bore kit, running c12 gas. The powervalves are operated via cable from the throttle trigger. The saw has been very competitive against many other much larger cc saws.

Here is Matt pulling so hard it stalls out.
https://www.youtube.com/watch?v=e3e-Mvh ... e=youtu.be


not sure if non-facebook users can see this. This is me running it like a pansy. Just starting this thing is a scary and difficult task. The gyroscopic forces and insane vibration makes it a serious handful. Not sure what it makes for HP, but its probably in the 60+ range. I've run it before and it was just as scary as I remembered.
https://www.facebook.com/matt.marks.397 ... nref=story

hes trying to find a ktm300 to build a new saw. Hes also considering higher compression professional porting with a custom pipe to match.

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current:
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-the turbo tractor
past:
-11 second 90q junker
-20vt swapped 90q winter beater
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EDIGREG
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Re: HOTSAW! Not and audi, but still cool

Post by EDIGREG »

lol...wow. That thing looks like a handful
Ed
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dana
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Re: HOTSAW! Not and audi, but still cool

Post by dana »

yes, it is. The chain and bar is from a logging harvester like this. The raker teeth that set the cutting depth are filed down to basically nothing so the full cutting tooth can engage the wood. If you hit the wood with slow revs it will just suck you right in.

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current:
-mk4 tdi wagon with some mods
-TDI b3 90q, holset turbo, be strong little connecting rods!
-the turbo tractor
past:
-11 second 90q junker
-20vt swapped 90q winter beater
-efi 20vt 4kq
-way too many other long gone urs's, 200's 4000's, b5's
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ringbearer
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Re: HOTSAW! Not and audi, but still cool

Post by ringbearer »

07k?

Lol, that is insane as is.
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dana
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Re: HOTSAW! Not and audi, but still cool

Post by dana »

I think I almost had him convinced to go turbo. There is no oiling available for the turbo though..not sure if something could be made to work with ceramic bearings and super short run times with no oil.
current:
-mk4 tdi wagon with some mods
-TDI b3 90q, holset turbo, be strong little connecting rods!
-the turbo tractor
past:
-11 second 90q junker
-20vt swapped 90q winter beater
-efi 20vt 4kq
-way too many other long gone urs's, 200's 4000's, b5's
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ringbearer
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Re: HOTSAW! Not and audi, but still cool

Post by ringbearer »

Gravity feed oiling? Work for short runs.
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dana
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Re: HOTSAW! Not and audi, but still cool

Post by dana »

ringbearer wrote:Gravity feed oiling? Work for short runs.

i think you need some actual pressure for the bearings to work, but might work on a ball bearing turbo.
On a related note.....http://compturbo.com/spotlights/oil-less
current:
-mk4 tdi wagon with some mods
-TDI b3 90q, holset turbo, be strong little connecting rods!
-the turbo tractor
past:
-11 second 90q junker
-20vt swapped 90q winter beater
-efi 20vt 4kq
-way too many other long gone urs's, 200's 4000's, b5's
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ringbearer
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Re: HOTSAW! Not and audi, but still cool

Post by ringbearer »

Use regulated compressed air or gas to pressurize oil feed. Getting very complicated and heavy though.
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dana
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Re: HOTSAW! Not and audi, but still cool

Post by dana »

yes, definitely getting heavy and over complicated. I think professional port work and a bigger bore are probably the most cost effective way to go.
current:
-mk4 tdi wagon with some mods
-TDI b3 90q, holset turbo, be strong little connecting rods!
-the turbo tractor
past:
-11 second 90q junker
-20vt swapped 90q winter beater
-efi 20vt 4kq
-way too many other long gone urs's, 200's 4000's, b5's
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ringbearer
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Re: HOTSAW! Not and audi, but still cool

Post by ringbearer »

And lots of time working out just to handle it for more than a few minutes!
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All_Euro
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Re: HOTSAW! Not and audi, but still cool

Post by All_Euro »

That's awesome - def needs some forced induction though. Rotrex makes supercharger kits for sleds & bikes... wonder if you could create a saw kit. Oiling system would need a little simplifying but is self contained at least... http://www.rotrex.com/Home/Technology/Oil_Circuit
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roortube
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Re: HOTSAW! Not and audi, but still cool

Post by roortube »

Those things are pure awesome. I've always thought they were the perfect platform for nitrous as a power adder. Relatively simple and light weight for the extra power.
Rob

Prepping my 91 M5 Dinan for sale to fund 07K and EFR build for my UrQ. May also sell Lotus Elan resto project. PM if interested in either.
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Marc
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Re: HOTSAW! Not and audi, but still cool

Post by Marc »

I'm with Rob.

Nitrous.
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roortube
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Re: HOTSAW! Not and audi, but still cool

Post by roortube »

I think you'd need a way to introduce the N2o progressively...a big shot at once could produce dangerous recoil on a saw.
Rob

Prepping my 91 M5 Dinan for sale to fund 07K and EFR build for my UrQ. May also sell Lotus Elan resto project. PM if interested in either.
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loxxrider
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Re: HOTSAW! Not and audi, but still cool

Post by loxxrider »

EF that!


But you definitely should turbo it. Turbo ALL THE THINGS
-Chris

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uberaudi
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Re: HOTSAW! Not and audi, but still cool

Post by uberaudi »

That is incredible! Never knew they 'converted' saws like that...it would no doubt leave me legless!
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dana
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Re: HOTSAW! Not and audi, but still cool

Post by dana »

Good idea with the nitrous. I'm not sure what the rules say about that, but i think any fuel is acceptable. Only rules are single cylinder and pull start with no recoil I believe.

uberaudi wrote:That is incredible! Never knew they 'converted' saws like that...it would no doubt leave me legless!

Its been a timber sport event for 20 years or so. Popular in parts of the country where logging is still a thing.
Here is Matt competing with it a few years ago, on the left. This next weekend will be covered by ESPN.
[youtube]https://www.youtube.com/watch?v=30YJe5M86_8[/youtube]
current:
-mk4 tdi wagon with some mods
-TDI b3 90q, holset turbo, be strong little connecting rods!
-the turbo tractor
past:
-11 second 90q junker
-20vt swapped 90q winter beater
-efi 20vt 4kq
-way too many other long gone urs's, 200's 4000's, b5's
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