Chainsaw Dyno rework finally complete and ready for some mod testing.

I finally got my hyd fittings after almost two months backordered. The fittings were just 5/8" hose barb in 3/4 pipe and orb. Thought maybe my supplier was pulling my chain but they must have really been on backorder because I couldn't get them online from anywhere either.

I now have my flow control valve right at the pump with low pressure 5/8" oil cooler hose running to a cooler and to the suction side of the pump. Now there is no extra drag from the hoses. Before the 4000 psi hose would get really stiff when I would pull the saw down causing drag on the rotating pump resulting in inaccurate readings.

I ran my 460 on it tonight and really liked how it worked this time. The oil now just gets warm with the oil cooler. Tomorrow evening I'm going to mess around with an o2 sensor. I plan to install the o2 sensor in the muffler and hopefully get accurate fuel ratio readings so my mod tests will be more accurate if the carb is adjusted to the exact same ratio for all the mods.
I have this Saturday off so I should get some testing done as far as dual port vs oem muffler and hd vs hd2 and max flow.

Here's a picture of the old setup with the hose that would try to straighten out and cause inferior readings when the hyd pressure would increase.

Are you goin to be able to dyno all kinds of different saws with that?

Sweet! opcorn:

Nate66n1 said:

Are you goin to be able to dyno all kinds of different saws with that?

Click to expand...

Should be able to test most saws. Has to have a 3/8 sprocket

Sweet dude!

I have plenty of saws waiting to burn some gas. OEM and AM BB together running basically unmolested, yet. Some ported OEM's and AM BB. Several types of air filters and plenty of mufflers in various stages of mods.

The line up will be stock, modified and ported.

009
009L
011
191
192
020AV
020T
200T
and more tops many makes and models

018C
025
250
026
260
260Pro
029
029S
290
360
360Pro
361
390
391
046
460
066
660
088

031
041
048
056


6401
8400



Have several of some models. I'm sure I missed more than a few.

Two worth mentioning is a bone stock 460M my friend owns that needs mods and a bone stock 046 yet to be hacked.

pile of older Swiss Jreds most in the 40-50cc class

I won't mention the stuff really not worth testing. Oops, might have already done that lol.


Name your poison.

Naked Arborist said:

Sweet dude!

I have plenty of saws waiting to burn some gas. OEM and AM BB together running basically unmolested, yet. Some ported OEM's and AM BB. Several types of air filters and plenty of mufflers in various stages of mods.

The line up will be stock, modified and ported.

009
009L
011
191
192
020AV
020T
200T
and more tops many makes and models

018C
025
250
026
260
260Pro
029
029S
290
360
360Pro
361
390
391
046
460
066
660
088

031
041
048
056


6401
8400



Have several of some models. I'm sure I missed more than a few.

Two worth mentioning is a bone stock 460M my friend owns that needs mods and a bone stock 046 yet to be hacked.

pile of older Swiss Jreds most in the 40-50cc class

I won't mention the stuff really not worth testing. Oops, might have already done that lol.


Name your poison.

Click to expand...

I guess I better get some extra parts made up for the dyno. Sounds like it might be time for a rebuild after your done with all those saws. I think the bar and the chain will take the most beating.
Anybody else have a dyno or working on one?

Very cool! Im curious as to the numbers you will pull compared to the advertised HP numbers

The carb should be adjusted so the o2 readings in the muffler should be the same. This will take care of modded muffs and cylinders.

Nitroman said:

The carb should be adjusted so the o2 readings in the muffler should be the same. This will take care of modded muffs and cylinders.

Click to expand...

Yeah Man. Hopefully this o2 sensor works as planned

That is awesome!

I'll send you a PM850 to test once I get one done. It will not be stock, a woods port will be done on it.

Does it measure horsepower and torque? IIRC, all dynos need one figure to get the other.

Take it to Ag Progress Days next month.I'll bring you some stuff to test.

chadihman said:

Yeah Man. Hopefully this o2 sensor works as planned

Click to expand...

i'm curious to know how the o2 sensor works out. i'm sure you know you have to assure it gets no o2 from an exhaust leak or otherwise.

promac850 said:

That is awesome!

I'll send you a PM850 to test once I get one done. It will not be stock, a woods port will be done on it.

Does it measure horsepower and torque? IIRC, all dynos need one figure to get the other.

Click to expand...

Yes it measures HP and torque. The pump is centered on bearings with a torque arm that reads torque on a digital scale. I have an rpm sensor also so HP is torque x rpm /5252

Awesome. Subscribed.

don't run the engine from cold with the sensor in ex will really shorten it's life span or ruin it. Get the engine/muffler hot then fit the sensor after it to has warmed up with it's internal heater....never used a o2 on a 2stroke....oil smoke might disable it in a sort period of time...

good luck

I welded a bung in the front of the muffler cover and threaded in the o2 sensor. I warmed the 460 up then pulled it down to 9100 rpms and the o2 display was reading 13.2 I'm pretty stoked about the o2 sensor working. I ran the numbers on the OEM 460 and came up with 4.1 HP. That's low compared to Stihls 6 HP. I feel like my readings are accurate and that Stihl is testing without a bar and chain. 4.1 HP is the real world #. The low # bummed me out but who cares what's important is that I have base #

My hats off to you sir. Nice work on the dyno. It has crossed my mind a few times about a saw dyno but not a need for one here. A buddy of mine has a performance motorcycle shop here and has a dyno for bikes. I have helped him some when he is behind and helped dyno several hundred bikes over the past 10 years or so. It is neat to see what bikes make before and after on a race bike. You will need to get a small weather meter too. The temp, humidity, and air pressure will make big differances on small motors. I hope this small bit of info helps you on your dyno.
jnl

Couldn't get the pics up last night but heres the o2 sensor I need to make some little brackets to hold the rpm display and the o2 display. That wont be a problem.

Awesome!

The bung welded into the muffler is great for tuning one saw, what would be awesome as an improvement is finding a 02 sensor setup you can use for multiple saws.

Car dyno's usually have a lead they can connect to an 02 sensor on the manifold, but for older cars a probe that can be inserted in the tailpipe.

I think a section of steel pipe mounted with an 02 sensor with hose connecting it to the muffler and a PC fan drawing fumes out the other side (not enough vacuum to impact power but enough to draw even flow into the cylinder.