Mythbusters Max flow vs HD2 and Oem vs Dual port muffler

[chadihman]

I spent a couple hours tonight getting lots of numbers off the dyno. I have a full page full of chicken scratch. My test saw is my MS 460 with new oem mahle top end, crank bearings,seals and a fresh rebuilt carb. The saw now has had five tanks run through it.
The first run on the dyno was with a dual port muffler and HD2 filter tuned at 13600. 3.761 hp at 10,100 rpm 4.123 hp at 9500 rpms 4.131 hp at 9000 rpm 4.116 hp at 8500 rpms 4.07 hp at 7600 rpms 2.563 hp at 6200 rpms.
The highest hp was at 9000 rpms but I was amazed at how the hp held at at least 4.1 from 9500-8500 and still had 4.07 hp at 7600 rpms then the hp dropped fast at 6200 with only 2.563

The next run I put the green max flow filter on without the rain cover. The saw was still running the same tune at 13600 and the o2 reading was the same as the HD2 filter. I was really surprised that the saw really didn't gain any power at all. Dirty filters may have proven different but I'm sticking with the HD2.

The final run blew my socks off. I installed an oem muffler and retuned the carb. At 9000 rpms the hp was 3.426 A dual port muffler and a retune gave this saw a .705 hp gain

The next tests will be AM cylinders and BB kits. Then porting and ignition advances.

 

[04titanse]

I spent a couple hours tonight getting lots of numbers off the dyno. I have a full page full of chicken scratch. My test saw is my MS 460 with new oem mahle top end, crank bearings,seals and a fresh rebuilt carb. The saw now has had five tanks run through it.
The first run on the dyno was with a dual port muffler and HD2 filter tuned at 13600. 3.761 hp at 10,100 rpm 4.123 hp at 9500 rpms 4.131 hp at 9000 rpm 4.116 hp at 8500 rpms 4.07 hp at 7600 rpms 2.563 hp at 6200 rpms.
The highest hp was at 9000 rpms but I was amazed at how the hp held at at least 4.1 from 9500-8500 and still had 4.07 hp at 7600 rpms then the hp dropped fast at 6200 with only 2.563

The next run I put the green max flow filter on without the rain cover. The saw was still running the same tune at 13600 and the o2 reading was the same as the HD2 filter. I was really surprised that the saw really didn't gain any power at all. Dirty filters may have proven different but I'm sticking with the HD2.

The final run blew my socks off. I installed an oem muffler and retuned the carb. At 9000 rpms the hp was 3.426 A dual port muffler and a retune gave this saw a .705 hp gain

The next tests will be AM cylinders and BB kits. Then porting and ignition advances.

I am intrigued, good work. I am REALLY curious to see a bone stock saw to a woods ported saw.

 

[z71mike]

Awesome info, man. Keep it coming.

Subscribed.

 

[chadihman]

I am intrigued, good work. I am REALLY curious to see a bone stock saw to a woods ported saw.

Send me that 460 of yours that Brad tinkered with and we can do the test.

 

[moody]

Is your 372 stock? If so I'd be willing to send something out for testing when I get it finished.

 

[blsnelling]

No surprise on the lack of gain from the filter. The only benefit I see with them is extended service intervals in exceptionally dirty conditions.

 

[Stihl 041S]

No surprise on the lack of gain from the filter. The only benefit I see with them is extended service intervals in exceptionally dirty conditions.

Brad Lad. What you doing up at this hour. ;-))

 

[7sleeper]

How can this be that Stihl is not fullfilling it's advertised numbers? Now this would be really interesting to see how other saws compare with their advertised numbers or companies without advertised numbers....

:msp_wink:

7

 

[deepsouth]

Many variables to consider, including calibration of dyno, manufacturers measurement point (flywheel or at chain as per this dyno) - think cars with wheel dyno vs engine dyno with driveline losses.

Will be good to compare saws on this piece of equipment - noting even variations in ambient temperature between tests, engine heat soak etc cause result variation in vehicle dynos.

 

[splitpost]

REP sent

 

[c5rulz]

Great thread.

Kudos to the OP.

Who would have thunk, a modifying thread with actual statistical data to back it up.:msp_ohmy:

Rep sent.

 

[Duane(Pa)]

Hey man, nice work! Thanks for posting this up. Keep it coming

 

[porsche965]

Good work!

Thanks for taking all the time involved to make the test. Keep it coming.

Subscribed.

 

[chadihman]

I'm really having fun with this dyno. I love to share my findings and will surely keep them coming. I love this site you guys rock thanks for all the encouragement. I'm sorry my tests are only with the 460. My 361 and 660 will also be run through the wringer at some time. Lots of testing will happen when the snow gets deep.

 

[zogger]

I'm really having fun with this dyno. I love to share my findings and will surely keep them coming. I love this site you guys rock thanks for all the encouragement. I'm sorry my tests are only with the 460. My 361 and 660 will also be run through the wringer at some time. Lots of testing will happen when the snow gets deep.

You have done an outstanding job and providing a great service to everyone here. Just interesting.

 

[rocketnorton]

sub'd. rep sent... id be interested in cat/no cat difference.

 

[Stihlalltheway]

You truly have American ingenuity to be able to design, fabricate, and build such an incredible machine. I am very curious as to what the porting hp gains will be.

 

[Steve NW WI]

I'd be interested to see a retest on the filters after you've gotten all you can get out of the saw. I don't know much about either one (not a Stihlhead), but I'm thinking that as you start needing greater flow with the mods, one might come out on top.

Either way, great work and a cool tool you've built, I would rep ya if I could, but it's gonna have to wait a bit.

 

[sawfun9]

I would think more carb would have a bigger effect than the air filter, especially since it's designed for an 880 to run. This is great information, please continue, thanks.

 

[chadihman]

Flow max states that a Stihl saw can use as much as 53 cfm. The hd filter is 89 FM max flow is 135 cfm. The saw will not gain from max flow until dirty conditions. So its not worthless but didn't seem worthwhile in gaining any power when its clean.