Modifying airboxes alongside mufflers....I can't be the only one!!

[Cerberus]

THIS!!!

You and @huskyboy are saying my mods here (OP) fail because

How much faster will the saw be when you defeat the air injection and the filter clogs faster ? Imo modifying the air box should only apply to old style filter setups with no air injection. Then it makes sense.

What, specifically, are you guys talking about? You realize my post shows standard-type airboxes(my scheppach & my echo 355t, although every saw I own has the same airbox restraints and the same mods to overcome them)

Would like to hear what on earth you mean, are you confusing the Husqvarna air-injection system somehow? Plz do explain as I can hardly figure out what's meant by their "air injection"....

Echo (and the saws I'm familiar with) have negative pressure at the airbox courtesy of that lil rubber hose/porting to the flywheel-face of the saw, see the Echo video in my OP post#1 for "proof".......My 355t, for instance, already has openings on the back of the case's airbox They simply put several ~4mm wide bars/rectangles along the bottom of the airbox.....I filtered those and added an additional inlet up higher on the same face of the airbox, and I rubber-plugged the H&L port.....For my 355t, and all the saws I own actually, this:
- allows more air-intake at the airbox,
- lets less debris in despite more air-intake (wayyyyy less debris, although that should be expected when you eliminate the wide-open pathways on many saws' airboxes, tsk-tsk to the manufacturers there!)
Coupled w/ muff-mod & retune (and run on canned gas, though next week will be in LA doing storm-damage & setup doesn't allow it so will be 1st time relying on mixed pump fuel ), all of my saws have run great I never need to tinker w/ them anymore just cleanings and I never want for power as I don't over-size the bars I use (and all of my saws would happily take 2-->4" longer bars but I've got them all paired 'appropriately')

Plz be clear in describing whatever Husqvarna(or other/any) 'air injection' would have been defeated by my mods, you make it seem like "old style" is anything w/o this "air injection" but google was not heavy w/ any explanations on the husqvarna air-inject (and if you're talking about another type, please be specific....but if you're just guessing that what I've done hurts an echo 355t, or most types of climbsaw, I can assure you it does not I've been running saws hard this way and they just get stronger as they're aging )

 

[rogue60]

I open up the airbox on some models for more air like the 088/880 IMHO they are a little restricted in airflow.
Depends on the saw after looking over it if it looks restrictive I'll mod the airbox to let more air in so the engine can breath.

 

[rogue60]

Cutting old dead dry hardwood you get lots of fine sawdust I only own a couple of smaller air injected saw's the air injection seems to pump more fine dust in than without it.
CR888 says he blocks the air injection off on his saw's sounds like a good mod to me for slowing the filter blocking as fast with fine dust.
I was cutting old dry dead Ironbark for firewood the other week with this old 660 I just tap the filter out after every tank of fuel not much you can do about the fine dust.
I don't get all anal about fines getting past the filter or trying to stop it never in all my years of cutting hardwood have I seen any ill effects on a saw engine so it don't bother me lol
Disclaimer- This is all in my part of the world and the timber and conditions here I understand timber and conditions around the world change it's not all black and white one shoe does not fit all.

No chain it snapped on me not snapped many 404 chains over the years it's tuff stuff and can take a beating.

 

[Deets066]

Cutting old dead dry hardwood you get lots of fine sawdust I only own a couple of smaller air injected saw's the air injection seems to pump more fine dust in than without it.
CR888 says he blocks the air injection off on his saw's sounds like a good mod to me for slowing the filter blocking as fast with fine dust.
I was cutting old dry dead Ironbark for firewood the other week with this old 660 I just tap the filter out after every tank of fuel not much you can do about the fine dust.
I don't get all anal about fines getting past the filter or trying to stop it never in all my years of cutting hardwood have I seen any ill effects on a saw engine so it don't bother me lol
Disclaimer- This is all in my part of the world and the timber and conditions here I understand timber and conditions around the world change it's not all black and white one shoe does not fit all.
View attachment 257310 View attachment 257311 View attachment 257312

That looks awful.

 

[jacob j.]

That looks awful.

Fire saws sometimes end up looking similar - cutting blackened timber creates a lot of fine ash particulate. It's nasty stuff.

 

[rogue60]

Fire saws sometimes end up looking similar - cutting blackened timber creates a lot of fine ash particulate. It's nasty stuff.

Cutting through the burnt bark on timber like Stringybark here is like that the black ash and dust form cutting it is nasty stuff and don't know why but the burnt bark dulls ya chain faster as well.

 

[jacob j.]

Cutting through the burnt bark on timber like Stringybark here is like that the black ash and dust form cutting it is nasty stuff and don't know why but the burnt bark dulls ya chain faster as well.
View attachment 257334

It's because of the high carbon content remaining in charred wood. On fireline saws, we'd just run round ground chain so we could file in the field. When I was falling snags on
fires, I'd still run square-ground because you'd run into some pretty big, fire-weakened snags and it was important to have good cutting speed to minimize the time you're "in the bite."

 

[rogue60]

That looks awful.

I know but the plating and piston bearings will all be schmicko for such a high hr saw must be the oil I use lol

 

[Deets066]

Fire saws sometimes end up looking similar - cutting blackened timber creates a lot of fine ash particulate. It's nasty stuff.

Yeah, I bought a fire saw. I believe the saw was on fire for a bit too

 

[Terry Syd]

Cutting old dead dry hardwood you get lots of fine sawdust I only own a couple of smaller air injected saw's the air injection seems to pump more fine dust in than without it.

I clued into the problem of the 'air injection' system in Oz years ago. If you are cutting clean green softwood in Northern Europe, no problems, the chips go around on the outside with centrifugal force. However, the 'fines' like we get here in Oz can easily be pulled into the air box.

I first twigged to it when I cut up a blackened stump. The charcoal from the stump left a track from the bar across into the front of the recoil intake. With the fines going into the front of the recoil housing and then being sucked into the air box, there was an increased load on the filter.

I blocked off the air injection and the filter stayed a lot cleaner.

Also, the 'air injection' system takes air off the flywheel that could be going past the cooling fins on the cylinder. The more you mod a saw, the less air from the flywheel you have to cool the saw. Meanwhile the engine is trying to produce more power/heat and the 'air injection' system is sucking more cooling air off the fins.

In Oz, blocking off the 'air injection' system and putting some holes in the back of the air box is often a good mod. - Less filter loading, more power from less heat soak and better longevity of the engine.

 

[Sprinter]

I clued into the problem of the 'air injection' system in Oz years ago. If you are cutting clean green softwood in Northern Europe, no problems, the chips go around on the outside with centrifugal force. However, the 'fines' like we get here in Oz can easily be pulled into the air box.

I first twigged to it when I cut up a blackened stump. The charcoal from the stump left a track from the bar across into the front of the recoil intake. With the fines going into the front of the recoil housing and then being sucked into the air box, there was an increased load on the filter.

I blocked off the air injection and the filter stayed a lot cleaner.

Also, the 'air injection' system takes air off the flywheel that could be going past the cooling fins on the cylinder. The more you mod a saw, the less air from the flywheel you have to cool the saw. Meanwhile the engine is trying to produce more power/heat and the 'air injection' system is sucking more cooling air off the fins.

In Oz, blocking off the 'air injection' system and putting some holes in the back of the air box is often a good mod. - Less filter loading, more power from less heat soak and better longevity of the engine.

I opened a vent over the filter on my 562 thinking I would get cooler air to the carb. Turns out, I got a good outflow, so obviously air injection puts a positive pressure in there. Makes me wonder if I opened the vent and blocked off the air injection, would it improve air flow over the cylinder? Should I leave the air nozzle out? Would I get cooler air to the carb?

 

[Cerberus]

Can ANYONE please explain chainsaw air-injection to me please? @Sprinter your post ^ seems pretty in-the-know, you even mention "open vent and block-off air injection" and "leaving the air nozzle out"....where is this air-nozzle? What vent are you saying is injecting air? Cannot find this feature on any of my saws (are you talking of that "husqvarna air-injection" system?)
Really blowing my mind that there's supposedly air-injection functionality yet I can't find any clear evidence/pictures/vids on google to demonstrate it.. (Will reiterate here- that lil tube/port from the flywheel-area to your airbox pulls-away from the airbox it doesn't push-into it, that is not air injection)
[ @kneedeepinsaws and @huskyboy were basically mocking the principles behind what I've done in this thread, on-grounds of "I'm defeating my air injection", something I've requested they clarify but it's been crickets, hopefully you or someone else can clearly explain what types of saws have this air-injection system and how it works(or at least a part-number so I can go find a diagram and see it myself, it's feeling an awful lot like the pseudo-'feature' of echo's "G-Force" where airflow is used for forcing particulates to the sides&out, but that is a cleaning mechanism not an air-feeding mechanism..]

As for the Topic, I do see merit in opening the air box to keep the filter cleaner.

Run a saw with/without rear cover and see if it gains of loses. It’s usually not much different.

On 1128, I relieve the sealing ribs under the AF cover and a bit underneath like BonScott did above.

Not sure what the factory was thinking on some saws. Adding another vent keeps the airfilter much cleaner, even if it’s not needed for power.

On my own saws, I almost always put a Frogzskin on the cover, somewhere.

Cool stuff
Why use frogskinz instead of making your own? I'll admit I had that kneejerk reaction to just go ordering them when I learned of them, but quickly realized "if you really care about the aesthetics of your airbox-mods, you could simply go to home depot & then spend a lil more time doing them to make them come out looking 'good like a frogskinz would'!" so I never ordered any (actually if you look at my OP/Post#1 here you will see two of my saws' airboxes, one is the 1st ever time I modded an airbox and it's ugly as sin, but beside it in that pic is my echo 355t whose airbox's-opening has nice, matching orange colored metal-mesh screening, IMO that looks superior to any non-matching Frogskin I ever could've put there!)

Re "Run the saw w/o the filter and see if it gains power" suggestions/"tests", there's some reasons that such a test may not tell you a whole lot:
#1 - if your muffler is stock/blocked-up, then the increased air-potential from the airbox-mod wouldn't make much difference as your muffler is still your 'choke-point'
#2 - it'd need re-tuning afterwards, it's not just "allow more air & go to town", this is "mod airbox, mod muffler, adjust carb appropriately for those two mods, then see the gains. Simply removing an air filter on some off-the-shelf saw should not give any additional power..
#3 - I don't think you're going to see much/any power in the lower power range, nor just revving it on a bench, because the OEM airflow is already more-than enough for all that. Think about it, these mods are really just there to allow it to run a bit stronger at max-load, when it'd be wishing it had a lil more 02 or fuel, it's not gonna change the speed of your idle or make it feel different when revving it in-hand

Cutting old dead dry hardwood you get lots of fine sawdust I only own a couple of smaller air injected saw's the air injection seems to pump more fine dust in than without it.

Where is this air-injection system located like what parts / where? I cannot find a single good representation on google images, or youtube, of a chainsaw (of any brand) with active air-injection..

CR888 says he blocks the air injection off on his saw's sounds like a good mod to me for slowing the filter blocking as fast with fine dust.

But....wouldn't this choke the machine's engine if it were built-around an air-injection setup?

I don't get all anal about fines getting past the filter or trying to stop it never in all my years of cutting hardwood have I seen any ill effects on a saw engine so it don't bother me lol

I wouldn't say I "get anal"(heh) about it, I mean I use red permatex when setting my airfilter(or the airbox-covering) but that's just how I rebuild/reassemble things on my saws, not a pain/doesn't take real time so I just do it but yeah fines getting past isn't the end of the world I have known guys who've had air filters that, once going to swap them, found the filter had shrunken a lil and was allowing unfiltered air free passage to the block, that saw still runs to this day in fact! But I'll bet you it can't cut a 10" Oak as-quickly as it otherwise coulda..

Fire saws sometimes end up looking similar - cutting blackened timber creates a lot of fine ash particulate. It's nasty stuff.

Wow maybe it's the humid nature of my area but I get my saws "entirely caked" often enough and haven't seen fire-damaged wood yet

the burnt bark on timber like Stringybark here

WOWZERS thanks for sharing that pic, the new life (do we call it water-sprouts when it's in that circumstance?) coming-out-of the charred bark is just beautiful, both the coloration of course but moreso what it symbolizes (actually, live tissue/foliage/etc, wrapped-around deadwood, is a go-to technique we use in bonsai for many "older" specimen!!)

I know but the plating and piston bearings will all be schmicko for such a high hr saw must be the oil I use lol

I wish I could parse/understand this quote!!
Re oil.....I'm still using canned-only, was slated to go to LA today but got cancelled anyway that was gonna be the 1st time I'd be in a situation where I couldn't get canned / woulda been mixing my fuel, was cringing at the thought of my 'pure' machines drinking pump-fuel

 

[Sprinter]

Can ANYONE please explain chainsaw air-injection to me please? @Sprinter your post ^ seems pretty in-the-know, you even mention "open vent and block-off air injection" and "leaving the air nozzle out"....where is this air-nozzle? What vent are you saying is injecting air? Cannot find this feature on any of my saws (are you talking of that "husqvarna air-injection" system?)
Really blowing my mind that there's supposedly air-injection functionality yet I can't find any clear evidence/pictures/vids on google to demonstrate it.. (Will reiterate here- that lil tube/port from the flywheel-area to your airbox pulls-away from the airbox it doesn't push-into it, that is not air injection)

I am going to be away for a few days, when I get back I'll post pictures.

 

[kneedeepinsaws]

Can ANYONE please explain chainsaw air-injection to me please? @Sprinter your post ^ seems pretty in-the-know, you even mention "open vent and block-off air injection" and "leaving the air nozzle out"....where is this air-nozzle? What vent are you saying is injecting air? Cannot find this feature on any of my saws (are you talking of that "husqvarna air-injection" system?)
Really blowing my mind that there's supposedly air-injection functionality yet I can't find any clear evidence/pictures/vids on google to demonstrate it.. (Will reiterate here- that lil tube/port from the flywheel-area to your airbox pulls-away from the airbox it doesn't push-into it, that is not air injection)
[ @kneedeepinsaws and @huskyboy were basically mocking the principles behind what I've done in this thread, on-grounds of "I'm defeating my air injection", something I've requested they clarify but it's been crickets, hopefully you or someone else can clearly explain what types of saws have this air-injection system and how it works(or at least a part-number so I can go find a diagram and see it myself, it's feeling an awful lot like the pseudo-'feature' of echo's "G-Force" where airflow is used for forcing particulates to the sides&out, but that is a cleaning mechanism not an air-feeding mechanism..]


Cool stuff
Why use frogskinz instead of making your own? I'll admit I had that kneejerk reaction to just go ordering them when I learned of them, but quickly realized "if you really care about the aesthetics of your airbox-mods, you could simply go to home depot & then spend a lil more time doing them to make them come out looking 'good like a frogskinz would'!" so I never ordered any (actually if you look at my OP/Post#1 here you will see two of my saws' airboxes, one is the 1st ever time I modded an airbox and it's ugly as sin, but beside it in that pic is my echo 355t whose airbox's-opening has nice, matching orange colored metal-mesh screening, IMO that looks superior to any non-matching Frogskin I ever could've put there!)

Re "Run the saw w/o the filter and see if it gains power" suggestions/"tests", there's some reasons that such a test may not tell you a whole lot:
#1 - if your muffler is stock/blocked-up, then the increased air-potential from the airbox-mod wouldn't make much difference as your muffler is still your 'choke-point'
#2 - it'd need re-tuning afterwards, it's not just "allow more air & go to town", this is "mod airbox, mod muffler, adjust carb appropriately for those two mods, then see the gains. Simply removing an air filter on some off-the-shelf saw should not give any additional power..
#3 - I don't think you're going to see much/any power in the lower power range, nor just revving it on a bench, because the OEM airflow is already more-than enough for all that. Think about it, these mods are really just there to allow it to run a bit stronger at max-load, when it'd be wishing it had a lil more 02 or fuel, it's not gonna change the speed of your idle or make it feel different when revving it in-hand


Where is this air-injection system located like what parts / where? I cannot find a single good representation on google images, or youtube, of a chainsaw (of any brand) with active air-injection..


But....wouldn't this choke the machine's engine if it were built-around an air-injection setup?


I wouldn't say I "get anal"(heh) about it, I mean I use red permatex when setting my airfilter(or the airbox-covering) but that's just how I rebuild/reassemble things on my saws, not a pain/doesn't take real time so I just do it but yeah fines getting past isn't the end of the world I have known guys who've had air filters that, once going to swap them, found the filter had shrunken a lil and was allowing unfiltered air free passage to the block, that saw still runs to this day in fact! But I'll bet you it can't cut a 10" Oak as-quickly as it otherwise coulda..


Wow maybe it's the humid nature of my area but I get my saws "entirely caked" often enough and haven't seen fire-damaged wood yet


WOWZERS thanks for sharing that pic, the new life (do we call it water-sprouts when it's in that circumstance?) coming-out-of the charred bark is just beautiful, both the coloration of course but moreso what it symbolizes (actually, live tissue/foliage/etc, wrapped-around deadwood, is a go-to technique we use in bonsai for many "older" specimen!!)


I wish I could parse/understand this quote!!
Re oil.....I'm still using canned-only, was slated to go to LA today but got cancelled anyway that was gonna be the 1st time I'd be in a situation where I couldn't get canned / woulda been mixing my fuel, was cringing at the thought of my 'pure' machines drinking pump-fuel

I didnt mock anything, im not here to hurt anyones feelings im here for information. If i hurt your feelings, i apologize however looking back at my Post i quoted a another member who in no way made you feel stupid or silly.

Imo writing a post quoting every single member is a bit odd, it is clear to me that constructive criticism is something you have trouble dealing with. Take things Lightly around here.

 

[huskyboy]

I didnt mock anything, im not here to hurt anyones feelings im here for information. If i hurt your feelings, i apologize however looking back at my Post i quoted a another member who in no way made you feel stupid or silly.

Imo writing a post quoting every single member is a bit odd, it is clear to me that constructive criticism is something you have trouble dealing with. Take things Lightly around here.

+1

 

[Lightning Performance]

 

[Lightning Performance]

https://www.hlsproparts.com/Husqvarna-36-41-136-137-141-142-intake-horn-p/h50136.htm

 

[rogue60]

Here's a Cutaway of air injection out of a Husky I believe Stihl is much the same.


WTF lol

 

[Sprinter]

I did put my 2 bits in but it's over here. https://opeforum.com/threads/562-heat-management.21434/

 

[Cerberus]

https://www.hlsproparts.com/Husqvarna-36-41-136-137-141-142-intake-horn-p/h50136.htm

I'm uncertain what this shows? I mean I know what part that is, just don't get how it explains what "air injection" is (honestly I'd appreciate if anyone of this camp would just try plain-english to explain what air is doing what, specifically.... My understanding of this type of thing is that any diverted air - anything that "gets in the way" of optimal in&out for the block, would be sub-optimal, and furthermore I just don't even see what useful ways airflow is being "block&diverted" for any "air injection" uses)

I can see scavenged/diverted air being useful for a motor vehicle (boost/turbocharging/supercharging) but have never seen, and cannot think of, any good way to divert-and-use the airflow in a saw (if anything you'd just want to optimize the "in & out" streams for the powerhead, I would think....it's how I approach my saws & it's worked but no hard #'s sadly :/ )

Here's a Cutaway of air injection out of a Husky I believe Stihl is much the same.
View attachment 258074

WTF lol

wtf is right lol!! That looks different in concept though, it's an air-blower powerhead right? Blowers aren't anomalous here but, IMO, just add confusion (by adding the function of air-blowing, as feature, on top of our subject IE the airflow of the powerhead itself)

I did put my 2 bits in but it's over here. https://opeforum.com/threads/562-heat-management.21434/

A lil more than 2c, no? ;D Love that thread am not gonna be able to read it all right now but hope to later today after an appt., I can tell your approach's thought-process is very much like mine, when I got my 355t it ran hot [after correcting the carb, of course] so I:
- opened up a lot more plastic on the muffler-covering's body (the vents on it are only on the side, so I was especially focused on the "left" side of the muff-cover because that's "top side" when it's hanging from my belt)
- used painter's tape as "a form/template" to pour red Permatex onto the entire left-side face of my clutch-cover, creating a ~2mm heat-barrier between muff & clutch

Can I ask your thoughts on advanced timing? Don't want to derail my own thread lol but would like to know your thoughts since, from reading your thread, I can tell my approach is similar to yours so especially interested in your thoughts on it, as advanced-timing is the only thing I haven't done to my saws (or porting, though for my saws & any saws I like, I don't see much point/value in porting, seems a ton of work for very modest gains but sadly, and surprisingly, for all the porting work done & shown & discussed, I've yet to see any good before/after comparisons...I would think that a log, timer & video-camera would be a pretty requisite part of your gear & your presentation if/when doing porting jobs to make a saw run stronger..)