Does Compression make more power? Echo 590 620

[@cajun3197]

Could be the parasitic drag from the new piston. 10-15psi won’t notice much anyway. Too much compression will slow you down but it’s the sweet spot around 200-210psi I like

[@TightWad1]

👊🐊

[@Macgyver-ranch]

I put both of the Red Barns that I used on a diet. They were heavy and had a lot of flashing.

[@georgesjunk]

Background wall looks great!

[@CharlesBrisco]

In my testing in them red barn pops up.lost power over stock shuda welded up chamber an use stock piston prolly wuda had better outcome

[@novicelumberjack]

I can't weld the chamber.

[@Doc-Cole_Trickle-of-Chainsaws]

👊CB

[@ToddAdams1234]

@@novicelumberjackJBWeld that combustion chamber.😅

[@tylerheard1279]

​@@ToddAdams1234don't do it

[@ToddAdams1234]

@@tylerheard1279 That “smiling” emoji is trying to say that.

[@Smittyschainsaws]

Opinions aside, you have an opportunity for a cool video series if you want to put the time into it. 3 cuts per day and document the changes in performance no matter how small. Good or bad. That would be interesting.

[@Doc-Cole_Trickle-of-Chainsaws]

👊S

[@williamgrissom1995]

I wonder how much more power the saw would have with the pop-up piston after breaking it in? I'm thinking it would beat the lower compression setup then, but maybe not by much. I know very little about this stuff, and practically nothing about how to port a cylinder. But sometimes the result is very impressive. I have thought about cleaning up a cylinder and maybe polishing the exhaust port on my own saw if the cylinder has pretty bad molding, before I run it. But I haven't decided if I'm going to try it or not. Anyway, interesting video. 😎👍

[@adambatchelder4121]

Good video as a 2 t motorcycle builder I can tell you that higher compression is a mixed bag . Higher comp alone can equal less rpm. But with higher ports you loose compression so adding it back in can help. Higher compression defnetly adds low rpm torque but saws are about higher rpm power . It's completed right.

[@Archer_82]

So, in the saws then, how do we move that torque curve up in the rpm band, excluding pipes? Curious what the 2 stroke motorcycle thought is on this.

[@adambatchelder4121]

@Archer_82 bigger ports higher up in the cylinder especially exhaust ports typically make more upper end power. Although we can have the best of both worlds with power valves on our exhaust ports in the bike world that are tunable with different springs.

[@480r]

Compression is a variable that’s very difficult to isolate. Most changes of compression are also changing dome architecture or squish velocity. I generally like as much compression as a given fuel can tolerate, but there is definitely a point of diminishing returns. I once had a gauge with a faulty valve.. showed 185psi on multiple bikes, seemed suspicious so I changed out the valve and one bike was actually at 245psi.

[@rchighfield1]

Seriously, gorgeous background much better than the green screen.

[@aaronpowell4885]

Very interesting! but not really surprising. I believe most of the "gain" seen from base gasket deletes are due to dropping the intake and exhaust, giving them slightly more grunt. Be interesting to see how 170+ compares! Thanks for testing and sharing👍🏻

[@dannevaupptaget]

Great video! That just tells another side that ironhorse has said for years. It Will build compression in the cut if you have a good muffler etc

[@novicelumberjack]

Ehhh... no. It is most certainly NOT building more compression in the cut. That's kinda like saying that a person gets stronger when they walk uphill versus walking on flat ground. Nonsensical. Ironhorse has been spewing BS for years. Just because there is a load on the saw doesn't mean it is building more compression. It simply means that the piston has resistance on it as it tries to push down. Compression is measured as the piston goes up.

[@kraftzion]

I can't remember which book it was, probably gordon jennings that stated you needed .01mm squish for every mm of stroke. That is only .014" on my 36mm stroke 372. (Didnt try it) . If you want to experiment with higher compression, increasing squish velocity at the same time would probably get better results. I've never checked the compression on my saw now I'm curious. Have to check it tomorrow.

[@ejsocci2630]

I really enjoy your videos brother

[@robbevington1754]

Did you check the Pistons skirt on both make sure they’re the same size

[@johngardner3020]

Does the extra ring improve compression?

[@Banjoandguns]

I did this with a 390xp and it rips with the red barn piston

[@TomMFP]

I’ve ported 30 or so saws and I don’t have a lathe so I’ll just stick with easy starting low compression saws

[@BenSawyer72]

Pop up piston are too heavy for the gain they bring

[@troy3052]

Great video!!

[@coburnlowman]

A friend of mine has a 1965 XL12 Homelite , that his grandpa bought new. The piston , and jug are scored badly. It pulls at the roap like the spark plug was out. Once you get that old girl running, itll run with any of my XL12's. It doesn't make sense how it runs so well , but it sure does. Most if my old Homelites have compression to spare , but that old worn out saw will run with any of mine.

[@coryjones9573]

Great video

[@robertdixon4554]

I’m with Cajun on this one , I dont believe you went high enough to see any difference, but I am surprised that it was slower

[@shakdidagalimal]

Just the tune on the carb can make all the difference and a bigger difference. So how one controls that will always be a guess and a mystery. You can't really isolate out a carb tune.

[@dgoodman1484]

2 strokes are magic anyway so who knows but compression is everything on a 4 stroke. On the other hand, Continental (aircraft engine) pulled the rings out completely as a test one time and they still made 90% power. Knowledge is everything so testing is always beneficial! 👍🏼 On the other hand, if it ain’t broke don’t fix it! 😁 👍🏼👍🏼

[@jackdawg4579]

Would have been Interesting to see the compression variation with the saw hot.

[@novicelumberjack]

Dang. I'm all the time effing something up!

[@Super-Dave-Outdoors]

I wonder how much that big chungus pop up alters transfer flow and cylinder scavenging

[@pantigersizzle5761]

The RPM sounded VERY close

[@jeffdillard8789]

Compression is good for widening the powerband and helping the bottom end. Hell yeah raise those ports! Let's find that limit

[@crazyfeller5704]

👍👍 with these results, a dished piston- it’s ready for sawfest! 😂

[@marklivingstone3736]

FD rated oils like Red Armour are great for protection but they burn too slow for race 2 stroke engines TC FC oils contribute more to gas mix combustion than esters and synthetics . 50% caster even better. Will need more oil / gas ratio tho and that’s going to help up your compression. May have to change plug because it may run hotter

[@Super-Dave-Outdoors]

You will hit ring of death at the same distance you hit free porting.

[@coolestguyontheplanet723]

Compliments from me today 😊

[@Doc-Cole_Trickle-of-Chainsaws]

👊CG

[@tedneitzel]

Doc i cant see what make my cylinder is on the 61 without taking thing apart. Sorry.​@@Doc-Cole_Trickle-of-Chainsaws

[@Doc-Cole_Trickle-of-Chainsaws]

@@tedneitzel 👊 if you ever see who, let me know. Should be able 2 see on the clutch side of the cylinder minus sawdust, I think

[@Super-Dave-Outdoors]

20-40psi is the typical gain on a gauge switching from a 590 to a 620 piston on the same cylinder. But... if all port heights are the same then your peak cylinder pressure during combustion is roughly the same.

[@TightWad1]

👊SD

[@rncboy2]

Bring the weight down on the piston first. The height difference is also gonna have a play in this with the dual ring. The weight seems to be better for low-end highet difference also changes power band. 🤫 Wait the guys learning will figure it out. We are learning 🤔

[@mattsstuff1268]

Boedy must be busy between takes moving all those chainsaws on the shelf behind him. Sometimes the Stihl's are over his right shoulder, sometimes over the left shoulder.

[@redtiller1975]

Cool video. Any chance you checked the changes in the port timing with the pop up piston?

[@novicelumberjack]

I had checked the piston against the stock piston. Totally the same. So, same port timing numbers.

[@michellatour150]

Your compression tester's hose is IMO way too long to get an accurate reading in a small displacement engine as it's volume acts like a reservoir and the rubber expandable, rule of thumb for testing motocross engines is no longer than a 12" hose. Also no secret in small bore 2-stroke dirt bikes that increasing the compression often kills top end power and overrev capability.

[@Archer_82]

Agreed, my automotive tester is terrible in little 45cc saws, that hose has as much or more volume as the tdc chber. Short small diameter, with double shader valve.

[@Doc-Cole_Trickle-of-Chainsaws]

👍🆙BigGuy

[@Doc-Cole_Trickle-of-Chainsaws]

HOOOOO

[@TightWad1]

​@@Doc-Cole_Trickle-of-ChainsawsHOOOOO

[@masonmcqueen5059]

Ale8!!! Good drink!

[@Eganperformancesaws]

Build a head for it. It'll be time consuming, but you won't have to port it again.

[@Altruistic-Viking]

Judging by the look of the cut something is off with the chain

[@garengtutorial8923]

Keren bro

[@Bojangles1987]

Let the rings set in first

[@pantigersizzle5761]

Take 1 ring off and try it. Who knows?

[@sawmanbigtreeslayer2360]

Shapen that chain. I see micro saw dust.

[@coreycorp7048]

2 strokes are like women, you just never quite 100% figure them out.

[@davesteier-xf5lh]

If it’s one thing I know.. it’s women and covert ops

[@brandonsmith3447]

The placebo affect is very real and perception is reality. Plus this testing is hardly scientific level double blind stuff my friend. It’s great but so many variables are at play with this stuff.

[@brandonsmith3447]

I’ve also read that testing Compression on small engines with a tester like you used is highly inaccurate. Seems you need a very short hose or even a direct from the plug to a gauge connection to get actual numbers.