Snellerized Saws Conquers the 75cc 372XPW

[Edwad]

You run your mouth like some big shot. And you ain't jack shi...

This thread was fine until you got here.

 

[blsnelling]

If your XT based 75cc saw has the 19mm+ RWJ-4, and the 71cc you compared it to a stock 17.46mm HD-12, that should account for some of the difference in cutting speed.

The 71cc saw had either the RWJ4 or one bored to the same venturi size. I'm not sure which it is.

 

[Chris-PA]

Did he check the rpm of your saw brad?

I bet not. Which leads me back to my point,why would you check any of them anyway?

He said it was and you said it wasn't, what's it called when you tell someone there not telling the truth?

You guys crack me up.

I've checked many, and I showed others how to do it so any one can.

Are you going to back up your accusation that I called Carl a liar? Or are you going to prove that you are a liar?

 

[SawTroll]

You are totally missing or ignoring what I said and the point I was trying to make. Do dyno charts only show you max torque or max RPM? It's called a powerband.

It looks that way - a dyno should record the torque and the rpm at all points trough the power band. The respective max numbers are of little interest by themselves, as one of them without a decent amount of the other is ineffective.

As everyone here should know, power (kW/hp) is a function of torque and rpm at any given point of the rpm range. Some dynos no doubt have software that calculate and show the results as kW or hp, but what it measures still is torque and rpm.

Another issue is that say a 30% decrease in cutting time doesn't mean that there is a 30% gain in either max power or average power trough the cut - there are several factors involved that screw up such an assumption.

 

[blsnelling]

It looks that way - a dyno should record the torque and the rpm at all points trough the power band. The respective max numbers are of little interest by themselves, as one of them without a decent amount of the other is ineffective.

As everyone here should know, power (kW/hp) is a function of torque and rpm at any given point of the rpm range. Some dynos no doubt have software that calculate and show the results as kW or hp, but what it measures still is torque and rpm.

Another issue is that say a 30% decrease in cutting time doesn't mean that there is a 30% gain in either max power or average power trough the cut - there are several factors involved that screw up such an assumption.

Exactly. And since I I can't provide that, o do the best I can and choose several points to help demonstrate the powerband.

 

[procarbine2k1]

A few seconds off the best time in the same log? You think a few seconds difference in one cut isn't a big deal?

I do this all day every day and under no circumstance will a work saw with a good chain turn 13000 in the wood,I couldn't imagine why anyone would want a work saw that would do that,it wouldn't live long.

I own and have ran some very strong saws,some I've built and some others have built and the only way to get 13000 in the wood is to have a dull chain or lift on it.
Remember Carl getting called out? Why didn't you?

You say your not interested in cut times but the last I checked we port and modify saws so they cut faster,at least that's how I do it.

ROFL. You must be awake 24 hours a day, build saws all day eh, with as much bs as you post how would you have time?

You don't like getting called out, but do the same to someone else?

And what is this Bs about Carl Miller? You gonna post a link where someone called him a liar or what? Call the kettle black while you are at it, you've never talked crap about someone you didn't know... hahaha please.

And just because you can't build a work saw that won't hold 13k in the cut, doesn't mean someone else can't. Now that I think about it, dozer Dan and TM had saws out there someone videod holding more than that.

Talk to people like you would talk to them in person, and more people are going to respect ya. Work might even pick up for you. Starting some crap on as just makes you look thirsty for work man.

And btw, I don't have nothing against ya.. just some constructive criticism.

PS. You aren't going to change Brad, or the way he presents himself. This same argument has been hashed out for years. It's just the internet, don't get too bunched up over it.

 

[SawTroll]

Exactly. And since I I can't provide that, o do the best I can and choose several points to help demonstrate the powerband.

Yes, that was pretty much how I was "reading" you.

 

[Chris-PA]

Exactly. And since I I can't provide that, o do the best I can and choose several points to help demonstrate the powerband.

While it might not be apparent from just watching Brad's videos, in looking at the spectrum plots from several he is graduating the pressure, increasing it with each cut. He's also good at holding a steady pressure and not angling the saw all around during the cut. That allows for steadier rpms during the cut and makes it easy to get an accurate rpm measurement for each cut. The first cut will be high rpm and subsequent cuts the loading goes up and the rpms go down and vary more.

 

[Chainsaw Jim]

It has a smaller venturi than the RWJ-4 though (18.25mm) - about midway between the HD-12 and the RWJ-4....

I actually ran both carbs to see how they compare on my xpw build. I started with the 39 and expected the J4 to increase performance with the larger venturi but it actually lost a tad bit. I didn't remove the divider or modify the carbs, so it was a good carb to carb comparison...at least as far as the particular build in question.

 

[Big_Wood]

I actually ran both carbs to see how they compare on my xpw build. I started with the 39 and expected the J4 to increase performance with the larger venturi but it actually lost a tad bit. I didn't remove the divider or modify the carbs, so it was a good carb to carb comparison...at least as far as the particular build in question.

so did you run the stock 39 throttle shaft? the 39 throttle shaft is to long and creates and angle from the throttle cable holder up to the hookup on the throttle shaft. it works but not for long. don't ask me how i know lol. the tilly 296 throttle shaft fits in with some grinding on the carb body and works great. that's what i had to do to make it reliable on the 390.then the tilly choke shaft has to go in to match up the throttle for high idle and also because the eyelet on the 394 choke shaft is to big for the 372/290 choke lever and pops off all the time. i totally agree though. the RWJ4 while convenient is not the best carb for these saws. that's why mine has a modified 39 on it. it behaves better at idle and has a tad more pulling power at full speed. IMO, it's the carb the 372/390 should have came with. you must have had to solder the main jet closed on the 39. when i tried it on a 372 it ran to rich even with the high speed completely closed off. no soldering needed on the 390 though.

 

[Chainsaw Jim]

so did you run the stock 39 throttle shaft? the 39 throttle shaft is to long and creates and angle from the throttle cable holder up to the hookup on the throttle shaft. it works but not for long. don't ask me how i know lol. the tilly 296 throttle shaft fits in with some grinding on the carb body and works great. that's what i had to do to make it reliable on the 390.then the tilly choke shaft has to go in to match up the throttle for high idle and also because the eyelet on the 394 choke shaft is to big for the 372/290 choke lever and pops off all the time. i totally agree though. the RWJ4 while convenient is not the best carb for these saws. that's why mine has a modified 39 on it. it behaves better at idle and has a tad more pulling power at full speed. IMO, it's the carb the 372/390 should have came with. you must have had to solder the main jet closed on the 39. when i tried it on a 372 it ran to rich even with the high speed completely closed off. no soldering needed on the 390 though.

I didn't make any modifications other than shaving the edge off the throttle shaft plastic piece to keep the throttle cable from binding. The 372 boot can twist enough without losing its shape for that and the choke to work, but I chose to run the j4 because the stock air filter and cover fits that way.

 

[Big_Wood]

Just so you know, if you are talking about the HD cover the 39 will fit those too. You just gotta use the RWJ pump side cover on the 39. I got 2 RWJ's I'll trade guys for 296's, 116's, or 39's lol

 

[SawTroll]

I actually ran both carbs to see how they compare on my xpw build. I started with the 39 and expected the J4 to increase performance with the larger venturi but it actually lost a tad bit. I didn't remove the divider or modify the carbs, so it was a good carb to carb comparison...at least as far as the particular build in question.

The venturi size is of course not the only factor. I'm no carb expert, but I know that at least jet sizes also are factors - and then there is the "balanse" vs. intake, transfers and muffler...

 

[TonyK]

Hello gentlemen. Full stop on the personal stuff. Stay on point or use the ignore feature.

 

[SquareFile]

ROFL. You must be awake 24 hours a day, build saws all day eh, with as much bs as you post how would you have time?

You don't like getting called out, but do the same to someone else?

And what is this Bs about Carl Miller? You gonna post a link where someone called him a liar or what? Call the kettle black while you are at it, you've never talked crap about someone you didn't know... hahaha please.

And just because you can't build a work saw that won't hold 13k in the cut, doesn't mean someone else can't. Now that I think about it, dozer Dan and TM had saws out there someone videod holding more than that.

Talk to people like you would talk to them in person, and more people are going to respect ya. Work might even pick up for you. Starting some crap on as just makes you look thirsty for work man.

And btw, I don't have nothing against ya.. just some constructive criticism.

PS. You aren't going to change Brad, or the way he presents himself. This same argument has been hashed out for years. It's just the internet, don't get too bunched up over it.

Lol.

He's one of the greatest.......at going to other sites bad mouthing this site. Many others do the same, unless money could be involved.

IMO saws being modded on forums are slower and cost much more than they did years ago. I guess it not the builders fault. Its the tune and chain. Lol. Probably why builders dont like gtg's.

I've read enough post making fun of rpm in the wood, Ohio fast wood, 40% faster wood its funny. What's funnier is to see basement pissrevving, trailers tipping, punky pine with slow cut times, roped wood on some kind of pharked up stand showing poor operating skills. Pistons with notches ground from crown for clearance. Rofl. I find it amusing cracks towards me then I see and read y'alls stuff.

Anyone still grind bridgeports? Your welcome.....

Mike acers site is a great resource for bar mounts. It dont take a English major to figure them out if I can.

 

[farmer steve]

only read the last couple of pages . if the saw cuts wood what else could you want. stihl, hoosky or poolan . if if does the job and puts wood in the stove why get your panties in a bind. jeeez!!!!!!!!!

 

[Big_Wood]

it's all Brads fault!

 

[sunfish]

only read the last couple of pages . if the saw cuts wood what else could you want. stihl, hoosky or poolan . if if does the job and puts wood in the stove why get your panties in a bind. jeeez!!!!!!!!!

None of this has anything to do with cutting wood to put in the stove.

 

[fordf150]

Lol.

I've read enough post making fun of rpm in the wood, Ohio fast wood, 40% faster wood its funny. What's funnier is to see basement pissrevving, trailers tipping, punky pine with slow cut times, roped wood on some kind of pharked up stand showing poor operating skills.

dont make fun of my rotten pine video...its all i had and as far as my operating skills, well i went to Newcomerstown high school which is West by gosh Virginia to you northerners.

 

[fordf150]

Just to be clear since this thread went off the rails and i dont really feel like adding to it. the rotten pine comment was not a crack on any except myself.