372 X-torq Mod Discussion Final Woods Port Video Posted

[XP_Slinger]

First impressions are that it's pulling strong. I tuned it to 12,900 no load and it's holding 11,200 +/- 100 in the cut. I also noticed I can lug it harder than I could before. I took a video of first cuts in 18" frozen white ash. I'll try to get the video up later.

 

[XP_Slinger]

@mdavlee Unfortunately, I didn't tach it in the cut when it was stock. Is 11,200 better than stock? It sounds better than it ever has. Made me giggle a little.

 

[XP_Slinger]

 

[RIDE-RED 350r]

Sure sounds right to me!

Still wondering why your tach doesn't like my XPW....

 

[XP_Slinger]

Sure sounds right to me!

Still wondering why your tach doesn't like my XPW....

Me too...that was strange.

 

[Ray Bell]

Looks and sounds like a strong saw. Great job!

 

[mdavlee]

11.2k is pretty good. Don't think a stock one would do more than 10.5k

 

[darkimpulse]

Subbed, great work

 

[idiotwithasaw]

Did you put an unlimited coil on it. One would think that with all the extra air fuel mix going in that it should be able to rev higher. I could be wrong, not the first time.

 

[mdavlee]

A lot heavier piston in the xtorq. I wouldn't want to turn it up like the OE.

 

[XP_Slinger]

Did you put an unlimited coil on it. One would think that with all the extra air fuel mix going in that it should be able to rev higher. I could be wrong, not the first time.

I had considered it, but due to the heavier piston I'm keeping the tune around 13,000. Thanks for the question

 

[XP_Slinger]

A little more on RPMs. Down the road a bit I'm thinking about putting heavy duty bearings in. With the added strength in the bottom end I think at that point I could tune it higher, say 13,500ish. That is of course assuming it wouldn't be too lean. Any thoughts on this approach?

 

[XP_Slinger]

Here are the numbers I got, these are Stock with no base gasket. I didn't grind on ports.

Exhaust - open @ 100° ATDC, duration 160°

Transfers - open @ 121° ATDC, duration 134°

Intake - open @ 73° BTDC, duration 150°

Hopefully I've presented this information correctly. If not, let me know if more is needed.

How does this 21° blowdown compare?
Not fishing for your porting recipes, just looking to get some discussion going. I like how my saw runs, it has a very wide torque curve. That being said, I think it could benefit from widening the exhaust port to motivate gases out. There is also a notable step on the exhaust port roof just inside the port. As the gases exit they go straight out the port, then about an 1/8" into the port it hits the downward roof angle that directs it to the muffler. While looking at it yesterday my brain was thinking that if I smoothed it out to maintain a uniform angle to the port window it would make quite an improvement in exhaust flow. Any thoughts? Let's talk

 

[Mastermind]

The reason I said to leave the divider in the carb is because without it the low pressure signal in the venturi is far removed from the original design. I'm surprised it supplies enough fuel.

 

[XP_Slinger]

The reason I said to leave the divider in the carb is because without it the low pressure signal in the venturi is far removed from the original design. I'm surprised it supplies enough fuel.

I had that thought as well. So far, I think the experiment has been a success, but maybe I'll put it back in and see how it acts. Thanks for the input MM.

I wonder if removing the divider in the intake boot helped over come the affect on the lower pressure and atomization. The boot was a major restriction on the main intake. Most of the intake pulse was diverted to the strato ports. Hmmmmm

 

[mdavlee]

I tuned that one to 13.8k. It would have went a lot higher. The OE I have tuned to 16.2k depending on what I was doing. Usually stay under 14.5k for them.

 

[Mastermind]

Like I said earlier, I've done them both ways. I don't alter the intake tract at all except for the air filter base. The only difference between gutted and not gutted is fuel usage.

 

[ABarrick]

Another question. Why r the strato ports over the intake on husky and under on Stihl?

I believe it depends on whether the carb is mounted diaphragm up or down. That dictates which side the main nozzle is on, thus whether top or bottom of carb is going to be air/fuel or air only.

 

[XP_Slinger]

I tuned that one to 13.8k. It would have went a lot higher. The OE I have tuned to 16.2k depending on what I was doing. Usually stay under 14.5k for them.

16.2k! Woof! Definitely don't need any of my saws spinning that fast. After thinking on it, I'm going to leave it the way it is. I'm completely satisfied with the gains I've achieved, especially considering the cost of about $50. I say this now and then the topend will end up on the bench in a couple weeks...

 

[mdavlee]

It was just a switch from limited to unlimited On a ported one.