MS 400 muffler

[Ranger-692]

25” with skip but runs a full comp just fine as well, just wanted less to file.

 

[Woodchuckels]

Empirical evidence tells me the straight shot on my 400 is a good thing. More power immediately.

Did the mtronic take care of the carb, or did you have to do a reset?

 

[Ranger-692]

After I put the straight shot on I did a reset, honestly it probably didn’t need it but I’m guessing it sped up the calibration process. It would eventually get there while cutting.

 

[sbhooper]

I put a Straight Shot on my 400 and it is an amazing saw. Is it better than a simple muffler mod-who knows? I have read a lot about the BB falling apart. It is not nearly as well-made as the Straight Shot. My 400 runs a 25-inch bar with authority and kicks the s=== out of my muffler-modded 362. Jason is a great guy and good businessman. He is top notch for porting jobs, too. I think that my 362 may go there before long.

 

[wilfrie]

I have a 400 and want a little more power, preferably more torque, since I use it most for breaking down trunk pieces in trees and for bucking. So I wanted to modify the muffler, but what is the maximum percentage of the cilinder exhaust port I can enlarge the muffler outlet? I read that 80-85% is generally recommended, but what are your experiences with the Stihl ms 400? And for comparison, what outlet size do eq the Westcoast bark box or the Egain straight shots have compared to the cilinder exhaust port or to the stock muffler outlet size? Looking for help, thanks!

 

[scottr]

So you want the muffler inside area as large as possible to recieve and relieve the compressed gass from the cylinder.
The outlet should ideally be about one inch in diameter at 70cc, you do the math, thats about 33% of the cc.

What are you getting the 33% comparing 1" outlet to muffler displacement ?