Ec300 cylinder same from 2000-2019
 

I have a ec250 2018 and a ec300 2015. I want to change cylinder on the ec250 to a 300cc I have looked at the part lists and it has different part nr 2015-2018. But there are some s3 300cc cylinders on ebay and they claim that it fits 2000-2019. So are they any differences between the cylinders over the years or does a 2015 ec300 cylinder fit a 2018 ec250?

The cylinders may be physically the same.
But there have been some power valve changes in the recent year models.

They are not physically "exactly " the same in the detail of the logo cast in the side of the barrel. The port timing may have changed, don't know. But S3 were probably happy with their variant and clearly kept it the same, so you'd have to assume that they are at least interchangeable. PV aside. But perhaps even those interchangeable if barrel the same.

The S3 ones you see for sale are likely from North Tahoe Motorsports. He also sells the updated pv assembly as well which was updated in 2015. Shoot him a message on Ebay he is super knowledgeable and helpful. I have ordered a bunch of stuff from him. He has the S3 racing cylinders where they adjusted and cleaned up the porting.

Certainly I don't need more power but it would be nice if the exhaust port floor was higher by like 5mm, one so the port was smaller there but also so people didn't get obsessed by raising the barrel to match piston at BDC which is odd for a fixation. Mind you, they would probably try grind the bottom then.

I have the s3 racing cylinder and the bottom of the port matches the top of the piston at bdc with a .5mm base gasket on my 18 XC300

Yeah so the floor being another few mm higher would likely be better still. Flow at full open is pretty sluggish.

When the S3 barrels first came out on the 2013?s I think, I measured all the ports with my 04 cylinder and they were near as identical.

Wonder if its possible to make it fit or if any1 knows exacly whats the difference between them.