Exhaust port height / porting question

[ritchieb]

Hi BHQ members. Decided to set up the degree wheel again to make sure it was zeroed in correctly and came up with the same figures.

Exhaust ports open at 84 deg ATDC

Transfer ports open at 122 deg ATDC ??

 

As for the port mapping, placed the barrels on a flat surface deck down( no head studs ). Cut paper to suit bore diameter, pushed down to be flush with deck and taped in place,then shaded over the ports.Removed paper and measured ports to deck.

As some said it would be pipey, and it is, it's all top end.

This motor was built for me by a builder in Australia for motor X years ago.Now I ride just for fun. Thats why I would like some stock barrels that havn't been played with and have them ported by a reputable builder in the US, to suit what ever combiation ,pipes,carbs stroke, etc I'd like to run.

It's great to be able to communicate with people that know more than me as the ATV market is tiny over here. Appreciate everybody's input and advice.

P.S Mopar1rules- Where did you get the computer software and what's it called?

[mopar1rules]

yah, that's exactly why i was suggesting no more than 32, but best closer to 30

 

Yeah, I have mine set for 32* blow down now, and running more compression and now it works for moto-cross. I would not suggest anymore blow down than 32* either. If I wasn't running the 14.8:1 UCCR that I am running now, I think the 32* blow down would still be a bit much IMO for moto-cross.

[mopar1rules]

Hi BHQ members. Decided to set up the degree wheel again to make sure it was zeroed in correctly and came up with the same figures.

Exhaust ports open at 84 deg ATDC

Transfer ports open at 122 deg ATDC ??

 

As for the port mapping, placed the barrels on a flat surface deck down( no head studs ). Cut paper to suit bore diameter, pushed down to be flush with deck and taped in place,then shaded over the ports.Removed paper and measured ports to deck.

As some said it would be pipey, and it is, it's all top end.

This motor was built for me by a builder in Australia for motor X years ago.Now I ride just for fun. Thats why I would like some stock barrels that havn't been played with and have them ported by a reputable builder in the US, to suit what ever combiation ,pipes,carbs stroke, etc I'd like to run.

It's great to be able to communicate with people that know more than me as the ATV market is tiny over here. Appreciate everybody's input and advice.

P.S Mopar1rules- Where did you get the computer software and what's it called?

 

Oh, you said 122* deg ATDC for transfer opening....that would yield 116* deg of duration for transfers and now I see how you're coming up w/38* deg of blow down. If you want your transfers setup to better suite your riding style, I can work your cylinders over for you. For the program that I used to calculate your durations, its called "port mapper". I had gotten the program off this site last year some time. Some fella posted it and I downloaded it. Maybe someone can post the link to it, as I couldn't find it while searching. There also is a excel spreadsheet program floating around on the web somewhere that will do the same thing. I found that program as well on some moped forum:)

[TIM LUTZ]

How about the large step between the cylinder base and the lower cases. I would think a gasket match would do good in this area for a couple extra HP. Also, Has anybody had any luck with the Atheana or the WSM (German) forged pistons with the 3rd boost port? Any real gains if I cut these ports in a set of Wisecos? How about M&H forged pistons?

Edited July 14, 2010 by TIM LUTZ

[mopar1rules]

How about the large step between the cylinder base and the lower cases. I would think a gasket match would do good in this area for a couple extra HP. Also, Has anybody had any luck with the Atheana or the WSM (German) forged pistons with the 3rd boost port? Any real gains if I cut these ports in a set of Wisecos? How about M&H forged pistons?

 

I never heard of M&H pistons before. I'm going to be trying the WSM pistons on my next build. There is a guy on here named FouledOut, that runs WSM pistons w/good luck. The gasket match you speak of is talked about all the time on here and is worth it IMO, especially when looking for every little bit of HP. I "ported" my upper crankcase half myself. I didn't notice anything huge, just maybe slightly better throttle response.

[TIM LUTZ]

Looks like the dude is thrashing the piss out of his Shee in the video.

My link

[mopar1rules]

Looks like the dude is thrashing the piss out of his Shee in the video.

My link

 

I read the description of the pistons, in that link you posted, and it sounds like bs. C'mon, like pistons w/boost ports are just going to make you beat stroked and big bored banshees. Its going to take more than boost ported pistons IMO. And then for under $100 for a pair!! I'd like to see/hear of a longevity report, from someone that used them first.

[AKheathen]

hahahahahaha, i know i've seen that add before, and on different pistons, if i remember. those ones just have a little hole drilled in them. the wsm's are 100x better. the boost port is matched to the cyls, and the main windows completely reshaped. they are also redesigned for more strength with those port shapes, rather than a stock style piston that's modified

[TIM LUTZ]

Hey all.

Just thought I'd check in. I'm actually ass deep in Corel right now digitizing my stock ports and playing around with the new port heights/shapes. Yea. I think I'll go with the WSM or Wiseco. I wonder if it's safe to cut that boost port in a new set of 513's or if I should even worry about it. Are the WSM pistons the same Athena pistons?

[mopar1rules]

Hey all.

Just thought I'd check in. I'm actually ass deep in Corel right now digitizing my stock ports and playing around with the new port heights/shapes. Yea. I think I'll go with the WSM or Wiseco. I wonder if it's safe to cut that boost port in a new set of 513's or if I should even worry about it. Are the WSM pistons the same Athena pistons?

 

Just curious, but what the hell is "Corel"?

[TIM LUTZ]

Just curious, but what the hell is "Corel"?

 

It's a CAD/CAM program. CAD/CAM stands for Computer Aided Design/Computer Aided Manufacturing.

[blowit]

It's a CAD/CAM program. CAD/CAM stands for Computer Aided Design/Computer Aided Manufacturing.

 

 

You need Catia..

 

I would not waste the time with modeling unless you have other analysis or simulation workbenches. The flat pattern is most important so really, just using a 2D system would be easier. Also, I believe there are some stock Banshee cylinder models floating around somewhere. I am not familiar with Coral to know what file types it can deal with.

 

I think your time will be better spent working the 2D layout and studying the port time effects. What you would be able to do I guess is if you proceed with the 3D, you can do a surface etch or flat pattern of your port layout and apply it. Remember your bore size though. That changes things.

 

Brandon

[blowit]

What Corel are you using? I was just searching around to see what they could do. I was not able to find much on a 3D program and nothing yet on any CAM capable systems. Just curious. I like to know what is out there. We used to get all kinds of spam for something called "corel draw" or something.

 

Catia is the only one I know of with effective CAD and CAM platforms but will admit that the CAM system is not so user friendly.

 

Solid works seems to be the new "in" for solid models and works very similar to Catia. Probably because it is also made by Dassault. They just do not include a lot of the analysis functions such as FEA with solid works. Great program though...

[Sands]

In Portugal we use AutoCAD 2010. Very nice program.

[mopar1rules]

What Corel are you using? I was just searching around to see what they could do. I was not able to find much on a 3D program and nothing yet on any CAM capable systems. Just curious. I like to know what is out there. We used to get all kinds of spam for something called "corel draw" or something.

 

Catia is the only one I know of with effective CAD and CAM platforms but will admit that the CAM system is not so user friendly.

 

Solid works seems to be the new "in" for solid models and works very similar to Catia. Probably because it is also made by Dassault. They just do not include a lot of the analysis functions such as FEA with solid works. Great program though...

 

Yeah, I use solidworks and like it a lot. Seems pretty user friendly. I never tried catia, but always wanted to. I also wanted to try Pro-E.

 

Yeah, I know what CAD/CAM stands for. I deal w/it everyday. Just never heard of corel:)

 

One program that I think sucks and is a bear to use IMO is BobCam.