two stroke BSFc maps

[Tmoose]

There are tons of 4 stroke gas and diesel BSFC maps on the internet.

I could not find one for any gasoline variants of piston port 2 strokes (dirt bike, moped, outboard, motorcycle, even snowmobile, etc).

Does anyone know of any readily available? I'm Just looking for generic type info.

thanks

Dan T

 

[pickler]

my guess is that it will be pretty much similar to 4 stroke engines. Why are you looking for BSFC maps? is this for fuel economy purposes?

 

[Tmoose]

I found one for a Vespa of unknown level of design, equipment or modification.

It appears the penalty for straying very far from the best BSFC point in regards either BMEP or rpm is pretty severe.

 

[Lou Scannon]

I'm by no means a 2-stroke guru, but in the course of my inquiries I discovered that a lot of key research was conducted and published in the 60s and 70s. Major contributors were Japanese manufacturers [who tended to publish in SAE], and a chap named Jennings. I don't have the link handy, but there's a site out there somewhere hosting numerous useful publications on this topic.

"Schiefgehen will, was schiefgehen kann" - das Murphygesetz

 

[Tmoose]

Hi Hemi,

Thanks for the suggestion.
Here is one pretty good one I'm pretty familiar with that meets that description.

http://www.bridgestonemotorcycle.com/documents.htm

 

[dgallup]

Good old Gordon Jennings. I read every one of his articles and his Two Stroke Tuners Handbook back in high school and college. The book is out of print but you can find a scan of it on the interwebs. I used his theories to build my own expansion chambers and do my own cylinder porting. I was able to get the power so peaky on my Zundapp engined Rickman 125 that it could not pull the 1/2 gear shift. Fun times.

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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

 

[Tmoose]

EC Birt's Zundapp porting diagrams were in multi-issue feature article in an MXA or Dirt Bike magazine back in the 70s. I think I found scans on the Internet somewhere. I believe he insisted Exhaust ports should not be shaped like a "snake's bite."

I don't recall any BSFC stuff from either of them, but it's a good use to take another look.