Engine and Pipe Design

[LohringMiller]

I discovered some of the most comprehensive engine design information I've ever seen on another site. It combines empirical pipe design formulas with formulas for determining the port time area needed for a given power and rpm. The best part is that it's free. The only better information comes from a simulation program, and this is still what you need to get in the ball park. It will take a lot of carefully study to use, though.

Lohring Miller

excel : http://users.telenet.be/jannemie/Jan...oke%201.0.xlsm
manual : http://users.telenet.be/jannemie/Jan...oke%201.0.docx

 

[Carl Van Houten]

Lohring,
Thanks for the links. It's always intriguing to review information like this.

Comprehensive is the key word here. One can spend hours mulling over formulas and other peoples theories of what will produce the best pipe design. Back in the day we would spend a day cutting aluminum patterns, welding them together and then take a sack full of pipes to the pond to try and once we got one that was close to what we wanted it to do we called that pipe the "key pipe". Then we made a few more that were slightly varied from the key pipe and then spent weeks running and testing all these last few pipes. We then picked the best pipe from that group.

That is how the "J" pipe was developed. That was a LOT OF WORK and you were only getting started once you had the final pipe in your hand because then you had to build a set of dies to stamp them out and that was another huge job getting all that designed and worked out! After the die was finished you were then faced with the aluminum wanting to tear or wrinkle. Yea, by the time you finished all this you wondered why you even started the project.

I am glad to see that there is a better way to get that initial key pipe in your hands. I would think that even with a program that mathematically drives your design there would still be the need to tweak it slightly.

I wish we had information like this available back then. Thanks for the links!
-Carl

 

[LohringMiller]

Even with formulas like this I still used cut and tweak methods. I once built a series of test pipes only to find that I used an exhaust temperature that was too high and all the pipes were too short. The next two pipes worked much better. The example in the spreadsheet is for gasoline fuel, nitro fuels will have much lower exhaust temperatures. Glow ignition also doesn't have the precision of spark ignition. Dealing with all this is what makes nitro engine and pipe design more of an art than a science, even today.

Lohring Miller

 

[Michael Costanzo]

hi,i tried down loading this and told me i need "office" to open?? any help? thank,mike.