is it time to revise the jetspecs?

[stoffe64]

hello all!

maybe i am stumbeling around here now but i came to think that maybe it could be possible to make a revised jetspecs taking into consideration the HRR and such,to build a more compact working combustor, take for instance my scaniaten build it has a 2,99 inducer,i will use a 5" flametube for it about 35 centimeters tall,this as i have understood should work properly built, could it be possible with a revised jetspecs,telling what to and how to do it?,just a thought i had.
cheers/stephan

[racket]

Hi Stephan

It has been considered a few times, but trying to come up with a solution has been difficult.

The average first time builder always wants to "cut corners" , so by designing a revised Jetspecs with more "critical" proportions ( smaller, shorter) a first time builder would probably end up with a serverely undersized combustor that won't work unless the sophistication of the air and fuel presentation is up to high levels , which it invariably isn't for a first build .

Jetspecs should provide a working engine irrespective of the build level and/or the turbocharger configuration , ......................some turbochargers have oversized turbine stages which would allow the comp to flow more than an ideal "design" would dictate , a "generously proportioned" flametube will provide some flexibility .

The original Jetspecs designing process was filled with compromises , and we couldn't come up with a better end product then , just as I don't think we could now without a huge amount of information that most builders , first time or not , would be able to understand or use .

We want builders to have a working engine , not a compact engine that may or may not work unless made to very strict guidelines , very strict guidelines for a thousand differently configured turbos just isn't possible :-(

Cheers
John

[stoffe64]

mmm,yes i understand John, its a lot variables which i guess not everyone understand, i start to understand more thanks to you guys, i sure hope my engine will work when it is built, time will tell i guess.
cheers/stephan

[racket]

Hi Stephan

Yes , its the variables that end up beating us , thats why its "better??" to just provide a basic design that should cover all eventualities .

Even if Jetspecs provided exact measurements ( plans) for the perfect compact combustor for every conceivable turbo configuration , guys would still want to add their own personal "interpretation".

LOL, over the past decade whilst helping out on the Yahoo DIY Site, I've seen very few engines built to exactly what Jetspecs recommends .............including those built by myself :-)

But , if someone wants their engine to work, all they have to do is follow the Jetspecs recommendations ....................if they don't , then they've only got themselves to blame if it doesn't work .

Heh heh , if guys did follow Jetspecs, I'd be out of a job , no one would be wanting help to get their engines to work :-)

Cheers
John

[stoffe64]

yeahh,that was one way to look at it ofcourse, hehehe

[kevin]

Guys, just a thought. Maybe jetspecs could be migrated to an Android App? might open up DIY Turbine builds to a whole new audience.