Secondary Pipe Tuning???

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MD
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Re: Secondary Pipe Tuning???

Post by MD »

Same here.

Don't know where the megaphone stuff came from but I am not talking about it.

I know that BMW made some "continuously " expanding systems for some of their racing stuff starting with the headers but that's not what we are talking about here nor is the formula known to me.
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gran turismo
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Re: Secondary Pipe Tuning???

Post by gran turismo »

No graph option?
Is it possible to export the data then? Comma separated or excel or something?

Hmm, I really should learn to use GT-Power.
The only thing that I could figure out is to print it to a PDF converter then you can select the text and copy to excel or whatever. Not very friendly in that respect. :?

GT-Power looks like serious business. I'm sure you would have time to run all sorts of useful simulations for us. :D

gran turismo
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Re: Secondary Pipe Tuning???

Post by gran turismo »

Gran Turismo (my favorite game ), you refer to the secondary pipe as the the collector. I can see why this is so, but have never heard of it referred to like that.
I was thinking secondaries are for V8 tri-y headers but can see it either way too.

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Mats
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Re: Secondary Pipe Tuning???

Post by Mats »

gran turismo wrote:
No graph option?
Is it possible to export the data then? Comma separated or excel or something?

Hmm, I really should learn to use GT-Power.
The only thing that I could figure out is to print it to a PDF converter then you can select the text and copy to excel or whatever. Not very friendly in that respect. :?

GT-Power looks like serious business. I'm sure you would have time to run all sorts of useful simulations for us. :D
Too bad, graphs and export would sell it for me. Standalone numbers are maybe interesting buf not very user friendly. I wonder how difficult it would be to make that program do multiple sweeps with intervals on the input and do power-curve integration automatically..? Sort of like multi varable Newton-Raphson and present it as curve overlays..?

Who's up for that? :D

GT-Power is incredible, but it is equally incredibly hard to get started with. :cry:
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TS_turbo
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Re: Secondary Pipe Tuning???

Post by TS_turbo »

gran turismo wrote:My software came up with 1.303" dia and 26" long. Has anyone found the smaller primaries to be restrictive?
i talked to Larry at maxrace and he told me tnat smaller diameter pipes have more wall to cross area ratio (read wall friction) .... so with such small pipes you can take this dia as ID not OD .... general rule of thumb port exit primary id no more than 100 and no less than 85 % of valve diameter
btw pipemax is increadibly accurate even simulating F1 and superbike engines it predict results in 95 + % range

gran turismo
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Re: Secondary Pipe Tuning???

Post by gran turismo »

Pipemax also outputs stepped primary tube specs. A smaller dia tube is used for the upper half and a larger diameter for the lower half of the primary tubes. I am thinking about using the upprt halves of my old shankle headers as-is (with the 1.38" OD tubes) but with a new lower part (below the flange) with 1.5" OD primary tubes to make step headers.

I wanted to modify the lower halves anyway for ground clearance and for tuning. I don't know what other benefits there would be for step headers but this should reduce the wall friction some.

Jeff

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