Tri-Y vs. 4-1 Exhaust Manifold

[CSFX8588]

Does anyone know of a good reference for exhaust manifold design, or can speak from experience with both tuned? Looking for tri-y vs. 4-1 pros/cons and primary/secondary length calculations and rpm ranges. I've found calculators online but couldn't find the actual formulas they were using or the background info. I could probably sit down and work out the formulas but I'd probably miss something in the end and would rather just use a working formula.

Thanks,

CJ

 

[kiggly]

The separated pulses seem to be a little more tolerant with the split-volute turbine housings like you would use with a Tri-Y. Shortest octave length seems to be the best tuned length in turbo setups for both intake and exhaust sides. I made a new header over the winter that I will be testing soon. It is smaller primary tube and I went from the 2nd tuned length down to the 1st tuned length. I'll post up the results after the new one is run at the dyno, I already have pretty good data on what the old one does. I don't know that primary vs secondary tuning has been well exploited, or that there is much of anything there with a turbo car.

As for max power, people have had very good results with both open and split turbine housings. Several Hondas have broken 190mph with split volutes. Obviously people's experiences with v-band inlet turbos in the mitsu crowd have been great as well.

Kevin

 

[CSFX8588]

Thank you sir, you are a gentleman and a scholar.