Turbo question

[Rod]

Hi everyone,

I'm currently a member of the Ferris state formula sae team and we are in the process of designing a single cylinder turbo engine
for the 2019 season. I understand the basics of plotting points on a compressor map using predicted MFR and desired boost pressure.
However, i'm getting hung up with what happens when I reach choked flow within the restrictor. I calculated the choked flow from a 19mm
to be roughly 8.8lb/min so should I use a turbo that has the majority of its map under that such as GT06 or go with something larger like a GT12 and
choke the restrictor down soon while maintaining higher efficiencies.

Thank you in advance

[MCoach]

...designing a single cylinder turbo engine...


For single cylinder applications, especially with respect to the rules, your bigger focus should be on the pulsed flow effect across the turbine of the turbo.
My personal opinion is that at GT06 may be sized well under constant flow assumption for the engine size, but getting enough plenum volume is critical to the whole package.
The better you can reduce the pulse affects across the engine system, the more efficient your system will be.

Reading on the WATTARD engine would be a great resource for you:

https://minerva-access.unimelb.edu.au/bitstream/handle/11343/34452/66991_00002551_01_2006-01-3637.pdf?sequence=1

[ibanezplayer]

I second the review of William Attard's work - the full thesis is floating around somewhere too.