i don't understand the question.

because a turbo will alter the airflow of the engine so each and every turbo is going to push different volumes through the engine. unless you are asking what the starting airflow of a 13B-T is without a turbo on it.

all i know is that historically people have used 135lb+ turbos on 13B engines that had enough response to set records. does a 13BT factory engine pull 135lbs? no. but will it support that? yes, with the right fuel and EMS.

The point I was after was to see if the age old method of doubling our displacement really allows us to perfectly use the mathematical equation developed for turbo selection.

Or is it a really rough estimation.

Doubling the displacement is accurate for the displacement variable. However, the results of the equation are rough because you will need to guess at the volumetric efficiency variable.

not anymore! chart is S5 vs Rx8.

Where'd ya get that chart j9fd3s?

the Rx8 SAE paper, 2004-01-1790 Developed technologies of the new rotary engine (renesis), catchy title huh?

Yes, still, lol. That chart does not take into account variations in engine porting, wear, intake system, exhaust system, or turbine (if any).

Lol, I have that paper... but I looked around and nothing says what 13b SI is.

I actually think it's Renesis 6 port with the SDAIS on and Renesis 6 port with SDAIS off, then the rx8 4 port standard power model. Maybe?

it is confusing because the paper compares the 13B-MSP to the REW AND the "previous naturally aspirated peripheral exhaust port rotary"

i *think* they are talking about the S5 na in that graph, well and the MSP. anyways its the first VE graph of an NA engine i've ever seen from Mazda, we have the two NSU engines, the R100, and the JC cosmo engines