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Old 10-07-2014, 04:09 PM   #28 (permalink)
j12piprius
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higher MAP vs Rpm

Quote:
Originally Posted by ever_green View Post
Overview
For a naturally aspirate engine this means that you basically cannot exceed ~2900 RPM at sea level if you want to stay in oversquare engine operation. This is because at sea level atmospheric pressure is roughly 29 in-hg and 2900RPM/100 = 29. So for my driving I set 2900 RPM as my redline, but to keep the limits softer and add room for error i usually set 2500-2700 as the limit. I have also programmed MAP in in-hg for my scangauge to ensure i'm always operating in an "over square" fashion.
I'm curious how oversquare applys to Dfco and Eonc, vs DWL, which it sounds like is the main application.

I've been using abs kPa on the Ultragauge, which as far as I can tell doesn't have a reading for inHg. Standard atmosphere is 101.3 kPa, 29.92 inHg and 14.696 psi. The following would be relative to using kPa readings, i.e. 10 MAP ~ 300 rpm.

100 > 2992 rpm
90 > 2700 rpm
80 > 2400 rpm
70 > 2100 rpm
60 > 1800 rpm

What about accelerating, when MAP can be considerably higher relative to rpm, for example 1500 to 1800 rpm and 27 Hg ( 90 kPa ); is that acceptable or should MAP trend towards the 100:1 ratio?

Last edited by j12piprius; 10-07-2014 at 07:55 PM..
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