KPA to Vac-boost/injector worksheet

[Mister]

Here is a little chart I threw together for tuning purposes.
Kilopascal to what you see on vacuum boost gage.

KPA Vacuum
5 -28.5
10 -27.0
15 -25.5
20 -24.0
25 -22.5
30 -21.0
35 -19.5
40 -18.0
45 -16.5
50 -15.0
55 -13.5
60 -12.0
65 -10.5
70 -9.0
75 -7.5
80 -6.0
85 -4.5
90 -3.0
95 -1.5
100 0.0 ++BOOST
105 0.7 +
110 1.5 +
115 2.2 +
120 2.9
125 3.7
130 4.4
135 5.1
140 5.9
145 6.6
150 7.4
155 8.1
160 8.8
165 9.6
170 10.3
175 11.0
180 11.8
185 12.5
190 13.2
195 14.0
200 14.7
205 15.4


for setup I use this spread sheet,must have xcel.
injector calculator and other great worksheets.check the tabs.
Mister

[bauer5152]

Thank you so much for your post.

[NOTORIOUS VR]

you can also just figure it out by doing a little math.

KPA / 6.9 - ATM press (14.5) = gauge pressure

since KPA is absolute

of course it also works going the other way.

gauge psi + 14.5 * 6.9 = KPA

[everlast]

I just think of kPa as a 'percentage' of atmosphere. 100% is atmosphere, 150% is 1.5 bar and 200% is 2 bar.

Also, 14.7 psi above atmosphere is easy to remember for us tuners, since that's also stoich. So 2 bar (200 kPa) is 14.7 and 150 is half that, etc.

This is all rough, since this actually changes with altitude, etc. But good enough for my brain to work things out without any math.