MAP kPa to Boost PSI Equivalents

[Danny Cabral]

Every 6.9 kPa over 101, is 1 PSIG of boost:
100 kPa = 0.0 psi
101 kPa = 0.1 psi
102 kPa = 0.2 psi
105 kPa = 0.7 psi
108 kPa = 1.1 psi
115 kPa = 2.1 psi
122 kPa = 3.2 psi
129 kPa = 4.2 psi
136 kPa = 5.2 psi
143 kPa = 6.2 psi
150 kPa = 7.2 psi
157 kPa = 8.2 psi
164 kPa = 9.2 psi
171 kPa = 10 psi
177 kPa = 11 psi
184 kPa = 12 psi
191 kPa = 13 psi
198 kPa = 14 psi
205 kPa = 15 psi
212 kPa = 16 psi
219 kPa = 17 psi
226 kPa = 18 psi
233 kPa = 19 psi
239 kPa = 20 psi
246 kPa = 21 psi
253 kPa = 22 psi
260 kPa = 23 psi
267 kPa = 24 psi
274 kPa = 25 psi
281 kPa = 26 psi
288 kPa = 27 psi
295 kPa = 28 psi
301 kPa = 29 psi
308 kPa = 30 psi
315 kPa = 31 psi
322 kPa = 32 psi
329 kPa = 33 psi
336 kPa = 34 psi
343 kPa = 35 psi
350 kPa = 36 psi
357 kPa = 37 psi
363 kPa = 38 psi
370 kPa = 39 psi
377 kPa = 40 psi
384 kPa = 41 psi
391 kPa = 42 psi
398 kPa = 43 psi
405 kPa = 44 psi
412 kPa = 45 psi
419 kPa = 46 psi
425 kPa = 47 psi
432 kPa = 48 psi
439 kPa = 49 psi
446 kPa = 50 psi
453 kPa = 51 psi
460 kPa = 52 psi
467 kPa = 53 psi
474 kPa = 54 psi
481 kPa = 55 psi
487 kPa = 56 psi
494 kPa = 57 psi
501 kPa = 58 psi
508 kPa = 59 psi
515 kPa = 60 psi
522 kPa = 61 psi

Originally Posted by Danny Cabral 1 bar MAP = 100 kPa / 00.00 PSIG - 14.70 PSIA (sea level - naturally aspirated) 2 bar MAP = 200 kPa / 14.31 PSIG - 29.01 PSIA (sea level - forced induction) 3 bar MAP = 300 kPa / 28.81 PSIG - 43.51 PSIA (sea level - forced induction) 4 bar MAP = 400 kPa / 43.32 PSIG - 58.02 PSIA (sea level - forced induction) 5 bar MAP = 500 kPa / 57.82 PSIG - 72.52 PSIA (sea level - forced induction) 6 bar MAP = 600 kPa / 72.33 PSIG - 87.02 PSIA (sea level - forced induction) 7 bar MAP = 700 kPa / 86.83 PSIG - 101.5 PSIA (sea level - forced induction) FYI: The Holley EFI software MAP kPa load scale (Y axis) will display: 1 bar-105 kPa, 2 bar-210 kPa, 3 bar-315 kPa, 3.5 bar-350 kPa, 4 bar-420 kPa, 5 bar-520 kPa Don't confuse PSIG (boost gauge) & PSIA (absolute with atmosphere): http://www.turbobygarrett.com/turbob...Tech%20103.pdf (Read "Gauge Pressure" toward end of page one.) Here's an excellent pressure conversion calculator: https://www.calculator.org/properties/pressure.html (Enter kPa at left, and select psig or psia at right.)

Originally Posted by Danny Cabral Holley EFI Boost Control Quick Start Guide: http://documents.holley.com/techlibr...9r10629rev.pdf (A Step-By-Step Example) Holley EFI Boost Control Instruction Manual: http://documents.holley.com/techlibr...r10628rev3.pdf (Full Fundamental Instructions) Holley EFI 557-200 Boost Control 3-Port Solenoid Valves, 1 "Fill" & 1 "Vent": http://documents.holley.com/199r10534rev.pdf (Tech Resources Supplement For Proper Wiring) Holley EFI 557-201 High Flow Dual Solenoid Boost Control Kit: https://documents.holley.com/199r11722.pdf (Tech Resources Supplement For Proper Wiring) https://forums.holley.com/showthread...298#post260298 (Shop Air Tuning PID Boost Control)

Originally Posted by Danny Cabral The Holley EFI electronic boost controller uses one input & two outputs for the dual boost solenoid control type. The "Boost −" solenoid is the "Vent" solenoid, and the "Boost +" solenoid is the "Fill" solenoid. Both are Outputs. The solenoid +/− "Output Type" is selected in the Inputs/Outputs screen of the Boost ICF, then Pin-Mapped. http://documents.holley.com/199r10629rev.pdf (Boost Solenoid Wiring - Figure 21, Page 11) The HP ECU should use PWM− type of Output for the boost solenoids (LINK). The Dominator ECU can use either type of Output (PWM− or PWM+) for the boost solenoids. However, if using the PWM+ Outputs, they should be wired on the J2B connector. http://documents.holley.com/techlibr...10555rev17.pdf (Holley EFI Wiring Manual - Section 2.1 "Pin-Outs", Pages 6, 7 & 8) The dome pressure sensor should be a 554-102 pressure transducer, or a 554-108 5 bar MAP sensor (depending on your boost psi - LINK). http://forums.holley.com/showthread....6179#post46179 (Dome Pressure Sensor Wiring)

Originally Posted by Danny Cabral • Boost ICF (Individual Configuration File): The Boost function is an "Individual Configuration" of the Holley EFI software. It's an electronic boost controller. If your forced induction is entirely mechanical, you don't need it. At top of screen, Click "Toolbox" and "Add Individual Config". At top of new window, select "Individual Configuration Library". At bottom of new window, select "Holley EFI Boost Config". Select "Boost" and open "Sample Config 1 Boost". The Boost icon will then be present at top of screen. Review Boost menu options to determine which apply to you. Ensure you initially set all seven of the Boost "Safety Setup" parameters to "Ignore".

Originally Posted by Danny Cabral • EFI Software Help Information/Instructions: ‒ On the top Toolbar, click "Help" & "Contents". This opens all Help topics. ‒ When navigating the software, click "Help ?", drag it to any parameter and click again. ..This automatically opens the definitions for that specific parameter. ‒ Tuning information can be read by clicking the F1 key, when you're viewing any screen. http://documents.holley.com/techlibr...10555rev17.pdf (Holley EFI Wiring Manual) • Software & Firmware Versions: Software: click "Help" tab (top toolbar) & "About Holley EFI". Firmware: click "Sync With ECU" & "Get ECU Info" (Key-on/USB connected). The latest software & firmware can be downloaded here: https://www.holley.com/support/resou...Fuel_Injection (Holley EFI Technical Library) http://documents.holley.com/techlibr...r10546rev1.pdf (HP & Dominator Quick Start Guide) http://documents.holley.com/techlibr...rmwarerev1.pdf (How To Update ECU Firmware) Before updating firmware, ensure the current Global Folder is saved somewhere, since it will be erased from the ECU. • Latest V5 EFI Software & ECU Firmware: The latest Holley EFI V5 software & firmware can be downloaded HERE. Read the V5 Software Overview document HERE, or in the EFI software "Help" Contents. Be sure to successfully install the new V5 software, before installing the ECU firmware. Ensure the Holley EFI software is not open and the ECU is not powered on/connected when installing the new software.

Step 2 of the Garrett Boost Adviser App suggests an air/fuel ratio for various fuel types:
Pump Gas - 11.5:1
Race Gas - 12.5:1
Methanol - 5.0:1
Diesel - 18.0:1
E85 - 8.5:1
http://www.turbobygarrett.com/turbobygarrett/webadviser

With the MSD6BTM you can also run a stock or nearly stock ignition timing which will result in good 'off the line' performance but it also retards the timing a set amount as the boost pressure increases. The amount of retard is user adjustable from 0 to 3° per PSI of boost. A normal setting is 1° [or slightly less] per PSI, but more or less can be used depending on your setup and how the car is reacting to other variables such as air temp, gas octane, etc. So at 1 PSI of boost, it will retard out 1° of timing. At 6 PSI of boost, it will retard 6° of timing. When not on boost like at idle or cruising at a constant speed, it will not retard the timing at all. Again, this is user adjustable.

To tune your VE table, you must proceed with caution in the upper ranges of boost and rpm. Do not rush yourself, and jump ahead of a proper procedure. You can destroy your engine if you do not “sneak up” on the proper VE numbers. To start tuning the VE table, warm the engine to full operating temperature first. Install new spark plugs, then go for a "spirited" drive.

Let up on the throttle immediately if you hear the rattles of detonation, or if boost rises higher than you planned. Then remove and inspect your spark plugs. Look for evidence of detonation on the porcelain nose of the spark plug that surrounds the center electrode. Detonation will show as "salt and pepper", tiny flecks of carbon and/or aluminum that indicate detonation has occurred. (Note that those tiny specks of aluminum are bit of your pistons that are being destroyed - so you will want to pay attention to them, and fix it as soon as you can!)

If there are no rattles and no "salt & pepper", increase the boost by a few psi, and repeat. Check the spark plugs after each drive. As you continue to increase boost, you will eventually either hear detonation (let off the gas immediately!) or you will have evidence on the plugs that it has occurred. At this point, increase the VE at that point of the VE table, decrease the timing (in the 12x12 Spark Advance table if you have MS-II™, otherwise by whatever means you have!), or reduce your boost levels. Do not continue to operate an engine that shows signs of detonation, even if it is brief.

Do not retard the timing excessively to combat detonation. If you retard the timing too much, the exhaust gases will get very hot, causing the exhaust manifold to glow bright red hot, and there might be damage to the exhaust valves, turbine wheel, catalytic converters, and exhaust manifold. It can also cause engine compartment fires!

In OEM turbocharged applications, the engine tune is carefully planned so that exhaust gas temperatures will not exceed around 1600°F/870°C. If you find yourself taking out more than about 0.3° to 0.4° of advance for every kPa above 100 kPa (~2° to 3° per PSI of boost) to deter detonation, then you should stop removing timing and add fuel instead. Add fuel via the VE table in 2% to 3% increments until you are sure the detonation is avoided and the exhaust temperatures come down.

[Danny Cabral]

MAP kPa to inHg (vacuum gauge) to PSIG
105 kPa = +1.48 inHg = +0.72 psig
104 kPa = +1.18 inHg = +0.58 psig
103 kPa = +0.89 inHg = +0.43 psig
102 kPa = +0.59 inHg = +0.29 psig
101 kPa = +0.30 inHg = +0.14 psig
100 kPa = -0.0 inHg = -0.00 psig
99 kPa = -0.30 inHg = -0.14 psig
98 kPa = -0.59 inHg = -0.29 psig
97 kPa = -0.89 inHg = -0.43 psig
96 kPa = -1.18 inHg = -0.58 psig
95 kPa = -1.48 inHg = -0.72 psig
94 kPa = -1.78 inHg = -0.87 psig
93 kPa = -2.07 inHg = -1.01 psig
92 kPa = -2.37 inHg = -1.16 psig
91 kPa = -2.66 inHg = -1.30 psig
90 kPa = -2.96 inHg = -1.45 psig
89 kPa = -3.26 inHg = -1.59 psig
88 kPa = -3.55 inHg = -1.74 psig
87 kPa = -3.85 inHg = -1.88 psig
86 kPa = -4.14 inHg = -2.03 psig
85 kPa = -4.44 inHg = -2.17 psig
84 kPa = -4.73 inHg = -2.32 psig
83 kPa = -5.03 inHg = -2.46 psig
82 kPa = -5.33 inHg = -2.61 psig
81 kPa = -5.62 inHg = -2.75 psig
80 kPa = -5.92 inHg = -2.90 psig
79 kPa = -6.22 inHg = -3.04 psig
78 kPa = -6.51 inHg = -3.19 psig
77 kPa = -6.81 inHg = -3.33 psig
76 kPa = -7.11 inHg = -3.48 psig
75 kPa = -7.40 inHg = -3.62 psig
74 kPa = -7.70 inHg = -3.77 psig
73 kPa = -7.99 inHg = -3.91 psig
72 kPa = -8.29 inHg = -4.06 psig
71 kPa = -8.59 inHg = -4.20 psig
70 kPa = -8.88 inHg = -4.35 psig
69 kPa = -9.18 inHg = -4.49 psig
68 kPa = -9.47 inHg = -4.64 psig
67 kPa = -9.77 inHg = -4.78 psig
66 kPa = -10.07 inHg = -4.93 psig
65 kPa = -10.36 inHg = -5.07 psig
64 kPa = -10.66 inHg = -5.22 psig
63 kPa = -10.96 inHg = -5.36 psig
62 kPa = -11.25 inHg = -5.51 psig
61 kPa = -11.55 inHg = -5.65 psig
60 kPa = -11.84 inHg = -5.80 psig
59 kPa = -12.14 inHg = -5.94 psig
58 kPa = -12.44 inHg = -6.09 psig
57 kPa = -12.73 inHg = -6.23 psig
56 kPa = -13.03 inHg = -6.38 psig
55 kPa = -13.32 inHg = -6.52 psig
54 kPa = -13.62 inHg = -6.67 psig
53 kPa = -13.92 inHg = -6.81 psig
52 kPa = -14.21 inHg = -6.96 psig
51 kPa = -14.51 inHg = -7.10 psig
50 kPa = -14.80 inHg = -7.25 psig
49 kPa = -15.10 inHg = -7.39 psig
48 kPa = -15.40 inHg = -7.54 psig
47 kPa = -15.70 inHg = -7.68 psig
46 kPa = -15.99 inHg = -7.83 psig
45 kPa = -16.28 inHg = -7.97 psig
44 kPa = -16.58 inHg = -8.12 psig
43 kPa = -16.88 inHg = -8.26 psig
42 kPa = -17.17 inHg = -8.41 psig
41 kPa = -17.47 inHg = -8.55 psig
40 kPa = -17.77 inHg = -8.70 psig
39 kPa = -18.06 inHg = -8.84 psig
38 kPa = -18.36 inHg = -8.99 psig
37 kPa = -18.65 inHg = -9.13 psig
36 kPa = -18.95 inHg = -9.28 psig
35 kPa = -19.25 inHg = -9.42 psig
34 kPa = -19.54 inHg = -9.57 psig
33 kPa = -19.84 inHg = -9.71 psig
32 kPa = -20.13 inHg = -9.86 psig
31 kPa = -20.43 inHg = -10.00 psig
30 kPa = -20.73 inHg = -10.15 psig
29 kPa = -21.02 inHg = -10.29 psig
28 kPa = -21.32 inHg = -10.44 psig
27 kPa = -21.61 inHg = -10.58 psig
26 kPa = -21.91 inHg = -10.73 psig
25 kPa = -22.21 inHg = -10.87 psig
24 kPa = -22.50 inHg = -11.02 psig
23 kPa = -22.80 inHg = -11.16 psig
22 kPa = -23.09 inHg = -11.31 psig
21 kPa = -23.39 inHg = -11.45 psig
20 kPa = -23.69 inHg = -11.60 psig
19 kPa = -23.98 inHg = -11.74 psig
18 kPa = -24.28 inHg = -11.89 psig
17 kPa = -24.58 inHg = -12.03 psig
16 kPa = -24.87 inHg = -12.18 psig
15 kPa = -25.17 inHg = -12.32 psig
14 kPa = -25.46 inHg = -12.47 psig
13 kPa = -25.76 inHg = -12.61 psig
12 kPa = -26.06 inHg = -12.76 psig
11 kPa = -26.35 inHg = -12.90 psig
10 kPa = -26.65 inHg = -13.05 psig
9 kPa = -26.94 inHg = -13.19 psig
8 kPa = -27.24 inHg = -13.34 psig
7 kPa = -27.54 inHg = -13.48 psig
6 kPa = -27.83 inHg = -13.63 psig
5 kPa = -28.13 inHg = -13.77 psig
4 kPa = -28.42 inHg = -13.92 psig
3 kPa = -28.72 inHg = -14.06 psig
2 kPa = -29.02 inHg = -14.21 psig
1 kPa = -29.31 inHg = -14.35 psig
0 kPa = -29.61 inHg = -14.50 psig

Originally Posted by Danny Cabral Use conversion factor of .2953/29.53 @ 32°F or .2961/29.61 @ 60°F air temperature. Convert MAP kPa to inHg (vacuum gauge): MAP kPa x .2961 − 29.61 = inHg Vacuum Gauge Convert MAP kPa to psig (gauge): MAP kPa x .145 − 14.5 (slightly above sea level) = PSIG Convert MAP kPa to psia (absolute with atmosphere): MAP kPa x .145 = PSIA With PSIG, negative numbers are vacuum, and positive numbers are pressure. With PSIA, all numbers are positive. The Holley EFI software uses kPa & PSIG. The Holley EFI software uses kPa or PSIG (not PSIA). Here's an excellent pressure conversion calculator: https://www.calculator.org/properties/pressure.html (Enter kPa at left, and select psig or psia at right.)

Originally Posted by Danny Cabral Check your Preferences (Display MAP As PSIG) in Toolbox, at top toolbar. In the Sensors ICF, the MAP sensor should first be programmed/calibrated in kPa. MAP kPa is labeled on the left side of the Calibration Curve table (Sensors ICF). Then if you prefer to view its display as PSIG, select it in the Toolbox Preferences. https://forums.holley.com/showthread...SI-Equivalents (MAP kPa to PSI Equivalents) https://forums.holley.com/showthread...4437#post64437 (MAP kPa to inHg (vacuum gauge) to PSIG) Holley Digital Dash: http://forums.holley.com/showthread....4985#post74985 (Read post #7.)

[89stang]

So if I wanted my Secondary Fuel Pump to kick on at 5 psi boost, I would set my manifold pressure to 136 kPa?

[Danny Cabral]

Yes, 136 kPa = 5.2 psig.

[89stang]

You're the man!

[nitrousdan67]

How do you change the Math Channel to make the 553-106 Digital Dash read boost/vacuum?

[Danny Cabral]

To convert kPa to inHg (vacuum gauge) on the Digital Dash (Customize Gauge/Math Multiplier/Channel Math):
x^2 Term (a) 0
Multiplier (b) 0.2961
Offset (c) −29.61

To convert kPa to PSIG, read the end of page 26 in the Digital Dash User Manual (LINK):
x^2 Term (a) 0
Multiplier (b) 0.1450
Offset (c) 0

[nitrousdan67]

Thanks Danny!

[Justspeed]

So helpful! Thanks!

[jeepramz]

Can this be done to the Terminator X 3.5" TSLCD too?

[Danny Cabral]

I don't recall the 3.5" TSLCD having the Customize Gauge/Math Multiplier/Channel Math function.

[Wrenchhead67]

Thanks Danny! I came across a site with a "calculator" and I must've been reading it wrong. Your chart proves what I originally thought that kPa & inHg are inverse. "Perfect vacuum" of 30" = (+/-) 0 kPa. Thanks!