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Old 03-19-2009, 05:21 PM   #1
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Default How to Scale VE tabe for more boost

Planning to run around 10psi soon, so i was wondering how to add more cells for higher boost? Now VE table goes up to 230kpa.

Thanks, Taras
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Old 03-19-2009, 05:27 PM   #2
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Here's how you do it, step by step:

1. Ask a stupid ******* question on an internet forum
2. Get flamed for asking a stupid ******* question
3. Cry to your mommy
4. Hire a tuner who knows what the **** they're doing

Until you understand enough about your ECU to realize how stupid your question is, don't touch a damn thing.
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Old 03-19-2009, 05:27 PM   #3
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and 230kPa is 19psi....
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Old 03-19-2009, 05:51 PM   #4
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Quote:
Originally Posted by Savington View Post
Here's how you do it, step by step:

1. Ask a stupid ******* question on an internet forum
2. Get flamed for asking a stupid ******* question
3. Cry to your mommy
4. Hire a tuner who knows what the **** they're doing

Until you understand enough about your ECU to realize how stupid your question is, don't touch a damn thing.
How about you go and do these three things:
1. pull our pants down
2. bend over
3. take a 2x4 up your anus.

dick
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Old 03-19-2009, 05:51 PM   #5
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nice horns, queer.
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Old 03-19-2009, 05:54 PM   #6
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Quote:
Originally Posted by Braineack View Post
and 230kPa is 19psi....
i thought it was not relative to atmospheric pressure. so its more like 130kpa.

It says something about scaling VE map in the MSpnp manual when going over 6psi but does not tell how to do it exactly.

Boost (Tuning for it)

When setting up MSPNP on a boosted Miata, you won’t have to change very many settings other than properly tuning the VE and Ignition tables for the additional airflow and load. Start with making sure your VE and spark tables go up to the maximum amount of boost you plan to run. Since boost is gauge pressure and MegaSquirt works in absolute pressure, this table will help you convert the amount of boost to the maximum KPA level. These values go just a little above the maximum boost setting.
Boost Level Suggested Top kPa Bin
Naturally Aspirated 100
5psi 140
10psi 175
15psi 210
20-21psi 250



The MSPNP is equipped with a 2.5 bar MAP sensor, so the maximum amount of boost it can read is 21 psi of boost. While higher amounts of boost will not damage the sensor in most cases, it can damage your engine if you do not tune for it. The MSPNP will not add any more fuel above 21psi to compensate because it cannot detect the extra air, which can result in dangerous lean conditions if you boost beyond that point.

Since MSPNP is a speed density system, you do not need to recirculate the air in the intake. If you want to you can go ahead and install a monster blow off valve and vent it to the atmosphere without worrying about having it throw off your measurements.
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Old 03-19-2009, 05:59 PM   #7
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so because it already goes up to 230 i dont have to change anything?
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Old 03-19-2009, 06:25 PM   #8
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Quote:
Originally Posted by Rushin View Post
so because it already goes up to 230 i dont have to change anything?




Do you think everyone would be giving you **** if you did?
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Old 03-19-2009, 06:37 PM   #9
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Quote:
Originally Posted by Rushin View Post
so because it already goes up to 230 i dont have to change anything?
do you plan on running more than 19psi?
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Old 03-19-2009, 06:43 PM   #10
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Quote:
Originally Posted by Braineack View Post
do you plan on running more than 19psi?
nope.
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Old 03-19-2009, 07:08 PM   #11
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the text you copied from the MS manual, if you read it with an ounce of comprehension, answers this question.
It also does not say you need to re-scale if you go above 6 psi anywhere in there.
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Old 03-19-2009, 07:10 PM   #12
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i am just confused about relative pressure and absolute pressure.
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Old 03-19-2009, 07:33 PM   #13
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2.5 bar MAP sensor.


1 bar = 14.7psi = 100kpa. This is what the atmosphere's pressure at sea level is. The sensor in the PnP reads 2.5 bar. You've got to subtract 1 atmosphere (bar) from total kpa, because "boost" is pressure in the manifold OVER atmosphere.
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Old 03-19-2009, 07:34 PM   #14
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I use this webpage to convert kpa to psi:
PSI-KPA Pressure Converter

Then deduct 15 from psi result (eliminates atmospheric pressure) to get boost pressure
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Old 03-19-2009, 07:35 PM   #15
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then go to wikipedia....


0 KPA = pure vacuum. 100kpa = atmospheric pressure = 14.7psi ABSOLUTE pressure


Absolute pressure includes the pressure of the atmosphere. Relative pressure is the pressure RELATIVE to atmospheric. when someone says they are running 10psi they are running 14.7 + 10 = 24.7 PSI absolute

Remember: PSI = english units KPA = metric.
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Old 03-19-2009, 09:56 PM   #16
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Quote:
Originally Posted by Rushin View Post
i am just confused about relative pressure and absolute pressure.
So hire someone.
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Old 03-19-2009, 10:01 PM   #17
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why would i hire anyone. maybe the first thing you do is hire someone when you have a question.
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Old 03-19-2009, 10:08 PM   #18
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Quote:
Originally Posted by Rushin View Post
why would i hire anyone. maybe the first thing you do is hire someone when you have a question.
Actually, I use the search function, spend an hour or two reading, and (most importantly) refrain from making stupid shitty threads about the topic I am trying to learn about. The threads I do usually make are summing up what I learned and asking for clarification and/or confirmation.

You literally said, in your OP:

"I want to run around 10psi soon, so I want to add more cells for boost, how can I do that? The current map is scaled to 19psi."

If you don't understand why that is stupid, I can't help you, and my original recommendation stands.
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Old 03-20-2009, 12:23 AM   #19
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Quote:
Originally Posted by Savington View Post
Actually, I use the search function, spend an hour or two reading, and (most importantly) refrain from making stupid shitty threads about the topic I am trying to learn about. The threads I do usually make are summing up what I learned and asking for clarification and/or confirmation.

You literally said, in your OP:

"I want to run around 10psi soon, so I want to add more cells for boost, how can I do that? The current map is scaled to 19psi."

If you don't understand why that is stupid, I can't help you, and my original recommendation stands.
dickish comments like yours dont make me learn more. Seriously, is it that hard to be a little bit nicer even when people ask stupid questions?
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Old 03-20-2009, 12:51 AM   #20
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Quote:
Originally Posted by Rushin View Post
dickish comments like yours dont make me learn more. Seriously, is it that hard to be a little bit nicer even when people ask stupid questions?
Until I'm getting paid for it, yeah, it's really hard.
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