Forced Induction Superchargers | Turbochargers | Intercoolers

Trust MAP or boost gauge when looking for pressure?

Thread Tools
 
Search this Thread
 
Old Oct 15, 2013 | 10:23 AM
  #1  
jasonz28camaro's Avatar
Thread Starter
TECH Enthusiast
15 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (13)
 
Joined: Sep 2006
Posts: 593
Likes: 7
From: Houston
Default Trust MAP or boost gauge when looking for pressure?

I went to the dyno yesterday and the tuner said the map sensor was only showing 7lbs on the laptop. My autometer gauge says 14lbs though and has ever sense I installed the SC. The gauge is hooked up directly to the intake manifold and with my pulleys / engine mods it should be right at 14lbs.

I'm real curious to see what number is right, the car is making 600HP. I was expecting a little more with 14lbs. I know its just an LT1 but I was lookig for around 650-700, what do you guys think?

Another consideration was the IAT was high... 165. I'm not running meth just yet (next step of the project) and the intercooler is a little small. Not sure if the intercooler is restricting the air because the gauge says its still 14lbs after it, sure is heating it up though. The intercooler looks like the vertical procharger 2 core with the 3" inlet and outlets on the same side, bought is used and might be a knockoff.

The next step is to get a bigger A2a intercooler with some meth to help with the IAT. Is there anything I can do at he moment to determine whats what?

Thanks guys.
Reply
Old Oct 15, 2013 | 10:32 AM
  #2  
ren987's Avatar
Launching!
iTrader: (4)
 
Joined: May 2008
Posts: 265
Likes: 0
Default

what gauge is it? I have seen some of the auto meter gauges be pretty far off. Mine was 4-5 psi off.
Reply
Old Oct 15, 2013 | 10:32 AM
  #3  
smokeshow's Avatar
TECH Senior Member
iTrader: (17)
 
Joined: Feb 2009
Posts: 6,687
Likes: 44
From: Detroit
Default

I'd trust the gauge.
Reply
Old Oct 15, 2013 | 10:35 AM
  #4  
jasonz28camaro's Avatar
Thread Starter
TECH Enthusiast
15 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (13)
 
Joined: Sep 2006
Posts: 593
Likes: 7
From: Houston
Default

Originally Posted by ren987
what gauge is it? I have seen some of the auto meter gauges be pretty far off. Mine was 4-5 psi off.
Autometer vac/boost not a digital
Reply
Old Oct 15, 2013 | 10:37 AM
  #5  
ren987's Avatar
Launching!
iTrader: (4)
 
Joined: May 2008
Posts: 265
Likes: 0
Default

That is the same style I had, is it zeroed when the car is not running?
Reply
Old Oct 15, 2013 | 11:09 AM
  #6  
Ferocity02's Avatar
TECH Senior Member
iTrader: (60)
 
Joined: Apr 2003
Posts: 9,397
Likes: 4
Default

What does the MAP say with key on engine off?
Reply
Old Oct 15, 2013 | 11:14 AM
  #7  
jasonz28camaro's Avatar
Thread Starter
TECH Enthusiast
15 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (13)
 
Joined: Sep 2006
Posts: 593
Likes: 7
From: Houston
Default

the boost gauge is zeroed when off.

not sure on the map, trying to find a way to check that, dont have a scanner
Reply
Old Oct 15, 2013 | 11:22 AM
  #8  
T/A KID's Avatar
TECH Fanatic
iTrader: (12)
 
Joined: Jul 2004
Posts: 1,818
Likes: 2
Default

Trust the gauge, you can have incorrect MAP values in the tune and make that read a different KPA (been there done that lol)
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

10 Reasons Daily Driving a Swap Project SUCKS! (& 1 Reason to Do It Anyway)

 Michael S. Palmer
story-1

6 Gifts Neither Your Dad Nor Grad Will Shove Into the 'Trinket Drawer'

 Brett Foote
story-2

Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?

 Pouria Savadkouei
story-3

Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine

 Verdad Gallardo
story-4

7 Most Reliable High-Performance Engines GM Has Ever Built

 Verdad Gallardo
story-5

Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

 Verdad Gallardo
story-6

6 Common C5 Corvette Failures and What's Involved In Repairing Them

 Pouria Savadkouei
story-7

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-8

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-9

Top 10 Most Powerful Chevy Trucks Ever Made!

 
Old Oct 15, 2013 | 11:30 AM
  #9  
jasonz28camaro's Avatar
Thread Starter
TECH Enthusiast
15 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (13)
 
Joined: Sep 2006
Posts: 593
Likes: 7
From: Houston
Default

Wouldnt that affect the tune big time? the map thinks its lower than it actually is, is this a bad thing lol.
Reply
Old Oct 15, 2013 | 11:37 AM
  #10  
ren987's Avatar
Launching!
iTrader: (4)
 
Joined: May 2008
Posts: 265
Likes: 0
Default

If it is zeroed you are probably ok. I got my gauge for free from a friend so I "clocked" the needle to the correct position and now it reads fine. Once you get the map reading that should tell you what you need to know.
Reply
Old Oct 15, 2013 | 11:47 AM
  #11  
Ferocity02's Avatar
TECH Senior Member
iTrader: (60)
 
Joined: Apr 2003
Posts: 9,397
Likes: 4
Default

Originally Posted by jasonz28camaro
Wouldnt that affect the tune big time? the map thinks its lower than it actually is, is this a bad thing lol.
Yes, but tuning indirectly accounts for the MAP sensor being off. If you then correct the MAP then the tune will be off.

MAP should read ambient pressure with key on engine off, mine reads about 102 kPa.
Reply
Old Oct 15, 2013 | 12:11 PM
  #12  
jasonz28camaro's Avatar
Thread Starter
TECH Enthusiast
15 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (13)
 
Joined: Sep 2006
Posts: 593
Likes: 7
From: Houston
Default

MAP says 306 Kpa.
Reply
Old Oct 15, 2013 | 12:27 PM
  #13  
Ferocity02's Avatar
TECH Senior Member
iTrader: (60)
 
Joined: Apr 2003
Posts: 9,397
Likes: 4
Default

Originally Posted by jasonz28camaro
MAP says 306 Kpa.
At key on engine off? That's 3 times too high. Either the MAP is bad or the settings are wrong in the tune. What kind of MAP is it?
Reply
Old Oct 15, 2013 | 12:45 PM
  #14  
jasonz28camaro's Avatar
Thread Starter
TECH Enthusiast
15 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (13)
 
Joined: Sep 2006
Posts: 593
Likes: 7
From: Houston
Default

its a gm 2 bar, not sure the pn.

I read somewhere that if the tune is operating off the 1 bar map OS it will only read 1/2 the psi? That could explain the 7psi when the gauge says 14. Would this also cause the high Kpa when the key is on? cant get in touch with my tuner at the moment to ask.
Reply
Old Oct 15, 2013 | 12:51 PM
  #15  
Shownomercy's Avatar
Man-Crush Warning
15 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (1)
 
Joined: Jun 2009
Posts: 3,197
Likes: 130
Default

I make more than that at only 10psi, I would check why there is a discrepancy.
Reply
Old Oct 15, 2013 | 01:28 PM
  #16  
smokeshow's Avatar
TECH Senior Member
iTrader: (17)
 
Joined: Feb 2009
Posts: 6,687
Likes: 44
From: Detroit
Default

306kpa...sounds like its wired in backwards. lol
Reply
Old Oct 15, 2013 | 01:49 PM
  #17  
jasonz28camaro's Avatar
Thread Starter
TECH Enthusiast
15 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (13)
 
Joined: Sep 2006
Posts: 593
Likes: 7
From: Houston
Default

Its an EFI connection harness. anyone know what wires go where? its worth a shot.
Reply
Old Oct 15, 2013 | 01:57 PM
  #18  
soundengineer's Avatar
8 Second Club
20 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (16)
 
Joined: Jul 2003
Posts: 4,651
Likes: 17
From: Chicago IL
Default

Originally Posted by jasonz28camaro
its a gm 2 bar, not sure the pn.

I read somewhere that if the tune is operating off the 1 bar map OS it will only read 1/2 the psi? That could explain the 7psi when the gauge says 14. Would this also cause the high Kpa when the key is on? cant get in touch with my tuner at the moment to ask.
the pcm doesnt care what the sensor is... it just knows its a 0-5v signal...
you have to tell it in the tune what it represents....
if you only have a 1 bar OS, you wont ever see any boost, you will only see a max of 105kpa reported because thats what 5v represents in the tune....even when you are in boost, it will not register as a boost value because the maximum reported value is only 105kpa in a 1 bar tune.

but that 5v represents 210 kpa in reality...so you basically have a table that represents half values(which can get really screwy with the rest of the tune also seeing half kpa values of what it is supposed to be)

also, at key on engine not running, with a 2 bar map, but a 1 bar OS...it should read somewhere near 50kpa


so... to fix your issue, you need to put in a 2 bar OS to go with your 2 bar sensor
Reply
Old Oct 15, 2013 | 02:54 PM
  #19  
Ferocity02's Avatar
TECH Senior Member
iTrader: (60)
 
Joined: Apr 2003
Posts: 9,397
Likes: 4
Default

Originally Posted by jasonz28camaro
its a gm 2 bar, not sure the pn.

I read somewhere that if the tune is operating off the 1 bar map OS it will only read 1/2 the psi? That could explain the 7psi when the gauge says 14. Would this also cause the high Kpa when the key is on? cant get in touch with my tuner at the moment to ask.
I think you can "scale" the tune, but it's a timely process and you can easily make a mistake. It also adds confusion when trying to tune. But it can let you have more adjustability in boost as many tables are maxed out above 1 bar. Although your resolution in the tables is reduced. EFILive has custom operating systems that give adjustability in boost without scaling the tune.

If you have a 2 bar sensor, the tune should be setup for 2 bar. There's one 1 or 2 settings that need to be changed to run a 2 bar map.
Reply
Old Oct 15, 2013 | 03:09 PM
  #20  
soundengineer's Avatar
8 Second Club
20 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (16)
 
Joined: Jul 2003
Posts: 4,651
Likes: 17
From: Chicago IL
Default

Originally Posted by Ferocity02
I think you can "scale" the tune, but it's a timely process and you can easily make a mistake. It also adds confusion when trying to tune. But it can let you have more adjustability in boost as many tables are maxed out above 1 bar. Although your resolution in the tables is reduced. EFILive has custom operating systems that give adjustability in boost without scaling the tune.

If you have a 2 bar sensor, the tune should be setup for 2 bar. There's one 1 or 2 settings that need to be changed to run a 2 bar map.
you can "Scale the tune"...and it is a pain in the ***....
its the only way you used to be able to do it before custom OS's were built....
I've done it, as well as many other have done it...
I do not recommend doing that when its a cheap and simple upgrade to a 2bar SD system with HP tuners(1 credit...$50)if you have already purchased the license for your vehicle.
Reply



All times are GMT -5. The time now is 08:19 PM.

story-0
10 Reasons Daily Driving a Swap Project SUCKS! (& 1 Reason to Do It Anyway)

Slideshow: 10 reasons daily-driving a swap project might not be for you. Or is it?

By Michael S. Palmer | 2026-06-17 09:39:05


VIEW MORE
story-1
6 Gifts Neither Your Dad Nor Grad Will Shove Into the 'Trinket Drawer'

Don't get dad new socks or a grill brush this year.

By Brett Foote | 2026-06-09 14:55:56


VIEW MORE
story-2
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?

Slideshow: We take a close look at the ONE and Artidiag 800BT2 diagnostic tools from Topdon and the reasons to buy one over the other.

By Pouria Savadkouei | 2026-06-18 10:26:23


VIEW MORE
story-3
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine

Slideshow: The controversial Ferrari F6 swaps its original flat-12 for a Corvette Z06-derived LT4 V8 and sends power to four rear wheels through a custom-built drivetrain.

By Verdad Gallardo | 2026-05-26 18:23:54


VIEW MORE
story-4
7 Most Reliable High-Performance Engines GM Has Ever Built

Slideshow:These GM engines didn't just make huge power, they survived abuse, boost, track days, and six-digit mileage with a reputation for refusing to quit.

By Verdad Gallardo | 2026-05-21 16:45:27


VIEW MORE
story-5
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-6
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-7
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-8
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-9
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE