Map Sensor

[Spilner521]

I was just lookin on one of the j-body forums and a bunch of guys over there say that if the stock MAP sensor sees boost it will throw a check engine light. is this true? and if so can a check valve be used to avoid this?

[FormulaNERD]

wouldnt you be boosting after the map? i dont know if stock map's are even able to register air that compressed.

[Spilner521]

the map has a vacuum hose that connects directly to a port in the intake manifold right below the throttle body so that it reads all the manifold pressure. so you'd be boosting pretty much right into the map. but yeah thats what i was thinking....that the stock one can't read boost at all..just vacuum. but if it does throw a code can that be eliminated with a check valve in the vacuum line?

yeah just throw a check valve on it, thats what i did and it werks fine.

[Spilner521]

awesome..thanks :thumbsup:

[Oldsman]

yep 2 check valves inline.

our stock maps are a 1 bar which is up to 0 boost.

gm supercharger reflash..... 2bar map.... 320cc injectors... no check valve needed and done right.

[FormulaNERD]

Originally posted by Oldsman@Mar 13 2005, 09:58 PM
yep 2 check valves inline.

our stock maps are a 1 bar which is up to 0 boost.

1 bar is up to 14.5 psi.

[Spilner521]

Originally posted by FormulaNERD+Mar 14 2005, 12:31 AM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (FormulaNERD @ Mar 14 2005, 12:31 AM)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin-Oldsman@Mar 13 2005, 09:58 PM
yep 2 check valves inline.

our stock maps are a 1 bar which is up to 0 boost.

1 bar is up to 14.5 psi. [/b][/quote]
1 bar is 14.7 psi which is atmospheric pressure aka 0 boost. anything over 14.7 psi, is boost. the the stock map sensor only reads up to 1 bar and nothing over that. so you'd need a 2 bar map to read up to double that. so a 2 bar map can read up to 29.4 psi...which includes your 14.7 psi atmospheric pressure and up to 14.7 psi of boost from the turbo.

[Spilner521]

Originally posted by Spy@Mar 13 2005, 11:29 PM
gm supercharger reflash..... 2bar map.... 320cc injectors... no check valve needed and done right.

2 bar map and bigger injectors are easy to get.....but where would one aquire the gm supercharger reflash??

[FormulaNERD]

Originally posted by Spilner521+Mar 14 2005, 01:28 AM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Spilner521 @ Mar 14 2005, 01:28 AM)</td></tr><tr><td id='QUOTE'>

1 bar is up to 14.5 psi.

1 bar is 14.7 psi which is atmospheric pressure aka 0 boost. anything over 14.7 psi, is boost. the the stock map sensor only reads up to 1 bar and nothing over that. so you'd need a 2 bar map to read up to double that. so a 2 bar map can read up to 29.4 psi...which includes your 14.7 psi atmospheric pressure and up to 14.7 psi of boost from the turbo. [/b][/quote]
sounds logical to me....

but why do 1.2 bar ecu programs for vw's boost at 17-18 psi? wouldnt it be a higher "bar" than that?

[Spilner521]

Originally posted by FormulaNERD@Mar 14 2005, 02:33 AM

but why do 1.2 bar ecu programs for vw's boost at 17-18 psi? wouldnt it be a higher "bar" than that?

when you're talkin about turbos running "1 bar" or "1.2 bar" of pressure, it reffers to how much boost it produces beyond the level of 14.7 psi atmospheric pressure. i dont know specifically about the vw engine, but i'm guessing the 1.2 bar program you mention sets the turbo to run at 1.2 bar.....which, coincidentally, is 17.64 psi of boost, right there in your 17-18psi range. so that engine probably uses a 3 bar map sensor, or something close to it, which measures up to 44.1 psi...14.7 atmospheric and up to 29.4 psi of boost :thumbsup:

Originally posted by Spilner521+Mar 14 2005, 07:30 AM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Spilner521 @ Mar 14 2005, 07:30 AM)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin-Spy@Mar 13 2005, 11:29 PM
gm supercharger reflash..... 2bar map.... 320cc injectors... no check valve needed and done right.

2 bar map and bigger injectors are easy to get.....but where would one aquire the gm supercharger reflash?? [/b][/quote]
a dealership that's not a bitch about reflashing your computer with an easily accessable reprogram.

[Spilner521]

what exactly does the gm reflash reprogram the ecu to do? anyone know?

[Fast Eddie]

educated best guess....Definately expands the fuel map to account for the larger MAP sensor, I believe it adds some advance, probably plays with the auto's shift points, and hopefully, but doubtful, expands the resolution on the ignition system, also most definately adds some new code to the emission control system, esp. the post head O2 sensors.

Fast Eddie you are pretty much on the right track except it doesn't advance the timing but rather pull it back, and from what i heard it pulls it back pretty significantly!

Do they have a reprogram for the Autos?

[Oldsman]

yes they do

[Spilner521]

I've heard from some of the j-body guys that they can only reflash ecu's from 2000 and up models. true or false?

[Oldsman]

that is true.

they made some changes inbetween 99 and 00

[Fast Eddie]

Originally posted by nguyen187@Apr 1 2005, 01:01 AM
Fast Eddie you are pretty much on the right track except it doesn't advance the timing but rather pull it back, and from what i heard it pulls it back pretty significantly!

Quoted post

I would have guess they would pull timing to prevent detonation but from what i saw somewhere, maybe JBO, i could have swore someone said it added timing O well logic dictates it pulls timing so I will go with that.