Could someone explain "3 bar map" to me...

[Welby]

Not sure what it does, or even is, so help me out here, lol. I have a list of things I want to do to the car in the spring, and alky is on it. I want to know whether the 3 bar map is something I need, or just something I might want to have to reach a certain objective.

Right now the car is basically stock. I put in a Walbro 340 and 009 injectors, have a TT chip, but other than that, there's not much, other than a gutted cat and an aftermarket exhaust (Not sure what brand, it was on the car when I bought it).

Planning on:

TA-49 or TE44
Alky
3" DP (Probably Kirban's, it's all I could afford)

These things should be enough to have me hauling some a$$, so that's all I'm going to do. I'm probably going to get the alky first and run maybe 22-23 lbs on the stocker, then when I upgrade, 25 or 26 lb's.

So, any tips on this 3 bar map??

 

[Blazer406]

Razor's alky kit uses it for the PAC controller to work properly. Does it increase performance w/o an alky kit...... absolutely not. Your stock 2 BAR map sensor that is on the car now only serves the purpose to light up your boost gauge.... that is all. With the Razor kit..... more than 2 bar worth of boost is likely.... so you need the 3 bar so the PAC controller can read the higher boost level.... other than that.... don't bother.

Oh..... when you do install one... in the place of your stocker (i.e. the alky kit install).... you stock boost gauge will read lower than it did.... which doesn't matter anyway since the stock boost gauge is a POS IMHO and should NEVER be trusted to give you an accurate boost reading to set a wastegate by.

HTH

 

[Welby]

So I'm guessing it is something I'll want to have, and Razor offers the kit without it for the TTA guys that already have the 3 bar map?? (If I even read that correctly when searching. Bear with me, I'm Turbo stupid....)



Should add that I do have an Accufab regulator and FP guage as well...

 

[zeus87gn]

With the Razor kit..... more than 2 bar worth of boost is likely....

Do you mean to say that with the alky kit you can go upwards of 30psi boost?

1 bar = 14.5psi -> 2 bar = 29psi -> 3 bar = 43.5psi

I deal with metering everyday. I would believe it is used for greater accuracy because you have a better range. Maybe a singal comes from it to the controller? I am really guessing here as I have never investigated how it works, but I haven't heard of anyone running boost levels this high.

Or am I missing something else altogether?

 

[ttypewe4jim]

here is a good article to explain bar, psia, and psig(what your boost gauge reads in your car)

http://www.intendedacceleration.com/tip_1.html

see Ive seen that different people say 3 bar = so many psia but in general there all around 43.5 psia SO with that being said it measures out to around 28.8psig that it can measure....so you do need the 3 bar map because the pac uses this to judge how much boost your runing :biggrin:

 

[Blazer406]

So I'm guessing it is something I'll want to have, and Razor offers the kit without it for the TTA guys that already have the 3 bar map??

Yes I believe that is the main (and maybe the only) difference in the two kits... GN vs TTA.

 

[Razor]

The 3 bar GM sensor reads vacuum and boost. 2 of its bars are positive, in other words 1 bar=14.7 PSI. 2 bar= 29.4.

I use this sensor to allow the ability and increase drive to the pump. Once you hit 29.4 PSI my system does not add any additional alky. Unless you run a 5 bar sensor.

The TTA came factory with a 3 bar, so the controller attaches to it. The TTA kit lines/tank/mounting are totally different than the GN.

Your factory 15 PSI guage turns into a 30 PSI guage once you change to a 3 bar. It will start reading boost at 7 PSI=0 on the stocker.

If your GN has an aftermarket DFI computer, then we can attach to the 3 bar already in place. Else.. it will need it.

Someday you upgrade to speed density.... you'll have the 3 bar already in place.

HTH

 

[Blazer406]

Thanks for clearing that up Razor.

Razor has become one of the leading "practice-what-you-preach" guys..... if he tells you something.... it is because it works...... The proof is in his timeslips.

Just MHO

 

[zeus87gn]

The 3 bar GM sensor reads vacuum and boost. 2 of its bars are positive, in other words 1 bar=14.7 PSI. 2 bar= 29.4.

I get it. Thanks for the clarification.

 

[kshef]

Someday you upgrade to speed density.... you'll have the 3 bar already in place.

HTH

what exactly do you mean by "speed density"

 

[Blazer406]

what exactly do you mean by "speed density"

The two most common types of multi-port EFI is mass air (turbo buicks and TTA's) and speed density. Mass air cars use a mass air sensor that actually measures the "mass" of the incoming air and calculates the amount of fuel to add for combustion. Speed Density has no mass air sensor. It uses a MAP (or Manifold Absolute Pressure) sensor combined with RPM and TPS readings to calculate the "load" the engine is under and then the ECM can calculate how much fuel to add for combustion.

Our Buicks are mass air cars... but also use a MAP sensor..... BUT.... the only reason they need the MAP sensor is for the boost gauge to work.

What Razor was eluding to..... was that at some point.... if you wanted to upgrade to an aftermarket ECU i.e FAST system..... you most likely would have to convert over to speed density..... cause all (or almost all) aftermarket stand alone bad boy EFI systems are speed density..... and need that MAP sensor anyway.


HTH

 

[Welby]

Thanks to everyone for the info. Just wanted to make sure that I order everything that I need, or not order something that I don't

 

[DavzGN]

1 bar is about 14.5PSI of atmospheric pressure.

normal atmospheric(barometric) air pressure at sea level which is about 14.7 PSI, So at zero PSI boost you would be at 1.01bar)

0 Bar would be a vacuum.

2 bar is 2*14.PSI = 29.0psi (14.3PSI boost)

3 bar is triple atmosphere pressure 43.5psi (28.5psi boost)

HTH
David

 

[NHRA Super Gas]

Follow Up

OK, I have the VDO 30 psi gauge that comes with the GNX replica dash. If the previous owner didn't install a 3 bar map, am I getting some sort of bogus readings?

how would I know if the car has 3 bar map in it?

TIA,

EW

 

[Blazer406]

OK, I have the VDO 30 psi gauge that comes with the GNX replica dash. If the previous owner didn't install a 3 bar map, am I getting some sort of bogus readings?

how would I know if the car has 3 bar map in it?

TIA,

EW

Does that VDO gauge hook up electrically? I would have thought that it had a vacuum/boost hose going to the intake somewhere..... and not rely on a MAP sensor... like the factory gauge.