What's the rating for a 2bar map before it starts seeing boost?

 

depends on what altitude you are at. If you are at 5400 feet its going to read different then if you were at sea level.

liam

 

well, the nearest track to me is at 720 ft above sea level...so let's take that into consideration

 

might go to 23-24psi, who makes it is it GM??

 

What are you talking about?

Do you mean what voltage does it give at atmospheric, or do you want to know the voltage range for -1bar to atmospheric?

 

it's an AC Delco...

what I wanna know is what the max boost you can run before the 2bar maps start sensing boost(like the stock honda ones)...

 

Okay, I'm still not following you. The 2 bar map sensor can see 1 bar of vacuum and 1 bar of boost pressure. So at 0psi up it senses boost. That answer seems too simple, but I'm still not certain what your lookiing for. It can see up to 1bar (about 15psi) before it can't see anymore.

 

Is your plan to replace the factory MAP with a 2bar? Then run without any check valves, since the sclae of the voltage:boost ratio will be different? I think I am missing the point if that is what you are trying to do.

 

okay, here's the deal....I was sent a 2bar map sensor instead of the 3bar map that I was promised when my haltech came in...I'm planning to boost around 18-20psi's...should the 2bar map be good enough or will I need a 3bar map?

 

The 2 Bar should be fine dude. At sea level it is good to 29 lbs of boost. I am not sure the correction factor at your eleveation, but it should not be too much for the 2 Bar sensor.

 

incorrect!!! 2bar = boost to 14.7 psi. 3bar goes to 30psi. A 2 bar map sensor reads 1bar in vacuum and 1bar in boost (at sea level) ie 2bar. The stock honda MAP sensor is a 2bar.

You need a 3bar sensor to read boost over 14.7psi (at sea level). The 3bar reads 1bar in vacuum and 2bar in boost.

liam

 

**** I was not aware of that!! Hondata say right on their website the stock Honda MAP sensor reads only up to 11PSI. Is this wrong? Also, I thought that a 2 Bar sensor read up to 2 Bar of boost pressure. Why is vacuum included in the spec?

 

because its just airpressure. Vacuum/boost makes no difference to a map sensor...It just reads pressure. You need vacuum because when the throttle body is closed you are around -13psi of air pressure inside the intake manifold.

Hondata 11psi stock is a safe level i am guessing. I have got my stock honda map sensor to read 14psi above sealevel pressure without problem.

liam

 

The stock Honda map sensor is a 2 bar but is only capable of reading 11psi before taking a crap. The GM 3bar is a good choice for people who want to go over 11psi.

 

i dont agree...i have boosted to 16-17psi at 5400 feet which is around 13-14psi over sea level..and my honda map sensor worked fine. My afc showed ~14psi boost reading (after converting that from hg/km2 or something).

liam

 

Hondata is saying that the stock MAP can read 2 bar, but has a chance of breaking over 11psi. If you're running 14psi, well then, according to them your lucky it hasn't broken, yet.

Like everyone else is saying; you'll need the 3 bar for anything over 14.7psi.

 

haha..i just bought a 3bar sensor...so i am going to convert to using that. Althought he honda works great for low boost work!!

liam

 

how much did you get your map sensor for and from where? How much does GM charge for it and what' the GM part number?

 

i bought a MSD 3bar sensor. I think i paid like $40 for it. You can buy it from anywhere that sells MSD stuff (although it was a special order item).

If you goto GM its like $105 for the 3bar sensor. GM only used that sensor on one car for only one year...its the 89 Turbo Trans AM. GM part #16040749

liam

 

Great tip!
The MSD has the same voltage specs as the GM 3bar? I need to toss my 2bar sensor for a 3bar soon.

 

thanks liam

 

The MSD 3bar its the same voltage as the GM 3bar...it even looks the same. Notice that the part number on the sensor is the *same* GM part number???

(i took some pictures for ya guys..)





liam


[Modified by liam821, 10:19 AM 12/5/2001]

 

$40 for a 3bar sensor!! Liam, U dam man!!!!

 

MSD, WELLS, CRANE all use the GM 466 map sensor, they just repackage it.