Pyros777

iTrader: (4)

Yep I had a hard time too. Seems this sensor is popular in a lot of european cars apparently.

Heres a link to where I bought mine: Summitracing.com

To be honest I thought I wanted a 3 bar tune, but in fact all I wanted was a 3-bar sensor. No funky scaling as described in the OP.

My reason for wanting the sensor was vain at best. I wanted to be able to use the SS T/C gauge, which I'm pretty sure is driven off the 0-5v value from the MAP sensor.

If thats the case, changing the linear and offset values to the appropriate ones for this piece and changing nothing else should theoretically work.

The numbers I came up with just by doing the math are 322.5806 (linear) and -8.05 (offset).

I have yet to test it though.

Edubs

I actually have a SS/TC boost gauge sitting around and I was able to source that from a local diesel shop for pretty cheap.

I've been contacting more knowledgeable tuners, and it seems as if this won't do much other than what you intend it for, as (just like Area said), the MAF is used to calculate fuel at high RPMs. At this point, concerns of the other tuners, like Vince, are running out of room w/ the MAF since I'll be moving A LOT of air...

Thanks!

StreetDreamz

In light of the fact that when this post was originally made I was completely unaware of the Bosch 3bar TMAP being available to just plug right in to the stock wiring with a simple rescale, I am modifying this section:

The next problem is that the MAP sensor in my manifold maxes out about 22.4psi by just 5500rpm, my boost gauge tells me I’m running much higher than that. What to do? Obviously the first step is to obtain a MAP sensor that can read to that level. GM Part number 12223861, a 3 bar MAP sensor good to ~29psi, will do just that. So I wire it in to my stock MAP sensor signal line, tapping the ground reference and 5V feed from that sensor, making sure the IAT2 sensor in that housing is still getting signal to spit out its information to the PCM.

To instead read this:

The next problem is that the MAP sensor in my manifold maxes out about 22.4psi by just 5500rpm, my boost gauge tells me I’m running much higher than that. What to do? Obviously the first step is to obtain a MAP sensor that can read to that level. Bosch 0281002437, a 3 bar MAP sensor good to ~29psi, will do just that. This will plug right in to the stock wiring with no modifications needed and still provide the vital manifold temperature to the PCM like the stock 2.5 bar sensor does.

StreetDreamz

I assure you rescaling the VE table like this will by far out run the stock MAS. You have perfect resolution clear to 7200rpm. If you have serious airflow by this point and are still building boost and making power, then you need to go to stand alone to be accurate or upgrade to a MUCH larger MAS.

Pyros777

iTrader: (4)

FYI the TMAP used on the GMS1 kits might be a better alternative to the part I posted back then.

3 Bar MAP Sensor 55206797 - Crate Engine Depot

GM P/N: 55206797
Bosch P/N: 0281002845
Linear: 329.43750
Offset: -6.35156

I've used this sensor on my car with those values and it ran perfectly on a regular tune. Knowing those values would allow you to scale it down to where you need it for a 3 bar tune with less guess work.

Note: This doesn't solve the T/C gauge issue though. The problem there is in the scaling of the signal to the gauge from the PCM. It is indirectly related to the MAP sensor, so no amount of playing with the values could ever make it work properly. You'd have to be able to rescale the signal just before it goes out to the gauge.

StreetDreamz

Nevermind. Yes that does have the ability to read slightly higher. Either or seems like a decent alternative. Scaling the true 3 bar may be easier though.

Pyros777

iTrader: (4)

Why yes it is. Pin 2 is temp, as seen here:

http://www.crateenginedepot.com/pdfs/frsp19212711.pdf

More info: http://www.bmotorsports.com/shop/pro...oducts_id/1721

Yeah I guess using either would have its pros and cons. For one, 0281002845 was calibrated for the LNF stage kit. That would mean the numbers I posted are correct, at least per GM.

As for 0281002437, yeah it reads closer to 300 so its a "truer" 3 bar sensor and would have an ounce more resolution. Still, as long as you have known values you can get the job done with either. Also the GMS1 sensor is cheaper by far.

So, did you ever create a 3 bar tune for yourself or was this thread mainly just for brainstorming?

StreetDreamz

Oh no, I ran my car like that for several months without a hitch. This was when I was using the Injector Dynamics 1000cc injectors and needed more resolution than the MAF table could supply.

Area47

funny. when i ran id1k's i had zero issue running them with the maf.

StreetDreamz

Really? On a 2.6 pullied Harrop with ported head using a Saturn MAS? (Please note, the Saturn MAS is different than the Cobalt one. But I'm sure you know that since you know everything.)

Area47

Ported head, 2.5 pulley. Oh, i forgot. You put the top hats on the wrong side and had incorrect inj scaling for the lsj calcs.

What you tried to do was a novel idea. Just not needed by any means.