My car is a stock 05. Ive been playing around with the UTEC on map 0 just to see how everything works, how to log data, etc. So far the car seems to run the same as it did before the install (which it should). Anyways, ive installed the optional MAP sensor just to have an additional point of reference in my logging.

So far, it hasnt been working well. I think it is calibrated correctly....
gradient - 233
intercept - 190

The problem isnt the actual reading, its the response time of the sensor. Basically, my setup is that i have a boost line running in to my car. At the center dash area, it splits off at a T. One way goes about 2-3 feet for my boost gauge, the other goes 6 inches to the MAP sensor, which is mounted below the UTEC more or less.

Now my boost gauge seems to react fine to changes in boost/vacuum. It reads the same as it always has. If I stab the throttle at idle, it quickly shoots to 0 vac and then back down as i let off around 2k rpm. The map readings I get dont do this. The map reading might go from -10 psi up to -8 psi in the same time frame. On a 3rd gear pull, my boost gauge will read full boost at around 3700 rpm, wheras the MAP wont say I reach 21 psi until ~4800 rpm. Its almost like it has a response time constant of close to a second or something.

I dont think any of the lines are plugged, so i dont think that is the issue. The cable is still full length (I dont like cutting and soldering wire when I dont have to), but that shouldnt add this much phase lag.

Anyone else have this problem? As it is right now, the thing is almost useless at measuring transient boost levels. Forget closed loop boost. Any suggestions? Im thinking about just taking the darn thing off if it doesnt work right.

 

I'm suspecting its either the diameter or length of the line for the sensor, move the MAP sensor under the hood and keep the length of hose as short as possible, it should eliminate the "laggy" response that your seeing.

The GM map sensor that I use needs a pretty large line and kept as short as possible, about a foot long in my car, but the longer the line, the more thats T'ed off those lines, etc. is probably contributing to it.

 

Thanks, Ill give it a try.

Malibujack, do you use the same pressure source for both your MAP and boost gauge?

 

Yep, but the sensors are connected seperately....