Odd boost problem...

[BplantCivic]

I did a search and the closest post that I could find was this: AndyE's problem
Here is my current setup:
'00 Si
stock JRSC
stock b16a
Comptech Icebox
DC 4-2-1 ceramic header
Thermal exhaust
stage 4b
RC 440 injectors

This last Saturday I had a CRV crank pulley installed. That night I tried to datalog a third gear pull. Two things went awry.
First: I got onto the tollway entrance and put the car into third gear @ about 3500 rpms and accelerated. Somewhere around 4000-5000 rpms the engine cut out and I glanced at the boost gauge. It appeared to indicate 12-13psi. I still have the factory map sensor. I immediately let off the throttle and eased up to the toll booth. After going through the booth, I pulled over to check my datalog.
Second:My laptop battery died right before I came to a stop. I forced it to turn on and possibly salvage the recording. So I'm not sure if the recording is accurate.
Here's the kicker: after getting home and plugging the laptop in to use and recharge, I noticed something scary in the datalog. Boost was off the chart at 4550 rpms and the injector duty cycle was only 50%. The highest the map sensor read was 1.725mbar. It's obvious that I need a different map sensor. But has anyone encountered such high boost levels that early in the rpm band?

Thanks.
Alf

[BplantCivic]

But has anyone encountered such high boost levels that early in the rpm band?

Doug? Derick?

[AndyE]

Are you sure you weren't hitting the boost cut? That would cause your injector duty cycle to drop dramatically (although I'd expect it to drop to 0%) if you exceeded the boost cut.

The default boost cut is at 11.2 psi, which is the theoretical maximum that the stock MAP sensor can handle. I have an Endyn stepper pulley that claims 8-10 psi but I regularly see 11-13 psi as well. I've slammed into the boost cut a few times myself; when I get some time I'm going to disable it, since it doesn't make a lot of sense for a fixed-boost application like a supercharger.

The real question is, how does the stock MAP sensor behave (and how does a Hondata ECU interpret this behavior) when the boost rises above 11.2? I'd assume that the MAP voltage levels out at a certain point above 11.2 psi, which wouldn't be a huge deal since the amount of fuel required for 11.2 psi vs. 12-13 psi is pretty much the same (i.e. "lots").

Can you offer up your datalogging session so we can see what it looks like?

-Andy

[BplantCivic]

When I get the chance, I will post what I captured on the datalog. The default boost cut may be 11.2, but according to the datalog it cut out at 10.5(1725mbar). I hope a 3bar sensor will help.