I was messing around yesterday with a Durametric to see if I could translate the value it logs as Boost Pressure to the BAR reading on my dash.

In doing so, I recorder through Durametric and saw on my dash a reading of 1.2 BAR. Never saw that before (not even a spike - Highest I have ever seen is 1.0). My sustained boost seems to be .7 to .8 which I believe is normal on a stock 996. I am just wondering if this type of spike is normal, can it do damage, does it have anything to do with 80 degree temps?

I will try it again tonight to see if it happenes again if I don't get arrested.

Car has 57k miles, new plugs and new MAF. Battery was recently disconnected. Completely stock. Running better than it ever has....

 

The 996tt DV's are controlled by a vacuum solenoid thats cycled by the ecu. At high rev's, when you let off the gas quickly, the throttle plate will actually beat the ecu to open the DV's.

This will cause a boost "spike" on the dash that will never reach beyond the throttle plate.

 

Thanks Tony....that is the best explanation from 5 different sources so far.

 

Where in chicago are you? I am datalogging tonight too... Tony, can a stock car still spike to 1.2 bar?

 

Tony is totally right. The spike is caused from the closing throttle plate when you reached the rpm limiter. It's not real "boost"...