The car I just bought have some mods. It has an agency power exhaust with high-flow cats and an K&N filter in a stock air box. Previous owner said that this is as far as the mods went.

However, on the few drives I've taken I noticed that the boost gets up to 0.8-0.9 bars. I wonder if the car has a flashed ECU and/or aftermarket diverters?

Reason I'm asking is that I'm going to buy extended warranty for it and rather than the ECU in stock form to avoid any hassle in case repairs are needed.

 

i used to see 0.9 on mine when it was stock

 

Oh good, I was under impression that stock diverters won't hold the pressure above 0.7bar.

 

stock diverters will be fine even with a flash, i had them on mine hitting 1.1 all the time, i recently upgraded them though to baileys, i'm sure there are people on here still running the stock bosch ones with mods like a flash etc

 

Are you talking spikes or sustained boost in a WOT pull in third or fourth? Spikes yes, sustained no...

 

These were indeed spikes. Sustained boost was somewhere at 0.5-0.6 bar

 

After I changed my exhaust to a speedtech I began to see .8 spikes and sustained .7 which is more then I used to see before the exhaust.

 

It does make sense, doesn't it? Less back pressure = higher boost.

 

Explanation from Tony@epl is spot on
https://www.6speedonline.com/forums/2394361-post2.html

"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. "

 

I would see .7bar sustained stock.