ok, you mean MAP. 36 psi absolute is fine, or perhaps even a bit low for an Evo 10 as its only 21.5 psi gauge.

 

ABS (Absolute) Pressure - atmosphere pressure (around 14.5) = boost pressure

So that means, 36 - 14.5 = 21.5 psi boost

 

K that does seem low as most of the time. what do i do about the knock retard. this is just the cobb off the self stage 1 map and its making me knock ... i do not have any access to 100 oct. gas. and the map is supposed to be for 93 anyway.

thanks guys

 

It is safe to keep driving on it. The ECU is doing its job. Keep and eye on it and see if it keeps doing it with different gas. I don't know about where you are, but here we get dog sh*t gas in the winter. We went out today to do some logs in my friend's VIII and we did 10 pulls on the same map without a single knock count. We pulled into a station and filled up on Shell 93 and the next several logs on the same map had knock everywhere from 3500 up (1-4 counts)

BP is the WORST. I used to spray a 175 shot of nitrous on pump gas in my VIII and I had the most trouble with BP 93...and suprisingly had the best luck with Speedway/Marathon 92.

Just keep an eye on it and try another filling station.

 

I thought avg. atmospheric pressure was 14.7. If that is the case i am running negative boost most of the time. Anyone have time to explain that?


thanks

 

No, abs pressure = gauge pressure + atmospheric pressure...

So, pisG = psia-atm = 36-14.5 = 21.5psig

 

Depends on where you live, where I live the average is usually around 100kpa which is roughly 14.5psi

We are talking about absolute pressure not boost pressure. If absolute pressure was 36 psi then you subtract atmosphere pressure (14.5 psi) and you will get boost pressure. What you see on a boost gauge is boost pressure and not absolute pressure.
And if you are talking being negative boost at idle or light throttle, then yes, it will be negative because your engine is in vacuum...............

 

I think the sensor in our car may max out at 2.5 bar, which is why AP always shows a max of 37 psi. I haven't had a chance to log it to see if the signals looks clipped at around 36.75 psi.

 

It's almost impossible to not see a bit of knock on a turbo vehicle through the seasons. As others have mentioned the ECU is doing it's job in keeping the motor healthy. One thing you can try would be to flash a 91 octane map checking if that will efface any knock.

Thanks,

 

No sir, I have logged the internal map sensor (Via EcuTek tools) and it tracks along just fine at 24psig +/- 1 psig which would be 39psia so it should be at least 3bar.

 

The Evo 10 MAP sensor is good to about 46.5 psia. Must be a limitation of the data being read by the AP or something with the AP.

 

Robb@Cobb can you answer this. I have no boost gauge in my car and am only going by what the AP says so I am curious. Thanks

 

Yes but at what point does this affect the performance of the car?

 

Rob is there any chance we are gonna get: Boost , Knock cnt and a possible AFR solution ( with logging ) Added to the monitoring anytime soon ( i'd pay for the wideband kit )?

 

Currently the ECU limits the max value to 36 PSI when converting from voltage (counts) into KPa. We have not attempted to change the max value in the ECU as of yet, but is something I can try.

Thanks,