What psi does a stock JCW make w/ overboost?

 

19psi

 

I have shown 21 with a CAI and turbo back exhaust

 

tight! how much do you think tuners will push it up, 25? 30?

 

I have seen 30 psi on mine with stage 2 tune and more stuff on my sig

 

So Leo you got this much HP from your mods? Do you have the dyno charts to post?

 

Actually its a little bit more complicated. The ecu sets a target of a certain manifold pressure, which is atmospheric pressure + boost. This is 33.5psi up to 35.5psi in short periods of overboost. If you take atmospheric pressure off this you get the boost.

So at "normal" atmospheric pressure (14.5psi) the car makes up to 19psi boost or 21psi in short periods of overboost.

However, the problem is that the atmospheric pressure is rarely 14.5psi. If you are in the middle of a low pressure weather system at an altitude well above sea level the atmospheric might be 13.5, so the car will then boost to 20 and 22psi to make the same absolute manifold pressure. Likewise if you are at sea level in the middle of high pressure system the atmospheric might be 15.5, so the car will only boost 18 and 20 psi etc.

The ECU only cares what the absolute manifold pressure is. That is why it is better to monitor the absolute manifold pressure, which should not vary from day to day or location to location.

Edit : the highest boost is only achieved in 3rd, 4th and 5th gears, slightly less in 1st, 2nd and 6th

 

Stock showed 15 psi at over boost. 13 psi without overboost and this is measured via Prosport boost gauge, sensor placed on MAP sensor. After Jan's tune, I'm regularly hitting 23 psi-which always surprises me since I've read multiple times that the ECU cuts boost at 22 psi. But hey I'm not complaining.

 

Just curious...anyone know if the AccessPort tune changed that and highest boost is available on all gears? Or is 1,2 and 6 still lower than 3,4, and 5?

 

I believe so.

 

The AP wouldn't have changed that. The mini doesn't do gear based boost levels. That's only found in more advanced aftermarket ECUs. The reason you only hit peak boost in 3,4,5 is because of the load/requested torque tables in the ECU. First and second gear don't provide enough load on the engine for the car to really build any boost. It's the same as pretty much any other turbo car.