I have a 94WRX wagon with TD05 and decat. This set up seems to result in DET on the Z4 ecu (at least in my case) due to the higher compression ration of the engine. Anyway, got a scoobyecu mapped for it a few weeks ago and as I am still getting a little bit of DET I will have the option to get the map fine tuned in November.

I am sure that the mapper will give me good advice when I get the map changed a bit but I just wanted to learn more about it before I go.

On the current scoobyecu map it is producing 17psi boost, which is a bit high perhaps?? Although much better than before I was betting a bit of DET with this map.

I reduced it temporarily to 15psi with a Dawes and this quietened it up, although I got a few DET spikes with an apparently bad tank of fuel the other day (even though it was optimax).

I think I will ask if I can get the map changed so that the boost is reduced to about 15psi, just for peace of mind. If I ask to retard the ignition timing a bit as well, to make it extra DET free, will I lose a lot of power.

Am I better off, keeping the boost at 15/16 and retarding the ignition, or kepping the ignition advanced and reducing the boost to 13/14?

Cheers in advance.