Just doing some research for a future ej207 swap into my 02 wrx.

What kind of gas milage do you guys get for these kind of swaps, and what level of mods have you done for that milage? I was also curious about the octane level that you're using. Can you just take a ver7/8, drop it in, and run on 93 or 94, or does it need a reflash right away to take the lower octane?

Any input would be much appreciated!

My ver8 swap is getting about 350 km to a tank of gas. I use 94 or 92 octane most of the time, and its not reflashed. Running a stock jdm v8 ecu. It runs fine, but I would like to flash it to a lower octane like 92 which I can get everywhere here.

If mileage is a primary concern don't even think about doing the swap.

I have a ver 7 running 565cc pinks and 10psi and it gets about 24mpg hwy and about14-16mpg city (stop-and-go with boosty, agressive starts). 14 gallon tank gets 320 miles hwy. City driving, about 200. Never been flashed or tuned... running 92 for a year with no probs.

Milage really wasn't a concern, I was just curious. I had figured it would be close to the USDM STI but wasn't sure. That's interesting that you can the JDM ECU and still run US 92-94 octane, good enough for me!!

Kreeger,

Why are you only hitting 10psi? I thought the ver 7 had a turbo that was comparable to the VF34.

I detuned mine to only run 14psi and be able to beat the snot out of it on 91oct. I wouldn't be feeling so secure about that without the reflash. Just a little food for thought. But yes, the JDM ecu seems to adjust just fine to out urine blended gas.

Doctornick has the answer. I am running a VF34 and a MBC... I was getting knock and fuel cut at 14psi so I turned it down to 10psi and still managed to put down 301 hp to the wheels on the dyno.