Hi guys, so i had a catastrophic failure on my 06 supercharged gt. Learned 10 pounds of boost was too much on a stock bottom end 3v the hard way. Got a replacement motor and transmission put in and fired it up this week. The brain that came with the donor motor would not fire the motor because of the theft protection. Stuck the supercharged brain in and it fired right up. No check engine lights of any kind. My question is since that brain was out of the supercharged motor will i have to run premium gas on this stock motor? It's tune was 91 octane of course. Thanks

 

If it was tuned for 91 before, yes you should run 91 . . . I assume when you say "brain" you are talking about the ECU, which would still have the same tune from before.

You might even want to run 93; we don't know what caused the catastrophic failure, but detonation due to not enough octane might have contributed to it; it depends on how aggressive was the tune. You might want to have the tune checked too while you're at it.

 

As mentioned above, the ECU which came from the supercharged engine was tuned to run 91 octane fuel.. Therefore, If you intend to run anything below 91 octane fuel, you must have the ECU re-flashed/re-tuned to run on lower octane fuels like either 87 or 89 octane, otherwise you risk damage to the engine resulting from detonation.

 

ok, appreciate the reply. Was turned for 91. It had made 450 hp on the tire. I read 8pounds of boost is really max for a stock low end

 

On a supercharged 4.6L 3v with stock internals, I most definitely would not run any higher than 8 pounds of boost.. For what it's worth, I run a 3.6" pulley with my Saleen series VI supercharger that produces between 6.0- 7.5 pounds boost max and does so safely.

 

Speaking of my situation, i'm going to leave the stock motor in for now. Would you guys recommend having the facotory ecu (i call it the brain) that came with the donor motor programmed to match the key fob, which i assume ford can do. Or would you have the supercharged tuned brain have a stock flash put back on it? Anyone in the KC area that can do a stock tune minus cat-deletes?

 

If I recall correctly, you mentioned in your initial post that you weren't able to use the ECU from the donor engine, as it would not fire up the engine because of the anti-theft protection.. Therefore, if this is accurate, you have 2 options, either use the ECU which is programmed for the supercharger or have the ECU from the donor engine reprogrammed by Ford