Originally posted by SVTNupe:
Yes, I have an SVT. However, it's the fuel and spark maps that I want. It would seem to be much easier to change the redline than to change fuel and spark maps. Although it is true that it has been optimized for best performance, that best peformance was for a 2.5L and not a 3L. I figure this, worse case, it's easy to repin a connector should I have to go back to the 2.5L PCM. I want this rebuild to provide me with a durable and reliable engine that can give me years of faithful service.
Our PCM is based on the amount of air coming into the engine (MAF) and not base on absolute manifold pressure. If you had a MAP and increased the engine size you would have a big problem since the MAP wouldn't change but the amount of air being sucked in would. The ECU simply wouldn't know there is more air coming in and run lean.
In the MAF situation the air coming in is directly related to the engine size (all else equal), increase the engine size and your increasing the amount of air coming in. The ECU takes this into account and adds more fuel accordingly. Now the SVT ECU is special since its ALLREADY programmed for a higher compression and has the timing for it, take a look at the dyno's and you will see that the SVTs are running rich.
Now take a ECU thats NOT designed for high compression and that doesn't run rich and you will have problems. Look at the NON-SVT guys that did 3L swap and they are running lean because they don't have the fuel flow. I wouldn't take a chance with the 3L ECU thats made for a hauling the kids to soccer practice.
I'm running a stock fuel and ECU system, I'm at the limits of the stock system with all the mods that I have done. But I'm not running lean nor do I ping (as long as a I keep a good 91 octane in it), I know Roger had a stock SVT ECU in his 3L and that swap was done by the first person that did a 3L, the owner of sho shop. He himself is also running a SVT ECU.
If you want to change the amount of fuel going in at WOT then you have to chance the fuel regulator. I picked up 5 ft lbs of torque when I barrowed one from Vadim for a dyno.
