i am new to this side of the forum. I have seen lots of information on tuning your cars in this forum. I have a simple question that i am sure many of you can answer. I was thinking of purchasing a Predator to tune my car, but i was not sure how it works. Can someone help me?

 

look in the c6 tech section there's a good post going about the predator tune

 

I did but it is very confusing.

 

the predator is only available on the 05 a4 at this point. The a6 will be out in a month or so. Either will not tune as precisely as a dyno shop tune with either hp tuners or ls2 edit program. However my buddy just plugged in the diablo performance tune in his a4 and loves the torque. He just pushed the button for the standard diablo program. If you want to play with all the attributes you have another option to do so but then it becomes more detailed and intricate.

 

Forget the Predator; get the car dyno-tuned. Best way to go because the tuner tuning the car can adjust specifically for YOUR CAR. The hand held tuners are set for general setups that will work for most cars but you won't be maximizing you engine's output. i.e. I had no idea my A/F mixture ratio was set at 10!!! The tuner technician recalibrated it the car is dynomite-along with all of the other settings that were changed for optimum performance. There's not much difference in price and you get so much more for your money.
Good Luck

 

Let me give it a try. Forgive me if I get too basic, but sometimes its best to start at the beginning.

Much of the LS2 (like most modern engines) is controlled by a computer, called the ECM (Engine Control Module). Mostly, this computer controls the throttle opening, amount of fuel injected, and timing. The valves are still controlled by the cam (but just wait a few years - maybe as soon as 2008).

The ECM "decides" the throttle opening mainly based on the position of your right foot, but can close it for some reasons like wheelspin or a condition it thinks may damage the car.

The ECM "decides" the spark advance (ignition timing) mostly based on a value looked up from one of two tables for the current engine RPM. There is one table for 91 octane gas and one for lower octane (87?) gas. It can also modify this if it senses knock or under certain other load conditions.

The ECM "decides" the amount of fuel to inject based on another set of tables, some "learned" trim factors, and a few other things. Well, actually a lot of other things.

Normally, when you're cruising along at part throttle the ECM uses the oxygen sensors in the exhaust manifolds to determine the current fuel/air mixture and uses this information to "learn" by recording a set of short- and long-term fuel trim values. This is called "closed-loop" operation.

The reason that it doesn't use closed-loop operation all the time is that the oxygen sensors aren't that fast, and a slightly richer than "ideal" mixture works best at or near full power operation. So it reverts to the predictive mode when things are changing, or you're way into the throttle. But it uses the learned data from the closed loop operation to modify it's tables when in predictive mode.

Now of course GM doesn't want to fix cars under warranty, so they are a little conservative with the table values and general ECM rules. And of course these values and rules apply to the stock car. Making significant changes, like a lot more cam, require changing these values.

Basically, the "canned" tuners apply somewhat less conservative values to some of these tables. For example, if you're running 93 octane gas instead of 91, you can advance the spark a little more. And the WOT (Wide Open Throttle) mix is a little too rich, you'll probably pick up a few horsepower by leaning it out a bit.

So you may get a few horsepower, you may lose a little reliability or flexibility (like if you tune for 93 octane gas and then can only find 91 octane).

 

I understand. Thank you for taking the time to explain in such detail.