The only thing I have tuned is a Harley VRod, where tuning was required when changing the exhaust and air intake. I have 2 questions.
1. Can someone explain why tuning isn' needed when changing exhaust and air intake for cars as someone told me on this forum.
2. Can someone define each type of tune and give positive and negative. Thanks rob
#1
The Stinger uses a MAP (Manifold Absolute Pressure) sensor. It uses the changes in engine vacuum or manifold pressure to determine engine load. It is not impacted by how much air can flow into the engine (i.e. a less restrictive intake). The issues with changing intakes without a tune comes into play when the engine uses a MAF sensor (Mass Air Flow). It does exactly what it says, it measures how much air is flowing into the engine. Increase the amount flowing into the engine with a less restrictive intake and the stock calibration for the sensor thinks there is an error. This has to be tuned out and modified to take advantage of the new airflow. MAF sensors can also become fowled by the oil used to aid filtration on some high flow aftermarket filters (K&N for example). A cat back exhaust does not dramatically reduce back pressure or increase exhaust velocity, so the engine can adapt to the change. Remove large restrictions like cats and you may have issues with over speeding the turbo, never mind throwing all kinds of codes from the O2 sensors, etc.
# 2
Piggyback
This is an electrical harness that is attached to sensors on the engine and it "tricks" the engine into thinking it is getting less boost, fuel rail pressure, etc. than has been requested. So it requests more and you get more power. Cheapest option but you won't get max power gains and there may be some smoothness issues. But it is the hardest to detect once removed.
ECU Tunes
OTS (Off the Shelf) - This is a tune designed to increase power but be used by multiple clients in all kinds of different climates. They tend to be more conservative for safety reasons. They also tend to me more expensive than piggybacks as you need hardware to hook up to the engine to apply the tune or you have to pull the ECU to have it bench flashed, etc.
Custom Tune: This tune goes above and beyond the OTS tune. It allows the tuner to take into consideration your specific car, your fuel from your favorite gas station, your climate, your driving style, the list goes on and on.
This can be accomplished in several ways:
Mail Order: They send you a base map. You data log, send it back, they mod the tune, you load again. Rinse and repeat until you get what you want/like. This costs more than the OTS tune mostly due to the labor cost for the log reading and tune modification.
Road Tune: Again, they load a base map. Data log while you drive around and modify as you go. Cost is similar to above.
Dyno Tune: Same as above but with more hard-lined sensors attached. Cost adds in the dyno rental fee as well.
The best combination for a DD, with power and safety, is to have a dyno tune. Then do a road tune to fine tune any drive-ability issues.
And remember, all ECU tunes can likely be detected, even if removed, if the manufacturer digs deep enough.