stub-kb-2 wrote:
i don't have any question that tuners make definite power improvements on deisels (speaking from experience).
my greatest interest in the tuner for the small block is the mpg gain that evey tuner manufacturer claims.
at today's fuel prices a 1 mpg improvement on daily driving could pay itself off in as little as 15,000 miles. although that is a long time, i keep my vehicles well over 100k miles. everything staying the same (more likely to go up in $) that is a fuel savings of $1,700 over the life of the vehicle.
very intriguing...
You're trying to compare apples and oranges.
Diesels and gasoline engines make their power in different ways. Diesels are easy to make power with. You just throw more fuel at them.
No so with a gasoline engine. They need more air to make a lot more power.
Sure you can make a few HP by playing with a gasoline engines timing. This will also send the NOX reading sky high.
And you can make a few more by taking the rpm and torque management limit system off. This can also break things as Beemer already pointed out.
As far as fuel mileage goes. There will be next to no measureable increase because the airflow will be the same. The O2 sensor will keep the fuel air ratio as close to 14.7 at all times. You will never see a 1 MPG gain.
What they will do for you is make the shift points where you want them. Only you can say if that is worth it.