To tune or not to tune. Some basic questions.

Discussion in 'Fox 5.0 Mustang Tech' started by 90blacknight, Jan 16, 2007.

  1. Need some advice on custom tuning. Basically I was looking to dyno the car just to see what kind of numbers it puts out, as the previous owner, who himself didn't build the motor, had never had it dynoed either. Now I'm faced with the option of custom tuning, which from what I understand can get expensive. I'm wondering if I should bother spending the money; money being a bit short right now. The car runs great, no problems so far (knock on wood). It's vortech supercharged and running an FMU. The shop tells me I would have to get rid of the FMU and most likely get larger injectors. Also, I need to get an o2 bung installed, among other things. Is this true? It's getting expensive already. What would you do? Run the car, get the numbers, and walk away? or prepare to spend money? Save, then get it tuned? Like I said, the car runs great, would tuning be necessary at all? Could evil things be lurking even though it seems like it's running good? Need advice. Thanks.
  2. The only way to find out if the car is running correct is put it on a dyno with a wideband. The dyno should have a wideband available to check your A/F ratio. If you buy a custom tuner such as a pms or equivalent, you can weld a 02 bung in it to check your a/f on the street. You can tune the car on the dyno with their wideband, but if the car has cats it can throw the a/f off by .5 to 1 point, because they usually have a tailpipe snffer. If it has cats weld the o2 bung in front of the cats to get a correct a/f. You should put the car on a dyno anyhow especially with a blower to check your a/f, and if you dont want to buy a tuner, you can mess with the diaphragm in the FMU to try and help the a/f a bit, or take it to a dyno and have someone do a chip for the car. Best of luck with it!!