[Official] "Do I need a tune with bolt-ons?" thread

[SurfDog]

Originally Posted by seymore4

Basically the way the etunes work is they give you a base map that gets the tune kind of in the ballpark, then you have to datalog certain engine parameters while you drive around (rpm, load, AFR, throttle position, etc etc) and email it in, they compare that to the tune file and make some adjustments. You get the updated rom file in your inbox, flash it onto the ecu, and repeat.

Honestly etune or dyno tune it all comes down to the tuner. Yes a dyno tune will give you more exact IMMEDIATE results, and the maximum power potential if performed correctly, but I've seen a lot of tunes that were FUBAR'd.. just because the guy owns a shop and has a dyno doesn't mean he knows what he's doing. With an etune you can get pretty darn close with these new cars but it is not immediate. It takes time, patience, and can't be done in 1 or 2 updates.

I have read some great results and satisfaction from etunes. 1 hp and <1 whp less than a full dyno tune will probably not be noticed in the final analysis, and you will have some DIY pride of ownership in you tune too!!! Also, you will not be running "lean" after your bolt ons (I read but do not understand WHY this might be harmful to your engine). With an E-tune you can flash the moment you finish tightening your last bolt and be pretty close with a ballpark tune right away.

From what I read of your situation, I think this is how I would go in your shoes. (It won't cost as much either!)