tutone56

I'm trying to understand the "tune" everyone talks about. What exactly does a new "tune" do? My guess is that the new tune will take advantage of a higher octane gas. Am I close? Thanks

AZ MSCL

You buy a tuner (Brenspeed, Diablo Sport, Bamachips) which generally comes with about three different tunes for your car. You can get custom tunes made also, for a fee. It's not just octane based, it also depends on your mods.

Nuke

The PCM (Power Control Module) is the "computer" that runs your engine. It is a program that controls all of the operating parameters such as timing, air fuel ratio, shift points plus many others while making adjustments due to temperature and a host of other inputs. A custom tune basically is a new program that changes many of these parameters to provide increased performance and drivability. The "shop" that writes the new tune will do so based on your mods and desires, tailoring the tune to your car. Included in that tailoring are the octanes you want it setup for. The shop can write you tunes to provide increased HP and/or torque or for fuel economy (reduced performance... YUCK). The majority of the parameters that provide the overall gains are NOT user (a.k.a. you) adjustable. However, there are certain user adjustable parameters that are available from the handheld such as adjusting for different gears, tire sizes, rev limiter, timing and a few others. Unless you know what you're doing, the average guy should just leave all of the engine-related settings pretty much to the shop (a.k.a. tuner).

tutone56

Thanks for the explanation. So I guess you would have the option of going back to the original tune or using one of the custom ones without having to go back to the shop. Would you be required to have your own tuner to switch back and forth?

Nuke

Typically, it goes like this:

You purchase a CAI & tune combo or just the tuner from one of the BETTER vendors such as Brenspeed, Bama, Tillman or others. They write excellent tunes. You typically get 3 tunes loaded into the handheld as part of the package; in most cases you simply select what 3 octanes you have in your area. Once the combo arrives, the CAI takes about an hour to install with basic hand tools and no rocket science. The tune is simply plug n' play and takes about 2-4 minutes. Just follow the prompts.

Once everything is in, you can switch back to the stock intake in about 10 minutes time (IF you are a wus and worry about the warranty intimidation bullchit) and reload the stock tune in about 2.

I keep the handheld in the car and run my 89 tune about 99% of the time. It performs better in the low and mid RPM ranges than my 93 tune and suits my driving style. I've been on road trips where I was only able to get 87 octane so it was simply a matter of whipping out the tuner and loading the 87 custom tune (which, btw, kicks azz over the stock 87 tune) and I was back on my way.

tutone56

Thanks Nuke and AZ - I'm trying to gather as much knowledge as I can so when I start my mods in the spring I won't be so clueless.