What is done on a dyno Tune?
 

I am guessing its mostly timeing and fuel pressure. That pretty much all they can due except if you are getting a chip burned right?
I am just wondering because I have heard of some big gains from dyno tunes and was wondering where they would find the extra ponys.

Yes fuel pressure and timing is critical for optimum HP. The dyno simply finds the ideal setting for timing and fuel pressure wich can net big gains in HP I have heard of people picking up 20+HP from a dyno tune.

Later,

I found out I was running way rich and picked up about 15 hp. People pay a lot more for 15 hp than what I payed for my dyno session.

On my first dyno tune, I gained peak numbers of 40rwhp/15rwtq. I later added a larger crank pulley and didn't gain much peak power but gained throughout the rpm band. At 4000rpm, I gained 30rwhp/41rwtq. This is what a good dyno-tuner can do for you. :)

I just had a dyno tune on my 93 gt and you are basically right. The timing, fuel pressure, air fuel ratio were dialed in. Also I had an autologic chip installed and had to have the curve for my new mass air meter programmed in to work with 36#/hr fuel injectors. My initial numbers on the dyno were:

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Run #1: RWHP 258.6 RWTQ 299.7
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The final numbers after tuning were:
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Run #32: RWHP 301.0 RWTQ 353.3
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I have the following mods installed:
· 80 mm Pro M mass air meter
· 75 mm throttle body
· 255 lph in tank fuel pump
· Anderson power pipe
· Kirban adjustable fuel pressure regulator
· Bosch 36 lb/hr fuel injectors
· Autologic computer chip
· Dynomax exhaust
. Mac full length headers
. Powerdyne 9 lb supercharger kit
. Centerforce dual friction clutch
. 3.73:1 gears

It runs like a scalded dog and I couldn't have been happier when it came off the dyno. I had John Sealock of Woodbridge Dynotech in Virginia do the some of the mods and the tuning, what a differerence the tuning made. Money well spent. I still have not gone into the engine, the car only has 80k miles on it, but I'm making plans to put a 331 stroker and go with a vortech s-trim supercharger when I get some more cash. I have a picture of the dyno graph posted at:

http://www.sendpix.com/albums/020409/1715240000005d39a532841bf24278/]Dyno graph[/URL]

You cannot "dial in" air/fuel ratio with a adaptive strategy computer which is what Mustangs have. You will see gains on the dyno but they will quickly be lost when the computer adjusts for the added or lost fuel. Air/fuel ratio can only be changed by modifying the computer with a chip. Timing is about the only thing you can adjust and any tuner that you can trust would tell you that.