GT Bob

Speaking as someone who does their own tuning with a tuner suite (HP tuners is what I use), and has tuned a good couple dozen cars let me chime in here... Keep in mind, I am speaking in generalizations here, and not attacking any of the popular tuners.

The difference between a Mail order tune and a dyno tune is simple... A mail order tune is an educated guess, while a dyno tune is set right at what the tuner has monitored to be the best setting that the car wants. How good a mail order tune is depends on the shop and the experience, and really even a dyno tune is only that good as well. A mailorder tune, by nature, has to have adecent amount of "fat" built into it. Simply put,since the tuner doesn't have the ability to monitor if that extra 2 or 3 degrees of timing will cause knock, chances are your not going to get it.

Another major difference is in the driveability. A mailorder tuner will always have a harder time with driveability issues. Part throttle driveability, cold startand really any Non WOT type throttle is really very hard to get right without datalogging. This very thing is what started me tuning. I had a Heads/cam LS1 that no one could seem to resolve a very bad part throttle heistation via mail order and even two local guys couldn't resolve. A few hours of Datalogging later, and it was as tame and responsive as the car was when it was stock.

That being said, Brent at Brenspeed has one of the best reps around both as a dyno tuner and as a mail order. His tunes are considered to be the closest at mailorder you can get.

When your evaluating gains, don't just look at the peak number.. Peak HP or Torque is only a tiny piece of the pie. You spend all of about .3 seconds at either peak torque or HP before your car either revs past it or you shift.. off peak gains are where you will feel a serious difference.

poohflingr

Dude that is crazy! I got 264rwhp and 287 rwtq on a mustang dyno with the same mods as you and same conditions! That proves that it really depends on who does your tune.

TOMBSTANG

Not a chance those numbers are right, sounds like your dyno guy is on glue. I would have drove right to another dyo shop if I had same mods as you gusy listed. stock I would be upset with those numbers.

I ran 292 hp/ 308 tq with caI/93 xcal2 lamotta tune, udp, cmcv. it was also 97 degrees out. I will be going back the the dynoas soon as I get my 4 10 and Lt installed along with my o/r mid pipe and hope to be in 320 ish range, gona go while its nice and cool out in florida.

dr350rider

An earlier post in this thread said that 4.6L Mustangs come from the factory with a 25 hp variable difference. Do most of you concur with this? I'm curious. I so why does Ford do that or is it just a quality control issue. I'd think most of that wouldcome from the factory tune. My 2005 was built in January of 2005. It is a GT model. I often thought it wasn't as fast as others. Just a week ago I finally got a tuner and a Brenspeed tune and now it feels like a beast.

ThumperMX113

I'm going to put this debate to an end, this is coming from a tuner.

Gains between mail order tunes and dyno tunes can be from 0-3 rwhp.

Pwny

Dyno is off. There is no way that is right.

howarmat

25 HP is huge difference.....from what everone posts is more like a 10 HP variance

ThumperMX113

Are you saying there is a 10 rwhp between a mail order and dyno tune?

howarmat

nono...there was a post that stated a variance of 25 HP from the cars off the assembly line.....i was saying from autos range from 250-260 and manuals range from 260-270...so there is generally not 25 HP difference from car to car with the same tranny...i do see to many manuals that dyno stock @ 250 and 275....most are with in the 260-270 range give or take 2 hp each way

ThumperMX113

Gotcha and I'll toast to that.