A good dyno will repeat runs within 1 or 2%. Something else is clouding the issue here...like the engine, trans, rear oil not up to temp...or the HP correction factor is drifting from room heat or something affecting the weather instruments.

 

Do you have the site for SCT forum?

 

www.sctflash.net EDIT: s/b www.sctflash.com

 

Did you run 91 Octane on your first 'stock' pulls?? If you ran 87 octane the knock system would have been retarding spark more so than with 91 octane. 1 octane point roughly correlates to advance or retard of 1 degree.

 

Oops, sorry just reread. The differences could partially be blamed on the octane differences. With the 91 octane I would imagine the engine management system was advancing spark ~3 to 4 degrees compared to your stock runs. Thus you potentially are running MBT for a good part of your pull, and making more power with the advanced spark.

 

Good question. I'll find this out for sure and give you the answer they give me. I was assured in the beginning though that once the car was flashed back to stock, I would have no warranty problems, (relating to the flash issue). [/b][/quote]
yes they can tell. during a talk with the guys at horse power engineering in houston i found out why. whenever you flash the compy in the car the computer knows that it has been adjusted. whenver ford plugs the car in to their computer they can see this also. then they just refrence their database, it was called OASIS i think, and they can see that a ford dealer had not had to reset your system back to factory defaults. so they know you got it done.

probably not the best explination in the world, but that's how i can describe what he said.

B)

 

Anyone know what happens if someone mistakenly puts 87 octane in the tank after a 92 octane tune?

 

doesn't run as well i would guess. maybe a knock and ping. i don't think anything really serious.

 

I'm no expert but I believe you will run lean (too much air to fuel ratio). If it is too lean then it can cause engine damage.

Don't know if putting 87 in a 92 tuned system is "too Lean"

 

Using 87 in a car tuned for premium won't cause a lean condition. The AF ratios will remain the same, but the car would likely suffer from preignition under any load condition since the premium tune will have greater spark advance. This could lead to engine damage.