ecoboost or 3.7 engine

TURTL3 said:

Yes. I have taller tires than stock and shorter gears so I used the SCT Tuner to update both values and flashed the car. I have confirmed with the GPS app on my phone that the speedo is correct. If you have an auto that process is much more complicated.

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Actually the SCT Tuner does nothing for speedometer / gearing changes for the S550. That value is not in the ECU (which is what tuner deals with) it's stored in the BCM (FORScan programming).

But changing from 3.15 to 3.55 requires NO changes. I GPS Verified my speedo after installing 3.55 gears with NO changes whatsoever and the speedo was dead on. The ABS wheel sensors actual deal with detecting speed / wheel rotation.

^Ah ok, I guess it's just for the tune then. He knows better than me, so listen to him lol

Fuse said:

What tire size are you running?

Yeah from what I read you need to go into forscan or have the dealer flash it for 3:55. I'm still thinking of doing though, might be an alternative to FI.

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255/35/20, 27" tall. I think FI is only worth it if you have deep pockets and just have to have a SC'd Cyclone. The gains you get put you smack even with a coyote and you're look at well over $5k all accounted for. Car pulls like a stabbed rat with 3.55s.

TURTL3 said:

My insurance premium for the GT was almost double. i haven't had an accident in 8 years and I wasn't even at fault for it and I even tried to get quotes from other companies. I think a lot of people start pricing a GT and realize that 30K is still a lot of money to finance for a car and the insurance is going to get them coming and going.

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This is a more recent example of why Mustang premiums are high...

http://www.miamiherald.com/news/nation-world/national/article212733744.html

It's affordable performance, available to the masses, including morons that shouldn't own it. In addition to lives being lost & affected, responsible Mustang owners are stereotyped & literally must pay for it.

ctandc72 said:

But changing from 3.15 to 3.55 requires NO changes. I GPS Verified my speedo after installing 3.55 gears with NO changes whatsoever and the speedo was dead on. The ABS wheel sensors actual deal with detecting speed / wheel rotation.

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I assume this would also hold true for the automatic transmission?

So far it is only true for the manuals. Autos need forscan to make changes in gearing.

I originally thought you needed to make a change in the BCM when going from 3.15 to 3.55 and my dealer wouldn't do it for me. They said Ford said it had to remain as it came out of the factory in the BCM. Turns out you don't need to change it with a manual. With the auto you need to change it to get the shift points correct or so I have been told. Shelby has a 3.31 pumpkin on evilbay right now starting bid at $99 right now. Another 3.55 in classified on here for $600.

Edit: nvm I forgot I asked shelby auctions and they stated 90lbs.